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Meadowdale_SW Site Plan_11-19-2018EdmondsDRAFT November 2018 Meadowdale Beach Park and Estuary Restoration Project Stormwater Site Plan Prepared for Snohomish County Parks and Recreation Department This document prepared for and submitted to Snohomish County. Information on City of Edmonds resources is included; this report would also be submitted to City of Edmonds as part of permit applications. Project Number: 160723-02.01 \\fuji\Anchor\Projects\Snohomish County\Meadowdale Beach Park\Park and Habitat Design\Task 5.3 90% Design\Stormwater\SW Site Plan Report\Meadowdale_SW Site Plan_DRAFT_11-16-2018.docx DRAFT November 2018 Meadowdale Beach Park and Estuary Restoration Project Stormwater Site Plan Prepared for Snohomish County Parks and Recreation 6705 Puget Park Drive Snohomish, Washington 98296 Prepared by Anchor QEA, LLC 720 Olive Way, Suite 1900 Seattle, Washington 98101 Stormwater Site Plan i November 2018 DRAFT This Stormwater Site Plan was prepared under the supervision of a registered Professional Engineer. DRAFT – STAMP TO BE SIGNED FOR FINAL David W. Rice, PE Anchor QEA, LLC Stormwater Site Plan ii November 2018 DRAFT This page intentionally left blank. Stormwater Site Plan iii November 2018 DRAFT TABLE OF CONTENTS 1 Project Overview ........................................................................................................................ 1 2 Site Description and Project Background ............................................................................ 4 2.1 Site History ............................................................................................................................................................. 4 2.2 Site Description .................................................................................................................................................... 4 2.3 Existing Stormwater Facilities and Drainage ............................................................................................. 5 2.4 Other On-Site Utilities .................................................................................................................................... 12 2.5 Proposed Site Improvements ...................................................................................................................... 13 2.6 Proposed Stormwater Facilities and Drainage ...................................................................................... 14 2.6.1 Proposed Drainage Area 1 ............................................................................................................ 14 2.6.2 Proposed Drainage Area 2 ............................................................................................................ 16 2.6.3 Proposed Drainage Area 3A ......................................................................................................... 16 2.6.4 Proposed Drainage Area 3B ......................................................................................................... 16 2.6.5 Proposed Drainage Area 4 ............................................................................................................ 16 2.6.6 Proposed Drainage Area 5 ............................................................................................................ 17 2.6.7 Proposed Drainage Area 6 ............................................................................................................ 17 2.7 Proposed Drainage Area Characterization ............................................................................................. 17 3 Minimum Stormwater Requirements ................................................................................. 19 3.1 Minimum Requirement 1 – Preparation of a Stormwater Site Plan ............................................. 21 3.2 Minimum Requirement 2 – Construction Stormwater Pollution Prevention Plan .................. 22 3.3 Minimum Requirement 3 – Source Control of Pollution .................................................................. 22 3.4 Minimum Requirement 4 – Preservation of Natural Drainage Systems and Outfalls ........... 23 3.5 Minimum Requirement 5 – On-Site Stormwater Management ..................................................... 23 3.6 Minimum Requirement 6 – Runoff Treatment ...................................................................................... 24 3.7 Minimum Requirement 7 – Flow Control................................................................................................ 24 3.8 Minimum Requirement 8 – Wetlands Protection ................................................................................ 25 3.9 Minimum Requirement 9 – Operations and Maintenance .............................................................. 26 4 Drainage Analysis and Conceptual Design ...................................................................... 27 4.1 Hydrologic Analyses ........................................................................................................................................ 27 4.2 BMP Selection and Analysis ......................................................................................................................... 28 4.2.1 BMP Selection Based on Feasibility ........................................................................................... 28 4.2.2 Treatment Menu and BMP Selection ........................................................................................ 31 4.2.3 Threshold Discharge Area 1 ......................................................................................................... 32 Stormwater Site Plan iv November 2018 DRAFT 4.2.4 Threshold Discharge Area 2 ......................................................................................................... 33 4.3 Off-Site Analysis ................................................................................................................................................ 33 4.4 Storm Drain System Sizing and Hydraulic Analysis ............................................................................ 33 5 Conclusions and Recommendations .................................................................................. 34 6 References ................................................................................................................................ 35 TABLES Table 2-1 Existing Drainage Areas ......................................................................................................................... 10 Table 2-2 Proposed Drainage Areas ..................................................................................................................... 18 Table 3-1 Summary and Comparison of Minimum Requirements ......................................................... 20 Table 4-1 Proposed Post-Developed Conditions – Flow Rate Estimates ............................................. 28 Table 4-2 Proposed Drainage BMP Feasibility and Selection ................................................................... 29 FIGURES Figure 1-1 Vicinity Map ................................................................................................................................................... 3 Figure 2-1 Location Map ................................................................................................................................................ 6 Figure 2-2 Existing Drainage Area Boundaries ..................................................................................................... 7 Figure 2-3 Existing Drainage Facilities ...................................................................................................................... 8 Figure 2-4 Proposed Drainage Areas and Facilities ......................................................................................... 15 APPENDICES Appendix A Utility Plans Appendix B Drainage Area and Land Cover Analysis Appendix C Minimum Requirements Flow Charts Appendix D Construction SWPPP Appendix E Hydrologic Model Input and Results Appendix F Hydraulic Analysis and Facility Sizing Calculations Appendix G BMP Selection and Treatment Menus Stormwater Site Plan v November 2018 DRAFT ABBREVIATIONS ADA Americans with Disabilities Act ADT average daily traffic BMP best management practice BNSF BNSF Railway Company cf cubic feet cfs cubic feet per second County Snohomish County CPE corrugated polyethylene Drainage Manual Snohomish County Drainage Manual ECDC Edmonds Community Development Code Ecology Washington State Department of Ecology LID low-impact development MHHW mean higher high water MR Minimum Requirement MRs Minimum Requirements O&M operations and maintenance PGHS pollution-generating hard surfaces PGPS pollution-generating pervious surfaces ROW right-of-way SCC Snohomish County Code sf square feet SSP Stormwater Site Plan Standard Specifications WSDOT Standard Specifications for Road, Bridge, and Municipal Construction SWPPP Stormwater Pollution Prevention Plan TDA threshold discharge area WQ water quality WSDOT The Washington State Department of Transportation Stormwater Site Plan 1 November 2018 DRAFT 1 Project Overview The Snohomish County Parks and Recreation Department (County) is proposing to construct the Meadowdale Beach Park and Estuary Restoration Project, which will improve beach access, reduce localized flooding, improve maintenance, and reduce fish barrier issues associated with sediment deposition in an existing box culvert that conveys Lund’s Gulch Creek under the BNSF Railway (BNSF) railroad at the park. The park is located at the northern end of Brown’s Bay on Puget Sound, in Snohomish County, Washington, as shown on Figure 1-1. The park consists of multiple parcels totaling 108 acres and extends from the rim of Lund’s Gulch through a deeply incised forested ravine to the shoreline of Puget Sound. The project site encompasses approximately 10 acres of lawn area, tideland area, recreational facilities, forested slopes, and riparian area at the lower end of Lund’s Gulch Creek. The BNSF railroad runs through the park along the shoreline and separates the beach/tidelands from the upland area of the park. The majority of the park, including the tidelands, is located within unincorporated Snohomish County, but the most southwest parcel landward (east) of the railroad, totaling approximately 23 acres, is located entirely within the City of Edmonds. The park is centered around Lund’s Gulch Creek, a salmon-bearing perennial stream. The creek runs through the park, from east to west, and discharges to Puget Sound through a 6-foot-wide box culvert under BNSF Railway tracks. The lower creek and estuarine delta are habitat for multiple salmonid species, including juvenile Chinook salmon, which are listed as threatened under the Endangered Species Act, as well as coho and chum salmon, and cutthroat trout. The concrete box culvert conveys creek flow, passes sediment, and provides pedestrian access to the beach. To facilitate pedestrian access, a boardwalk (first wooden, then recently replaced with steel grating) was installed above the approximately 2-foot-deep by 4-foot-wide channel in the bottom of the culvert. The culvert is significantly undersized for the creek, and during high flow conditions a wide portion of the lower park is flooded. Deposition of sediment also occurs during high-flow events at the upstream end of the box culvert. This material restricts the movement of fish into and out of the creek. The sediment also deposits on adjacent park recreational areas and the trapping of sediment in these areas degrades an important nearshore habitat-forming process. The combination of sediment deposition and high-water conditions also impacts beach access and significant park resources are required to remove sediment and maintain conditions in a sensitive aquatic environment. The water and sediment conditions also create railroad crossing safety and Americans with Disabilities Act (ADA) compliance issues for public access to the beach. The primary objectives of the project are to restore ecological functions and expand the Lund’s Gulch Creek estuary, improve habitat conditions for salmon and other wildlife in lower Lund’s Gulch Creek, address public safety issues involving the existing railroad crossing, and improve access (including ADA-compliant access) to the beach. Stormwater Site Plan 2 November 2018 DRAFT Additional elements of the design include the following: • Converting portions of the lower lawn area to stream marsh and riparian habitat • Enhancing riparian vegetation along the creek • Placing in-stream wood structures • Enhancing existing habitat north of the existing foot-bridge • Connecting existing fresh water wetland to the creek • Providing picnic viewpoints • Re-routing paths • Providing a new, portable restroom enclosure • Constructing a new foot-bridge over Lund’s Gulch Creek • Addressing other ADA issues within the lower park area • Improving stormwater runoff controls and treatment The project will also include improvements to the ADA access road and parking, as needed to support construction activity and improve ADA access, as well as interpretive/educational signage. Improvements will be designed to meet the requirements of the following County documents: • Snohomish County Code (SCC; Snohomish County 2017) • Snohomish County Engineering and Design Standards (Snohomish County 2016a) • Snohomish County Drainage Manual (Snohomish County 2016b) Because the park and proposed improvements span the boundary between the City of Edmonds and unincorporated Snohomish County, the improvements will also need to be designed to meet the requirements outlined in the following City of Edmonds documents: • Edmonds Community Development Code (ECDC; City of Edmonds 2017a) • The Washington State Department of Transportation (WSDOT) 2018 Standard Specifications for Road, Bridge, and Municipal Construction (Standard Specifications; WSDOT 2017), and the City of Edmonds Modifications to the Standard Specifications (City of Edmonds 2007) • City of Edmonds Standard Details (City of Edmonds 2016) • The Stormwater Management Manual for Wester Washington (SWMMWW; Ecology 2014) • City of Edmonds Stormwater Addendum (City of Edmonds 2017b) This report identifies the stormwater Minimum Requirements (MRs) that apply to the project and presents analysis of improvements and best management practices (BMPs) that have been incorporated into the design of the project to meet those requirements. This report is intended to serve as the Stormwater Site Plan (SSP) required for the project, in accordance with MR1 from the Snohomish County Drainage Manual and the City of Edmonds Stormwater Addendum. This SSP reflects the design of drainage improvements reflected in the 90% Design set of drawings and specifications for the project. The final report will reflect a more detailed level of design that will be submitted for construction permits. Meadowdale BeachCounty Park City of Edmonds Lund's Gulch Creek Puget Sound City ofLynnwood Unincorporated Snohomish County 76th AVE W168th ST SW 52nd AVE WI-5SR-525SR-99[LEGEND:Park BoundaryCity/County Boundary Publish Date: 2018/03/07, 4:39 PM | User: jsextonFilepath: I:\Projects\Snohomish County\Meadowdale Beach Park\Park and Habitat Design\Task 5.2 60% Design\Stormwater\SW Site Plan Report\Figures\GIS\Figure1-1_VicinityMap.mxd Figure 1-1Vicinity MapPreliminary Stormwater Site PlanMeadowdale Beach Park Recreation and Habitat Improvements Project )Project Site 0 2,000 Feet Stormwater Site Plan 4 November 2018 DRAFT 2 Site Description and Project Background 2.1 Site History Meadowdale Beach County Park is located at 6026 156th Place SW, Edmonds, Washington. The park spans the boundary between the City of Edmonds and unincorporated Snohomish County, as shown on Figure 2-1. The 108-acre park consists of several parcels and is owned, operated, and maintained by the Snohomish County Parks and Recreation Department. Lund’s Gulch was first homesteaded by John Lund in 1878. The BNSF railroad was also constructed in the late 1800s. The gulch saw many subsequent landowners and was logged prior to eventually being acquired by the Meadowdale Country Club. The country club was a much more intensively developed facility than the current park and was located in what is now the lower creek and lawn area. The club closed in the late 1960s, due to repeated landslides, which damaged the access road, and other factors. In 1971, Snohomish County acquired the land for developing a public park with beach access. The buildings, which had been badly vandalized, were demolished and removed, along with the remains of the clubhouse, which had been destroyed by fire. The public was allowed to drive into the park on the access road until its condition degraded due to unstable soils. The park was closed to the public in 1979, after which a wide range of unsanctioned activities occurred, including firearms use, motorcycle riding, and large parties (Bruce Dees 1986; Snohomish County 2015). Planning and development of the park commenced in 1986 and included extensive public involvement with the following key issues identified: • Develop a park access arrangement that addressed surrounding neighborhood traffic concerns and disabled access requirements • Create a safe environment for the public to recreate in • Preserve and restore the natural environment • Build recreation facilities that supported passive recreation use Park improvements were completed in 1988. The park was closed in the late 1980s due to a slide on the access road. the park was closed again briefly in 1996 due to excessive storm damage from flooding and re-opened in 1997. 2.2 Site Description The park’s natural forests, stream, beach, and trails are the main attractions and are popular with residents throughout Snohomish County and nearby areas, attracting 50,000 to 70,000 annual visitors. The beach access is currently one of two available access points, along with Picnic Point County Park, between downtown Edmonds and Mukilteo. The park is also extensively used for environmental education by local schools, Boy and Girl Scouts, and Edmonds Community College Stormwater Site Plan 5 November 2018 DRAFT (Dailer 2015). The park is also an official Washington Water Trails campsite, providing beach camping to people using a non-motorized watercraft. The park’s main public access is from a parking lot located off of 156th Street SW. This upper portion of the park includes a small playground, portable toilets, a trailhead, and 30 parking stalls. A 1.25-mile earthen trail begins at the upper parking lot and follows Lund’s Gulch Creek to a partially paved loop trail in the lower park area. This loop trail connects recreational amenities to the box culvert that provides beach access under the BNSF railroad. Facilities at the lower park include paved and unpaved trails, a sand volleyball court, picnic shelter, five uncovered picnic tables on concrete pads, a lawn area, pedestrian bridge, ADA parking, portable toilets, and a ranger residence. The main recreational activities at the park include beach access, walking and hiking, picnicking, bird watching/nature enjoyment, and environmental education programs. The existing earthen railroad embankment parallels the beach, separating the County tidelands from the park lawn. The embankment is heavily armored with riprap and boulder-sized rock and is approximately 30 feet wide at the top and 60 feet wide at the base. The top of the embankment is approximately 8 feet above the adjacent foot-path. The embankment lies within the 100-foot BNSF-owned right-of-way (ROW). The embankment supports two tracks: Main 1 track (west track) and Main 2 track (east track). The corridor, a segment of the BNSF Scenic Subdivision (Line Segment 50, Milepost 21.8; Seattle to Wenatchee, Washington), has a high daily volume of freight, passenger, and commuter railroad traffic, which will likely increase over time. This line also serves Amtrak and Sound Transit passenger trains. The existing concrete box culvert is located at the beginning of an approximately 4.5-degree curve in the railroad line. The culvert opening is 6 feet high by 6 feet wide and has an upstream invert elevation of 9.59 feet and a downstream invert elevation of 9.07 feet North American Vertical Datum of 1988. Following construction of the culvert, a wooden deck was placed approximately 2 feet above the bottom of the culvert to accommodate public beach access and maintenance of the culvert. The wooden deck has since been replaced with steel grating. 2.3 Existing Stormwater Facilities and Drainage Local drainage basins that discharge stormwater runoff to Lund’s Gulch Creek or Puget Sound within or adjacent to the project site are shown on Figure 2-2. Existing stormwater facilities at the site are shown on Figure 2-3. Existing stormwater facilities are also shown on the existing conditions maps included with the utility drawings included in Appendix A. The locations of existing drainage facilities within the park are based on topographic survey of utility features. The existing park has limited stormwater conveyance and control infrastructure. Existing stormwater facilities within the project site include the following: DRAFT 0 200 Feet LEGEND: Park Boundary Project Limits Steep Slopes >33% Parcel Boundaries City/County Boundary Existing Wetlands BNSF Right-of-Way Publish Date: 2018/03/08 9:37 AM | User: jsexton Filepath: I:\Projects\Snohomish County\Meadowdale Beach Park\Park and Habitat Design\Task 5.2 60% Design\Stormwater\CAD\0723-RP-Figure 2-1 Location Map.dwg Figure 2-3 Figure 2-1 Location Map Preliminary Stormwater Site Plan Meadowdale Beach Park Recreation and Habitat Improvements Project Lund's Gulch Creek73RD AVE W151ST ST SW 72ND AVE W72ND AVE W73RD AVE WLUNDS GULCH ROAD6' x 6' Culvert Under BNSF ROW to Puget Sound City of Edmonds Unincorporated Snohomish County 1 23 4 5 6 DRAFT 0 Feet 300 LEGEND: Park Boundary Project Limits Steep Slopes >33% Parcel Boundaries City/County Boundary Lund's Gulch Creek Drainage Basin Existing Wetlands BNSF Right-of-Way Existing Drainage Areas Publish Date: 2018/03/08 12:50 PM | User: jsexton Filepath: I:\Projects\Snohomish County\Meadowdale Beach Park\Park and Habitat Design\Task 5.2 60% Design\Stormwater\CAD\0723-RP-Figure 2-2 Existing Drainage Area Boundaries.dwg Figure 2-3 Figure 2-2 Existing Drainage Area Boundaries Preliminary Stormwater Site Plan Meadowdale Beach Park Recreation and Habitat Improvements Project72ND AVE W156TH ST SW 68TH AVE. W70TH AVE W6' x 6' Culvert Under BNSF ROW to Puget Sound City of Edmonds Unincorporated Snohomish County Lund's Gulch Creek Drainage Basin Project Site Lund's Gulch Creek Wetland I Wetland D Wetland CWetland E Wetland G Wetland B Wetland F Wetland A Wetland H 1 23 4 5 DRAFT 0 100 Feet LEGEND: Existing Storm Drain Drainage Area Flow Direction Existing Storm Structure City/County Boundary BNSF ROW Project Limits Existing Wetlands Publish Date: 2018/03/08 12:26 PM | User: jsexton Filepath: I:\Projects\Snohomish County\Meadowdale Beach Park\Park and Habitat Design\Task 5.2 60% Design\Stormwater\CAD\0723-RP-Figure 2-3 Exist Drainage Facilities(2).dwg Figure 2-3 Privileged and Confidential | Attorney Work Product | Prepared at Request of Counsel Figure 2-3 Existing Drainage Facilities Preliminary Stormwater Site Plan Meadowdale Beach Park Recreation and Habitat Improvements Project Lund's Gulch Creek 6' x 6' Culvert Under BNSF ROW Drainage Swale Ranger Residence Picnic Shelter Drinking Fountain & Drain Portable Restroom Enclosure Stormwater Site Plan 9 November 2018 DRAFT • Access Road Swale: A paved swale runs along the upslope side of the existing access road that provides ADA-compliant and ranger access to the lower park. The access road is sloped so that runoff from the access road and forested slope south of the access road collects in the swale and discharges through a vegetated area towards Lund’s Gulch Creek, where the access road makes a hairpin turn into the ADA parking area. As-built drawings of the park indicate that the swale is 1 foot deep and is paved with asphalt, similar to the adjacent access road. Existing water, sewer, electrical, and communications service lines are buried under the swale. • Catch Basin and Drain to Creek in ADA Parking Lot: A single catch basin is located in the lowest (northwest) corner of the ADA parking area at the bottom of the access road, behind the ranger residence. The catch basin discharges runoff through a 6-inch-diameter PVC pipe north to Lund’s Gulch Creek. The catch basin only captures runoff from a small portion of the paved parking area surface. Runoff from most of the paved parking area and lower access road discharges via sheet flow runoff to adjacent vegetated areas. • Roof Drains: Gutters and downspouts collect and discharge runoff from rooftops over the ranger residence, an existing picnic shelter, and a portable restroom enclosure directly to adjacent lawn, landscaping, or paved areas. • Drinking Fountain Drain: A drinking fountain adjacent to the existing picnic shelter drains to the soil below the adjacent lawn area through a small sump with an inlet grate and a subsurface trench drain. • Lund’s Gulch Creek and Culvert: Runoff from all of the upland area of the project site drains to Lund’s Gulch Creek. As noted, the creek flows through a concrete box culvert through the BNSF railway embankment to Puget Sound. Topographic survey data for the project site, along with light detection and ranging (LiDAR) data and aerial photography, were used to delineate existing drainage areas that discharge to Lund’s Gulch Creek or Puget Sound within or adjacent to the project site. Table 2-1 summarizes existing drainage areas, which are characterized by pervious and impervious surfaces (referred to in the Snohomish County Drainage Manual and the City of Edmonds Stormwater Addendum as “hard surfaces”). Areas within the proposed project site were characterized by evaluating existing land cover conditions based on the topographic survey. Off-site areas were characterized by evaluating existing land cover conditions based on aerial photography. Most of the site discharges stormwater runoff directly to Lund’s Gulch Creek, which then discharges to Puget Sound at the west end of the site. The area draining to Lund’s Gulch Creek was divided into the following sub-basins: Stormwater Site Plan 10 November 2018 Table 2-1 Existing Drainage Areas Area TDA 1 TDA 2 Area 1 Access Road and Parking Area (sf) Area 2 Ranger Residence Area (sf) Area 3 Hillside and Park Area South of Creek (sf) Area 4 Hillside and Park Area North of Creek (sf) Area 5 Railroad Berm and Beach (sf) TOTAL Areas 1–5 (sf) Overall Lund’s Gulch Creek Drainage Basin (acres) Area 6 Access Road Entrance and Off-Site Areas (sf) Within Project Site Area Hard Surface Area 22,836 1,184 14,211 12,159 10,206 60,596 1.4 5,108 Pervious Surface Area 9,442 7,800 112,276 39,786 27,368 196,672 4.5 3,520 Subtotal 32,278 8,984 126,487 51,945 37,574 257,268 5.9 8,628 Off-Site Areas that Drain through Project Site Hard Surface Area 5,865 4,778 0 0 14,795 25,438 362.9 617 Pervious Surface Area 210,883 30,112 67,331 461,931 16,408 786,665 1,071.2 131,991 Subtotal 216,748 34,890 67,331 461,931 31,203 812,103 1,434.1 132,608 Total Drainage Area Hard Surface Area 28,701 5,962 14,211 12,159 25,001 86,034 364.3 5,725 Pervious Surface Area 220,325 37,912 179,607 501,717 43,776 983,337 1,075.7 135,511 Total 249,026 43,874 193,818 513,876 68,777 1,069,371 1,440.0 141,236 Stormwater Site Plan 11 November 2018 DRAFT • Area 1 – Access Road and Parking: Drainage from the access road that provides access for ADA guests, the park ranger, and other maintenance vehicles is collected and conveyed in a paved swale that runs along the south side of the access road. The swale ends at the hairpin turn near the parking area and discharges runoff from the access road to Lund’s Gulch Creek through a low-lying area at the base of the slope, designated for the project design as “Wetland D.” The only other constructed stormwater facilities in this area include a single catch basin at lowest corner (northwest corner) of the parking area that discharges to Lund’s Gulch Creek through a short segment of 6-inch-diameter PVC storm drain pipe. • Area 2 – Near Ranger Residence: No constructed stormwater collection or conveyance facilities exist in the area near the ranger residence, with the possible exception of some type of buried foundation drain around the building. This area consists of the ranger residence, a storage area and shed, a paved pathway, landscaping and grass, trails, a gravel access road, and riparian areas. Runoff from these areas infiltrates, disperses, or sheet flows to Lund’s Gulch Creek through the riparian area adjacent to the creek. • Area 3 – West of Ranger Residence on South Side of Creek: No constructed stormwater collection or conveyance facilities exist in the park area south of the creek, except for a small sump and buried infiltration trench drain that were designed primarily to drain the drinking fountain at the existing picnic shelter. This area consists of a picnic shelter, a portable toilet enclosure, paved pathways, landscaping and grass, and riparian areas in the lower park area south of the creek. Runoff from these areas infiltrates, disperses, or sheet flows to the creek through the riparian area. Roof runoff from the roofs over the picnic shelter and portable toilet enclosure discharges from downspouts to paved areas or lawn areas. • Area 4 – North Side of Creek: No constructed stormwater collection or conveyance facilities exist in the park area north of the creek, except for a single 12-inch culvert that conveys water across a gravel pathway. This area consists primarily riparian area and forested slopes, with of crushed rock pathway. • Area 5 – Railroad Berm and Beach: As noted earlier, the BNSF railroad runs along a berm across the mouth of Lund’s Gulch. The only drainage through the railroad berm is through the approximately 6-foot-wide, 6-foot-high box culvert. Surfaces adjacent to the railroad and along the shoreline are pervious. Any runoff infiltrates or runs off to the shoreline. The following also drains through a portion of the project area: • Area 6 – Access Road and Off-site Areas: Drainage Area 6 includes areas that drain through a small portion of the project area along the south end of the access road at the entrance to the park. This area consists of a small portion of forested hillside upslope of the access road within the park and a forested hillside downstream of the access road to the BNSF ROW. A swale along the uphill side of the access road near the entrance conveys runoff from the hillside above the access road north to an inlet structure near the entrance to the park. An Stormwater Site Plan 12 November 2018 DRAFT 18-inch-diameter concrete storm drain pipe appears to convey runoff from the swale to drainage facilities in and near the residence at 15500 75th Place NW, adjacent to the park entrance. Those facilities drain west to the BNSF ROW and Puget Sound between 15500 and 15520 75th Place NW. Drainage Areas 1 through 4 represent the lower part of the larger Lund’s Gulch Creek Drainage Basin. The Lund’s Gulch Creek Drainage Basin includes approximately 1,440 acres (2.25 square miles) that drain to Puget Sound through the outlet of Lund’s Gulch Creek within the project site. Most of that area is upstream of the project area and extends into urban areas within the City of Lynnwood, the City of Edmonds, and unincorporated Snohomish County. Hydrology for the basin was evaluated as part of the Puget Sound Tributaries Drainage Needs Report (Snohomish County 2002), and the results were used to develop the hydraulic analysis presented in the Meadowdale Beach County Park Feasibility Study (Anchor QEA 2016). The hydrologic analysis from those reports indicates that the overall existing Lund’s Gulch Creek drainage basin land cover consists of approximately 25.3% hard surfaces and 74.7% pervious surfaces. Future conditions are expected to increase the hard surface coverage to approximately 37.6% of the land cover within the basin. Drainage Areas 1 through 5 were identified as areas that drain through the park to a common discharge location to Puget Sound at or near the mouth of Lund’s Gulch Creek. For the purpose of this analysis, these areas were determined to comprise a single threshold discharge area (TDA), referred to herein as TDA 1. Drainage Area 6 appears to outlet to Puget Sound through the BNSF railroad embankment south of the project area, although the specific outlet location could not be verified as part of this analysis. An inlet near the park entrance appears to convey runoff from the roadway and upslope areas near the entrance to facilities that drain west to the BNSF ROW and Puget Sound between 15500 and 15520 75th Place NW. For this analysis, Drainage Area 6 was assumed to be a separate TDA, referred to herein as TDA 2. 2.4 Other On-Site Utilities Other existing utilities at the site include potable water, sanitary sewer, power, and communications. Potable water facilities include a 1.5-inch water meter at the property boundary on the east side of the access road and a 2.5-inch PVC water service main extending from the meter along the access road to the ranger residence and picnic shelter, with a 1-inch PVC water service line extending to the portable toilet enclosure. Sanitary sewer facilities include a small lift station and 1.5-inch force main that serve the ranger residence. Power and communication conduits also extend into the site along the access road to the ranger residence. The utilities are primarily located in a common trench under the drainage swale on the east and south sides of the access road. The intent of the design of park improvements is to minimize the impact to existing utilities. Stormwater Site Plan 13 November 2018 DRAFT 2.5 Proposed Site Improvements The project improvements will include the following: • Railroad Bridge: The existing box culvert will be replaced with a four-span railroad bridge with two 40-foot clear center spans and two 25-foot abutment spans centered on the location of the current culvert and creek outlet alignment. • Beach Access: A pedestrian access path to the beach will be located under the railroad bridge and will provide the 80-inch minimum vertical clearance required for ADA-compliant access. • Habitat Restoration: The lower lawn area and part of the upper lawn area will be converted to estuary, stream, marsh, and riparian habitat, with additional habitat area restored by enhancing riparian vegetation and in-stream wood structures. Existing habitat will also be enhanced upstream of the pedestrian footbridge across Lund’s Gulch Creek by installing large woody debris and enhancing existing riparian vegetation. • Pedestrian Bridge: A new pedestrian bridge will be installed across the restored stream channel downstream of the existing pedestrian bridge to connect pathways on the north and south sides of the stream. • Paths: The path connecting the picnic shelter to the pedestrian bridge and path on the north side of the creek will be partially re-aligned. The loop path north of the creek and proposed marsh will be truncated to avoid habitat fragmentation. Other existing paths will be resurfaced and modified, as needed, to accommodate restoration and new park facilities. • Lawn Renovation: Drainage of remaining lawn areas will be improved by regrading lawn areas and adding a more permeable subsurface layer, and the volleyball court will be converted to lawn area. • ADA-Compliant Access: ADA-compliant access will be extended throughout the park by constructing accessible walkways from the parking area to the beach. • Site Furnishings: New benches, picnic tables, and other site furnishings will be provided to enhance the park and recreational facilities. • Picnic Shelter: The existing picnic shelter will be maintained as is. • Restroom Enclosure: A new structure will be constructed to house portable restroom facilities. The enclosure will include a handwashing station and will be located adjacent to the existing picnic shelter. It will replace an existing enclosure that must be relocated to allow for restoration of the estuary and avoid conflicts with construction in the BNSF ROW. • Viewpoints: Two picnic viewpoints will be established at the new path terminus. • Access Road and Parking Area: The existing access road will be modified, as needed, to provide construction access for a 100-ton crane and other construction equipment that will be needed to construct improvements at the site. This will likely include adjustment of the profile along the lower half of the access road, modification to the swale along the south side of the access road, and widening of the hairpin curve at the bottom of the access road. The Stormwater Site Plan 14 November 2018 DRAFT parking area will also be slightly reconfigured to improve the parking layout and ensure adequate ADA access. Both the parking area and the access road will be resurfaced to repair damage that will be done during construction. • Utilities: Utilities will be modified, as needed, to accommodate grading and improvements. 2.6 Proposed Stormwater Facilities and Drainage Proposed stormwater improvements were identified and designed based on the MRs outlined in Section 3. The proposed drainage improvements are illustrated on Figure 2-4. Proposed drainage areas and flow directions are also shown. Detailed utility plans, showing drainage improvements in plan view with profiles and details, are also included in Appendix A (Drawings CU-1 through CU-4). The following summarizes the overall drainage improvement concept. Additional details about the improvements are provided in Section 4. 2.6.1 Proposed Drainage Area 1 Proposed Drainage Area 1 will include the access road and parking area that provide ADA and ranger access to the lower park and areas tributary to the access road and parking area. Most of the access road will be resurfaced by grinding and overlaying the existing asphalt. The lower end of the access road will be regraded to reduce the slope of the access road to a maximum of 15%, to allow for adequate construction access. The access road at the hairpin turn will also be widened to improve access. The ADA parking facility will be reconfigured to include an additional ADA-accessible parking space. As part of this work, the drainage swale along the south edge of the access road will be replaced with a rock-lined swale with an impervious liner. At the downstream end of the swale, a catch basin will be installed to collect all runoff from the access road. A system of additional catch basins and storm drains will be installed along the edges of the hairpin turn and in the ADA- accessible parking area to capture runoff from these pollution-generating hard surfaces (PGHS) for conveyance to a bio-filtration swale for treatment in Proposed Drainage Area 2. 1 2 3A 4 5 3B 6 LEGEND: Proposed Storm Drain Project Limits Flow Direction Proposed Storm Structure City/County Boundary BNSF ROW Proposed Drainage Area Existing Wetlands Proposed Contour Drainage Swale Restroom Enclosure Drinking Fountain & Drain Wet Bio-filtration Swale DRAFT 0 100 Feet Publish Date: 2018/03/08 12:35 PM | User: jsexton Filepath: I:\Projects\Snohomish County\Meadowdale Beach Park\Park and Habitat Design\Task 5.2 60% Design\Stormwater\CAD\0723-RP-Figure 2-4 Proposed Drainage Areas and Facilities.dwg Figure 2-4 Figure 2-4 Proposed Drainage Areas and Facilities Preliminary Stormwater Site Plan Meadowdale Beach Park Recreation and Habitat Improvements Project Lund's Gulch Creek Proposed BNSF Bridge Restored Estuary Stormdrain System for Driveway and ADA Parking Area Rock-Lined Swale to MHHW Picnic Shelter Ranger Residence Stormwater Site Plan 16 November 2018 DRAFT 2.6.2 Proposed Drainage Area 2 Proposed Drainage Area 2 will include the area around the ranger residence, lower park areas, and forested slope areas that will be tributary to the proposed treatment swale. Improvements within this area will include resurfacing paved pathways, regrading and replacing existing lawn areas, and construction of new storm drainage facilities. A series of storm drains and catch basins will be installed to convey runoff from PGHS in Proposed Drainage Area 1 to the wet bio-filtration swale that will be installed along the south edge of the paved loop pathway west of the ranger residence. The swale will be designed to provide basic treatment, in accordance with the MRs outlined in Section 3. 2.6.3 Proposed Drainage Area 3A Proposed Drainage Area 3A will include the portion of the lower park area that will be tributary to the drainage system downstream of the treatment swale. Downstream of the wet bio-filtration swale, treated runoff will be conveyed through storm drains to a rock-lined swale that will convey runoff through the restored estuary to the mean higher high water (MHHW) mark. Improvements within this area will include resurfacing paved pathways, regrading and replacement of lawn areas, installation of recreation facilities (benches, viewpoints, picnic tables, a new paved pathway, and a new portable restroom enclosure), and restoration of estuary and riparian areas. 2.6.4 Proposed Drainage Area 3B Proposed Drainage Area 3B will include the portion of the lower park area south of Lund’s Gulch Creek that is not tributary to proposed stormwater facilities. No constructed stormwater facilities are planned for this area. Runoff from this area will continue to infiltrate, disperse, or sheet flow to Lund’s Gulch Creek through the riparian area adjacent to the creek. Improvements within this area will include resurfacing paved pathways, regrading and replacement of lawn areas, installation of recreation facilities (benches, viewpoints, picnic tables, and a new bridge over Lund’s Gulch Creek), and restoration of estuary and riparian areas. 2.6.5 Proposed Drainage Area 4 Proposed Drainage Area 4 will include the lower park area that drains to Lund’s Gulch Creek through the project site. No new constructed stormwater collection or conveyance facilities are planned in the lower park area north of the creek. This area consists primarily riparian area and forested slopes, with a crushed-rock pathway. Other improvements will include installation of recreation facilities (benches, viewpoints, and a new bridge over Lund’s Gulch Creek), and restoration of estuary and riparian areas. Runoff from these surfaces will continue to infiltrate, disperse, or sheet flow to Lund’s Gulch Creek through the riparian area adjacent to the creek. Stormwater Site Plan 17 November 2018 DRAFT 2.6.6 Proposed Drainage Area 5 Proposed Drainage Area 5 will include the railroad ROW and beach area. Surfaces adjacent to the railroad and along the shoreline are pervious. Any runoff will continue to infiltrate or run off to the shoreline or restored estuary area. 2.6.7 Proposed Drainage Area 6 Drainage Area 6 will include areas that drain through a small portion of the project area along the south end of the access road at the entrance to the park. This area will consist of a small portion of forested hillside upslope of the access road within the park and a forested hillside downstream of the access road to the BNSF ROW. The access road through this area will be resurfaced by grinding and overlaying the asphalt roadway surface. No construction of or modification to stormwater facilities in this area is proposed. 2.7 Proposed Drainage Area Characterization Proposed drainage areas are characterized in Table 2-2 and illustrated on Figure 2-4. A more detailed breakdown of the existing and proposed land cover is provided in Appendix B. Proposed drainage areas are characterized by pervious and hard surfaces. Hard surfaces within the project site have also been characterized as those that are existing and will remain, those that will replace existing hard surfaces, and new hard surfaces. For this analysis, areas within the proposed project site were characterized by evaluating proposed land cover shown on the site plans and material plans for the project from the 60% drawings for the project. Off-site areas were characterized based on aerial photography. Stormwater Site Plan 18 November 2018 DRAFT Table 2-2 Proposed Drainage Areas Area TDA 1 TDA 2 Area 1 Access Road and Parking Area (sf) Area 2 Ranger Residence Area (sf) Area 3A Hillside and Park Area South of Creek (sf) Area 3B Hillside and Park Area South of Creek (sf) Area 4 Hillside and Park Area North of Creek (sf) Area 5 Railroad Berm and Beach (sf) TOTAL Areas 1–5 (sf) Overall Lund’s Gulch Creek Drainage Basin (acres) Area 6 Access Road Entrance and Off-Site Areas (sf) Within Project Site Area Hard Surface Area 22,178 5,267 7,250 2,723 10,196 25,829 73,443 1.7 5,108 Existing 21,372 0 542 0 10,196 25,000 57,110 0.8 5,108 New 806 63 2,155 1,529 0 243 4,796 0.1 0 Replaced 0 5,204 4,553 1,194 0 586 11,537 0.8 0 Pervious Surface Area 8,625 16,753 46,971 69,615 42,915 12,432 197,311 4.5 3,520 Subtotal 30,803 22,020 54,221 72,338 53,111 38,261 270,754 6.2 8,628 Off-Site Areas that Drain through Project Site Hard Surface Area 7,329 3,806 0 0 0 0 11,135 362.6 617 Pervious Surface Area 210,894 40,486 44,113 708 460,765 30,516 787,482 1,071.2 131,991 Subtotal 218,223 44,292 44,113 708 460,765 30,516 798,617 1,433.8 132,608 Total Drainage Area Hard Surface Area 29,507 9,073 7,250 2,723 10,196 25,829 84,578 364.3 5,725 Pervious Surface Area 219,519 57,239 91,084 70,323 503,680 42,948 984,793 1,075.7 135,511 Total 249,026 66,312 98,334 73,046 513,876 68,777 1,069,371 1,440.0 141,236 Stormwater Site Plan 19 November 2018 DRAFT 3 Minimum Stormwater Requirements Because the project spans the boundary between unincorporated Snohomish County and the City of Edmonds, the project must meet the minimum stormwater requirements for both jurisdictions. Minimum stormwater requirements for projects within Snohomish County are subject to the requirements of Chapter 30 of the SCC, as supplemented by the Snohomish County Drainage Manual and the Snohomish County Engineering and Design Standards. Minimum stormwater requirements for projects within the City of Edmonds are subject to the requirements of the ECDC, which requires compliance with the Ecology SWMMWW, as supplemented or modified by the City of Edmonds Stormwater Addendum. A summary and comparison of the minimum requirements from Snohomish County and the City of Edmonds is included in Table 3-1. The Snohomish County Drainage Manual and the SWMMWW allow for evaluation of minimum requirements based on TDAs. Two TDAs have been identified for stormwater that drains through the project site. The main TDA (TDA 1) includes the clear majority of the project site and drains directly to Lund’s Gulch Creek or to the shoreline adjacent to the mouth of Lund’s Gulch Creek. The only portion of the project site not included in TDA 1 is the access road entrance, from the property boundary to the crest of the hill at the first curve in the access road, and those areas tributary to it, including both park and private property upslope and downslope of the access road to the BNSF ROW. This area is considered a separate TDA (TDA 2). SCC 30.91R distinguishes “New Development” from “Redevelopment” based on the percentage of the existing site covered with hard surfaces. Projects developed on sites with 35% or less hard surface coverage are characterized as “New Development” rather than “Redevelopment.” The hard surfaces at the project site comprise less than 5% of the total acreage within the site. Therefore, the project is characterized as “New Development” rather than “Redevelopment.” ECDC 18.30 does not distinguish between new projects and redevelopment projects. The following subsections summarize the minimum requirements from Snohomish County. Where the City of Edmonds requirements differ and are more stringent, those requirements are also presented. Appendix C includes a mark-up of Figure 1.1 from the Snohomish County Drainage Manual and Figure 3.1 from the City of Edmonds Stormwater Addendum identifying the MRs that apply to the project. The thresholds and triggers for minimum requirements are generally consistent between the two jurisdictions. The project will add or replace more than 5,000 square feet (sf) of hard surface within TDA 1, so all the MRs outlined in the Snohomish County Drainage Manual and City of Edmonds Stormwater Addendum will apply to stormwater runoff from new and replaced impervious surfaces and converted vegetation areas in TDA 1. The project will not result in more than 2,000 sf of new or replaced hard surface in that TDA 2, so only MR2 will need to be met in TDA 2. Stormwater Site Plan 20 November 2018 DRAFT Table 3-1 Summary and Comparison of Minimum Requirements MR Description Snohomish County SMMWW and City of Edmonds Stormwater Addendum 1 Preparation of Stormwater Site Plans • Site Analysis: Collect and Analyze Information on Existing Conditions • Prepare Preliminary Development Layout • Perform Off-site Analysis • Determine Applicable Minimum Requirements • Prepare a Permanent Stormwater Control Plan • Prepare a Construction Stormwater Pollution Prevention Plan • Complete the Stormwater Site Plan • Site Analysis: Collect and Analyze Information on Existing Conditions • Prepare Preliminary Development Layout • Perform Off-site Analysis • Determine Applicable Minimum Requirements • Prepare a Permanent Stormwater Control Plan • Prepare a Construction Stormwater Pollution Prevention Plan • Complete the Stormwater Site Plan • Complete Checklists 1, 2, and 3 in Edmonds Stormwater Addendum 2 Stormwater Pollution Prevention Plan • Mark Clearing Limits • Establish Construction Access • Control Flow Rates • Install Sediment Controls • Stabilize Soils • Protect Slopes • Protect Drain Inlets • Stabilize Channels and Outlets • Control Pollutants • Control De-Watering • Maintain BMPs • Manage the Project • Protect On-site Stormwater Management BMPs for Runoff from Roofs and Other Hard Surfaces • Preserve Vegetation/Mark Clearing Limits • Establish Construction Access • Control Flow Rates • Install Sediment Controls • Stabilize Soils • Protect Slopes • Protect Drain Inlets • Stabilize Channels and Outlets • Control Pollutants • Control De-Watering • Maintain BMPs • Manage the Project • Protect Low Impact Development BMPs • Edmonds Stormwater Addendum provides increased level of detail for the protection of LID BMPs 3 Source Control of Pollution • Source control shall be provided through the application of source control BMPs during construction and on the developed site following construction • BMPs shall be appropriate for the proposed construction activities, buildings, facilities, and intended post-development site uses in accordance with Volume IV of the Drainage Manual • All known, available and reasonable source control BMPs must be applied to prevent stormwater from coming in contact with pollutants as outlined in Volume IV of the SMMWW 4 Preservation of Natural Drainage Systems and Outfalls • Natural drainage patterns shall be maintained, and discharges from the project site shall occur at the natural location • The manner by which runoff is discharged from the project site must not cause a significant adverse impact to downstream receiving waters or down gradient properties • Mitigation of off-site drainage impacts shall be provided pursuant to the requirements of Volume I of the Drainage Manual • Natural drainage patterns shall be maintained, and discharges from the project site shall occur at the natural location • The manner by which runoff is discharged from the project site must not cause a significant adverse impact to downstream receiving waters or down gradient properties • Existing upstream flows must be accommodated without causing erosion or flooding impacts • Mitigation is required to prevent flooding or erosion problems as determined by the off-site analysis 5 On-Site Stormwater Management • Projects exempt from MR7 must implement the following BMPs if feasible: o BMP T5.13 Post-Construction Soil Quality and Depth o BMP T5.10A Downspout Full Infiltration Systems, BMP T5.10B Downspout Dispersion Systems, or BMP T5.10C Perforated Stub-out Connections o BMP T5.11 Concentrated Flow Dispersion or BMP T5.12 Sheet Flow Dispersion • Projects that do not drain to the City’s MS4 system are required to either discharge to the downstream property or to an on-site system from List No. 1 from ECDC 18.30.060 6 Runoff Treatment • Stormwater treatment facilities shall be provided in accordance of Volume V of the Drainage Manual for each threshold discharge area • Stormwater treatment facilities shall be provided in accordance with the SMMWW 7 Flow Control • The Project does not discharge stormwater directly or indirectly into a fresh water system and it therefore not subject to the requirements of MR7 8 Wetland Protection • The Project does not discharge stormwater directly or indirectly into a fresh water system and it therefore not subject to the requirements of MR8 9 Operation and Maintenance • An operation and maintenance manual is required for proposed stormwater treatment BMPs that is consistent with the provisions in Volume V of the Drainage Manual • An operation and maintenance manual is required for proposed stormwater treatment BMPs that is consistent with the provisions in Volume I and Volume V of the SMMWW Stormwater Site Plan 21 November 2018 DRAFT 3.1 Minimum Requirement 1 – Preparation of a Stormwater Site Plan MR1 requires that a Stormwater Site Plan (SSP) be prepared for the proposed project in accordance with Chapter 3 of the Snohomish County Drainage Manual. This report is intended to include all the technical information and analysis required for a SSP. The requirements outlined in the Snohomish County Drainage Manual indicate that the SSP report should include the following elements: • A project overview narrative describing pre-developed and developed site conditions • A vicinity or location map that shows the project location, identifies roads bordering the site, shows the route of stormwater through the site, and shows significant geographic features • Stormwater site planning sheets (maps and drawings) that show drainage basin boundaries, existing drainage to and from the site, routes of existing drainage, flow lengths, proposed control and treatment facilities, significant geographic features, critical areas, and soils • A summary of existing site conditions • A description of any areas of site limitation • An off-site analysis evaluating impacts to upstream and downstream properties • Proposed drainage design, including the basis of BMP selection • A construction stormwater pollution prevention plan (SWPPP) • Drawings and a description of permanent stormwater control facilities • Special reports, studies, and maps prepared to support the SSP report • A list of necessary permits and approvals required by other agencies • An operation and maintenance manual for each flow control and treatment facility • Documentation to establish the appropriate security device amount when required under Chapter 30.84 of the SCC. The requirements outlined in Appendix C of the City of Edmonds Stormwater Addendum indicate that the SSP report should comply with the requirements for a SSP from Volume I, Chapter 3, of the SWMMWW and include the following elements: • A project overview narrative describing pre-developed and developed site conditions, including any maps or drawings needed to support the project overview • A summary of existing site conditions • A summary of developed site hydrology, including scaled drawings, a summary of how the site will comply with applicable stormwater management requirements, justification for selection of stormwater BMPs, an off-site analysis, and other supporting documentation • A soils report • A construction SWPPP • Establishment of a Maintenance Covenant, including operations and maintenance (O&M) requirements and completion of a City-approved maintenance covenant form Stormwater Site Plan 22 November 2018 DRAFT This report has been prepared as the required SSP for the project and is intended to include information to satisfy both the Snohomish County and City of Edmonds requirements. 3.2 Minimum Requirement 2 – Construction Stormwater Pollution Prevention Plan MR2 requires that a construction Stormwater Pollution Prevention Plan (SWPPP) be prepared in accordance with Volume II, Chapter 3, of the Snohomish County Drainage Manual and SWMMWW, Chapter 2, Section 2.5.2, as supplemented by the City of Edmonds Stormwater Addendum. The required SWPPP should include a narrative, drawings, and a turbidity and pH monitoring plan. The SWPPP is required to demonstrate compliance with the following elements: 1. Preserve Vegetation/Mark Clearing Limits 2. Establish Construction Access 3. Control Flow Rates 4. Install Sediment Controls 5. Stabilize Soils 6. Protect Slopes 7. Protect Drain Inlets 8. Stabilize Channels and Outlets 9. Control Pollutants 10. Control Dewatering 11. Maintain BMPs 12. Manage the Project 13. Protect Low Impact Development BMPs The SWPPP also requires temporary erosion and sediment control drawings, summaries of construction BMPs that will be implemented to satisfy the minimum elements required by the Snohomish County Drainage Manual, recommended forms and methods for inspecting and maintaining BMPs, and other documentation needed to secure a construction stormwater permit for the project. A draft SWPPP for the project is included as Appendix D to this SSP report. The SWPPP will be finalized and submitted for construction permits. Snohomish County anticipates that the Construction Stormwater General Permit compliance responsibility will be transferred to the Contractor during construction, and that the Contractor will ultimately be responsible for reviewing and update the SWPPP, as needed to demonstrate compliance. 3.3 Minimum Requirement 3 – Source Control of Pollution Source control of pollutants during the construction phase of the project will be addressed in accordance with the SCC, the ECDC, approved SWPPP, and permit requirements. Post-construction BMPs will include both operational and structural BMPs. Operational BMPs are practices or procedures that prevent or reduce pollutants from entering stormwater. Structural BMPs are physical or mechanical devices that prevent or reduce pollutants from entering stormwater or that remove pollutants through treatment after entrainment in stormwater. Post-construction structural BMPs proposed for the project are described in Section 4. Stormwater Site Plan 23 November 2018 DRAFT Because the project involves the restoration of a County park, no industrial activities will be conducted on site. Operational BMPs will consist of those applicable to landscaping and lawn or vegetation management and management of waste from recreational facilities. The County will be responsible for landscape management consistent with established maintenance procedures regarding the use of pesticides, herbicides, and fertilizers adjacent to a marine environment. The County will also be responsible for management of waste from recreational facilities, including portable restroom facilities, consistent with County maintenance procedures to prevent waste or untreated sewage from entering the stormwater system or Puget Sound. Because this is a jurisdiction-owned public facility, a formal source control plan is not required. 3.4 Minimum Requirement 4 – Preservation of Natural Drainage Systems and Outfalls MR4 requires that natural drainage patterns be maintained and that discharge from the site occur at the natural location, to the maximum extent practicable. Runoff from the completed project will be infiltrated runoff to Lund’s Gulch Creek or drain to Puget Sound via a storm drain system and constructed open channel discharging at the MHHW mark within the restored estuary. The natural outlet for runoff from the site is Lund’s Gulch Creek outlet to Puget Sound. Runoff from the site will continue to flow to Lund’s Gulch Creek or the restored estuary at the mouth of Lund’s Gulch Creek. Proposed drainage improvements have been designed to preserve existing drainage systems. To the maximum extent feasible, runoff from impervious surfaces near Lund’s Gulch Creek or the shoreline has been designed to sheet flow to adjacent vegetated areas, consistent with existing drainage conditions. Storm drainage improvements have also been designed to maintain flow capacity through the site for off-site flows. 3.5 Minimum Requirement 5 – On-Site Stormwater Management MR5 requires that stormwater management BMPs be implemented to infiltrate, disperse, or retain stormwater runoff on site, where feasible, without causing flooding or erosion impacts. To the extent possible, the design includes BMPs that will disperse runoff. However, the depth to the seasonal groundwater is relatively shallow through most of the lower ravine, and the native soils are not likely to provide capacity for infiltration. Where required, on-site runoff will be collected, conveyed, and treated prior to discharge to Puget Sound, as described in this report. Where new landscaping and lawn areas are established, soil quality BMPs will be implemented. BMPs will be in accordance with the requirements of Snohomish County Drainage Manual and the SWMMWW, as supplemented or modified by the City of Edmonds Stormwater Addendum. The process for selecting and evaluating feasibility of BMPs for projects within Snohomish County is outlined in Volume I, Chapters 2 and 4, of the Snohomish County Drainage Manual. Projects triggering the need to meet MRs 1–9 are either required to demonstrate compliance with the low Stormwater Site Plan 24 November 2018 DRAFT impact development (LID) Performance Standard or use on-site stormwater management BMPs from List No. 2 in Section 2.5.5 of Volume I of the Snohomish County Drainage Manual. The selection of appropriate BMPs requires evaluation of the potential for priority BMPs that infiltrate, disperse, or retain stormwater runoff on-site. The first BMP considered feasible from List No. 2 is used for meeting the appropriate stormwater control requirements for runoff from each surface. Projects that require compliance with MRs 1–9 are referred to as Category 2 projects by the City of Edmonds EDCD 18.30. Category 2 projects are also required to either demonstrate compliance with the LID Performance Standard outlined in the City of Edmonds EDCD 18.30 or use on-site stormwater management BMPs from List No. 2. The EDCD requires use of the first BMP considered feasible from list No. 2 for meeting the appropriate stormwater control requirements. 3.6 Minimum Requirement 6 – Runoff Treatment MR6 requires that runoff treatment BMPs be incorporated into the project to treat runoff from PGHS prior to discharge to Puget Sound or to groundwater. The Snohomish County Drainage Manual requires treatment for projects where the total PGHS in a TDA is 5,000 sf or more, or where the total of pollution-generating pervious surfaces is 0.75 acre or more. As shown in Table 2-2 and Appendix B, the project will result in more than 5,000 sf of PGHS within TDA 1, so treatment of runoff from all PGHS and pollution-generating pervious surfaces (PGPS) within TDA 1 will be required. Off-site flows and runoff from other on-site surfaces (non-pollution generating surfaces and existing impervious surfaces to remain) must also be treated if those flows enter the site and mix with flows from PGHS or PGPS upstream of treatment. To the extent possible, on-site flows from PGHS will be segregated from off-site or run-on flows upstream of treatment facilities. Where flows are not segregated, treatment will be provided for flows from surfaces requiring treatment and run-on flows. Treatment BMPs are identified in Section 4. The City of Edmonds requires that all projects not zoned as single-family residential that collect runoff from five or more parking spaces shall install floatable controls in catch basins if another approved floatable control system is not employed. 3.7 Minimum Requirement 7 – Flow Control MR7 requires that projects meeting certain thresholds provide flow control to reduce the impacts of stormwater runoff from impervious surfaces and land cover conversions. However, the Snohomish County Drainage Manual indicates that flow control only applies to projects that discharge stormwater directly or indirectly into a fresh water system. The SWMMWW provides flow control requirements that apply to the City of Edmonds and also indicates that flow control applies only to projects that discharge directly or indirectly to fresh water. Concentrated, treated runoff from the project site will be conveyed via storm drains and swales designed to discharge flows to Puget Stormwater Site Plan 25 November 2018 DRAFT Sound at the MHHW mark within the restored estuary at the mount of Lund’s Gulch Creek. Therefore, no flow control BMPs are required for the project. 3.8 Minimum Requirement 8 – Wetlands Protection MR8 applies to development and redevelopment projects that discharge stormwater to a stream that leads to a wetland, or to a wetland that has an outflow to a stream. MR8 requires that projects protect wetland functions and values by preserving wetland hydrology and preventing increase in the amount of pollutants discharged to a wetland. A wetlands survey was completed as a basis for permitting the project, and several small wetland areas were identified at the project site, as shown in Figures 2-3 and 2-4 and Drawings EC-1 through EC-3 (Appendix A). The existing wetland areas are summarized as follows: • Wetland A: Wetland A is a 0.13-acre wetland (Category III, per both Ecology and Snohomish County Rating Systems) located in a depression east of the BNSF railroad embankment and south of the toe of a steep slope at the NE corner of the site. No work will occur in the wetland area. Wetland hydrology and water quality will not be impacted by the project. • Wetland B: Wetland B is a 0.21-acre wetland (Category II, per both Ecology and Snohomish County Rating Systems) adjacent to the south side (left bank) of Lund’s Gulch Creek within the lower park area. A small, raised wooden walkway will be constructed across the wetland to a connect pathways in the lower park to a new bridge that will cross Lund’s Gulch Creek. Wetland hydrology and water quality will not be impacted by the project. • Wetland C: Wetland C is a 0.03-acre wetland (Category II, per both Ecology and Snohomish County Rating Systems) adjacent to the south side (left bank) of Lund’s Gulch Creek just north of the ADA and ranger access parking area. No work will occur in the wetland area. Wetland hydrology and water quality will not be impacted by the project. • Wetland D: Wetland D is a 0.10-acre wetland (Category III, per both Ecology and Snohomish County Rating Systems) adjacent to the south side (left bank) of Lund’s Gulch Creek just east of the hairpin turn at the lower end of the access road. No work will occur in the wetland area. Some runoff that currently discharges from the access road to the wetland area will be captured by the new storm drain system in the access road. However, it appears that wetland hydrology is primarily sustained by seepage from the hillside, so no significant change is wetland hydrology or water quality is anticipated as part of the project. • Wetland E: Wetland E is a 0.05-acre wetland (Category III, per both Ecology and Snohomish County Rating Systems) adjacent to the north side (right bank) of Lund’s Gulch Creek just upstream of the existing bridge. No work will occur in the wetland area. Wetland hydrology and water quality will not be impacted by the project. • Wetland F: Wetland F is a 0.08-acre wetland (Category IV, per both Ecology and Snohomish County Rating Systems) located in a depression between the pathway that loops around the Stormwater Site Plan 26 November 2018 DRAFT south side of the lower park and the toe of a steep slope to the south. No work will occur in the wetland area. The pathway adjacent to the wetland will be resurfaced and designed so that runoff from the pathway flows away from the wetland. Runoff from the existing pathway likely flows to the wetland. However, it appears that wetland hydrology is primarily sustained by seepage from the hillside above the wetland, so no significant change in wetland hydrology or water quality is anticipated as part of the project. • Wetland G: Wetland G is a 0.22-acre wetland (Category III, per both Ecology and Snohomish County Rating Systems) adjacent to the north side (right bank) of Lund’s Gulch Creek across from the lower park area. No work will occur in the wetland area. Wetland hydrology and water quality will not be impacted by the project. • Wetland H: Wetland H is a 0.05-acre wetland (Category II, per both Ecology and Snohomish County Rating Systems) adjacent to the south side (left bank) of Lund’s Gulch Creek downstream of the existing pedestrian bridge. No work will occur in the wetland area. Wetland hydrology and water quality will not be impacted by the project. 3.9 Minimum Requirement 9 – Operations and Maintenance MR9 requires that the agency or parties responsible for O&M of drainage facilities in Snohomish County adhere to requirements set forth in Volume 5, Chapter 4, of the Snohomish County Drainage Manual, and SCC 30.63A.575 through 30.63A.605. In the City of Edmonds, the requirements are set forth in ECDC 18.30.060.D.9 and the submittal checklist from Appendix C of the City of Edmonds Stormwater Addendum. It is anticipated that the proposed drainage improvements will be operated and maintained by Snohomish County Parks and Recreation Department, in accordance with an established O&M manual for their park facilities. Consequently, a project-specific O&M manual will not be prepared for this project. Manufacturer-supplied operation and maintenance information specific to the facilities installed as part of the project will be submitted to the County for inclusion with its existing O&M documentation. Stormwater Site Plan 27 November 2018 DRAFT 4 Drainage Analysis and Conceptual Design Hydrologic and hydraulic analyses were completed to estimate design flow rates and verify sizing and capacity for the proposed drainage improvements illustrated on Figure 2-4 and detailed in the utility drawings included in Appendix A. Detailed results of the hydrologic analysis are provided in Appendix E. Detailed hydraulic analysis of storm drainage improvements is provided in Appendix F, which also includes sizing calculations and channel stability analysis for the rock-lined drainage channel and wet bio-filtration swale. 4.1 Hydrologic Analyses MGS Flood (version 4.46) hydrologic modeling software was used to estimate peak runoff flow rates from the drainage areas at the site, for the design of improvements that will discharge stormwater runoff to Puget Sound through or from the site under developed project conditions. MGS Flood was developed by MGS Engineering Consultants for WSDOT to facilitate design of stormwater facilities, primarily storage and treatment, for roadway projects in western Washington. MGS Flood is approved by Ecology, Snohomish County, and the City of Edmonds for hydrologic analysis of stormwater improvements. It uses the HSPF algorithm to simulate runoff from long-term precipitation records. The model features extended precipitation and evaporation time-series: 120 to 158 years in length. All three runoff components (surface flow, interflow, and recharge to groundwater) are evaluated by the model. Proposed drainage areas and drainage improvements are illustrated on Figure 2-4. Table 2-1 includes a summary of existing pervious and hard surface areas within each existing drainage area at the site. Table 2-2 includes a summary of proposed pervious and hard surface areas within each proposed drainage area at the site. A more detailed breakdown of existing and post-development land cover is included in Appendix B. Both off- and on-site components of the runoff discharging from the site were evaluated. Each drainage area was evaluated to estimate peak recurrence interval runoff rates. Pervious surfaces were modeled using till-grass or till-forest land cover parameters. Roads, paved pathways, parking areas, and rooftops were modeled as impervious or hard surface. MGS Flood model results for this analysis, including inputs, computed peak discharge rates, and runoff volumes for the storm events, are included in Appendix E. Table 4-1 summarizes the flow rates modeled for the post-developed conditions from each drainage area at the proposed site. Stormwater Site Plan 28 November 2018 DRAFT Table 4-1 Proposed Post-Developed Conditions – Flow Rate Estimates Area Drainage Area Description Q2-year (cfs) Q25-year (cfs) Q100-year (cfs) QWQ1 (cfs) VWQ1 (cf) TDA 1 1 Access Road and Parking Area 0.31 0.63 0.75 0.15 10,191 2 Ranger Residence Area – Drains to Bio-filtration Swale 0.11 0.27 0.30 0.04 2,839 3A Area West of Ranger Station – Drains to Rock Swale 0.13 0.38 0.49 0.06 4,223 3B Area West of Ranger Station – Drains Directly to Creek/Estuary 0.07 0.21 0.30 0.04 3,054 4 North Side of Creek – Drains Directly to Creek/Estuary 0.30 0.78 0.95 0.26 20,159 5 Railroad Berm and Beach – Drains Directly to Puget Sound 0.21 0.35 0.52 0.09 2,924 TDA 2 6 Access Road Entrance and Off-Site Areas 0.10 0.23 0.29 0.07 5,540 Note: 1. Water quality flow rates and volumes represent 15-minute, on-line water quality analysis results. 4.2 BMP Selection and Analysis 4.2.1 BMP Selection Based on Feasibility Compliance with MR5 requires compliance with the LID Performance Standard or selection of permanent stormwater control BMPs based on a determination of feasibility or infeasibility of potential BMPs from a prioritized list. Because MRs 1–9 only apply to TDA1, BMPs will only apply to runoff from surfaces within TDA1. In Snohomish County, projects triggering the need to meet MRs 1–9 are either required to demonstrate compliance with the LID Performance Standard or use on-site stormwater management BMPS from List No. 2 in Section 2.5.5 of Volume I of the Snohomish County Drainage Manual. The first BMP considered feasible from List No. 2 is used to meet the appropriate stormwater control requirements for runoff from each surface. Projects that require compliance with MRs 1–9 are referred to as Category 2 projects by the City of Edmonds EDCD 18.30. Category 2 projects are also required to either demonstrate compliance with the LID Performance Standard outlined in the City of Edmonds EDCD 18.30 or use on-site stormwater management BMPs from List No. 2. The EDCD requires use of the first BMP considered feasible from list No. 2 for meeting the appropriate stormwater control requirements. Table 4-2 summarizes how BMPs were selected from these lists and applied to the proposed design of stormwater improvements for the project, by drainage area and surface type. Stormwater Site Plan 29 November 2018 DRAFT Table 4-2 Proposed Drainage BMP Feasibility and Selection BMP Selection List No. 2 Snohomish County BMP Selection List No. 2 City of Edmonds TDA 1 Area 1 Access Road and Parking Area Area 2 Ranger Residence Area Area 3A Area West of Ranger Station – Drains to Rock Swale Area 3B Area West of Ranger Station – Drains to Rock Swale Area 4 Hillside and Park Area North of Creek Area 5 Railroad Berm and Beach Lawn and Landscaped Areas 1. BMP T5.13: Post-construction Soil Quality and Depth 2. BMP T5.13: Post-construction Soil Quality and Depth BMP 5.13 is feasible, will be applied to new or replaced lawn and landscape areas. BMP 5.13 is feasible, will be applied to new or replaced lawn and landscape areas. BMP 5.13 is feasible, will be applied to new or replaced lawn and landscape areas. BMP 5.13 is feasible, will be applied to new or replaced lawn and landscape areas.. BMP 5.13 is feasible, will be applied to new or replaced lawn and landscape areas. BMP 5.13 is feasible, will be applied to new or replaced lawn and landscape areas. Roofs 1. BMP T5.30: Full Dispersion 1. BMP T5.30: Full Dispersion There are no proposed new rooftops in Area 1. There are no proposed new rooftops in Area 2. A flowpath length of 100 feet through forest or native vegetation cannot be achieved. There are no proposed new rooftops in Area 3B. There are no proposed new rooftops in Area 4. There are no proposed new rooftops in Area 5. 2. Bio-retention 2. BMP T 5.14A: Rain Gardens There are no proposed new rooftops in Area 1. There are no proposed new rooftops in Area 2. Soil investigation indicates that vertical separation to seasonal high groundwater is less than 3 feet and that hydraulic conductivity of underlying soils is low. There are no proposed new rooftops in Area 3B. There are no proposed new rooftops in Area 4. There are no proposed new rooftops in Area 5.. 3. BMP T5.10B: Downspout Dispersion 3. BMP T5.10B: Downspout Dispersion There are no proposed new rooftops in Area 1. There are no proposed new rooftops in Area 2. BMP T5.10B appears to be feasible. Runoff from new roofs will be dispersed from downspouts through adjacent lawn area. There are no proposed new rooftops in Area 3B. There are no proposed new rooftops in Area 4. There are no proposed new rooftops in Area 5. 4. BMP T5.10C: Perforated Stub-out Connections 4. BMP T5.10C: Perforated Stub-out Connections There are no proposed new rooftops in Area 1. There are no proposed new rooftops in Area 2. N/A There are no proposed new rooftops in Area 3B. There are no proposed new rooftops in Area 4. There are no proposed new rooftops in Area 5. 5. Detention Vaults or Pipes There are no proposed new rooftops in Area 1. There are no proposed new rooftops in Area 2. N/A There are no proposed new rooftops in Area 3B. There are no proposed new rooftops in Area 4. There are no proposed new rooftops in Area 5. Stormwater Site Plan 30 November 2018 DRAFT BMP Selection List No. 2 Snohomish County BMP Selection List No. 2 City of Edmonds TDA 1 Area 1 Access Road and Parking Area Area 2 Ranger Residence Area Area 3A Area West of Ranger Station – Drains to Rock Swale Area 3B Area West of Ranger Station – Drains to Rock Swale Area 4 Hillside and Park Area North of Creek Area 5 Railroad Berm and Beach Other Hard Surfaces 1. BMP T5.30: Full Dispersion 1. BMP T5.30: Full Dispersion Some slopes are steeper than 15%. A flowpath length of 100 feet through forest or native vegetation cannot be achieved. A flowpath length of 100 feet through forest or native vegetation cannot be achieved. A flowpath length of 100 feet through forest or native vegetation cannot be achieved. A flowpath length of 100 feet through forest or native vegetation cannot be achieved. A flowpath length of 100 feet through forest or native vegetation cannot be achieved. A flowpath length of 100 feet through forest or native vegetation cannot be achieved. 2. Permeable Pavement 2. BMP T5.15: Permeable Pavement, or Soil investigation indicates that vertical separation to seasonal high groundwater is less than 3 feet and that hydraulic conductivity of underlying soils is low. Soil investigation indicates that vertical separation to seasonal high groundwater is less than 3 feet and that hydraulic conductivity of underlying soils is low. Soil investigation indicates that vertical separation to seasonal high groundwater is less than 3 feet and that hydraulic conductivity of underlying soils is low. Soil investigation indicates that vertical separation to seasonal high groundwater is less than 3 feet and that hydraulic conductivity of underlying soils is low. Soil investigation indicates that vertical separation to seasonal high groundwater is less than 3 feet and that hydraulic conductivity of underlying soils is low. Soil investigation indicates that vertical separation to seasonal high groundwater is less than 3 feet and that hydraulic conductivity of underlying soils is low. 3. Bio-retention 3. BMP T5.14A: Rain Gardens Soil investigation indicates that vertical separation to seasonal high groundwater is less than 3 feet and that hydraulic conductivity of underlying soils is low. Soil investigation indicates that vertical separation to seasonal high groundwater is less than 3 feet and that hydraulic conductivity of underlying soils is low. Soil investigation indicates that vertical separation to seasonal high groundwater is less than 3 feet and that hydraulic conductivity of underlying soils is low. Soil investigation indicates that vertical separation to seasonal high groundwater is less than 3 feet and that hydraulic conductivity of underlying soils is low. Soil investigation indicates that vertical separation to seasonal high groundwater is less than 3 feet and that hydraulic conductivity of underlying soils is low. Soil investigation indicates that vertical separation to seasonal high groundwater is less than 3 feet and that hydraulic conductivity of underlying soils is low. 4. BMP T5.12: Sheet Flow Dispersion, or BMP T5.11: Concentrated Flow Dispersion 4. BMP T5.12: Sheet Flow Dispersion, or BMP T5.11: Concentrated Flow Dispersion BMP T5.12 appears to be feasible for hard pathway surfaces. BMP T5.11 does not appear to be feasible for concentrated flow from access road and parking area due to size of drainage area and flowpath limitations. BMP T5.12 appears to be feasible for hard pathway surfaces. BMP T5.12 appears to be feasible for hard pathway surfaces. BMP T5.12 appears to be feasible for hard pathway surfaces. BMP T5.12 appears to be feasible for hard pathway surfaces. BMP T5.12 appears to be feasible for hard pathway surfaces. 5. Detention Vaults or Pipes Concentrated flow from access road and parking area to be conveyed in storm drain facilities to discharge point at MHHW mark in restored estuary. N/A N/A N/A N/A N/A Stormwater Site Plan 31 November 2018 DRAFT The primary limitation to incorporation of BMPs that rely on infiltration (infiltration, rain gardens, bio-retention) is that the seasonal depth to high groundwater is very shallow, so the minimum 3-foot separation required between the bottom of infiltration facilities and the seasonal high groundwater cannot be achieved at the site. Shannon & Wilson completed a preliminary assessment of infiltration potential and groundwater at likely infiltration locations using hand borings (Shannon & Wilson 2018). Two hand borings were completed in March 2017, as follows: • HB-1 was drilled in the island adjacent to the existing ADA parking area. The summary of conditions observed (depths referenced to adjacent parking lot pavement grade) is as follows: ‒ 0 to 1.3 feet: moist to wet, poorly graded gravel with silt and sand, wet (perched water) below about 0.8 feet. ‒ Perching layer, 1.3 to 2 feet: wet, silty sand/sandy silt. ‒ Potential infiltration receptor: 2 to 5.5 feet: moist, silty sand. ‒ Aquifer: 5.5 to 9.9 feet: wet, silty sand. ‒ Static water level was about 5.5 feet below pavement grade, based on a measurement made on March 19, 2017, about 1 day after a period of heavy rain. • HB-2 was drilled in the lawn west of the ranger residence. The summary of conditions, observed (measured relative to lawn surface) is as follows: ‒ 0 to 1 foot: wet, silty gravel with sand and cobbles and quarry spalls – perched water. ‒ Perching layer, 1 to 2 feet: moist, sandy silt with gravel. ‒ Potential infiltration receptor: 2 to 3 feet: moist, silty sand with gravel and cobbles. ‒ Aquifer: 3 to 6 feet: wet, interlayered silty sand and poorly graded sand with silt. ‒ Static water level was about 3.1 feet below grade, based on a measurement made on March 19, 2017, about 1 day after a period of heavy rain. Based on infiltration requirements provided in the Snohomish County Drainage Manual, Volume III, the results indicate that subsurface soil conditions would not meet the site suitability criteria for infiltration. Specifically, Site Suitability Criteria 5 requires that the base of the infiltration basin or trench system shall be greater than or equal to 5 feet above the seasonal high-water mark, bedrock (or hardpan), or other low permeability layer. This can be reduced down to 3 feet if a groundwater mounding analysis is done to show that some other specific criteria are met. An infiltration facility, such as pervious pavement, rain garden, or bio-retention facility, at any of these locations would require a depth of at least 1 to 3 feet from the existing surface to the bottom of the infiltration layer. Consequently, there is insufficient separation to the seasonal high groundwater to make an infiltration facility feasible. 4.2.2 Treatment Menu and BMP Selection Stormwater treatment is required for runoff from the access road and parking area surfaces, which are PGHS, according to treatment menus provided in Chapter 4 of Volume I of the Snohomish County Stormwater Site Plan 32 November 2018 DRAFT Drainage Manual and in Chapter 3 of Volume V of the SWMMWW. The menus are provided in Appendix G. The following menus were evaluated, consistent with those guidelines: • Oil Control Menu: The project does not require oil-control BMPs because it is not a commercial or industrial site with an average daily traffic (ADT) count equal to or greater than 100 vehicles per 1,000 sf of gross building area; is not subject to petroleum storage and transfer; will not provide parking, storage, or maintenance for 25 or more vehicles over 10 tons gross weight; and does not include a roadway intersection with an ADT count of 25,000 vehicles on the main roadway or more than 15,000 vehicles on any intersecting roadway. • Phosphorus Treatment Menu: The project, which will discharge stormwater directly to Puget Sound, does not require phosphorus-removal BMPs. • Enhanced Treatment Menu: The project does not meet the thresholds for enhanced treatment. Although it is within an Urban Growth Management Area, it does not include partially or fully controlled limited-access highways, and it does not include any roadways with an annual ADT count of 7,500 or greater. • Basic Treatment Menu: The project does require basic treatment of stormwater from PGHS and PGPS. The design assumes that lawn and landscape areas will not be subject to traffic or use of pesticides, fertilizers, or loss of soil and are not considered PGPS. Treatment will be provided for runoff from PGHS in the access road and parking area. Basic Treatment BMPs are designed to achieve 80% removal of total suspended solids for influent concentrations greater than 100 milligrams per liter. Basic treatment BMPs include bio-infiltration swales, infiltration, sand filters, bio-filtration swales, filter strips, wet ponds, wet vaults, wet bio- filtration swales stormwater treatment wetlands, detention and wet-pool facilities, bio- retention/ rain gardens, ecology embankments, and other approved manufactured filtration devices. 4.2.3 Threshold Discharge Area 1 TDA 1 includes Drainage Areas 1–5, as shown on Figure 2-4. Stormwater runoff from TDA 1 will drain to Puget Sound via a series of pipes and constructed channels. The following improvements are proposed to improve drainage collection and convey runoff within this threshold discharge area: • A network of 8- and 12-inch-diameter corrugated polyethylene (CPE) storm drain pipe and catch basins will be installed to route runoff from PGHS in the access road and parking area to a wet bio-filtration swale located in Drainage Area 2. • The wet bio-filtration swale will be installed along the south edge of the paved loop pathway near the lawn area. The wet bio-filtration swale will serve as the treatment BMP for runoff from the access road, parking area, and other surfaces tributary to the storm drain facilities. • Flow from the bio-filtration swale will be conveyed to a rock-lined swale located in the estuary area via a 12-inch-diameter CPE storm drain pipe. Stormwater Site Plan 33 November 2018 DRAFT • The rock-lined swale will be constructed to convey the stormwater to the MHHW mark within the estuary to meet requirements for discharging directly to Puget Sound through manmade conveyance facilities. • Runoff from impervious pathways will be dispersed through adjacent sheet flow dispersion areas that will consist of a gravel dissipating strip and landscaping that will provide the needed 10 feet of vegetated flow path for every 20 feet of contributing surface. • Runoff from roofs will be dispersed through adjacent lawn areas or landscaping. Sizing calculations for the wet bio-filtration swale and rock-lined swale are provided in Appendix F. 4.2.4 Threshold Discharge Area 2 A portion of the proposed work is located in TDA 2, which comprises Drainage Area 6. TDA 2 is not tributary to the outlet of Lund’s Gulch Creek, but instead discharges to Puget Sound through a culvert in the railroad berm somewhere south of the project site. Improvements in this area will result in less than 5,000 sf of new or replaced impervious surface and will only be subject to MR2. 4.3 Off-Site Analysis The MRs require that an off-site analysis be conducted to assess potential off-site impacts of stormwater discharges that extend downstream from the site to the receiving water. The project site borders Puget Sound, and all stormwater runoff will be conveyed directly to Puget Sound or dispersed on site; therefore, no downstream impacts are expected. The analysis must also extend upstream to a point beyond any backwater effects caused by the project. Because all runoff will be dispersed on site or conveyed to Puget Sound utilizing an entirely man-made conveyance system, no backwater effects are expected. 4.4 Storm Drain System Sizing and Hydraulic Analysis Storm drain system improvements are shown on Figure 2-4 and in more detail on the utility drawings included in Appendix A. Hydraulic analysis needed to size and evaluate new storm drains, catch basins, and other facilities was completed using a Microsoft Excel-based spreadsheet that calculates the hydraulic profile in a gravity pipe system, using the standard step-backwater method; this analysis is provided in Appendix E. New storm drain pipe will be CPE conforming to ASTM F2648, and will include 8- and 12-inch-diameter pipe. Analysis was also used to verify sizing of cobbles and boulders that will be used to stabilize the open channel that will be created to convey runoff through the restored estuary to Puget Sound. This analysis was completed using methods presented in the U.S. Army Corps of Engineers publication Hydraulic Design of Flood Control Channels (USACE 1991) and is also included in Appendix F. Stormwater Site Plan 34 November 2018 DRAFT 5 Conclusions and Recommendations The proposed Meadowdale Beach Park and Estuary Restoration project will restore ecological functions and expand the Lund’s Gulch Creek estuary, improve habitat conditions for salmon and other wildlife in lower Lund’s Gulch Creek, address public safety issues involving the existing railroad crossing, and improve access (including ADA-compliant access) to the beach. The project requires stormwater improvements that meet the requirements of the Snohomish County Drainage Manual, the SWMMWW, and the City of Edmonds Stormwater Addendum. Proposed improvements will result in the addition of 4,769 sf of new hard surface and replacement of 32,909 sf of existing hard surface. The proposed site will include a total of 73,443 sf of hard surfaces, including approximately 35,738 sf of existing impervious surface that will not be modified by the project. Existing impervious surfaces make up less than 2% of the existing park site, so the project is characterized as a “New Development” project by the Snohomish County Drainage Manual. Due to the quantity of new and replaced impervious surfaces that will result from the project, all of the MRs outlined in the Snohomish County Drainage Manual and the City of Edmonds Stormwater Addendum will apply to new and replaced impervious surfaces and converted pervious surfaces within TDA 1, which includes all project areas that drain to Lund’s Gulch Creek or the Puget Sound shoreline. Based on BMP selection, hydrologic modeling, and hydraulic analysis, the following stormwater improvements are recommended to meet the MRs for the developed site condition: • A network of 8- and 12-inch-diameter CPE storm drain pipe and catch basins will be installed to capture and convey runoff from PGHS in the access road and parking area to a wet bio- filtration swale located in Drainage Area 2. • The wet bio-filtration swale will be installed along the south edge of the paved loop pathway near the lawn area. The wet bio-filtration swale will serve as the treatment BMP for runoff from the access road, parking area, and other surfaces tributary to the storm drain facilities. • Flow from the bio-filtration swale will be conveyed to a rock-lined swale located in the estuary area via a 12-inch-diameter CPE storm drain pipe. • The rock-lined swale will be constructed to convey the stormwater to the MHHW mark within the estuary to meet requirements for discharging directly to Puget Sound through manmade conveyance facilities. • Runoff from impervious pathways will be dispersed through adjacent sheet flow dispersion areas that will consist of a gravel dissipating strip and landscaping that will provide the needed 10 feet of vegetated flow path for every 20 feet of contributing surface. • Runoff from roofs will be dispersed through adjacent lawn areas or landscaping. The detailed design analysis, utility plans, and other supporting documents provided with this report are intended to be submitted to meet the requirements for SSP review, approval, and permitting. Stormwater Site Plan 35 November 2018 DRAFT 6 References Anchor QEA (Anchor QEA, LLC), 2016. Feasibility Report: Meadowdale Beach County Park Feasibility Study. Prepared for Snohomish County. August 2015. Available at: http://bit.ly/2pXV8le Bruce Dees (Bruce Dees & Associates), 1986. Master Plan Report: Meadowdale Beach County Park. September 1986. City of Edmonds, 2007. City of Edmonds Modifications to the Standard Specifications. April 2, 2007. City of Edmonds, 2016. Edmonds Standard Details. Amended 2016. City of Edmonds, 2017a. Edmonds Community Development Code. Passed August 15, 2017. City of Edmonds, 2017b. Addendum to Edmonds Community Development Code Chapter 18.30 (Edmonds Stormwater Addendum). Dailer, Doug (Park Ranger, Snohomish County Parks and Recreation), 2015. Personal communication with Peter Hummel (Anchor QEA) during site visit on March 5, 2015. Ecology (Washington State Department of Ecology), 2014. Stormwater Management Manual for Western Washington, as amended in December 2014. Shannon & Wilson, 2018. Geotechnical Report: Meadowdale Beach Park and Estuary Restoration. Prepared for Snohomish County Parks & Recreation. February 2018. Snohomish County, 2002. Puget Sound Tributaries Drainage Needs Report. DNR No. 11. Snohomish County Public Works Department, Surface Water Management Division. December 2002. Available at: http://snohomishcountywa.gov/1079/Urban-Drainage. Snohomish County, 2015. Snohomish County website. Accessed March 2015. Available at: http://snohomishcountywa.gov/Facilities/Facility/Details/Meadowdale-Beach-Park-56 Snohomish County, 2016a. Snohomish County Engineering and Design Standards. Effective January 22, 2016. Snohomish County, 2016b. Snohomish County Drainage Manual. January 2016. Snohomish County, 2017. Snohomish County Code. Chapter 30.63A (Drainage). Passed September 13, 2017. USACE (U.S. Army Corps of Engineers), 1991. Hydraulic Design of Flood Control Channels. Engineer Manual No. 1110-2-1601. July 1991. WSDOT (Washington State Department of Transportation), 2017. 2018 Standard Specifications for Road, Bridge, and Municipal Construction. Appendix A Utility Plans Nov 16, 2018 3:30pm chewett k:\Projects\0723-snohomish county\meadowdale park\construction plans\0723-PL-Cover Sheet.dwg G-1G-1 PLAN COVER SHEET 1 75 PH/BS CH/TG BS PH AS NOTED NOVEMBER 2018 PERMIT SUBMITTAL MEADOWDALE BEACH PARK AND ESTUARY DESIGN SNOHOMISH COUNTY PARKS AND RECREATION PROJECT SITE Prime Consultant Project Manager: Peter Hummel, PLA Landscape Architect: Betsy Severtsen, PLA Civil Engineer: David Rice, PE 720 Olive Way Suite 1900 Seattle WA, 98101 (206) 287-9130 VICINITY MAPSOURCE: ESRI 0 SCALE IN FEET 2000 4000 NORTH Not to Scale TACOMA VANCOUVER BELLINGHAM WASHINGTON EDMONDS EDMONDS LYNNWOOD PUGET SOUND SEATTLE APPROVED FOR CONSTRUCTION BY: R/W PERMIT NO. DATE DESCRIPTIONAPP'DDATEBY REVISIONS REV ONE INCHAT FULL SIZE, IF NOT ONEINCH SCALE ACCORDINGLYDESIGNED BY: APPROVED BY: CHECKED BY: DRAWN BY: DATE: SCALE: MEADOWDALE BEACH PARK AND ESTUARY DESIGN 18-XXXXX SHEET # OF LDA PERMIT SUBMITTAL, NOT FOR CONSTRUCTION 720 Olive Way | Suite 1900 | Seattle, WA 98101 PFN: 18-XXXXX LDA SECTION 5, TOWNSHIP 27 N., RANGE 4 E STATE OFWASHINGTON LICENSEDLANDSCAPE ARCHITECT CERTIFICATE NO. 422 PETER C. HUMMEL COUNTY EXECUTIVE: DAVE SOMERS DIRECTOR OF PARKS AND RECREATION: TOM TEIGEN COUNCIL DISTRICT 1: ROB PUTNAM COUNCIL DISTRICT 2: JULIE LANGABEER COUNCIL DISTRICT 3: JOHN BRINEY COUNCIL DISTRICT 4: STEVE YANDL COUNCIL DISTRICT 5: BOB MCCARTY SITE ADDRESS: 15433 75TH PLACE WEST EDMONDS, WA 98026 TAX PARCEL NUMBERS: 00500900000500, 27040500200100, 27040500200200 LEGAL DESCRIPTIONS: SEE DRAWING G-3 PROJECT CESCL: TO BE DETERMINED BY CONTRACTOR Owner Logan Daniels Snohomish County Parks and Recreation 6705 Puget Park Drive Snohomish, WA 89296 (425) 388-6619 logan.daniels@snoco.org EARTHWORK - APPROXIMATE GRADING QUANTITIES GRADING LIMIT OF DISTURBANCE: 191,878 SF CUT: 19,100 CY FILL: 7,800 CY SLOPES GREATER THAN 33% WITHIN PROJECT SITE AREA: 6,070 SF (0.14 AC) DRAWING INDEX SHT #DWG #TITLE 1 G-1 PLAN COVER SHEET 2 G-2 PLAN COVER SHEET 2a G-3 PLAN COVER SHEET 3 CS-1 COMPOSITE SITE PLAN (1 OF 3) 4 CS-2 COMPOSITE SITE PLAN (2 OF 3) 5 CS-3 COMPOSITE SITE PLAN (3 OF 3) 6 TA-1 TEMPORARY ACCESS AND STAGING PLAN 7 EC-1 EXISTING CONDITIONS PLAN (1 OF 3) 8 EC-2 EXISTING CONDITIONS PLAN (2 OF 3) 9 EC-3 EXISTING CONDITIONS PLAN (3 OF 3) 10 T-1 TEMPORARY EROSION AND SEDIMENT CONTROL (TESC) PLAN (1 OF 3) 11 T-2 TEMPORARY EROSION AND SEDIMENT CONTROL (TESC) PLAN (2 OF 3) 12 T-3 TEMPORARY EROSION AND SEDIMENT CONTROL (TESC) PLAN (3 OF 3) 13 D-1 CLEARING AND DEMOLITION PLAN (1 OF 3) 14 D-2 CLEARING AND DEMOLITION PLAN (2 OF 3) 15 D-3 CLEARING AND DEMOLITION PLAN (3 OF 3) 16 CV-1 LAYOUT CONTROL PLAN (1 OF 3) 17 CV-2 LAYOUT CONTROL PLAN (2 OF 3) 18 CV-3 LAYOUT CONTROL PLAN (3 OF 3) 19 C-1 GRADING PLAN (1 OF 3) 20 C-2 GRADING PLAN (2 OF 3) 21 C-3 GRADING PLAN (3 OF 3) 22 C-4 GRADING CROSS-SECTIONS (1 OF 4) 23 C-5 GRADING CROSS-SECTIONS (2 OF 4) 24 C-6 GRADING CROSS-SECTIONS (3 OF 4) 25 C-7 GRADING CROSS SECTIONS (4 OF 4) 26 CM-1 CONSTRUCTION MATERIALS PLAN (1 OF 3) 27 CM-2 CONSTRUCTION MATERIALS PLAN (2 OF 3) 28 CM-3 CONSTRUCTION MATERIALS PLAN (3 OF 3) 29 CM-4 CONSTRUCTION MATERIAL DETAILS (1 OF 6) 30 CM-5 CONSTRUCTION MATERIAL DETAILS (2 OF 6) 31 CM-6 CONSTRUCTION MATERIAL DETAILS (3 OF 6) 32 CM-7 CONSTRUCTION MATERIAL DETAILS (4 OF 6) 33 CM-8 CONSTRUCTION MATERIAL DETAILS (5 OF 6) 34 CM-9 CONSTRUCTION MATERIAL DETAILS (6 OF 6) 35 RD-1 ROADWAY PLAN AND PROFILE (1 OF 2) 36 RD-2 ROADWAY PLAN AND PROFILE(2 OF 2) 37 RD-3 TYPICAL ACCESS ROADWAY SECTIONS 36 RD-2 ROADWAY PLAN AND PROFILE(2 OF 2) DRAWING INDEX SHT #DWG #TITLE 37 RD-3 TYPICAL ACCESS ROADWAY SECTIONS 38 RD-4 TYPICAL PARKING AREA SECTIONS 39 RD-5 ROADWAY AND PARKING AREA DETAILS 40 RD-6 ROADWAY REINFORCEMENT ELEVATIONS AND SECTIONS 41 RD-7 SPIRAL NAIL ROADWAY REINFORCEMENT DETAILS 42 RD-8 PARKING AREA STRIPING PLAN 43 CU-1 UTILITY PLAN (1 OF 2) 44 CU-2 UTILITY PLAN (2 OF 2) 45 CU-3 STORM DRAIN PROFILE 46 CU-4 DRAINAGE DETAILS 47 A1.0 ARCHITECTURAL GENERAL INFORMATION 48 A1.1 ARCHITECTURAL GENERAL NOTES 49 A2.0 PORTABLE TOILET ENCLOSURE FOUNDATION AND FLOOR PLANS 50 A2.1 ROOF PLANS 51 A3.0 PORTABLE TOILET ENCLOSURE ELEVATIONS 52 A3.1 EXISTING PICNIC SHELTER ELEVATIONS 53 A7.0 PORTABLE TOILET ENCLOSURE DETAILS 54 A7.1 PORTABLE TOILET ENCLOSURE ENLARGED ELEVATION, PICNIC SHELTER COLUMN BASE DETAIL 55 S1.1 GENERAL STRUCTURAL NOTES 56 S1.2 GENERAL STRUCTURAL NOTES 57 S2.1 STRUCTURAL OVERVIEW SITE PLAN 58 S2.2 TOILET ENCLOSURE STRUCTURAL PLANS 59 S2.3 PEDESTRIAN BRIDGE ABUTMENT AND BOARDWALK PLANS 60 S3.1 TOILET ENCLOSURE STRUCTURAL TYPICAL CONCRETE DETAILS 61 S3.2 TOILET ENCLOSURE STRUCTURAL CONCRETE DETAILS 62 S3.3 PEDESTRIAN BRIDGE CONCRETE ABUTMENT DETAILS 63 S3.4 BOARDWALK DETAILS 64 S4.1 TOILET ENCLOSURE DETAILS 65 S-4 PEDESTRIAN BRIDGE DETAIL 66 E-1 ELECTRIC SITE PLAN 67 E-2 ELECTRIC NOTES, DETAILS AND SCHEDULES 68 I-1 IRRIGATION PLAN (1 OF 3) 69 I-2 IRRIGATION PLAN (2 OF 3) 70 I-3 IRRIGATION PLAN (3 OF 3) 71 I-4 IRRIGATION DETAILS 72 L-1 PLANTING PLAN (1 OF 3) 73 L-2 PLANTING PLAN (2 OF 3) 74 L-3 PLANTING PLAN (3 OF 3) 75 L-4 PLANTING DETAILS MEADOWDALE BEACH PARK 168TH ST SW 164TH ST SW INTERSTATE 575TH PL WN MEADOWDALE ROAD Architectural Consultant Salt Studio LLC 66 Bell Street Unit #1 Seattle, WA 98121 (206) 948-2104 Surveyor Duane Hartman and Associates 16928 Woodinville-Redmond Road, Suite B-107 Woodinville, WA 98072 (425) 483-5355 Structural Engineering Consultant Swenson Say Faget 2124 Third Ave, Suite 100 Seattle, WA 98121 (206) 443-6212 Mechanical Engineering Consultant Rainbow Consulting 336 NW 50th St Seattle, WA 98107 (206) 235-6002 Irrigation Consultant William Stewart Design 9220 58th Avenue SE Olympia, WA 98513 (206) 605-9863 Electrical Engineering Consultant Cross Engineers 923 Martin Luther King Jr. Way Tacoma, WA 98405 (253) 759-0118 Activity Snohomish County City of Edmonds Total New impervious surfaces 3,964 666 4,630 Replaced impervious surfaces 17,103 26,584 43,687 Removed impervious surfaces -6,562 -2,839 -9,401 Net Change Total -2,598 -2,173 -4,771 BNSF RAILWAYPUGET SOUND LUND S CREEK GUL C H LUNDS G U L C H CREEK OFF-CHANNELPOND APPROVED FOR CONSTRUCTION BY: R/W PERMIT NO. DATE DESCRIPTIONAPP'DDATEBY REVISIONS REV ONE INCHAT FULL SIZE, IF NOT ONEINCH SCALE ACCORDINGLYDESIGNED BY: APPROVED BY: CHECKED BY: DRAWN BY: DATE: SCALE: MEADOWDALE BEACH PARK AND ESTUARY DESIGN 18-XXXXX SHEET # OF LDA PERMIT SUBMITTAL, NOT FOR CONSTRUCTION 720 Olive Way | Suite 1900 | Seattle, WA 98101 PFN: 18-XXXXX LDA SECTION 5, TOWNSHIP 27 N., RANGE 4 E STATE OFWASHINGTON LICENSEDLANDSCAPE ARCHITECT CERTIFICATE NO. 422 PETER C. HUMMEL Nov 16, 2018 3:30pm chewett k:\Projects\0723-snohomish county\meadowdale park\construction plans\0723-PL-Site Context and Layout Plan.dwg 2 G-20 SCALE IN FEET 80 160 NORTH X-1 X-2 X-3 PUGET SOUND LEGEND: PROJECT BOUNDARY CITY OF EDMONDS/SNOHOMISH COUNTY BOUNDARY PARK BOUNDARY PARCEL BOUNDARY BNSF RIGHT-OF-WAY BNSF CENTERLINE EXISTING OHWM EXISTING MHHW (EL. +9.0' MLLW) EXISTING LUND GULCH CREEK THALWEG EXISTING WETLAND TO BE PROTECTED 75TH PL W.G-2 PLAN COVER SHEET 2 75 PH/BS CH/TG BS PH 1" = 80' NOVEMBER 2018 NOTES: 1.HORIZONTAL DATUM: WASHINGTON STATE PLANE NORTH ZONE, NAD 83, U.S. FEET. 2.VERTICAL DATUM: NAVD 88 3.DRAWINGS ARE INTENDED TO BE VIEWED IN COLOR. SOME INFORMATION WILL BE LOST WITH BLACK AND WHITE VIEWING. RANGER RESIDENCE Nov 16, 2018 3:30pm chewett k:\Projects\0723-snohomish county\meadowdale park\construction plans\0723-PL-Cover Sheet.dwg 2a G-3G-3 PLAN COVER SHEET 2A 75 PH/BS CH/TG BS PH AS NOTED NOVEMBER 2018 APPROVED FOR CONSTRUCTION BY: R/W PERMIT NO. DATE DESCRIPTIONAPP'DDATEBY REVISIONS REV ONE INCHAT FULL SIZE, IF NOT ONEINCH SCALE ACCORDINGLYDESIGNED BY: APPROVED BY: CHECKED BY: DRAWN BY: DATE: SCALE: MEADOWDALE BEACH PARK AND ESTUARY DESIGN 18-XXXXX SHEET # OF LDA PERMIT SUBMITTAL, NOT FOR CONSTRUCTION 720 Olive Way | Suite 1900 | Seattle, WA 98101 PFN: 18-XXXXX LDA SECTION 5, TOWNSHIP 27 N., RANGE 4 E STATE OFWASHINGTON LICENSEDLANDSCAPE ARCHITECT CERTIFICATE NO. 422 PETER C. HUMMEL GENERAL NOTES: 1.ALL EMPLOYEES MUST COMPLY WITH BNSF SAFETY REQUIREMENTS. THIS INCLUDES, BUT IS NOT LIMITED TO, PASSING A SAFETY COURSE, OBTAINING DOCUMENTATION OF SUCCESSFULLY PASSING THE COURSE, AND ADHERING TO REQUIREMENTS IDENTIFIED IN THE COURSE. THE REQUIRED BNSF SAFETY COURSE MAY BE ACCESSED AT THE FOLLOWING WEBSITE: WWW.RAILROADCOURSES.COM. 2.A BNSF FLAGGER SHALL BE PRESENT ANY TIME THE CONTRACTOR IS WORKING WITHIN 25 FEET OF THE TRACKS. THE CONTRACTOR SHALL COMMUNICATE WITH THE OWNER TO ARRANGE FOR A FLAGGER TO BE PRESENT DURING THESE TIMES. 3.DRAWINGS ARE INTENDED TO BE VIEWED IN COLOR. SOME INFORMATION WILL BE LOST WITH BLACK AND WHITE VIEWING. SURVEY NOTES: 1.SURVEY BY DUANE HARTMAN & ASSOCIATES, INC IN 2017. 2.HORIZONTAL DATUM: WASHINGTON STATE COORDINATE SYSTEM, NORTH ZONE NAD83(91), U.S. FEET UTILIZING RTK GPS FIELD PROCEDURES 3.VERTICAL DATUM: TO CONVERT ELEVATIONS SHOWN HEREON TO MEAN LOWER LOW WATER DATUM PLEASE ADD 2.05 FEET. 4.UTILITIES MAPPING: ALL EXISTING UTILITIES SHOWN HEREIN ARE TO BE VERIFIED HORIZONTALLY AND VERTICALLY PRIOR TO ANY CONSTRUCTION. ALL EXISTING FEATURES INCLUDING BURIED UTILITIES ARE SHOWN AS INDICATED BY RECORD LOCATION OR FIELD TIED AS A RESULT OF A UTILITY PAINT-OUT DURING THE COURSE OF THE FIELD SURVEY. DUANE HARTMAN & ASSOCIATES, INC. (DHA) ASSUMES NO LIABILITY FOR THE ACCURACY OF THE RECORD INFORMATION. FOR THE FINAL LOCATION OF THE EXISTING UTILITIES IN AREAS CRITICAL TO CONSTRUCTION, CONTACT THE UTILITY OWNER/AGENCY AND UTILITIES UNDERGROUND CENTER (800/424-5555). 5.TOPOGRAPHIC MAPPING: THE MAP SHOWN HEREON IS THE RESULT OF A TOPOGRAPHIC SURVEY BY DUANE HARTMAN & ASSOCIATES, INC. (DHA) COMPLETED ON OCTOBER 2016. DHA ASSUMES NO LIABILITY, BEYOND SAID DATE, FOR ANY FUTURE SURFACE FEATURE MODIFICATIONS OR CONSTRUCTION ACTIVITIES THAT MAY OCCUR WITHIN OR ADJOINING THE PERIMETER OF THIS SURVEY. CONTACT DHA (425) 483-5355 FOR SITE UPDATES AND VERIFICATIONS. 6.RAILROAD RIGHT OF WAY LINES: THE BNSF RAILWAY RIGHT OF WAY LINES SHOWN HEREON HAVE BEEN CALCULATED USING TRACK STATIONING, RAILROAD GEOMETRY AND CADASTRAL CALL OUTS AS SHOWN ON "BNSF RAILWAY RIGHT OF WAY". LEGAL DESCRIPTION: DETAIL AND SECTION REFERENCING: DETAIL REFERENCE NUMBER DRAWING ON WHICH DETAIL APPEARS "-" INDICATES TYPICAL OR ON SAME DRAWING DETAIL REFERENCE NUMBER SECTION "A" IS SHOWN ON DRAWING "C-2" INDICATES DIRECTION OF CUTTING PLAN SECTION REFERENCE NUMBER 1 C-1 SCALE: DETAIL1 -1" = 10' A C-2 SCALE: SECTIONA -1" = 10' GENERAL CONSTRUCTION NOTES: 1.UNLESS OTHERWISE INDICATED ON THE DRAWINGS OR IN THE SPECIFICATIONS, ALL MATERIALS AND WORKMANSHIP SHALL BE ACCOMPLISHED IN ACCORDANCE WITH THE CURRENT SNOHOMISH COUNTY ENGINEERING DESIGN AND DEVELOPMENT STANDARDS, THE CITY OF EDMONDS COMMUNITY DEVELOPMENT CODE, THE SNOHOMISH COUNTY DRAINAGE MANUAL, THE CITY OF EDMONDS STORMWATER MANAGEMENT CODE, THE WSDOT STANDARD SPECIFICATIONS FOR ROAD, BRIDGE, AND MUNICIPAL CONSTRUCTION (CURRENT EDITION), AND OTHER APPLICABLE CODES AND STANDARDS. 2.THE CONTRACTOR SHALL HAVE COPIES OF THE APPROVED DRAWINGS, APPLICABLE SNOHOMISH COUNTY AND CITY OF EDMONDS STANDARDS, AND THE WSDOT STANDARD SPECIFICATIONS FOR ROAD, BRIDGE, AND MUNICIPAL CONSTRUCTION (CURRENT EDITION) ON THE JOB SITE WHENEVER CONSTRUCTION IS IN PROGRESS. 3.THE CONTRACTOR SHALL VISIT THE JOB SITE PRIOR TO CONSTRUCTION AND SHALL BE RESPONSIBLE FOR VERIFYING FIELD CONDITIONS AND DIMENSIONS, AND CONFIRMING THAT THE WORK CAN BE ACCOMPLISHED AS SHOWN ON THESE DRAWINGS. ANY DISCREPANCIES BETWEEN THE EXISTING FIELD CONDITIONS AND THE DRAWINGS OR ANY INCONSISTENCIES OR AMBIGUITIES BETWEEN THE DRAWINGS AND OTHER CONTRACT DOCUMENTS SHALL BE REPORTED IN WRITING TO THE OWNER (SNOHOMISH COUNTY) PRIOR TO PROCEEDING WITH THE WORK. WORK DONE BY THE CONTRACTOR INVOLVING SUCH DISCREPANCIES WITHOUT A WRITTEN REPORT AND RESPONSE FROM THE OWNER SHALL BE DONE AT THE CONTRACTOR'S SOLE RISK AND EXPENSE. 4.THE CONTRACTOR SHALL ASSUME SOLE AND COMPLETE RESPONSIBILITY FOR JOB SITE CONDITIONS DURING THE COURSE OF CONSTRUCTION, INCLUDING THE SAFETY OF ALL PERSONS AND PROPERTY. THIS REQUIREMENT SHALL APPLY CONTINUOUSLY AND IS NOT LIMITED TO NORMAL WORKING HOURS. 5.THE CONTRACTOR SHALL BE RESPONSIBLE FOR PROVIDING ADEQUATE SAFEGUARDS, SAFETY DEVICES, PROTECTIVE EQUIPMENT, FLAGGERS, AND ANY OTHER NEEDED ACTIONS TO PROTECT THE LIFE, HEALTH, AND SAFETY OF THE PUBLIC, AND TO PROTECT PROPERTY IN CONNECTION WITH THE PERFORMANCE OF WORK COVERED BY THE CONTRACT. 6.THE CONTRACTOR SHALL PROVIDE TEMPORARY CUT SLOPES AND SHORING AS NECESSARY FOR THE CONSTRUCTION AS SHOWN ON THESE DRAWINGS. THE STABILITY OF ALL TEMPORARY SLOPES AND SHORING IS THE SOLE RESPONSIBILITY OF THE CONTRACTOR. 7.THE CONTRACTOR SHALL BE SOLELY RESPONSIBLE FOR ALL CONSTRUCTION MEANS, METHODS, TECHNIQUES, SEQUENCES, AND PROCEDURES AND FOR COORDINATING ALL PORTIONS OF THE WORK UNDER THIS CONTRACT. 8.THE CONTRACTOR SHALL MAKE ALL NECESSARY PROVISIONS TO PROTECT EXISTING STRUCTURES, SIGNS, FENCES, GATES, CURBS, ROADWAYS, DRAINAGE WAYS, CULVERTS, VEGETATION, AND OTHER IMPROVEMENTS UNLESS AND UNTIL SUCH ITEMS ARE TO BE DISTURBED OR REMOVED AS INDICATED ON THE DRAWINGS. IF SUCH ITEMS ARE DAMAGED OR NEED TO BE REMOVED OR MODIFIED TO FACILITATE CONSTRUCTION, THE CONTRACTOR SHALL FIRST NOTIFY SNOHOMISH COUNTY AND THEN REPLACE OR REPAIR THE ITEMS TO EQUAL OR BETTER CONDITION TO THE SATISFACTION OF SNOHOMISH COUNTY. 9.THE CONTRACTOR SHALL NOT DISTURB OR DESTROY ANY EXISTING SURVEY MONUMENT OR BENCHMARK. ANY SURVEY MONUMENT OR BENCHMARK DISTURBED OR DESTROYED BY THE CONTRACTOR SHALL BE REPLACED AS DIRECTED BY SNOHOMISH COUNTY AT THE CONTRACTOR'S SOLE EXPENSE. 10.THE CONTRACTOR SHALL MAINTAIN CONTINUOUS ACCESS TO THE RANGER RESIDENCE THROUGHOUT CONSTRUCTION OF THE PROJECT. ANY TEMPORARY DISRUPTION OF ACCESS TO THE RANGER RESIDENCE SHALL BE AND APPROVED BY SNOHOMISH COUNTY. 11.WHERE A CONSTRUCTION DETAIL IS NOT SHOWN OR NOTED, THE DETAIL SHALL BE THE SAME AS FOR OTHER SIMILAR WORK. 12.THE DETAILS AND NOTES PROVIDED ON THE DRAWINGS AND IN THE SPECIFICATIONS SHALL TAKE PRECEDENCE OVER THESE GENERAL NOTES. 13.DIMENSION CALL-OUTS SHALL TAKE PRECEDENCE OVER SCALES SHOWN ON THE CONTRACT DOCUMENTS. 14.ALL MATERIALS SHALL BE NEW AND UNDAMAGED, UNLESS OTHERWISE APPROVED BY SNOHOMISH COUNTY AND THE ENGINEER. THE SAME MANUFACTURER OF EACH ITEM SHALL BE USED THROUGHOUT THE WORK UNLESS OTHERWISE APPROVED BY SNOHOMISH COUNTY AND THE ENGINEER. 15.RUBBISH, DEBRIS, AND GARBAGE SHALL BE REMOVED FROM THE JOB SITE AND DISPOSED OF LEGALLY, AS ALLOWED BY THE SNOHOMISH COUNTY ENGINEERING DESIGN AND DEVELOPMENT STANDARDS AND THE WSDOT STANDARD SPECIFICATIONS FOR ROAD, BRIDGE, AND MUNICIPAL CONSTRUCTION (CURRENT EDITION). 16.THE CONTRACTOR SHALL MAINTAIN HAND DRAWN REDLINES, FIELD NOTES AND PHOTOGRAPHS ("FIELD DOCUMENTATION") OF ALL IMPROVEMENTS AS THE WORK PROGRESSES, AS REQUIRED BY THE SPECIFICATIONS. THE CONTRACTOR SHALL ALSO TAKE PHOTOGRAPHS AND VIDEO TO DOCUMENT CONDITIONS PRIOR TO CONSTRUCTION. THE CONTRACTOR'S FIELD DOCUMENTATION SHALL BE MAINTAINED ON SITE AND SHALL BE AVAILABLE FOR REVIEW BY SNOHOMISH COUNTY AND THE ENGINEER AT ALL TIMES. EXISTING UTILITY NOTES: 1.THE LOCATIONS OF EXISTING UTILITIES SHOWN ON THESE DRAWINGS ARE APPROXIMATE AND ARE BASED ON SURVEYED UTILITY MARKINGS AND FEATURES VISIBLE AT THE SURFACE, SUPPLEMENTED BY AS-BUILT INFORMATION PROVIDED BY SNOHOMISH COUNTY. 2.THE CONTRACTOR SHALL BE RESPONSIBLE FOR FIELD LOCATING ALL UTILITIES PRIOR TO CONSTRUCTION. THE CONTRACTOR SHALL CALL THE UTILITY LOCATION REQUEST CENTER (ONE-CALL CENTER) AT 811 OR 1-800-424-5555 FOR UTILITY LOCATIONS NOT LESS THAN TWO (2) BUSINESS DAYS BEFORE THE SCHEDULED DATE FOR TRENCHING OR EARTHWORK THAT MAY IMPACT EXISTING UTILITIES. 3.THE SIZE, LOCATION, AND TYPE OF UNDERGROUND UTILITIES EXPOSED OR MODIFIED BY THE CONTRACTOR SHALL BE ACCURATELY NOTED AND PLACED ON THE CONTRACTOR'S RECORD DRAWINGS. 4.THE CONDITION OF ALL ABANDONED UTILITIES THAT INTERFERE WITH EXECUTION OF THE WORK SHALL BE VERIFIED BY THE UTILITY OWNER PRIOR TO DISTURBANCE OR MODIFICATION. THE CONTRACTOR MAY ONLY TAKE ACTION AFTER WRITTEN APPROVAL HAS BEEN RECEIVED FROM THE UTILITY OWNER BY THE SNOHOMISH COUNTY. 5.THE CONTRACTOR SHALL ENSURE THAT OPERATIONS OF EXISTING SEWER, WATER, POWER, TELECOMMUNICATIONS, AND OTHER UTILITY SYSTEMS SERVING THE RANGER RESIDENCE ARE NOT DISRUPTED DURING CONSTRUCTION WITHOUT PRIOR AUTHORIZATION OF THE SNOHOMISH COUNTY. 2704050020010027040500200100 00500900000500 00500900001602 00500900001601 BNSF RAILWAYPUGET SOUND LUN D S CREEKGUL C H HD AA AA AA AA HD HD HD HDHD SD SD SD SD SDSDSDPICNIC TABLE (TYP) BENCH (TYP) 8' WIDECRUSHED ROCK PATH 10' WIDEASPHALT PATH 40' PEDESTRIANBRIDGE BOARDWALK PATH 6' WIDE CRUSHED ROCK PATH BEACH SAND RESTROOM ENCLOSURE, SEE SHEET A-2.1 FOOTWASH ANDLANDSCAPE BOULDER DRINKING FOUNTAIN CONCRETE SEATWALL 10' WIDE ASPHALT PATH CONCRETE PLINTH STORMWATER TREATMENT SWALE ROCK ARMOR GRILL (TYP) ESTUARY RESTORATION RESTORED CREEK MOUTH (INTERIM POST-CONSTRUCTION CONFIGURATION) LANDSLIDE PROTECTIVE BARRIER STORMWATER SWALE EXISTING PICNIC SHELTER RAILROAD BRIDGE SEE NOTE 4 RS-20 R-9,600 ALDERWOOD ALDERWOOD ALDERWOOD-EVERETT-COMPLEX ALDERWOOD-EVERETT-COMPLEX FLUVAQUENTS FIRM PANEL #53061C1305E Nov 16, 2018 3:31pm chewett k:\Projects\0723-snohomish county\meadowdale park\construction plans\0723-PL-COMPOSITE Plan_Permit.dwg 3 CS-1 (PERMIT)0 SCALE IN FEET 30 60 NORTH APPROVED FOR CONSTRUCTION BY: R/W PERMIT NO. DATE DESCRIPTIONAPP'DDATEBY REVISIONS REV ONE INCHAT FULL SIZE, IF NOT ONEINCH SCALE ACCORDINGLYDESIGNED BY: APPROVED BY: CHECKED BY: DRAWN BY: DATE: SCALE: MEADOWDALE BEACH PARK AND ESTUARY DESIGN 18-XXXXX SHEET # OF LDA PERMIT SUBMITTAL, NOT FOR CONSTRUCTION 720 Olive Way | Suite 1900 | Seattle, WA 98101 PFN: 18-XXXXX LDA SECTION 5, TOWNSHIP 27 N., RANGE 4 E STATE OFWASHINGTON LICENSEDLANDSCAPE ARCHITECT CERTIFICATE NO. 422 PETER C. HUMMEL LEGEND: PROJECT BOUNDARY PARK BOUNDARY 12" BEACH SAND/GRAVEL LARGE WOODY DEBRIS ROCK ARMORING STREAMBED AND SWALE COBBLES CRUSHED ROCK PATH OR TRENCH ASPHALT PAVEMENT CONCRETE PATH/PAD PEDESTRIAN BRIDGE BOARDWALK PATH PICNIC TABLE BENCH LAWN ROCK-LINED SWALE WILDLIFE TREE SNAGS PROPOSED CONTOUR PROPOSED CLEARING LIMITS PROPOSED STORMWATER PIPE TREE TO REMAIN EXISTING WETLAND TO BE PROTECTED WETLAND BUFFER EXISTING ORDINARY HIGH WATER MARK (OHWM) EXISTING MHHW (EL. +9.0' MLLW) PROPOSED MHHW (EL. +9.0' MLLW) BNSF RIGHT OF WAY 10 CS-1 COMPOSITE SITE PLAN (1 OF 3)3 75 PH/BS CH/TG BS PH AS NOTED NOVEMBER 2018 MATCH LINE, SEE SHEET CS-2NOTES: 1.FOR EXISTING PROPERTY BOUNDARIES, EASEMENTS, EXISTING CONTOURS, DRAINAGE, TOPOGRAPHIC FEATURES, AND STRUCTURES, SEE DRAWINGS EC-1 THROUGH EC-3. 2.FOR PROPOSED CONTOURS, CUT, FILL, AND GRADING FEATURES, SEE DRAWINGS C-1 THROUGH C-3. 3.FOR TREE REMOVAL AND PROTECTION, SEE DRAWINGS D-1, THROUGH D-3. 4.FOR TEMPORARY EROSION CONTROL MEASURES, SEE DRAWINGS T-1 THROUGH T-3. 5.FOR SOIL SPECIFICATIONS AND COMPACTION REQUIREMENTS, SEE DRAWING CS-3. 6.FOR PLANTING, SEE DRAWINGS L-1 THROUGH L-4. NOTES: 1.HORIZONTAL DATUM: WASHINGTON STATE PLANE NORTH ZONE, NAD 83, U.S. FEET. 2.VERTICAL DATUM: NAVD 88 3.DRAWINGS ARE INTENDED TO BE VIEWED IN COLOR. SOME INFORMATION WILL BE LOST WITH BLACK AND WHITE VIEWING. 4.PATHWAY WIDENING TO 10 FEET REQUIRES WORK ON ADJACENT PROPERTY. OBTAINING AN EASEMENT FOR THIS WORK IS UNDERWAY AND WILL BE COMPLETED PRIOR TO CONSTRUCTION START DATE. SD OHWM BUFFER SOIL TYPE BOUNDARY ZONING EARTH SUBSIDENCE AND LANDSLIDE AREA MINIMUM BUFFER ADJACENT TO HAZARD 100-YEAR FLOODPLAIN RS-20 ALDER- WOOD 27040500200100 00500900000500 00500900000500 00500900001602 27040500200100 LUN D S CREEKGUL C H LUN D S G U L C H CREE K OFF-CHANNEL POND SD SD SD SD SD SDSD SD SOIL REINFORCEMENT AREA, TYP, SEE SHEETS RD-1 AND RD-2 CRUSHED ROCK PATH RESTRIPED ADA PARKING STALLS VAN-ACCESSIBLE ADA PARKING STALL ROADSIDE SWALE, PAVED EX ROADSIDE SWALE, PAVED OVERLAY EX. ROADWAY ROADSIDE SWALE, PAVED SEE NOTE 4 EXISTING RANGER RESIDENCE EXISTING PEDESTRIAN BRIDGE ALDERWOOD-EVERETT-COMPLEX ALDERWOOD RS-20 R-9,600 Nov 16, 2018 3:31pm chewett k:\Projects\0723-snohomish county\meadowdale park\construction plans\0723-PL-COMPOSITE Plan_Permit.dwg 4 CS-2 (PERMIT)APPROVED FOR CONSTRUCTION BY: R/W PERMIT NO. DATE DESCRIPTIONAPP'DDATEBY REVISIONS REV ONE INCHAT FULL SIZE, IF NOT ONEINCH SCALE ACCORDINGLYDESIGNED BY: APPROVED BY: CHECKED BY: DRAWN BY: DATE: SCALE: MEADOWDALE BEACH PARK AND ESTUARY DESIGN 18-XXXXX SHEET # OF LDA PERMIT SUBMITTAL, NOT FOR CONSTRUCTION 720 Olive Way | Suite 1900 | Seattle, WA 98101 PFN: 18-XXXXX LDA SECTION 5, TOWNSHIP 27 N., RANGE 4 E STATE OFWASHINGTON LICENSEDLANDSCAPE ARCHITECT CERTIFICATE NO. 422 PETER C. HUMMEL CS-2 COMPOSITE SITE PLAN (2 OF 3)4 75 PH/BS CH/TG BS PH AS NOTED NOVEMBER 2018 LEGEND: PARK BOUNDARY PROJECT BOUNDARY 12" BEACH SAND/GRAVEL LARGE WOODY DEBRIS ROCK ARMORING STREAMBED AND SWALE COBBLES CRUSHED ROCK PATH OR TRENCH ASPHALT PAVEMENT CONCRETE PATH/PAD PEDESTRIAN BRIDGE BOARDWALK PATH PICNIC TABLE BENCH LAWN ROCK-LINED SWALE WILDLIFE TREE SNAGS PROPOSED CONTOUR PROPOSED CLEARING LIMITS PROPOSED STORMWATER PIPE TREE TO REMAIN EXISTING WETLAND TO BE PROTECTED WETLAND BUFFER EXISTING ORDINARY HIGH WATER MARK (OHWM) REINFORCED TURF SPIRAL NAIL ROAD REINFORCEMENT PAVEMENT TO BE REMOVED AND REPLACED GRIND AND OVERLAY EXISTING PAVEMENT 10MATCH LINE, SEE SHEET CS-1MATCH LINE, SEE SHEET CS-3 NOTES: 1.FOR EXISTING PROPERTY BOUNDARIES, EASEMENTS, EXISTING CONTOURS, DRAINAGE, TOPOGRAPHIC FEATURES, AND STRUCTURES, SEE DRAWINGS EC-1 THROUGH EC-3. 2.FOR PROPOSED CONTOURS, CUT, FILL, AND GRADING FEATURES, SEE DRAWINGS C-1 THROUGH C-3. 3.FOR TREE REMOVAL AND PROTECTION, SEE DRAWINGS D-1, THROUGH D-3. 4.FOR TEMPORARY EROSION CONTROL MEASURES, SEE DRAWINGS T-1 THROUGH T-3. 5.FOR SOIL SPECIFICATIONS AND COMPACTION REQUIREMENTS, SEE DRAWING CS-3. 6.FOR PLANTING, SEE DRAWINGS L-1 THROUGH L-4. SD NOTES: 1.HORIZONTAL DATUM: WASHINGTON STATE PLANE NORTH ZONE, NAD 83, U.S. FEET. 2.VERTICAL DATUM: NAVD 88 3.DRAWINGS ARE INTENDED TO BE VIEWED IN COLOR. SOME INFORMATION WILL BE LOST WITH BLACK AND WHITE VIEWING. 4.PATHWAY WIDENING TO 10 FEET REQUIRES WORK ON ADJACENT PROPERTY. OBTAINING AN EASEMENT FOR THIS WORK IS UNDERWAY AND WILL BE COMPLETED PRIOR TO CONSTRUCTION START DATE. 5.CONTRACTOR SHALL PROVIDE CONTINUOUS UTILITY SERVICE AND DRIVEWAY ACCESS TO RANGER RESIDENCE. OHWM BUFFER SOIL TYPE BOUNDARY ZONING EARTH SUBSIDENCE AND LANDSLIDE AREA MINIMUM BUFFER ADJACENT TO HAZARD 100-YEAR FLOODPLAIN RS-20 ALDER- WOOD 0 SCALE IN FEET 30 60 NORTH 00500900000500 00500900000100 SWALE, PAVED EX ROADSIDE SWALE, PAVEDROADSIDESWALE, PAVED SOIL REINFORCEMENT AREA, TYP, SEE SHEETS RD-1 AND RD-2 RS-12 ALDERWOOD-EVERETT-COMPLEX ALDERWOOD-EVERETT-COMPLEX ALDERWOOD ALDERWOOD-EVERETT-COMPLEX RS-20 Nov 16, 2018 3:31pm chewett k:\Projects\0723-snohomish county\meadowdale park\construction plans\0723-PL-COMPOSITE Plan_Permit.dwg 5 CS-3 (PERMIT)APPROVED FOR CONSTRUCTION BY: R/W PERMIT NO. DATE DESCRIPTIONAPP'DDATEBY REVISIONS REV ONE INCHAT FULL SIZE, IF NOT ONEINCH SCALE ACCORDINGLYDESIGNED BY: APPROVED BY: CHECKED BY: DRAWN BY: DATE: SCALE: MEADOWDALE BEACH PARK AND ESTUARY DESIGN 18-XXXXX SHEET # OF LDA PERMIT SUBMITTAL, NOT FOR CONSTRUCTION 720 Olive Way | Suite 1900 | Seattle, WA 98101 PFN: 18-XXXXX LDA SECTION 5, TOWNSHIP 27 N., RANGE 4 E STATE OFWASHINGTON LICENSEDLANDSCAPE ARCHITECT CERTIFICATE NO. 422 PETER C. HUMMEL CS-3 COMPOSITE SITE PLAN (3 OF 3)5 75 PH/BS CH/TG BS PH AS NOTED NOVEMBER 2018 NOTES: 1.FOR EXISTING PROPERTY BOUNDARIES, EASEMENTS, EXISTING CONTOURS, DRAINAGE, TOPOGRAPHIC FEATURES, AND STRUCTURES, SEE DRAWINGS EC-1 THROUGH EC-3. 2.FOR PROPOSED CONTOURS, CUT, FILL, AND GRADING FEATURES, SEE DRAWINGS C-1 THROUGH C-3. 3.FOR TREE REMOVAL AND PROTECTION, SEE DRAWINGS D-1, THROUGH D-3. 4.FOR TEMPORARY EROSION CONTROL MEASURES, SEE DRAWINGS T-1 THROUGH T-3. 5.FOR SOIL SPECIFICATIONS AND COMPACTION REQUIREMENTS, SEE THIS DRAWING. 6.FOR PLANTING, SEE DRAWINGS L-1 THROUGH L-4. MATCH LINE, SEE SHEET CS-2 0 SCALE IN FEET 30 60 NORTH NOTES: 1.HORIZONTAL DATUM: WASHINGTON STATE PLANE NORTH ZONE, NAD 83, U.S. FEET. 2.VERTICAL DATUM: NAVD 88 3.DRAWINGS ARE INTENDED TO BE VIEWED IN COLOR. SOME INFORMATION WILL BE LOST WITH BLACK AND WHITE VIEWING. 4.CONTRACTOR SHALL PROVIDE CONTINUOUS UTILITY SERVICE AND DRIVEWAY ACCESS TO RANGER RESIDENCE.75TH PL. WOVERLAY EX. ROADWAY LEGEND: PARK BOUNDARY PROJECT BOUNDARY EXISTING CONTOUR PROPOSED MAJOR CONTOUR PROPOSED MINOR CONTOUR PROPOSED CLEARING LIMITS TREE TO REMAIN PAVEMENT TO BE REMOVED AND REPLACED GRIND AND OVERLAY EXISTING ASPHALT PAVEMENT SPIRAL NAIL ROAD REINFORCEMENT 10 11 OHWM BUFFER SOIL TYPE BOUNDARY ZONING EARTH SUBSIDENCE AND LANDSLIDE AREA MINIMUM BUFFER ADJACENT TO HAZARD 100-YEAR FLOODPLAIN RS-20 ALDER-WOOD PERCENTAGE OF MAXIMUM DENSITY REQUIREMENTS: COMPACT SOIL TO NOT LESS THAN THE FOLLOWING PERCENTAGES FOR MAXIMUM DRY DENSITY FOR SOILS DETERMINED IN ACCORDANCE WITH ASTM 1557 (MODIFIED PROCTOR). 1.BACKFILL: a)UTILITY PIPE ZONE BEDDING – 95% b)UTILITY PIPE ZONE BACKFILL – 95% c)UTILITY TRENCH BACKFILL (PAVED AREA) – 95% d)UTILITY TRENCH BACKFILL (UNPAVED AREA) – 90% e)IRRIGATION PIPE BEDDING BELOW PIPE – 95% f)IRRIGATION PIPE BACKFILL OVER PIPE – HAND TAMP TO 75% WHERE NOT IN PAVED AREA; WHERE IRRIGATION PIPE IS UNDER PAVING, COMPACT TO 95% g)GENERAL LANDSCAPE BACKFILL – 85% h)OVER EXCAVATION BACKFILL OF EXISTING SUB-GRADE TO REMAIN – 95% 2.SUB-GRADES: a)SUBGRADE SOILS IN PAVING AREAS – 90% b)IMPORT AGGREGATE BASE IN PAVING AREAS – 95% c)SUBGRADE FOR TOPSOIL AND SOIL AMENDMENTS (PLANTED/SEEDED AREAS) – 85% 3.SURFACE FILLS: a)STRUCTURAL FILL – 95% b)EMBANKMENT FILL – 95% C) FILLS ON SLOPES EXCEEDING 3:1, TO PREVENT EROSION – 90% 2704050020010027040500200100 00500900000500 00500900001602 00500900001601 BNSF RAILWAYPUGET SOUND LUN D S CREEKGUL C H 100' BNSF ROW PICNIC SHELTER VOLLEYBALL COURT ASPHALTPATH CONCRETE CULVERT, SLABS,GRATING, AND CHANNEL MATERIALS CRUSHED ROCK PATH RESTROOM ENCLOSURE,FOUNDATION,AND CONC. SLAB EXISTING PEDESTRIANLIGHT WITH SECONDARYUNDERGROUND POWER CONC. PAD, PICNIC TABLE, GRILL EXTENT OF TOPOGRAPHIC SURVEY EXTENT OF TOPOGRAPHIC SURVEY CONTOURS FROM LIDAR CONTOURS FROM LIDAR EXISTING BEACHTOPOGRAPHY (SEE NOTE 5) EXISTINGINFORMAL TRAILTO GAP IN FENCE SANITARY SEWER MANHOLE JUNCTION BOX WATER METER ROCKERY STORM DRAIN CATCH BASIN(TYPE I) MONUMENT IN CASE CONIFER DECIDUOUS SIGN EDGE OF ASPHALT PLAT CENTERLINE BNSF RIGHT OF WAY PLAT LOT LINE UNDERGROUND STORM LINE UNDERGROUND SEWER GRAVITY LINE UNDERGROUND TELEPHONE LINE UNDERGROUND WATER LINE UNDERGROUND POWER LINE FENCING PVC CONC P.A. POLYVINYL CHLORIDE PIPE ABBREVIATIONS: PLANTED AREA CONCRETE YARD LIGHT POWER VAULT TREES: C CEDAR P F PINE FIR DEC DECIDUOUS HEM HEMLOCK DHA SURVEY CONTROL YARD DRAIN BOLLARD (A)APPROXIMATE PRD PER RECORD DRAWING CTN A COTTONWOOD ALDER ORN ORNAMENTAL B BIRCH WETLAND/ ORDINARY HIGH WATER FLAG WP WOOD POST SANITARY/ STORM CLEAN-OUT M MAPLE GRAVEL PATH LOG DEBRIS UNDERGROUND SEWER FORCEMAIN LINE PICNIC TABLE x 13 MONITOR WELL RD ROOF DRAIN CO CLEAN-OUT CREEK TOP CREEK TOE RAILROAD SIGNAL PARK BOUNDARY LINE ORDINARY HIGH WATER MARK WETLAND BOUNDARY BNSF CENTERLINE MEAN HIGHER HIGH WATER (EL. +9.0' MLLW) PARK BOUNDARY PROJECT BOUNDARY Nov 16, 2018 3:32pm chewett k:\Projects\0723-snohomish county\meadowdale park\construction plans\0723-PL-Existing Plan.dwg 7 EC-10 SCALE IN FEET 30 60 LEGEND: NORTH EC-1 EXISTING CONDTIONS PLAN (1 OF 3)7 75 PH/BS CH/TG BS PH 1" = 30' NOVEMBER 2018 APPROVED FOR CONSTRUCTION BY: R/W PERMIT NO. DATE DESCRIPTIONAPP'DDATEBY REVISIONS REV ONE INCHAT FULL SIZE, IF NOT ONEINCH SCALE ACCORDINGLYDESIGNED BY: APPROVED BY: CHECKED BY: DRAWN BY: DATE: SCALE: MEADOWDALE BEACH PARK AND ESTUARY DESIGN 18-XXXXX SHEET # OF LDA PERMIT SUBMITTAL, NOT FOR CONSTRUCTION PFN: 18-XXXXX LDA SECTION 5, TOWNSHIP 27 N., RANGE 4 E MATCH LINE, SEE SHEET EC-2NOTES: 1.SURVEY PROVIDED BY DHA, DATED JUNE 2017 16928 WOODINVILLE-REDMOND ROAD SUITE B-107 WOODINVILLE, WASHINGTON 98072 (425) 483-5355 2.HORIZONTAL DATUM: WASHINGTON STATE PLANE NORTH ZONE, NAD 83, U.S. FEET. 3.VERTICAL DATUM: NAVD 88 4.DRAWINGS ARE INTENDED TO BE VIEWED IN COLOR. SOME INFORMATION WILL BE LOST WITH BLACK AND WHITE VIEWING. 5.BEACH TOPOGRAPHY REPRESENTS JUNE 2016 CONDITIONS AND ARE SUBJECT TO CHANGE. CONTRACTOR IS RESPONSIBLE FOR VERIFYING GRADES AND BEACH CONDITIONS PRIOR TO GRADING. CONFIRMED LOCATIONS OF BURIED DEBRIS 27040500200100 00500900000500 00500900000500 00500900001602 27040500200100 LUN D S CREEKGUL C H LUN D S G U L C H CREE K OFF-CHANNEL POND RANGERRESIDENCE ASPHALTPARKING LOT ASPHALTROAD CONTOURS FROM LIDAR CONTOURS FROM LIDAR EXTENT OF TOPOGRAPHIC SURVEY EXTENT OF TOPOGRAPHIC SURVEY SANITARY SEWER MANHOLE JUNCTION BOX WATER METER ROCKERY STORM DRAIN CATCH BASIN(TYPE I) MONUMENT IN CASE CONIFER DECIDUOUS SIGN EDGE OF ASPHALT PLAT CENTERLINE BNSF RIGHT OF WAY PLAT LOT LINE UNDERGROUND STORM LINE UNDERGROUND SEWER GRAVITY LINE UNDERGROUND TELEPHONE LINE UNDERGROUND WATER LINE UNDERGROUND POWER LINE FENCING PVC CONC P.A. POLYVINYL CHLORIDE PIPE ABBREVIATIONS: PLANTED AREA CONCRETE YARD LIGHT POWER VAULT TREES: C CEDAR P F PINE FIR DEC DECIDUOUS HEM HEMLOCK DHA SURVEY CONTROL YARD DRAIN BOLLARD (A)APPROXIMATE PRD PER RECORD DRAWING CTN A COTTONWOOD ALDER ORN ORNAMENTAL B BIRCH WETLAND/ ORDINARY HIGH WATER FLAG WP WOOD POST SANITARY/ STORM CLEAN-OUT M MAPLE GRAVEL PATH LOG DEBRIS UNDERGROUND SEWER FORCEMAIN LINE PICNIC TABLE x 13 MONITOR WELL RD ROOF DRAIN CO CLEAN-OUT CREEK TOP CREEK TOE RAILROAD SIGNAL PARK BOUNDARY LINE ORDINARY HIGH WATER MARK WETLAND BOUNDARY BNSF CENTERLINE MEAN HIGHER HIGH WATER (EL. +9.0' MLLW) PARK BOUNDARY PROJECT BOUNDARY Nov 16, 2018 3:32pm chewett k:\Projects\0723-snohomish county\meadowdale park\construction plans\0723-PL-Existing Plan.dwg 8 EC-2LEGEND: APPROVED FOR CONSTRUCTION BY: R/W PERMIT NO. DATE DESCRIPTIONAPP'DDATEBY REVISIONS REV ONE INCHAT FULL SIZE, IF NOT ONEINCH SCALE ACCORDINGLYDESIGNED BY: APPROVED BY: CHECKED BY: DRAWN BY: DATE: SCALE: MEADOWDALE BEACH PARK AND ESTUARY DESIGN 18-XXXXX SHEET # OF LDA PERMIT SUBMITTAL, NOT FOR CONSTRUCTION PFN: 18-XXXXX LDA SECTION 5, TOWNSHIP 27 N., RANGE 4 E EC-2 EXISTING CONDITIONS PLAN (2 OF 3)8 75 PH/BS CH/TG BS PH 1" = 30' NOVEMBER 2018 0 SCALE IN FEET 30 60 NORTHMATCH LINE, SEE SHEET EC-1MATCH LINE, SEE SHEET EC-3 NOTES: 1.SURVEY PROVIDED BY DHA, DATED JUNE 2017 16928 WOODINVILLE-REDMOND ROAD SUITE B-107 WOODINVILLE, WASHINGTON 98072 (425) 483-5355 2.HORIZONTAL DATUM: WASHINGTON STATE PLANE NORTH ZONE, NAD 83, U.S. FEET. 3.VERTICAL DATUM: NAVD 88 4.DRAWINGS ARE INTENDED TO BE VIEWED IN COLOR. SOME INFORMATION WILL BE LOST WITH BLACK AND WHITE VIEWING. 00500900000500 00500900000100 ACCESS GATE CONTOURS FROM LIDAR CONTOURS FROM LIDAR EXTENT OF TOPOGRAPHIC SURVEY EX. 1-1/2" WATER METER, TO PARK SANITARY SEWER MANHOLE JUNCTION BOX WATER METER ROCKERY STORM DRAIN CATCH BASIN(TYPE I) MONUMENT IN CASE CONIFER DECIDUOUS SIGN EDGE OF ASPHALT PLAT CENTERLINE BNSF RIGHT OF WAY PLAT LOT LINE UNDERGROUND STORM LINE UNDERGROUND SEWER GRAVITY LINE UNDERGROUND TELEPHONE LINE UNDERGROUND WATER LINE UNDERGROUND POWER LINE FENCING PVC CONC P.A. POLYVINYL CHLORIDE PIPE ABBREVIATIONS: PLANTED AREA CONCRETE YARD LIGHT POWER VAULT TREES: C CEDAR P F PINE FIR DEC DECIDUOUS HEM HEMLOCK DHA SURVEY CONTROL YARD DRAIN BOLLARD (A)APPROXIMATE PRD PER RECORD DRAWING CTN A COTTONWOOD ALDER ORN ORNAMENTAL B BIRCH WETLAND/ ORDINARY HIGH WATER FLAG WP WOOD POST SANITARY/ STORM CLEAN-OUT M MAPLE GRAVEL PATH LOG DEBRIS UNDERGROUND SEWER FORCEMAIN LINE PICNIC TABLE x 13 MONITOR WELL RD ROOF DRAIN CO CLEAN-OUT CREEK TOP CREEK TOE RAILROAD SIGNAL PARK BOUNDARY LINE ORDINARY HIGH WATER MARK WETLAND BOUNDARY BNSF CENTERLINE MEAN HIGHER HIGH WATER (EL. +9.0' MLLW) PARK BOUNDARY PROJECT BOUNDARY Nov 16, 2018 3:33pm chewett k:\Projects\0723-snohomish county\meadowdale park\construction plans\0723-PL-Existing Plan.dwg 9 EC-3LEGEND: 75TH PL W.75TH PL W.APPROVED FOR CONSTRUCTION BY: R/W PERMIT NO. DATE DESCRIPTIONAPP'DDATEBY REVISIONS REV ONE INCHAT FULL SIZE, IF NOT ONEINCH SCALE ACCORDINGLYDESIGNED BY: APPROVED BY: CHECKED BY: DRAWN BY: DATE: SCALE: MEADOWDALE BEACH PARK AND ESTUARY DESIGN 18-XXXXX SHEET # OF LDA PERMIT SUBMITTAL, NOT FOR CONSTRUCTION PFN: 18-XXXXX LDA SECTION 5, TOWNSHIP 27 N., RANGE 4 E EC-3 EXISTING CONDITIONS PLAN (3 OF 3)9 75 PH/BS CH/TG BS PH 1" = 30' NOVEMBER 2018 0 SCALE IN FEET 30 60 NORTH MATCH LINE, SEE SHEET EC-2 NOTES: 1.SURVEY PROVIDED BY DHA, DATED JUNE 2017 16928 WOODINVILLE-REDMOND ROAD SUITE B-107 WOODINVILLE, WASHINGTON 98072 (425) 483-5355 2.HORIZONTAL DATUM: WASHINGTON STATE PLANE NORTH ZONE, NAD 83, U.S. FEET. 3.VERTICAL DATUM: NAVD 88 4.DRAWINGS ARE INTENDED TO BE VIEWED IN COLOR. SOME INFORMATION WILL BE LOST WITH BLACK AND WHITE VIEWING. BNSF RAILWAYPUGET SOUND LUN D S CREEKGUL C H SD SD SD SDWW W W W W W W WSD SDSD92 LF 12" CPE SD 88 L F 12 " C P E 24 2 5 2610 9 12 13 14 17 18 2012 13 1415 16 17 20 11 10 9 9 1 0 1112131415212122 15 2311 22251 9 16 26212724292818 19 242322 1213111415161718192010 9 11 81098769 109101188 9272829303120191817 16 15 14 13 1211 TYPE 1 CB W/ HERRINGBONE GRATE WET BIO-FILTRATION SWALE 185 LF, S = 2% MAX 3' WIDE BOTTOM LOG DROP STRUCTURE COBBLE SCOUR PROTECTION IE SWALE = 22.04 TYPE 1 CB W/ BEEHIVE GRATE LOG EDGE, ONE 12" ∅ LOG HIGH TYPE 2 CB W/ SOLID COVER OUTLET TO ROCK-LINED SWALE IE = 11.00 (12" CPE) REPLACE EX DRINKING FOUNTAIN AND SUMP SHEET FLOW DISPERSION AREA SHEET FLOW DISPERSION AREA COBBLE SCOUR PROTECTION 2" X 3/4" TEE TO DRINKING FOUNTAIN 2" X 3/4" TEE TO EX VALVE BOX STORM DRAIN, SEE PROFILE A, SHEET CU-3 6 LF 12" CPE TYPE 1 CB W/ SOLID COVER DRINKING FOUNTAIN TRENCH DRAIN TYPE 1 CB W/ HERRINGBONE GRATE 57 LF8" CPESTORM DRAIN, SEE PROFILE C, SHEET CU-3 STORM DRAIN, SEE PROFILE B, SHEET CU-3 ROCK-LINED SWALE (STREAMBED COBBLE) EXTEND TO MHHW 2" X 1" REDUCER 270 L F 1" D R 1 1 HDP E CONNECT 1" HDPE WATER SERVICE TO FOOT WASH 24 LF 8" CP E OUTLET TO ESTUARY IE=11.75 (8" CPE) OUTLET PROTECTION TYPE 1 CB W/ BEEHIVE GRATE INSTALL GRAVEL SPLASH TRENCH AROUND RESTROOM SHELTER AT ROOF LINE ROCKERY PLAT CENTERLINE UNDERGROUND STORM LINE UNDERGROUND SEWER GRAVITY LINE UNDERGROUND TELEPHONE LINE UNDERGROUND WATER LINE UNDERGROUND POWER LINE FENCING UNDERGROUND SEWER FORCEMAIN LINE BNSF CENTERLINE Nov 16, 2018 3:41pm chewett k:\Projects\0723-snohomish county\meadowdale park\construction plans\0723-PL-Utility Plan.dwg 43 CU-1PARK BOUNDARY PROJECT BOUNDARY BNSF RIGHT OF WAY WATER PIPE STORMWATER PIPE FOUNDATION DRAIN SWALE CATCH BASIN, TYPE 1 CATCH BASIN, TYPE 2 DRINKING FOUNTAIN WETLAND TO BE PROTECTED TREE TO REMAIN W SD 0 SCALE IN FEET 30 60 NORTH NOTES: 1.SURVEY PROVIDED BY DHA, DATED JUNE 2017. 2.HORIZONTAL DATUM: WASHINGTON STATE PLANE NORTH ZONE, NAD 83, U.S. FEET. 3.VERTICAL DATUM: NAVD 88 4.DRAWINGS ARE INTENDED TO BE VIEWED IN COLOR. SOME INFORMATION WILL BE LOST WITH BLACK AND WHITE VIEWING. LEGEND:MATCH LINE, SEE SHEET CU-240265&#8 +&94+%'STAT E OF WASHIN G T ONREGISTEREDPROF ESSIONAL EN G IN EERAPPROVED FOR CONSTRUCTION BY: R/W PERMIT NO. DATE DESCRIPTIONAPP'DDATEBY REVISIONS REV ONE INCHAT FULL SIZE, IF NOT ONEINCH SCALE ACCORDINGLYDESIGNED BY: APPROVED BY: CHECKED BY: DRAWN BY: DATE: SCALE: MEADOWDALE BEACH PARK AND ESTUARY DESIGN 18-XXXXX SHEET # OF LDA PERMIT SUBMITTAL, NOT FOR CONSTRUCTION 720 Olive Way | Suite 1900 | Seattle, WA 98101 PFN: 18-XXXXX LDA SECTION 5, TOWNSHIP 27 N., RANGE 4 E B CU-4 C CU-4 CU-1 UTILITY PLAN (1 OF 2)43 75 PH/BS CH/TG BS PH 1" = 30' NOVEMBER 2018 A CU-4 GENERAL UTILITY NOTES: 1.FOR DEMOLITION OF EXISTING UTILITIES, SEE DRAWINGS D-1 THROUGH D-3. 2.EXISTING UTILITIES - THE CONTRACTOR SHALL FIELD VERIFY THE DEPTH, LOCATION, SIZE, AND MATERIAL OF EXISTING UTILITIES PRIOR TO CONSTRUCTION, AS OUTLINED IN THE SPECIFICATIONS AND IN THE EXISTING UTILITY NOTES ON DRAWING G-3. THE CONTRACTOR SHALL POTHOLE TO VERIFY THE DEPTH, LOCATION, SIZE, AND MATERIAL OF EXISTING BURIED UTILITIES. RECOMMENDED POTHOLE LOCATIONS ARE SHOWN ON THESE DRAWINGS FOR GUIDANCE, BUT ADDITIONAL OR DIFFERENT POTHOLES MAY NEED TO BE COMPLETED TO MEET THESE REQUIREMENTS. WHERE POTHOLING INDICATES A POTENTIAL CONFLICT AT A UTILITY CROSSING, THE CONTRACTOR SHALL IMMEDIATELY NOTIFY THE OWNER'S REPRESENTATIVE. 3.FOR UTILITY STORM DRAIN ELEVATIONS, SEE STORM DRAIN PROFILES ON DRAWING CU-3. 4.PIPE ZONE BEDDING AND BACKFILL SHALL BE PER 5.PARK WATER METER SHOWN ON SHEET EC-3. BNSF RIGHT OF WAY 1 CU-4 10/11 CM-5 11 CM-5 STANDARD UTILITY DETAILS SYMBOL AGENCY STANDARD DETAIL DESCRIPTION SNOHOMISH CO. PW 5-120 CATCH BASIN DETAILS WSDOT B-05.20-02 CATCH BASIN TYPE 1 WSDOT B-10.20-02 CATCH BASIN TYPE 2 WSDOT B-30.20-04 RECTANGULAR SOLID METAL COVER WSDOT B-30.30-03 RECTANGULAR VANED GRATE WSDOT B-30.50-03 RECTANGULAR HERRINGBONE GRATE WSDOT B-30.70-04 CIRCULAR FRAME (RING) AND COVER WSDOT B-55.20-00 PIPE ZONE BEDDING AND BACKFILL 1 2 3 4 5 6 7 8 1 2 1 2137 1 2 5 1 2 4 8 2 CU-4 2 CU-4 UTILITY LOCATIONS: THE CONTRACTOR SHALL CALL THE ONE-CALL UTILITY CENTER AT 811 OR 1-800-424-5555 FOR UTILITY LOCATIONS NOT LESS THAN TWO (2) BUSINESS DAYS BEFORE DEMOLITION WORK. FOR ADDITIONAL REQUIREMENTS SEE SHEET G-3. 3 CU-4 LUN D S CREEKGUL C H LUN D S G U L C H CREE K OFF-CHANNELPOND SD SD SD SD SD SDSD SD W W W 50 LF12" CPE 42 L F 12" C P E 52 LF 12" CPE30 LF8" CPE 61 LF 12" CPE 114 L F 12" CP E 104 LF 12" CP E 2 9 2 L F 2" D R 1 1 H D P E 2 6 50454025262730292831323334353639383736 55606570352 7 282930313233343535 34 TYPE 1 CB W/ BEEHIVE GRATE TYPE 1 CB W/ VANED GRATE TYPE 1 CB W/ VANED GRATE TYPE 1 CB W/ HERRINGBONE GRATE TYPE 1 CB W/ HERRINGBONE GRATE TYPE 1 CB W/ SOLID COVER TYPE 1 CB W/ HERRINGBONE GRATE OUTLET TO WET BIO-FILTRATION SWALE IE = 27.00 (12" CPE) OUTLET PROTECTIONWET BIO-FILTRATION SWALE 185 LF, S = 2% MAX 3' WIDE BOTTOM LOG EDGE, TWO 12" ∅ LOGS HIGH 24 LF 12" CPE LOG DROP STRUCTURE COBBLE SCOUR PROTECTION IE SWALE = 22.04 LOG EDGE, ONE 12" ∅ LOG HIGH CPLG, CONNECT TO EX 2-1/2" PVC W 2" 45° HDPE BEND STORM DRAIN, SEE PROFILE A, SHEET CU-3 STORMWATER SWALE, SEE RD-232 LF8" CPETYPE 1 CB W/ HERRINGBONE GRATE TYPE 1 CB W/ HERRINGBONE GRATE STORM DRAIN, SEE PROFILE D, SHEET CU-3 STORM DRAIN, SEE PROFILE E, SHEET CU-3 ROCKERY PLAT CENTERLINE UNDERGROUND STORM LINE UNDERGROUND SEWER GRAVITY LINE UNDERGROUND TELEPHONE LINE UNDERGROUND WATER LINE UNDERGROUND POWER LINE FENCING UNDERGROUND SEWER FORCEMAIN LINE BNSF CENTERLINE Nov 16, 2018 3:41pm chewett k:\Projects\0723-snohomish county\meadowdale park\construction plans\0723-PL-Utility Plan.dwg 44 CU-240265&#8 +&94+%'STAT E OF WASHIN G T ONREGISTEREDPROF ESSIONAL EN G IN EERAPPROVED FOR CONSTRUCTION BY: R/W PERMIT NO. DATE DESCRIPTIONAPP'DDATEBY REVISIONS REV ONE INCHAT FULL SIZE, IF NOT ONEINCH SCALE ACCORDINGLYDESIGNED BY: APPROVED BY: CHECKED BY: DRAWN BY: DATE: SCALE: MEADOWDALE BEACH PARK AND ESTUARY DESIGN 18-XXXXX SHEET # OF LDA PERMIT SUBMITTAL, NOT FOR CONSTRUCTION 720 Olive Way | Suite 1900 | Seattle, WA 98101 PFN: 18-XXXXX LDA SECTION 5, TOWNSHIP 27 N., RANGE 4 E CU-2 UTILITY PLAN (2 OF 2)44 75 PH/BS CH/TG BS PH 1" = 30' NOVEMBER 2018MATCH LINE, SEE SHEET CU-1A CU-4 1 CU-4 0 SCALE IN FEET 30 60 NORTH NOTES: 1.SURVEY PROVIDED BY DHA, DATED JUNE 2017. 2.HORIZONTAL DATUM: WASHINGTON STATE PLANE NORTH ZONE, NAD 83, U.S. FEET. 3.VERTICAL DATUM: NAVD 88 4.DRAWINGS ARE INTENDED TO BE VIEWED IN COLOR. SOME INFORMATION WILL BE LOST WITH BLACK AND WHITE VIEWING. 5.CONTRACTOR SHALL PROVIDE CONTINUOUS UTILITY SERVICE AND DRIVEWAY ACCESS TO RANGER RESIDENCE. GENERAL UTILITY NOTES: 1.FOR DEMOLITION OF EXISTING UTILITIES, SEE DRAWINGS D-1 THROUGH D-3. 2.EXISTING UTILITIES - THE CONTRACTOR SHALL FIELD VERIFY THE DEPTH, LOCATION, SIZE, AND MATERIAL OF EXISTING UTILITIES PRIOR TO CONSTRUCTION, AS OUTLINED IN THE SPECIFICATIONS AND IN THE EXISTING UTILITY NOTES ON DRAWING G-3. THE CONTRACTOR SHALL POTHOLE TO VERIFY THE DEPTH, LOCATION, SIZE, AND MATERIAL OF EXISTING BURIED UTILITIES. RECOMMENDED POTHOLE LOCATIONS ARE SHOWN ON THESE DRAWINGS FOR GUIDANCE, BUT ADDITIONAL OR DIFFERENT POTHOLES MAY NEED TO BE COMPLETED TO MEET THESE REQUIREMENTS. WHERE POTHOLING INDICATES A POTENTIAL CONFLICT AT A UTILITY CROSSING, THE CONTRACTOR SHALL IMMEDIATELY NOTIFY THE OWNER'S REPRESENTATIVE. 3.FOR UTILITY STORM DRAIN ELEVATIONS, SEE STORM DRAIN PROFILES ON DRAWING CU-3. 4.PIPE ZONE BEDDING AND BACKFILL SHALL BE PER 5.PARK WATER METER SHOWN ON SHEET EC-3 PARK BOUNDARY PROJECT BOUNDARY WATER PIPE STORMWATER PIPE SWALE CATCH BASIN, TYPE 1 CATCH BASIN, TYPE 2 DRINKING FOUNTAIN WETLAND TO BE PROTECTED TREE TO REMAIN W SD LEGEND: STANDARD UTILITY DETAILS SYMBOL AGENCY STANDARD DETAIL DESCRIPTION SNOHOMISH CO. PW 5-120 CATCH BASIN DETAILS WSDOT B-05.20-02 CATCH BASIN TYPE 1 WSDOT B-10.20-02 CATCH BASIN TYPE 2 WSDOT B-30.20-04 RECTANGULAR SOLID METAL COVER WSDOT B-30.30-03 RECTANGULAR VANED GRATE WSDOT B-30.50-03 RECTANGULAR HERRINGBONE GRATE WSDOT B-30.70-04 CIRCULAR FRAME (RING) AND COVER WSDOT B-55.20-00 PIPE ZONE BEDDING AND BACKFILL 1 2 3 4 5 6 7 8 8 1 2 6 1 2 4 1 2 6 1 2 6 1 2 6 1 2 6 1 2 5 1 2 5 1 2 UTILITY LOCATIONS: THE CONTRACTOR SHALL CALL THE ONE-CALL UTILITY CENTER AT 811 OR 1-800-424-5555 FOR UTILITY LOCATIONS NOT LESS THAN TWO (2) BUSINESS DAYS BEFORE DEMOLITION WORK. FOR ADDITIONAL REQUIREMENTS SEE SHEET G-3. C CU-4 ELEVATION IN FEETHORIZONTAL DISTANCE IN FEET 3X VERTICAL EXAGGERATION -10 0 10 20 30 40 50 -10 0 10 20 30 40 50 0+00 0+30 0+60 0+90 1+20 1+50 1+80 2+10 2+40 2+70 3+00 3+30 3+60 3+90 4+20 4+50 4+80 5+10 5+40 ELEVATION IN FEETHORIZONTAL DISTANCE IN FEET 3X VERTICAL EXAGGERATION 10 20 30 40 50 60 70 10 20 30 40 50 60 70 4+80 5+10 5+40 5+70 6+00 6+30 6+60 6+90 7+20 7+50 7+80 8+10 8+40 8+70 9+00 9+30 9+60TYPE 1 CB W/ BEEHIVE GRATERIM=22.21STA:3+22TYPE 2 CB W/ SOLID COVERRIM=21.10IE=16.96 (12" CPE, E)IE=11.88 (12" CPE, NW)IE=16.18 (8" CPE, N)STA:2+23TYPE 1 CB W/ BEEHIVE GRATERIM=51.00IE=46.12 (12" CPE, N)STA:9+56TYPE 1 CB W/ VANED GRATERIM=44.26IE=40.37 (12" CPE, S)IE=40.34 (12" CPE, NW)STA:9+06TYPE 1 CB W/ VANED GRATERIM=41.00IE=36.98 (12" CPE, SE)IE=36.95 (12" CPE, W)STA:8+64TYPE 1 CB W/ HERRINGBONE GRATERIM=37.28IE=33.28 (12" CPE, E)IE=33.25 (12" CPE, W)IE=33.28 (8" CPE, S)STA:8+11TYPE 1 CB W/HERRINGBONE GRATERIM=36.21IE=32.33 (12" CPE, E)IE=32.31 (12" CPE, W)IE=32.33 (8" CPE, S)STA:7+50TYPE 1 CB W/ SOLID COVERRIM=35.22IE=30.60 (12" CPE, E)IE=30.57 (12" CPE, SW)STA:6+36ROCK-LINED SWALE (EXTEND TO MHHW)WET BIO-FILTRATION SWALE (185 LF)88 LF 12" ∅ CPE SD S=1.00% 6 LF 12" ∅ CPE SD S=1.00% 104 LF 12" ∅ CPE SD S=2.50% 114 LF 12" ∅ CPE SD S=1.50% 61 LF 12" ∅ CPE SD S=1.50% 52 LF 12" ∅ CPE SD S=7.00% 42 LF 12" ∅ CPE SD S=8.00% 50 LF 12" ∅ CPE SD S=11.50% 3/4"∅ W STA 4+32LOG DROP STRUCTUREIE=26.20 (US)IE=25.20 (DS)STA 3+81LOG DROP STRUCTUREIE=24.20 (US)IE=23.20 (DS)2"∅ W 2% 2% 2% IE=11.00 24 LF 12" ∅ CPE SD S=1.00% 92 LF 12" ∅ CPE SD S=2.00%TYPE 1 CB W/HERRINGBONE GRATERIM=30.50IE=27.97 (12" CPE, NE)IE=27.94 (12" CPE, SW)STA:5+32TYPE 1 CB W/SOLID COVERRIM=23.57IE=18.82 (12" CPE, S)IE=18.80 (12" CPE, W)STA:3+154" ∅ SD 2"∅ W MATCHLINESEE BELOW1 1/2" ∅ SS FM, 3" ∅ SLEEVE 2"∅ P 2"∅ COMM 2 1/2"∅ W ELEVATION IN FEETHORIZONTAL DISTANCE IN FEET 3X VERTICAL EXAGGERATION -10 0 10 20 30 40 50 -10 0 10 20 30 40 50 0 30 60 80TYPE 2 CB W/SOLID COVERRIM=21.10IE=16.96 (12" CPE, E)IE=11.88 (12" CPE, NW)IE=16.18 (8" CPE, N)STA:2+23RIM=20.75IE=16.75 (8" CPE, S)TYPE 1 CB W/HERRINGBONE GRATE57 LF 8" ∅ CPE SD S=1.00%ELEVATION IN FEETHORIZONTAL DISTANCE IN FEET 3X VERTICAL EXAGGERATION 0 10 20 30 40 50 60 0 10 20 30 40 50 60 0 30 60TYPE 1 CB W/HERRINGBONE GRATERIM=36.21IE=32.33 (12" CPE, E)IE=32.31 (12" CPE, W)IE=32.33 (8" CPE, S)STA:7+5032 LF 8" ∅ CPE SD S=1.50%TYPE 1 CB W/HERRINGBONE GRATERIM=36.60IE=32.81 (8" CPE, N)STA:7+50ELEVATION IN FEETHORIZONTAL DISTANCE IN FEET 3X VERTICAL EXAGGERATION 10 20 30 40 50 60 70 10 20 30 40 50 60 70 0 30 60TYPE 1 CB W/HERRINGBONE GRATERIM=37.28IE=33.28 (12" CPE, E)IE=33.25 (12" CPE, W)IE=33.28 (8" CPE, S)STA:8+11TYPE 1 CB W/HERRINGBONE GRATERIM=38.10IE=33.73 (12" CPE, N)STA:8+2530 LF 8" ∅ CPE SD S=1.50%ELEVATION IN FEETHORIZONTAL DISTANCE IN FEET 3X VERTICAL EXAGGERATION -20 -10 0 10 20 30 40 -20 -10 0 10 20 30 40 0 30 40RIM=14.35IE=11.99 (8" CPE, NE)TYPE 1 CB W/BEEHIVE GRATE Nov 16, 2018 3:42pm chewett k:\Projects\0723-snohomish county\meadowdale park\construction plans\0723-PL-Utility Plan.dwg 45 CU-30 SCALE IN FEET 30 60 NOTES: 1.SURVEY PROVIDED BY DHA, DATED JUNE 2017 2.HORIZONTAL DATUM: WASHINGTON STATE PLANE NORTH ZONE, NAD 83, U.S. FEET. 3.VERTICAL DATUM: NAVD 88 4.SEE SHEETS CU-1 AND CU-2 FOR STANDARD UTILITY DETAIL LEGEND. 40265&#8 +&94+%'STAT E OF WASHIN G T ONREGISTEREDPROF ESSIONAL EN G IN EERAPPROVED FOR CONSTRUCTION BY: R/W PERMIT NO. DATE DESCRIPTIONAPP'DDATEBY REVISIONS REV ONE INCHAT FULL SIZE, IF NOT ONEINCH SCALE ACCORDINGLYDESIGNED BY: APPROVED BY: CHECKED BY: DRAWN BY: DATE: SCALE: MEADOWDALE BEACH PARK AND ESTUARY DESIGN 18-XXXXX SHEET # OF LDA PERMIT SUBMITTAL, NOT FOR CONSTRUCTION 720 Olive Way | Suite 1900 | Seattle, WA 98101 PFN: 18-XXXXX LDA SECTION 5, TOWNSHIP 27 N., RANGE 4 E HORIZ. SCALE:VERT. SCALE:1" = 30' STORM DRAIN PROFILEA CU-1/CU-2 1" = 10' LEGEND, PROFILE EXISTING GRADE PROPOSED GRADEMATCH LINE, SEE ABOVECU-3 STORM DRAIN PROFILE 45 75 PH/BS CH/TG BS PH AS NOTED NOVEMBER 2018 HORIZ. SCALE: VERT. SCALE: 1" = 30' STORM DRAIN PROFILEC CU-1 1" = 10' HORIZ. SCALE: VERT. SCALE: 1" = 30' STORM DRAIN PROFILED CU-2 1" = 10' HORIZ. SCALE: VERT. SCALE: 1" = 30' STORM DRAIN PROFILEE CU-2 1" = 10' HORIZ. SCALE: VERT. SCALE: 1" = 30' STORM DRAIN PROFILEB CU-1 1" = 10' IE = 11.75 OUTLET PROTECTION 1 CU-4 IE=27.70 OUTLET PROTECTION 1 CU-4 1 3 7 1 2 4 1 2 1 2 6 1 2 4 1 2 6 1 2 6 1 2 5 1 2 5 1 2 1 2 1 3 7 1 2 5 1 2 6 1 2 6 1 2 6 1 2 6 A CU-4 C CU-4 C CU-4 SCALE: TYPICAL WET BIO-FILTRATION SWALE SECTIONA C-12 1" = 3' 3H 1V 3H1V 3' MIN BASE 8" MIN. COMPOST AMENDED SOIL WITHOUT LOG EDGE EX GROUND VARIES 3' MIN WITH LOG EDGE 12" MIN CRUSHED SHOULDER 6" MIN. CRUSHED BASE COURSE ASPHALT PATHWAY 1.5% 3' MIN BASE 3H1V 8" MIN. COMPOST AMENDED SOIL MIN 12" ∅ LOG EDGE , TYP 3H 1V EX GROUND SCALE: WET BIO-FILTRATION SWALE - LOG DROP DETAILC C-12 1" = 3' SECTION D-D' PROFILE 3H 1V 3H1V 3' MIN BASE EX GROUND 8" MIN. COMPOST AMENDED SOILMIN 12" ∅ LOG EDGE, TYP LOGS AND CHANNEL DOWNSTREAM OF DROP 4" DESIGN DEPTH 4" DESIGN DEPTH 4" DESIGN DEPTH 2.0% 2.0% 8" MIN. COMPOST AMENDED SOIL MIN 12" ∅ LOG EDGE, TYP STREAMBED AND SWALE SUBSTRATE, MIN 8" DEEP 5' MIN 12" DROP SWALE INVERT TOP OF BANK SCALE: TYPICAL OUTFALL SWALE SECTIONB C-12 1" = 3' STREAMBED AND SWALE SUBSTRATE, MIN 12" DEEP 3' MIN BASE 7'-0" 2H1V2H1V12" 6" TOPSOIL WITH HIGH TIDAL MARSH PLANTING DD'12" MIN CRUSHED SHOULDER 6" MIN. CRUSHED BASE COURSE ASPHALT PATHWAY 1.5% 12" MIN 12" MIN CRUSHED SHOULDER 6" MIN. CRUSHED BASE COURSE ASPHALT PATHWAY 1.5% SCALE: SHEET FLOW DISPERSION AREA2 CU-1 1" = 3' 12" MIN CRUSHED SHOULDER 6" MIN. CRUSHED BASE COURSE ASPHALT PATHWAY 1.5% 10' VEGETATED FILTER STRIP 15% MAX TOPSOIL SCALE: SPLASH TRENCH3 CU-1 1" = 3' 2' SPLASH TRENCH (UNDER ROOF LINE) 1'-6" SLAB ON GRADE FOR RESTROOM ENCLOSURE (SEE DWG S2.2) 2.0% 23 CM-9 LOG EDGE 23 CM-9 23 CM-9 D STREAMBED AND SWALE SUBSTRATE, MIN 12" DEEP STREAMBED COBBLES 2xD MIN.2xD MIN. 1xD MIN. (MEASURED ALONG SLOPE) 5xD MIN. (MEASURED ALONG SLOPE) D 5xD MIN. 1xD MIN. PROFILE SEE SECTION SECTION SCALE: OUTLET PROTECTION1 CU-1 NTS 40265&#8 +&94+%'STAT E OF WASHIN G T ONREGISTEREDPROF ESSIONAL EN G IN EERAPPROVED FOR CONSTRUCTION BY: R/W PERMIT NO. DATE DESCRIPTIONAPP'DDATEBY REVISIONS REV ONE INCHAT FULL SIZE, IF NOT ONEINCH SCALE ACCORDINGLYDESIGNED BY: APPROVED BY: CHECKED BY: DRAWN BY: DATE: SCALE: MEADOWDALE BEACH PARK AND ESTUARY DESIGN 18-XXXXX SHEET # OF LDA PERMIT SUBMITTAL, NOT FOR CONSTRUCTION 720 Olive Way | Suite 1900 | Seattle, WA 98101 PFN: 18-XXXXX LDA SECTION 5, TOWNSHIP 27 N., RANGE 4 E Nov 16, 2018 3:42pm chewett k:\Projects\0723-snohomish county\meadowdale park\construction plans\0723-PL-Utility Plan.dwg 46 CU-4CU-4 DRAINAGE DETAILS 46 75 PH/BS CH/TG BS PH AS NOTED NOVEMBER 2018 Appendix B Drainage Area and Land Cover Analysis Meadowdale Beach ParkStormwater Analysis - Existing Land Cover and Drainage AreasTDA 1TDA 2AREA 1 AREA 2 AREA 3 AREA 4 Area 5 TOTAL AREA 6Designation(SF) (AC) (SF) (AC) (SF) (AC) (SF) (AC) (SF) (AC) (SF) (AC) (SF) (AC)Sidewalks Non PGIS 0 0 760 0.02 12,133 0.28 12,096 0.28 0 0 24,989 0.57 0 0Gravel Paths Non PGIS 0 0 424 0.010000004240.01 0 0Concrete Pads Non PGIS00001,175 0.03 63 0.00 0 0 1,238 0.03 0 0Roofs Non PGIS00009030.0200009030.02 0 0Railroad AlignmentNon PGIS0000000010,206 0.23 10,206 0.23 0 0SUBTOTAL Non PGIS 0 0 1,184 0.03 14,211 0.33 12,159 0.28 10,206 0.23 37,760 0.8700RoadwaysPGIS22,836 0.520000000022,836 0.525,1080.12SUBTOTALPGIS22,836 0.520000000022,836 0.52 5,108 0.12SUBTOTALImpervious 22,836 0.52 1,184 0.03 14,211 0.33 12,159 0.28 10,206 0.23 60,596 1.39 5,108 0.12Forested, TreesNon PGPS 8,5900.205,9690.14 53,805 1.24 39,786 0.9100108,150 2.483,5200.08LandscapingNon PGPS 8520.021,8310.04 58,471 1.34000061,154 1.4000BeachNon PGPS0000000027,368 0.63 27,368 0.6300EstuaryNon PGPS00000000000000SUBTOTAL Non PGPS 9,442 0.22 7,800 0.18 112,276 2.58 39,786 0.91 27,368 0.63 196,672 4.51 3,520 0.08SUBTOTALPervious 9,442 0.22 7,800 0.18 112,276 2.58 39,786 0.91 27,368 0.63 196,672 4.51 3,520 0.08TOTALAll32,278 0.74 8,984 0.21 126,487 2.90 51,945 1.19 37,574 0.86 257,268 5.91 8,628 0.20SidewalksNon PGIS004830.010000004830.0100Gravel PathsNon PGIS002,8520.070000002,8520.0700Concrete PadsNon PGIS00000000000000RoofsNon PGIS 5,8650.131,4430.030000007,3080.1700Railroad AlignmentNon PGIS0000000014,795 0.34 14,795 0.34 0 0SUBTOTAL Non PGIS 5,865 0.13 4,778 0.11000014,795 0.34 25,438 0.58 0 0Roadways PGIS0000000000006170.01SUBTOTAL PGIS0000000000006170.01SUBTOTAL Impervious 5,865 0.13 4,778 0.11000014,795 0.34 25,438 0.58 617 0.01Forested, Trees Non PGPS 210,883 4.84 26,506 0.61 67,331 1.55 461,931 10.6000766,651 17.60 131,991 3.03LandscapingNon PGPS003,6060.080000003,6060.0800BeachNon PGPS0000000016,408 0.38 16,408 0.3800EstuaryNon PGPS00000000000000SUBTOTAL Non PGPS 210,883 4.84 30,112 0.69 67,331 1.55 461,931 10.60 16,408 0.38 786,665 18.06 131,991 3.03SUBTOTALPervious 210,883 4.84 30,112 0.69 67,331 1.55 461,931 10.60 16,408 0.38 786,665 18.06 131,991 3.03TOTALAll216,748 4.98 34,890 0.80 67,331 1.55 461,931 10.60 31,203 0.72 812,103 18.64 132,608 3.04Within Project Site AreaOff-Site Areas that Drain through Project AreaAccess Driveway and Parking Area, Drains to CreekRanger Residence Area, Drains to CreekWest of Ranger Residence and South of Creek, Drains to Creek North Side of Creek, Drains to CreekRailroad Berm and BeachAreas 1-5Access Driveway and Off-Site Areas, Drains to Puget Sound South of Project SiteSurfaceDescriptionStormwater Site PlanMeadowdale Beach Park and Estuary Restoration ProjectDRAFTPage 1 of 5November 2018 Meadowdale Beach ParkStormwater Analysis - Existing Land Cover and Drainage AreasTDA 1TDA 2AREA 1AREA 2AREA 3AREA 4Area 5TOTALAREA 6Designation(SF)(AC)(SF)(AC)(SF)(AC)(SF)(AC)(SF)(AC)(SF)(AC)(SF)(AC)Access Driveway and Parking Area, Drains to CreekRanger Residence Area, Drains to CreekWest of Ranger Residence and South of Creek, Drains to Creek North Side of Creek, Drains to CreekRailroad Berm and BeachAreas 1-5Access Driveway and Off-Site Areas, Drains to Puget Sound South of Project SiteSurfaceDescriptionSidewalksNon PGIS001,2430.03 12,133 0.28 12,096 0.280025,472 0.5800Gravel PathsNon PGIS003,2760.080000003,2760.0800Concrete PadsNon PGIS0001,1750.03630.00001,2380.0300RoofsNon PGIS 5,8650.131,4430.039030.0200008,2110.1900Railroad AlignmentNon PGIS0000000025,001 0.57 25,001 0.57 0 0SUBTOTAL Non PGIS 5,865 0.13 5,962 0.14 14,211 0.33 12,159 0.28 25,001 0.57 63,198 1.4500RoadwaysPGIS22,836 0.5200000022,836 0.525,7250.13SUBTOTALPGIS22,836 0.520000000022,836 0.52 5,725 0.13SUBTOTALImpervious 28,701 0.66 5,962 0.14 14,211 0.33 12,159 0.28 25,001 0.57 86,034 1.98 5,725 0.13Forested, TreesNon PGPS 219,473 5.04 32,475 0.75 121,136 2.78 501,717 11.52874,801 20.08 135,511 3.11LandscapingNon PGPS 8520.025,4370.12 58,471 1.340064,760 1.4900BeachNon PGPS0000000043,776 1.00 43,776 1.0000EstuaryNon PGPS00000000 0000SUBTOTAL Non PGPS 220,325 5.06 37,912 0.87 179,607 4.12 501,717 11.52 43,776 1.00 983,337 22.57 135,511 3.11SUBTOTALPervious 220,325 5.06 37,912 0.87 179,607 4.12 501,717 11.52 43,776 1.00 983,337 22.57 135,511 3.11TOTALAll249,026 5.72 43,874 1.01 193,818 4.45 513,876 11.80 68,777 1.58 1,069,371 24.55 141,236 3.24Notes:PGIS: Pollution Generating Impervious SurfacePGPS: Pollution Generating Pervious SurfaceTotal Drainage AreaStormwater Site PlanMeadowdale Beach Park and Estuary Restoration ProjectDRAFTPage 2 of 5November 2018 Meadowdale Beach ParkStormwater Analysis - Proposed Land Cover and Drainage AreasAREA 1AREA 2AREA 3AAREA 3BAREA 4Area 5TOTALAREA 6Designation(SF)(AC)(SF)(AC)(SF)(AC)(SF)(AC)(SF)(AC)(SF)(AC)(SF)(AC)(SF)(AC)SidewalksNon PGIS004,4250.104,3860.101,1940.03 10,1960.230020,201 0.4600Existing (Remain) Non PGIS0000000010,196 0.23 0 0 10,196 0.23 0 0Replaced Non PGIS 0 0 4,425 0.10 4,386 0.10 1,194 0.03000010,005 0.23 0 0New Non PGIS0000000000000000Gravel Paths Non PGIS005440.01 1,0240.02 1,1990.0300002,7670.0600Existing (Remain) Non PGIS0000000000000000Replaced Non PGIS 0 0 544 0.01000000005440.01 0 0New Non PGIS00001,024 0.02 1,199 0.0300002,223 0.05 0 0Concrete Pads Non PGIS00630.006690.023300.01008290.02 1,891 0.0400Existing (Remain) Non PGIS0000000000000000Replaced Non PGIS00001670.0000005860.01 753 0.02 0 0New Non PGIS 0 0 63 0.00 502 0.01 330 0.01 0 0 243 0.01 1,138 0.03 0 0Roofs Non PGIS002350.01 1,171 0.030000001,4060.0300Existing (Remain) Non PGIS00005420.010000005420.01 0 0Replaced Non PGIS 0 0 235 0.01000000002350.01 0 0New Non PGIS00006290.010000006290.01 0 0Railroad Alignment Non PGIS000000000025,0000.5725,0000.5700Existing (Remain) Non PGIS000000000025,000 0.57 25,000 0.57 0 0Replaced Non PGIS0000000000000000New Non PGIS0000000000000000SUBTOTAL Non PGIS 0 0 5,267 0.12 7,250 0.17 2,723 0.06 10,196 0.23 25,829 0.59 51,265 1.1800RoadwaysPGIS22,1780.51000000000022,1780.51 5,1080.12Existing (Remain) PGIS 21,372 0.49000000000021,372 0.49 5,108 0.12Replaced PGIS0000000000000000New PGIS 806 0.0200000000008060.02 0 0SUBTOTAL PGIS 22,178 0.51000000000022,178 0.51 5,108 0.12SUBTOTAL Impervious 22,178 0.51 5,267 0.12 7,250 0.17 2,723 0.06 10,196 0.23 25,829 0.59 73,443 1.69 5,108 0.12Forested, TreesNon PGPS8,1600.190010,9970.2547,6171.0942,9150.9900109,6892.523,5200.08Landscaping Non PGPS4650.0116,7530.3811,2020.2600000028,4200.6500Beach Non PGPS000000000012,4320.2912,4320.2900EstuaryNon PGPS000024,7720.5721,9980.51000046,7701.0700SUBTOTAL Non PGPS 8,625 0.20 16,753 0.38 46,971 1.08 69,615 1.60 42,915 0.99 12,432 0.29 197,311 4.53 3,520 0.08SUBTOTAL Pervious 8,625 0.20 16,753 0.38 46,971 1.08 69,615 1.60 42,915 0.99 12,432 0.29 197,311 4.53 3,520 0.08TOTAL All 30,803 0.71 22,020 0.51 54,221 1.24 72,338 1.66 53,111 1.22 38,261 0.88 270,754 6.22 8,628 0.20TDA 1TDA 2Within Project Site AreaNorth Side of Creek, Drains to CreekRailroad Berm and Beach Areas 1-5Access Driveway and Parking AreaRanger Residence AreaArea West of Ranger Residence and South of Creek That Drains to Rock Swale Area West of Ranger Residence and South of Creek That Drains to Creek Access Driveway and Off-Site Areas, Drains to Puget Sound South of Project SiteSurfaceDescriptionStormwater Site PlanMeadowdale Beach Park and Estuary Restoration ProjectDRAFTPage 3 of 5November 2018 Meadowdale Beach ParkStormwater Analysis - Proposed Land Cover and Drainage AreasAREA 1AREA 2AREA 3AAREA 3BAREA 4Area 5TOTALAREA 6Designation(SF)(AC)(SF)(AC)(SF)(AC)(SF)(AC)(SF)(AC)(SF)(AC)(SF)(AC)(SF)(AC)TDA 1TDA 2North Side of Creek, Drains to CreekRailroad Berm and BeachAreas 1-5Access Driveway and Parking AreaRanger Residence AreaArea West of Ranger Residence and South of Creek That Drains to Rock Swale Area West of Ranger Residence and South of Creek That Drains to Creek Access Driveway and Off-Site Areas, Drains to Puget Sound South of Project SiteSurfaceDescriptionSidewalksNon PGIS004920.01000000004920.0100Existing (Remain) Non PGIS004920.01000000004920.0100ReplacedNon PGIS0000000000000000NewNon PGIS0000000000000000Gravel PathsNon PGIS002,2640.05000000002,2640.0500Existing (Remain) Non PGIS002,2640.05000000002,2640.0500ReplacedNon PGIS0000000000000000NewNon PGIS0000000000000000Concrete PadsNon PGIS0000000000000000Existing (Remain) Non PGIS0000000000000000Replaced Non PGIS0000000000000000New Non PGIS0000000000000000Roofs Non PGIS 5,8650.13 1,0500.02000000006,9150.1600Existing (Remain) Non PGIS 5,8650.131,0500.02000000006,9150.1600ReplacedNon PGIS0000000000000000NewNon PGIS0000000000000000Railroad Alignment Non PGIS0000000000000000Existing (Remain) Non PGIS0000000000000000Replaced Non PGIS0000000000000000New Non PGIS0000000000000000SUBTOTAL Non PGIS 5,865 0.13 3,806 0.09000000009,671 0.22 0 0Roadways PGIS 1,4640.0300000000001,4640.036170.01Existing (Remain) PGIS -19,908 -0.460000000000-19,908 -0.46 -4,383 -0.10Replaced PGIS 21,372 0.49000000000021,372 0.49 5,000 0.11New PGIS0000000000000000SUBTOTAL PGIS 1,464 0.0300000000001,464 0.03 617 0.01SUBTOTAL Impervious 7,329 0.17 3,806 0.090000000011,135 0.26 617 0.01Forested, TreesNon PGPS210,8914.8436,7290.8444,1131.017080.02460,76510.5800753,20617.29131,9913.03Landscaping Non PGPS30.003,7570.09000000003,7600.0900BeachNon PGPS000000000030,5160.7030,5160.7000EstuaryNon PGPS0000000000000000SUBTOTALNon PGPS 210,894 4.84 40,486 0.93 44,113 1.017080.02 460,765 10.58 30,516 0.70 787,482 18.08 131,991 3.03SUBTOTALPervious 210,894 4.84 40,486 0.93 44,113 1.017080.02 460,765 10.58 30,516 0.70 787,482 18.08 131,991 3.03TOTALAll218,223 5.01 44,292 1.02 44,113 1.017080.02 460,765 10.58 30,516 0.70 798,617 18.33 132,608 3.04Off-Site Areas that Drain Through Project AreaStormwater Site PlanMeadowdale Beach Park and Estuary Restoration ProjectDRAFTPage 4 of 5November 2018 Meadowdale Beach ParkStormwater Analysis - Proposed Land Cover and Drainage AreasAREA 1AREA 2AREA 3AAREA 3BAREA 4Area 5TOTALAREA 6Designation(SF)(AC)(SF)(AC)(SF)(AC)(SF)(AC)(SF)(AC)(SF)(AC)(SF)(AC)(SF)(AC)TDA 1TDA 2North Side of Creek, Drains to CreekRailroad Berm and BeachAreas 1-5Access Driveway and Parking AreaRanger Residence AreaArea West of Ranger Residence and South of Creek That Drains to Rock Swale Area West of Ranger Residence and South of Creek That Drains to Creek Access Driveway and Off-Site Areas, Drains to Puget Sound South of Project SiteSurfaceDescriptionSidewalksNon PGIS004,9170.11 4,3860.101,1940.03 10,1960.230020,693 0.4800Existing (Remain) Non PGIS004920.01000010,196 0.230010,688 0.2500ReplacedNon PGIS004,4250.104,3860.101,1940.03000010,005 0.2300NewNon PGIS0000000000000000Gravel PathsNon PGIS002,8080.061,0240.02 1,1990.0300005,031 0.1200Existing (Remain) Non PGIS002,2640.05000000002,2640.0500ReplacedNon PGIS005440.01000000005440.0100NewNon PGIS00001,0240.021,1990.0300002,2230.0500Concrete PadsNon PGIS00630.006690.023300.01008290.02 1,891 0.0400Existing (Remain) Non PGIS0000000000000000ReplacedNon PGIS00001670.0000005860.017530.0200NewNon PGIS00630.005020.013300.01002430.011,1380.0300RoofsNon PGIS 5,8650.13 1,2850.03 1,171 0.030000008,321 0.1900Existing (Remain) Non PGIS 5,8650.131,0500.025420.010000007,4570.1700ReplacedNon PGIS002350.01000000002350.0100NewNon PGIS00006290.010000006290.0100Railroad Alignment Non PGIS000000000025,0000.5725,0000.5700Existing (Remain) Non PGIS000000000025,000 0.57 25,000 0.57 0 0ReplacedNon PGIS0000000000000000NewNon PGIS0000000000000000SUBTOTALNon PGIS 5,865 0.13 9,073 0.21 7,250 0.17 2,723 0.06 10,196 0.23 25,829 0.59 60,936 1.4000RoadwaysPGIS23,6420.54000000000023,6420.54 5,7250.13Existing (Remain)PGIS1,4640.0300000000001,4640.037250.02ReplacedPGIS21,372 0.49000000000021,372 0.495,0000.11NewPGIS8060.0200000000008060.0200SUBTOTALPGIS23,642 0.54000000000023,642 0.54 5,725 0.13SUBTOTALImpervious 29,507 0.68 9,073 0.21 7,250 0.17 2,723 0.06 10,196 0.23 25,829 0.59 84,578 1.94 5,725 0.13Forested, TreesNon PGPS219,0515.0336,7290.8455,1101.2748,3251.11503,68011.5600862,89519.81135,5113.11LandscapingNon PGPS4680.0120,5100.4711,2020.2600000032,1800.7400BeachNon PGPS000000000042,9480.9942,9480.9900EstuaryNon PGPS000024,7720.5721,9980.51000046,7701.0700SUBTOTALNon PGPS 219,519 5.04 57,239 1.31 91,084 2.09 70,323 1.61 503,680 11.56 42,948 0.99 984,793 22.61 135,511 3.11SUBTOTALPervious 219,519 5.04 57,239 1.31 91,084 2.09 70,323 1.61 503,680 11.56 42,948 0.99 984,793 22.61 135,511 3.11TOTALAll249,026 5.72 66,312 1.52 98,334 2.26 73,046 1.68 513,876 11.80 68,777 1.58 1,069,371 24.55 141,236 3.24Notes:PGIS: Pollution Generating Impervious SurfacePGPS: Pollution Generating Pervious SurfaceTotal Drainage AreaStormwater Site PlanMeadowdale Beach Park and Estuary Restoration ProjectDRAFTPage 5 of 5November 2018 Appendix C Minimum Requirements Flow Charts EDMONDS STORMWATER ADDENDUM JUNE 2017 8 3. APPLICABILITY OF THE MINIMUM REQUIREMENTS Figure 3.1. Flow Chart for Determining Requirements for Development. Yes No Next Question Yes No Minimum Requirements No. 1 through 5 apply Minimum Requirement No. 2 applies Does the project add 5,000 square feet or more of new plus replaced hard surfaces? OR Convert 0.75 acres or more of vegetation to lawn or landscaped areas? OR Convert 2.5 acres or more of native vegetation to pasture? No Is this a road related project? Yes All Minimum Requirements apply to the new and replaced hard surfaces and converted vegetation areas. Does the project add 5,000 square feet or more of new hard surfaces? Does the project result in 2,000 square feet, or greater, of new plus replaced hard surface area? OR Does the land disturbing activity total 7,000 square feet or greater? Yes Do new hard surfaces add 50% or more to the existing hard surfaces within the project limits? No additional requirements. No No Yes All Minimum Requirements apply to the new hard surfaces and converted vegetation areas. Appendix D Construction SWPPP DRAFT Page | 1 Construction Stormwater Pollution Prevention Plan For Meadowdale Beach Park and Estuary Restoration Project Prepared For Department of Ecology – Northwest Regional Office 3190 – 160th Avenue SE Bellevue, WA 98008-5452 425-649-7000 Owner, Developer, and Operator/Contractor Snohomish County: Logan Daniels, P.E., Parks Engineer Snohomish County Parks and Recreation 6705 Puget Park Drive Snohomish WA 98296 Project Site Location 6026 156th Ave SW Edmonds, WA 98036 Certified Erosion and Sediment Control Lead Placeholder… SWPPP Prepared By Anchor QEA, LLC 720 Olive Way Suite 1900 Seattle, WA 98101 206-287-9130 David Rice, P.E – Project Civil Engineer SWPPP Preparation Date November 16, 2018 Project Construction Dates [Date] DRAFT Page | 2 Table of Contents 1 Project Information .............................................................................................................. 4 1.1 Existing Conditions ...................................................................................................... 5 1.2 Proposed Construction Activities .................................................................................. 9 2 Construction Stormwater Best Management Practices.......................................................11 2.1 The 13 Elements .........................................................................................................11 2.1.1 Element 1: Preserve Vegetation / Mark Clearing Limits .......................................11 2.1.2 Element 2: Establish Construction Access ...........................................................12 2.1.3 Element 3: Control Flow Rates ............................................................................13 2.1.4 Element 4: Install Sediment Controls ...................................................................14 2.1.5 Element 5: Stabilize Soils ....................................................................................15 2.1.6 Element 6: Protect Slopes....................................................................................16 2.1.7 Element 7: Protect Drain Inlets ............................................................................17 2.1.8 Element 8: Stabilize Channels and Outlets ..........................................................17 2.1.9 Element 9: Control Pollutants ...............................................................................18 2.1.10 Element 10: Control Dewatering ..........................................................................24 2.1.11 Element 11: Maintain BMPs .................................................................................24 2.1.12 Element 12: Manage the Project ..........................................................................25 2.1.13 Element 13: Protect Low Impact Development BMPs ..........................................26 3 Pollution Prevention Team .................................................................................................27 4 Monitoring and Sampling Requirements ............................................................................27 4.1 Site Inspection ............................................................................................................27 4.2 Stormwater Quality Sampling ......................................................................................27 4.2.1 Turbidity Sampling ...............................................................................................28 4.2.2 pH Sampling ........................................................................................................29 5 Reporting and Record Keeping ..........................................................................................30 5.1 Record Keeping ..........................................................................................................30 5.1.1 Site Log Book ......................................................................................................30 5.1.2 Records Retention ...............................................................................................30 5.1.3 Updating the SWPPP ...........................................................................................30 5.2 Reporting ....................................................................................................................30 5.2.1 Discharge Monitoring Reports ..............................................................................30 5.2.2 Notification of Noncompliance ..............................................................................31 DRAFT Page | 3 List of Acronyms and Abbreviations Acronym / Abbreviation Explanation ADA Americans with Disabilities Act BMP Best Management Practice(s) CESCL Certified Erosion and Sediment Control Lead CO2 Carbon Dioxide County Snohomish County Parks and Recreation Department CSWGP Construction Stormwater General Permit DMR Discharge Monitoring Report Ecology Washington State Department of Ecology ESC Erosion and Sediment Control NTU Nephelometric Turbidity Units sf square feet SSP Stormwater Site Plan SPCC Spill Prevention, Control, and Countermeasure su Standard Units SWPPP Stormwater Pollution Prevention Plan TESC Temporary Erosion and Sediment Control TMDL Total Maximum Daily Load DRAFT Page | 4 1 Project Information This Stormwater Pollution Prevention Plan (SWPPP) has been prepared as part of the National Pollutant Discharge Elimination System stormwater permit requirements for the Meadowdale Beach Park and Estuary Restoration project (Project). Project information is as follows: Project/Site Name: Meadowdale Beach Park and Estuary Restoration Street/Location: 6026 156th SW City: Edmonds State: Washington Zip code: 98036 Subdivision: N/A Receiving waterbody: Puget Sound The Snohomish County Parks and Recreation Department (County) is proposing to construct improvements to Meadowdale Beach County Park. The primary objectives of the project are to restore ecological functions and expand the Lund’s Gulch Creek estuary, improve habitat conditions for salmon and other wildlife in lower Lund’s Gulch Creek, address public safety issues involving the existing railroad crossing, and improve access (including Americans with Disabilities Act (ADA)- compliant access) to the beach. Additional elements of the design include the following: • Converting portions of the lower lawn area to stream marsh and riparian habitat • Enhancing riparian vegetation along the creek • Placing in-stream wood structures • Enhancing existing habitat north of the existing foot-bridge • Connecting existing fresh water wetland to the creek • Providing picnic viewpoints • Re-routing paths • Providing a new, portable restroom enclosure • Constructing a new foot-bridge over Lund’s Gulch Creek • Addressing other ADA issues within the lower park area • Improving stormwater runoff controls and treatment The project will also include improvements to the ADA access road and parking, as needed to support construction activity and improve ADA access, as well as interpretive/educational signage. The purpose of this SWPPP is to describe the proposed construction activities and temporary and permanent erosion and sediment control (TESC) measures, pollution prevention measures, inspection/monitoring activities, and recordkeeping that will be implemented during the proposed construction project. This SWPPP is intended to be reviewed with construction documentation to DRAFT Page | 5 support final project permitting for construction and to provide guidance for selection and implementation of required construction stormwater pollution prevention measures. The SWPPP has been prepared using the Washington State Department of Ecology Construction SWPPP template. A Stormwater Site Plan (SSP) report has been prepared and submitted with this SWPPP for the Project. The SSP is the comprehensive report containing the technical information and analyses to demonstrate compliance with stormwater requirements. The SSP incorporates the SWPPP by reference as Appendix D of the SSP. The SSP supports the stormwater design as shown on the Project construction plans. The Project construction plans include TESC drawings. The TESC drawings are included in Appendix A of this document and specifically address work to be undertaken in areas above the ordinary high water line. Work to be undertaken below the ordinary high water line shall comply with the Section 404 permit issued by the U.S. Army Corps of Engineers, the Hydraulic Project Approval issued by the Washington State Department of Fish and Wildlife, the Section 401 Certificate issued by Washington State Department of Ecology (Ecology), and other applicable permit requirements. 1.1 Existing Conditions Existing conditions and acreage of the existing project site are as follows: Total acreage: 108 acres (Park Total), 10 acres (Project Site) Disturbed acreage: 4.4 acres Existing structures: 0.02 acres Landscape topography: 1.4 acres Drainage patterns: See description below. Existing Vegetation: 4.0 acres Critical Areas (wetlands, streams, high erosion risk, steep or difficult to stabilize slopes): List of known impairments for 303(d) listed or Total Maximum Daily Load (TMDL) for the receiving waterbody: Ecology’s Water Quality Atlas indicates that Lund’s Gulch Creek, which flows through the Project site to Puget Sound, has a Category 5 bioassessment listing because the two most recent data points indicate that biological integrity is degraded based on benthic sampling by Snohomish County. There is also an area in Puget Sound just west of the Project Site that has a Category 2 sediment listing for 2,4-Dimethylphenol and Benzyl Alcohol. The site also has a Category 1 sediment listing for several chemical constituents. Another site along the shoreline of Puget Sound 1 mile south of the park has Category 1 listing for several constituents and a site approximately 1 mile north has a Category 1 sediment listing for several constituents. DRAFT Page | 6 The park spans the boundary between the City of Edmonds and unincorporated Snohomish County. The 108-acre Park consists of several parcels and is owned, operated, and maintained by the Snohomish County Parks and Recreation Department. The park extends from the rim of Lund’s Creek Gulch down to tidelands at the northern end of Browns Bay on Puget Sound. The park’s natural forests, stream, beach, and trails are the main attractions and are popular with residents throughout Snohomish County and nearby areas, attracting 50,000 to 70,000 annual visitors. The beach access is currently one of two available access points, along with Picnic Point County Park, between downtown Edmonds and Mukilteo. The park is also extensively used for environmental education by local schools, Boy and Girl Scouts, and Edmonds Community College (Dailer 2015). The park is also an official Washington Water Trails campsite, providing beach camping to people using a non-motorized watercraft. The park’s main public access is from a parking lot located off of 156th Street SW. This upper portion of the park includes a small playground, portable toilets, a trailhead, and 30 parking stalls. A 1.25-mile earthen trail begins at the upper parking lot and follows Lund’s Gulch Creek to a partially paved loop trail in the lower park area. This loop trail connects recreational amenities to the box culvert that provides beach access under the BNSF railroad. Facilities at the lower park include paved and unpaved trails, a sand volleyball court, picnic shelter, five uncovered picnic tables on concrete pads, a lawn area, pedestrian bridge, ADA parking, portable toilets, and a ranger residence. The main recreational activities at the park include beach access, walking and hiking, picnicking, bird watching/nature enjoyment, and environmental education programs. The existing earthen railroad embankment parallels the beach, separating the County tidelands from the park lawn. The embankment is heavily armored with riprap and boulder-sized rock and is approximately 30 feet wide at the top and 60 feet wide at the base. The top of the embankment is approximately 8 feet above the adjacent foot-path. The embankment lies within the 100-foot BNSF- owned right-of-way. The embankment supports two tracks: Main 1 track (west track) and Main 2 track (east track). The corridor, a segment of the BNSF Scenic Subdivision (Line Segment 50, Milepost 21.8; Seattle to Wenatchee, Washington), has a high daily volume of freight, passenger, and commuter railroad traffic, which will likely increase over time. This line also serves Amtrak and Sound Transit passenger trains. The existing concrete box culvert is located at the beginning of an approximately 4.5-degree curve in the railroad line. The culvert opening is 6 feet high by 6 feet wide and has an upstream invert elevation of 9.59 feet and a downstream invert elevation of 9.07 feet North American Vertical Datum of 1988. Following construction of the culvert, a wooden deck was placed approximately 2 feet above DRAFT Page | 7 the bottom of the culvert to accommodate public beach access and maintenance of the culvert. The wooden deck has since been replaced with steel grating. The culvert must accommodate creek flows, sediment, and fish passage, and it provides the only public beach access for park visitors. Year-round creek backwatering, high winter tides and stream flows, and sand and gravel deposition frequently render the culvert inaccessible. In addition, walkway grates are removed when sediments accumulate at the entrance, to facilitate fish passage. Without the grates installed, there is no suitable walking surface within the culvert for pedestrian beach access. Park users either traverse the culvert (sometimes in very cold knee-high water) or seek alternate routes to the beach, such as crossing the tracks, despite railroad right-of-way fencing and signs indicating the hazard and prohibiting trespassing. In addition, the culvert does not meet ADA guidelines for horizontal or vertical clearance. Description of Existing Drainage Areas and Patterns: Topographic survey data for the Project site, along with light detection and ranging (LiDAR) data and aerial photography, were used to delineate existing drainage areas that discharge to Lund’s Gulch Creek or Puget Sound within or adjacent to the Project site. Table 1 provides a summary of existing drainage areas. Drainage areas are characterized by pervious and hard surface areas. Most of the site discharges stormwater runoff directly to Lund’s Gulch Creek, which then discharges to Puget Sound at the west end of the site. Drainage Areas 1 through 4 represent the lower part of the larger Lund’s Gulch Creek Drainage Basin. The Lund’s Gulch Creek Drainage Basin includes approximately 1,440 acres (2.25 square miles) that drain to Puget Sound through the outlet of Lund’s Gulch Creek within the project site. Local stormwater drainage basins and existing stormwater facilities at the site are shown on the Site Maps in Appendix A. DRAFT Page | 8 Table 1 Existing Drainage Areas Area TDA 1 TDA 2 Area 1 Access Road and Parking Area (sf) Area 2 Ranger Residence Area (sf) Area 3 Hillside and Park Area South of Creek (sf) Area 4 Hillside and Park Area North of Creek (sf) Area 5 Railroad Berm and Beach (sf) TOTAL Areas 1–5 (sf) Overall Lund’s Gulch Creek Drainage Basin (acres) Area 6 Access Road Entrance and Off-Site Areas (sf) Within Project Site Area Hard Surface Area 22,836 1,184 14,211 12,159 10,206 60,596 1.4 5,108 Pervious Surface Area 9,442 7,800 112,276 39,786 27,368 196,672 4.5 3,520 Subtotal 32,278 8,984 126,487 51,945 37,574 257,268 5.9 8,628 Off-Site Areas that Drain through Project Site Hard Surface Area 5,865 4,778 0 0 14,795 25,438 362.9 617 Pervious Surface Area 210,883 30,112 67,331 461,931 16,408 786,665 1,071.2 131,991 Subtotal 216,748 34,890 67,331 461,931 31,203 812,103 1,434.1 132,608 Total Drainage Area Hard Surface Area 28,701 5,962 14,211 12,159 25,001 86,034 364.3 5,725 Pervious Surface Area 220,325 37,912 179,607 501,717 43,776 983,337 1,075.7 135,511 Total 249,026 43,874 193,818 513,876 68,777 1,069,371 1,440.0 141,236 Notes: TDA = Threshold Drainage Area SF = square foot DRAFT Page | 9 1.2 Proposed Construction Activities Description of Site Development: The Project will include significant investment by Snohomish County to improve recreation in the park and restore vital estuarine habitat. Improvements are envisioned to include the following: • Railroad Bridge: The existing box culvert will be replaced with a four-span railroad bridge with two 40-foot clear center spans and two 25-foot abutment spans centered on the location of the current culvert and creek outlet alignment. • Habitat Restoration: The lower lawn area and part of the upper lawn area will be converted to estuary, stream, marsh, and riparian habitat, with additional habitat area restored by enhancing riparian vegetation and in-stream wood structures. Existing habitat will also be enhanced upstream of the pedestrian footbridge across Lund’s Gulch Creek by installing large woody debris and enhancing existing riparian vegetation. • Recreation Facilities: - Beach Access: A pedestrian access path to the beach will be located under the railroad bridge and will provide the 80-inch minimum vertical clearance required for ADA- compliant access. - Pedestrian Bridge: A new pedestrian bridge will be installed across the restored stream channel downstream of the existing pedestrian bridge to connect pathways on the north and south sides of the stream. - Paths: The path connecting the picnic shelter to the pedestrian bridge and path on the north side of the creek will be partially re-aligned. The loop path north of the creek and proposed marsh will be truncated to avoid habitat fragmentation. Other existing paths will be resurfaced and modified, as needed, to accommodate restoration and new park facilities. - Lawn Renovation: Drainage of remaining lawn areas will be improved by regrading lawn areas and adding a more permeable subsurface layer, and the volleyball court will be converted to lawn area. - ADA-Compliant Access: ADA-compliant access will be extended throughout the park by constructing accessible walkways from the parking area to the beach. - Site Furnishings: New benches, picnic tables, and other site furnishings will be provided to enhance the park and recreational facilities. - Picnic Viewpoints: Two picnic viewpoints would be established at the new path terminus. Description of construction activities: Construction activities will include site preparation, placement of temporary erosion control best management practices (BMPs), clearing and grubbing, upland demolition, construction of the new BNSF Railroad Bridge, mass upland grading, fill and excavation, creation of estuarine habitat, removal and replanting of native and ornamental tree and shrub vegetation, placing of habitat gravel and boulders for drainage channel daylighting, new utility construction and removal/abandonment of old DRAFT Page | 10 utilities, installation of a wet bio-filtration swale and other drainage swales, shoreline grading and nourishment with new beach habitat gravel, and access road and parking lot improvements. Description of site drainage including flow from and onto adjacent properties: Most of the site discharges stormwater runoff directly to Lund’s Gulch Creek, which then discharges to Puget Sound at the west end of the site. The existing park has limited stormwater conveyance and control infrastructure. Existing stormwater facilities within the project site include the following: • Access Road Swale: A paved swale runs along the upslope side of the existing a that provides ADA-compliant and ranger access to the lower park. The access road is sloped so that runoff from the access road and forested slope south of the access road collects in the swale and discharges through a vegetated area towards Lund’s Gulch Creek, where the access road makes a hairpin turn into the ADA parking area. As-built drawings of the park indicate that the swale is 1 foot deep and is paved with asphalt, similar to the adjacent access road. Existing water, sewer, electrical, and communications service lines are buried under the swale. • Catch Basin and Drain to Creek in ADA Parking Lot: A single catch basin is located in the lowest (northwest) corner of the ADA parking area at the bottom of the access road, behind the ranger residence. The catch basin discharges runoff through a 6-inch-diameter PVC pipe north to Lund’s Gulch Creek. The catch basin only captures runoff from a small portion of the paved parking area surface. Runoff from most of the paved parking area and lower access road discharges via sheet flow runoff to adjacent vegetated areas. • Roof Drains: Gutters and downspouts collect and discharge runoff from rooftops over the ranger residence, an existing picnic shelter, and a portable restroom enclosure directly to adjacent lawn, landscaping, or paved areas. • Drinking Fountain Drain: A drinking fountain adjacent to the existing picnic shelter drains to the soil below the adjacent lawn area through a small sump with an inlet grate and a subsurface trench drain. • Lund’s Gulch Creek and Culvert: Runoff from all of the upland area of the project site drains to Lund’s Gulch Creek. As noted, the creek flows through a concrete box culvert through the BNSF railway embankment to Puget Sound. Proposed drainage improvements to be constructed as part of the project include the following: • A reconstructed swale along the uphill side of the access road that will convey runoff from the access road to a catch basin at the downstream end of the swale. The catch basin will convey runoff to a storm drain system. • A network of 8- and 12-inch-diameter corrugated polyethylene storm drain pipe and catch basins will be installed to capture and convey runoff from PGHS in the access road and parking area to a wet bio-filtration swale located in Drainage Area 2. DRAFT Page | 11 • The wet bio-filtration swale will be installed along the south edge of the paved loop pathway near the lawn area. The wet bio-filtration swale will serve as the treatment BMP for runoff from the access road, parking area, and other surfaces tributary to the storm drain facilities. • Flow from the biofiltration swale will be conveyed to a rock-lined swale located in the estuary area via a 12-inch-diameter corrugated polyethylene storm drain pipe. • The rock-lined swale will be constructed to convey the stormwater to the mean higher high water mark within the estuary to meet requirements for discharging directly to Puget Sound through manmade conveyance facilities. • Runoff from impervious pathways will be dispersed through adjacent sheet flow dispersion areas that will consist of a gravel dissipating strip and landscaping that will provide the needed 10-foot of vegetated flow path for every 20 feet of contributing surface. • Runoff from roofs will be dispersed through adjacent lawn areas or landscaping. Description of final stabilization: Final stabilization will include more than 28,000 sf of new landscaping; native tree and shrub plantings; riparian enhancement planting and estuary restoration over an area of over 47,000 sf; placement of more than 15,000 sf of crushed rock, gravel, or beach sand and gravel surfaces; placement of more than 20,000 sf of paved walkway surface, and placement of more than 22,000 sf of new or overlaid roadway surface. Contaminated Site Information: The Project does not include or anticipate any proposed activities dealing with contaminated soils or groundwater. 2 Construction Stormwater Best Management Practices 2.1 The 13 Elements 2.1.1 Element 1: Preserve Vegetation / Mark Clearing Limits To protect adjacent properties and to reduce the area of soil exposed to construction, the limits of construction will be clearly marked before land-disturbing activities begin. Trees that are to be preserved, as well as all sensitive areas and their buffers, shall be clearly delineated and tree protection fencing shall be installed, as shown on the design drawings. In general, natural vegetation and native topsoil shall be retained in an undisturbed state to the maximum extent possible. High Visibility Plastic or Metal Fence will be used to mark clearing limits for the project and will be placed prior to construction. Fences will be maintained throughout the construction period. Natural vegetation will be preserved for any areas beyond the clearing limits; no disturbance or removal of ground cover beyond the clearing limits will be permitted. Where a silt fence is placed along the clearing limits, marking using High Visibility Plastic or Metal Fence will not be required. Tree protection and clearing limit marking and maintenance requirements are shown on the TESC drawings in Appendix A and on the details included in Appendix B. DRAFT Page | 12 List and describe BMPs: BMP C101 (Preserving Natural Vegetation) BMP C102 (Buffer Zones) BMP C103 (High Visibility Plastic or Metal Fence) Installation Schedules: Prior to Clearing and Grading. Inspection and Maintenance plan: All BMPs to be inspected at least once a week by the Certified Erosion and Sediment Control Lead (CESCL) and within 24 hours following any increase in discharge from the site. The site inspector will use the site inspection forms provided in Appendix D. Where the need is identified by the site inspection, maintenance and repairs will be made to each BMP and documented as soon as possible following site inspections. Responsible Staff: CESCL, Construction Contractor Primary Contact 2.1.2 Element 2: Establish Construction Access Construction access or activities occurring on unpaved areas shall be minimized; however, where necessary, access points shall be stabilized to minimize the tracking of sediment onto public roads. Stabilized Construction Entrances shall be required at each entrance to the site from public roads. Wheel washing, street sweeping, and street cleaning shall be employed, as needed, to prevent sediment from entering state waters. All wash wastewater shall be controlled on site. A Stabilized Construction Entrance will be placed at the entrance to the Project site and will remain throughout the full period of construction (or will be reconstructed as the entrance point from the paved access road changes). The entrance will initially be located at the access point from the paved parking lot at the end of the access road. The Construction Entrance will be relocated as needed as Project work proceeds. The entrance will consist of geotextile beneath 4- to 8-inch quarry spalls a minimum of 12 inches thick. The entrance pad will be a minimum of 15 feet wide and 100 feet long. Additional details are provided on the TESC drawings in Appendix A and in the BMP description in Appendix B. List and describe BMPs: • BMP C105 (Stabilized Construction Entrance) • BMP C107 (Construction Road/Parking Area Stabilization) Installation Schedules: DRAFT Page | 13 Prior to Clearing and Grading. Inspection and Maintenance plan: All BMPs to be inspected at least once a week by the CESCL and within 24 hours following any increase in discharge from the site. The site inspector will use the site inspection forms provided in Appendix D. Where the need is identified by the site inspection, quarry spalls, crushed rock, gravel base, or hog fuel shall be added to maintain a stable driving surface and prevent sediment from leaving the site. Responsible Staff: CESCL, Construction Contractor Primary Contact 2.1.3 Element 3: Control Flow Rates No properties or waterways downstream of the Project site require flow control protection. Stormwater runoff discharges from the site directly to Puget Sound. Because Puget Sound is listed a major receiving body and meets the criteria for flow control exemption, no permanent flow controls are required. However, Snohomish County requires temporary facilities to control discharge of sediment laden water to Puget Sound. Will you construct stormwater retention and/or detention facilities? Yes No Will you use permanent infiltration ponds or other low impact development (example: rain gardens, bio-retention, porous pavement) to control flow during construction? Yes No List and describe BMPs: • No BMPs are specified. Installation Schedules: N/A Inspection and Maintenance plan: N/A Responsible Staff: CESCL, Construction Contractor Primary Contact DRAFT Page | 14 2.1.4 Element 4: Install Sediment Controls All stormwater runoff from disturbed areas shall pass through an appropriate sediment removal BMP before leaving the construction site or prior to being discharged to an infiltration facility. Runoff from fully stabilized areas may be discharged without a sediment removal BMP. Full stabilization means concrete or asphalt paving; quarry spalls used as ditch lining; or the use of rolled erosion products, a bonded fiber matrix product, or established vegetative cover in a manner that will fully prevent soil erosion. Silt fences will be installed downslope of all disturbed upland areas. Silt Fences will be installed at the same time clearing limits are marked, after the Stabilized Construction Entrance is installed and prior to initiating other grading work. Silt Fences will remain during the duration of the Project, but may be relocated to accommodate grading and riparian and shoreline work. Silt Fence will consist of steel or wood posts no more than 6 feet apart with welded wire backing and filter fabric material no less than 2 feet high. Additional details are provided on the TESC drawings in Appendix A and in the BMP description in Appendix B. Where soil materials and imported materials will be stockpiled on or adjacent to existing pavement, inlet protection or other appropriate sediment control device will be installed around all inlets and on the paved surface downslope of these areas, to prevent sediment from leaving the site. Additional details are provided on the TESC drawings in Appendix A and in the BMP description in Appendix B. In addition, sediment will be removed from paved areas in and adjacent to construction work areas manually or using mechanical sweepers, as needed, to minimize tracking of sediments on vehicle tires away from the site and to minimize washoff of sediments from adjacent streets in runoff. Whenever possible, sediment-laden water shall be dispersed into on-site, relatively level, vegetated areas. List and describe BMPs: • BMP C233 (Silt Fence) • BMP C220 (Storm Drain Inlet Protection) Installation Schedules: Prior to clearing and grading, following construction entrance construction. Inspection and Maintenance plan: All BMPs to be inspected at least once a week by the CESCL and within 24 hours following any increase in discharge from the site. The site inspector will use the site inspection forms provided in Appendix D. Where the sediment controls are damaged or do not provide a complete barrier for sediment transport from the site, as indicated by the inspection, maintenance and repairs will be made to each BMP and documented as soon as possible following site inspections. DRAFT Page | 15 Responsible Staff: CESCL, Construction Contractor Primary Contact 2.1.5 Element 5: Stabilize Soils Exposed and unworked soils shall be stabilized with the application of effective BMPs to prevent erosion throughout the life of the Project. The specific BMPs for soil stabilization that shall be used on the Project include Temporary and Permanent Seeding, Mulching, and Nets and Blankets. If needed, Plastic Covering may also be used. Nets and Blankets or Plastic Covering will be provided as temporary cover for exposed soils during construction. Additional details are provided on the TESC drawings in Appendix A and in the BMP descriptions in Appendix B. Mulching and Permanent Seeding will be used to stabilized permanent slopes or slopes that will be exposed for an extended period of time. In general, cut and fill slopes will be stabilized as soon as possible, and soil stockpiles will be temporarily covered with plastic. All stockpiled soils shall be stabilized from erosion, protected with a silt fence or block and gravel filter, and where possible, be located away from storm drain inlets, waterways, and drainage channels. West of the Cascade Mountains Crest Season Dates Number of Days Soils Can be Left Exposed During the Dry Season May 1 – September 30 7 days During the Wet Season October 1 – April 30 1 day Soils must be stabilized at the end of the shift before a holiday or weekend if needed based on the weather forecast. Anticipated project dates: Start date: XXX XX, 20XX End date: XXX XX, 20XX Will you construct during the wet season? Yes No List and describe BMPs: • BMP C120 (Temporary and Permanent Seeding) • BMP C121 (Mulching) • C122 (Nets and Blankets) • C123 (Plastic Covering) DRAFT Page | 16 Installation Schedules: When soils are exposed or stockpiles are stablished, as indicated in the table above or at the end of a shift before a holiday or weekend, if needed, based on the weather forecast. Inspection and Maintenance plan: All BMPs to be inspected at least once a week by the CESCL and within 24 hours following any increase in discharge from the site. The site inspector will use the site inspection forms provided in Appendix D. Where exposed soils or stockpiles are not well covered or coverings are not in good contact with the ground, as indicated by the inspection, maintenance and repairs will be made to each BMP and documented as soon as possible following site inspections. Responsible Staff: CESCL, Construction Contractor Primary Contact 2.1.6 Element 6: Protect Slopes All cut and fill slopes will be designed, constructed, and protected in a manner that minimizes erosion. The specific BMPs for slope protection that shall be used on this project include Temporary and Permanent Seeding, Mulching, and Nets and Blankets. Nets and Blankets or Plastic Covering will be provided as temporary cover for exposed slopes during construction. Additional details are provided on the TESC drawings in Appendix A and in the BMP descriptions in Appendix B. Mulching and Permanent Seeding will be used to stabilize permanent slopes or slopes that will be exposed for an extended period of time. Steep slopes will be present at the site during construction. Will steep slopes be present at the site during construction? Yes No List and describe BMPs: • BMP C120 (Temporary and Permanent Seeding) • BMP C121(Mulching) • BMP C122 (Nets and Blankets) • BMP C123 (Plastic Covering) Installation Schedules: When steep slopes are exposed, as indicated in the table above or at the end of a shift before a holiday or weekend, if needed, based on the weather forecast. Inspection and Maintenance plan: All BMPs to be inspected at least once a week by the CESCL and within 24 hours following any increase in discharge from the site. The site inspector will use the site inspection forms provided in Appendix D. Where exposed slopes are not well covered or coverings are not in good contact with DRAFT Page | 17 the ground, as indicated by the inspection, maintenance and repairs will be made to each BMP and documented as soon as possible following site inspections. Responsible Staff: CESCL, Construction Contractor Primary Contact 2.1.7 Element 7: Protect Drain Inlets All existing storm drain inlets, or any new storm drain inlets and culverts made operable during construction, shall be protected to prevent unfiltered or untreated water from entering the drainage conveyance system. There is only one existing storm drain inlet at the site. The first priority is to keep all access roads clean of sediment and sediment-laden water from entering storm drains until treatment can be provided. A Storm Drain Inlet Protection (catch basin insert) will be implemented for all drainage inlets and culverts that could potentially be impacted by sediment-laden runoff on and near the project site. The Storm Drain Inlet Protection shall consist of catch basin filters located at all catch basin inlets within the Project area. They will consist of a geotextile fabric that captures sediment for removal. Each insert shall have a built-in overflow or runoff that will allow water to pass through to the storm drain system during a storm event when the catch basin filter is full or plugged. Additional details are provided on the TESC drawings in Appendix A and in the BMP description in Appendix B. List and describe BMPs: • BMP C220 (Storm Drain Inlet Protection) Installation Schedules: Install prior to clearing and grading and prior to installation of construction entrances, after clearing limits are marked. Inspection and Maintenance plan: All BMPs to be inspected at least once a week by the CESCL and within 24 hours following any increase in discharge from the site. The site inspector will use the site inspection forms provided in Appendix D. If the catch basin insert becomes clogged, as indicated by the inspection, clean or replace the insert as soon as possible following site inspections. Do not wash sediment from inserts or other inlet controls into storm drains while clearing. Responsible Staff: CESCL, Construction Contractor Primary Contact 2.1.8 Element 8: Stabilize Channels and Outlets Where site runoff is to be conveyed in channels or discharged to a stream or some other natural drainage point, efforts will be taken to prevent downstream erosion. An existing stream channel and DRAFT Page | 18 natural outlet are part of the existing natural drainage system at the Project site. Construction of permanent drainage channels are also proposed as part of the Project; however, neither the proposed permanent drainage channels, nor the natural drainage channel will be used to convey runoff during construction. Runoff will be diverted around the channels during construction by temporary pumps and piping. Therefore, no BMPs from this element will be implemented. All temporary on-site conveyance facilities shall be designed, constructed, and stabilized to minimize erosion from the expected peak flow from a Type 1A, 10-year, 24-hour recurrence interval storm for the developed condition. Alternatively, the 10-year, 1-hour peak flow rate indicated by an approved continuous runoff simulation model, increased by a factor of 1.6, may be used. Stabilization, including armoring material adequate to prevent erosion of outlets, adjacent streambanks, slopes, and downstream reaches shall be provided at the outlets of all conveyance systems. Permanent channels will be armored with streambed boulder, cobbles, and large woody debris prior to diverting flow into the channels. List and describe BMPs: • No BMPs are specified Installation Schedules: N/A Inspection and Maintenance plan: N/A Responsible Staff: N/A 2.1.9 Element 9: Control Pollutants The following pollutants are anticipated to be present on-site: Table 1 – Pollutants Pollutant Waste Materials Demolition Debris Fuel for Construction Equipment Mechanical Fluids for Construction Equipment All pollutants, including waste materials and demolition debris, that occur on site shall be handled and disposed of in a manner that does not cause contamination of stormwater. Good housekeeping and preventative measures will be taken to ensure that the site will be kept clean, organized, and free DRAFT Page | 19 of debris. If required, BMPs noted below shall be implemented to control specific sources of pollutants. Cover, containment, and protection from vandalism shall be provided for all chemicals, liquid products, petroleum products, and other materials that have the potential to pose a threat to human health or the environment. On-site fueling tanks shall include secondary containment. Application of fertilizers and pesticides shall be conducted in a manner and at application rates that will not result in loss of chemical to stormwater runoff. Manufacturers’ label requirements for application rates and procedures shall be followed. Maintenance, fueling and repair of heavy equipment and vehicles shall be conducted using spill prevention and control measures consistent with Volume IV, Chapters 2 and 3 of the Snohomish County Drainage Manual and Chapter 7.53 of the Snohomish County Code. • All vehicles, equipment, and petroleum product storage/dispensing areas will be inspected regularly to detect any leaks or spills, and to identify maintenance needs to prevent leaks or spills. • Spill prevention measures, such as drip pans, will be used when conducting maintenance and repair of vehicles or equipment. • In order to perform emergency repairs on site, temporary plastic will be placed beneath and, if raining, over the vehicle. • Contaminated surfaces shall be cleaned immediately following any discharge or spill incident. • Water from wheel washes shall be disposed of in accordance with the requirements of BMP C106 – Wheel Wash. • Contaminated surfaces shall be cleaned immediately following any spill incident. Excavation and dewatering waste: • Dewatering BMPs and BMPs specific to the excavation (including handling of contaminated soils) are discussed under Element 10. Demolition: • Dust released from demolished paved pathways, buildings, or structures will be controlled using Dust Control measures. • Storm drain inlets vulnerable to stormwater discharge carrying dust, soil, or debris will be protected using Storm Drain Inlet Protection. • Process water and slurry resulting from sawcutting and surfacing operations will be prevented from entering the waters of the State by implementing Sawcutting and Surfacing Pollution Prevention measures. Concrete and grout: BMPs shall be used to prevent or treat contamination of stormwater runoff by pH modifying sources. These sources include, but are not limited to, bulk cement, cement kiln dust, fly ash, new concrete DRAFT Page | 20 washing, curing waters, waste streams generated from concrete grinding and sawing, exposed aggregate processes, dewatering concrete vaults, concrete pumping and mixer washout waters. • Concrete trucks shall only be washed out off-site or in designated concrete washout areas, and shall not be washed out onto the ground, or into storm drains, open ditches, streets, or streams. Excess concrete shall not be dumped on site, except in designated concrete washout areas. • Adjustment to the pH of stormwater will be performed if necessary to prevent violations of water quality standards. Written approval shall be obtained from the Washington State Department of Ecology prior to using chemical treatment other than carbon dioxide (CO2) or dry ice to adjust pH. Sanitary wastewater: • Portable sanitation facilities shall be located away from sensitive areas and will be firmly secured, regularly maintained, and emptied and cleaned regularly as needed. Solid Waste: • Solid waste will be stored in secure, clearly marked containers. Other: • Other BMPs will be administered as necessary to address any additional pollutant sources on site. As per the Federal regulations of the Clean Water Act and according to Final Rule 40 CFR Part 112, as stated in the National Register, a Spill Prevention, Control, and Countermeasure (SPCC) Plan is required for construction activities. The Contractor shall be responsible for preparing and maintaining an SPCC Plan per the requirements of the Contract Documents. This Plan must: • Be well thought out in accordance with good engineering • Achieve three objectives: prevent spills, contain a spill that occurs, and clean up the spill • Identify the name, location, owner, and type of facility • Include the date of initial operation and oil spill history • Name the designated person responsible • Show evidence of approval and certification by the person in authority • Contain a facility analysis Mobile refueling, maintenance and repair of heavy equipment, and concrete washing and sawing operations will occur per the approved SPCC Plan. Any spill locations will be immediately cleaned and waste material appropriately disposed of following any discharge or spill incident, as required by the approved SPCC Plan. List and describe BMPs: • BMP C140 (Dust Control) DRAFT Page | 21 • BMP C150 (Materials On Hand) • BMP C151 (Concrete Handling) • BMP C152 (Sawcutting and Surfacing Pollution Prevention) • BMP C220 (Storm Drain Inlet Protection) Installation Schedules: Install, maintain, or upgrade BMPs, as needed throughout construction to control pollutants. Inspection and Maintenance plan: All BMPs to be inspected at least once a week by the CESCL and within 24 hours following any increase in discharge from the site. The site inspector will use the site inspection forms provided in Appendix D. If a BMP is damaged or if additional control measures need to be applied to control pollution, as indicated by an inspection, repair, replace, or upgrade BMPs as soon as possible after site inspections. Responsible Staff: CESCL, Construction Contractor Primary Contact Will maintenance, fueling, and/or repair of heavy equipment and vehicles occur on-site? Yes No If maintenance, fueling, and/or repair of heavy equipment and vehicles occur on-site, the project specifications require that the Contractor comply with the following: Storage tank placement: The Contractor shall place fuel or other petroleum product (hereinafter referred to collectively as fuel) storage tanks or containers at least 20 feet from saltwater bodies, streams, flowing or dry watercourses, lakes, wetlands, reservoirs, and any other water source in a discharge area. Storage area dikes: The Contractor shall construct storage area dikes at least 12 inches high or graded and sloped to permit safe containment of leaks and spills equal to the capacity located in each area plus a sufficient amount of freeboard to contain the 25-year rainstorm. Diked area barriers: The Contractor shall provide diked areas with an impermeable barrier at least 50 mils thick. The Contractor shall provide areas used for refueling operations with an impermeable liner at least 50 mils thick buried under 2 to 4 inches of soil. Underground tank prohibitions: The Contractor shall not use underground storage tanks. Installation schedules: Prior to fueling or maintenance of equipment on site. Inspection and Maintenance plan: All BMPs to be inspected at least once a week by the CESCL and within 24 hours following any increase in discharge from the site. The site inspector will use the site DRAFT Page | 22 inspection forms provided in Appendix D. If a BMP is damaged or if additional control measures need to be applied to control pollution, as indicated by an inspection, repair, replace, or upgrade BMPs as soon as possible after site inspections. Responsible Staff: CESCL, Construction Contractor Primary Contact Will wheel wash or tire bath system BMPs be used during construction? Yes No List and describe BMPs: • No BMPs are specified. Installation Schedules: N/A Inspection and Maintenance plan: N/A Responsible Staff: N/A Will pH-modifying sources be present on-site? Yes No If yes, check the source(s). Table 3 – pH-Modifying Sources None Bulk cement Cement kiln dust Fly ash Other cementitious materials New concrete washing or curing waters Waste streams generated from concrete grinding and sawing Exposed aggregate processes Dewatering concrete vaults Concrete pumping and mixer washout waters Recycled concrete Recycled concrete stockpiles Other (i.e., calcium lignosulfate) [please describe: ] DRAFT Page | 23 List and describe BMPs: • BMP C152 (Sawcutting and Surfacing Pollution Prevention) Installation Schedules: Prior to performing new concrete installations and sawcutting or surfacing concrete. Inspection and Maintenance plan: All BMPs to be inspected prior to and weekly during concrete installation and sawcutting work. The site inspector will use the site inspection forms provided in Appendix D. If a BMP is damaged or if additional control measures need to be applied to control pollution, as indicated by an inspection, stop concrete work and upgrade controls as soon as possible. Responsible Staff: Adjustment of pH will be performed if outside the range of 6.5 to 8.5 su. Written approval from Ecology shall be obtained before using chemical treatment with the exception of CO2 or dry ice to modify pH. The following shall be used to prevent pH-modifying sources from contaminating stormwater: List and describe BMPs: BMP C152 (Sawcutting and Surfacing Pollution Prevention) Installation Schedules: Prior to performing new concrete installations and sawcutting or surfacing concrete. Inspection and Maintenance plan: All BMPs to be inspected prior to and weekly during concrete installation and sawcutting work. The site inspector will use the site inspection forms provided in Appendix D. If a BMP is damaged or if additional control measures need to be applied to control pollution, as indicated by an inspection, stop concrete work and upgrade controls as soon as possible. Responsible Staff: CESCL, Construction Contractor Primary Contact Will uncontaminated water from water-only based shaft drilling for construction of building, road, and bridge foundations be infiltrated provided the wastewater is managed in a way that prohibits discharge to surface waters? Yes No DRAFT Page | 24 List and describe BMPs: • No BMPs are specified. Installation Schedules: N/A Inspection and Maintenance plan: N/A Responsible Staff: N/A 2.1.10 Element 10: Control Dewatering All dewatering water from open cut excavation, foundation work, trench, or underground vaults shall be dispersed over relatively flat, vegetated areas. Clean, non-turbid dewatering water will be dispersed or discharged to systems tributary to the receiving waters of the State in a manner that does not cause erosion, flooding, or a violation of state water quality standards in the receiving water. Highly turbid dewatering water from soils known or suspected to be contaminated, or from use of construction equipment, will require additional monitoring and treatment as required for the specific pollutants based on the receiving waters into which the discharge is occurring. Such monitoring is the responsibility of the contractor. Dewatering of soils known to be free of contamination will trigger BMPs to trap sediment and reduce turbidity. List and describe BMPs: • No BMPs are specified. Installation Schedules: N/A Inspection and Maintenance plan: N/A Responsible Staff: N/A 2.1.11 Element 11: Maintain BMPs All temporary and permanent Erosion and Sediment Control (ESC) BMPs shall be maintained and repaired as needed to ensure continued performance of their intended function. Maintenance and repair shall be conducted in accordance with each particular BMP specification (see Volume II of the Snohomish County Drainage Manual). Visual monitoring of all BMPs installed at the site will be DRAFT Page | 25 conducted at least once every calendar week and within 24 hours of any stormwater or non- stormwater discharge from the site. If the site becomes inactive and is temporarily stabilized, the inspection frequency may be reduced to once every calendar month. All temporary ESC BMPs shall be removed within 30 days after final site stabilization is achieved or after the temporary BMPs are no longer needed. Trapped sediment shall be stabilized on-site or removed. Disturbed soil resulting from removal of either BMPs or vegetation shall be permanently stabilized. Additionally, protection must be provided for all BMPs installed for the permanent control of stormwater from sediment and compaction. BMPs that are to remain in place following completion of construction shall be examined and restored to full operating condition. If sediment enters these BMPs during construction, the sediment shall be removed and the facility shall be returned to conditions specified in the construction documents. 2.1.12 Element 12: Manage the Project The project will be managed based on the following principles: • Construction of the project will be phased to the maximum extent practicable and seasonal work limitations will be taken into account. • Inspection and monitoring: o Inspection, maintenance and repair of all BMPs will occur regularly and as needed to ensure performance of their intended function. • Maintain an updated SWPPP. o As site work progresses the SWPPP will be modified routinely to reflect changing site conditions. The SWPPP will be reviewed monthly to ensure the content is current. As site work progresses the SWPPP will be modified routinely to reflect changing site conditions. The SWPPP will be reviewed monthly to ensure the content is current. Table 5 – Management Design the project to fit the existing topography, soils, and drainage patterns Emphasize erosion control rather than sediment control Minimize the extent and duration of the area exposed Keep runoff velocities low Retain sediment on-site Thoroughly monitor site and maintain all ESC measures Schedule major earthwork during the dry season Other (please describe) SEE BELOW DRAFT Page | 26 Because the Project Site is located west of the Cascade Mountain Crest, the Project will be managed according to the following key project components: • Phasing of Construction o The construction project will be phased to the extent practicable in order to prevent soil erosion, and, to the maximum extent possible, the transport of sediment from the site during construction; however, the construction schedule will extend through the wet season. o Revegetation of exposed areas and maintenance of that vegetation shall be an integral part of the clearing activities during each phase of construction. • Seasonal Work Limitations o Construction is anticipated to occur during the wet season, from October 1 through April 30. From October 1 through April 30, clearing, grading, and other soil disturbing activities shall be permitted with the approval of Snohomish County. The Contractor shall demonstrate that potential for sediment-laden runoff to leave the site is minimized through a combination of the following: - Site conditions, including existing vegetative coverage, slope, soil type, and proximity to receiving waters - Limitations on activities and the extent of disturbed areas - Proposed erosion and sediment control measures o Based on the information provided and/or local weather conditions, Snohomish County may expand or restrict the seasonal limitation on site disturbance. 2.1.13 Element 13: Protect Low Impact Development BMPs The proposed project does not include any Low Impact Development BMPs designed to infiltrate runoff into underlying soils. The project will include the following permanent stormwater control BMPs: • A wet biofiltration swale that will treat stormwater runoff from the access road, parking lot, pathways, and other hard surfaces near the Ranger Residence. • Sheet flow dispersion areas will receive runoff from the pathways west of the biofiltration swale. The sheet flow dispersion areas and biofiltration swale will both be constructed to prevent sedimentation during construction. These BMPs will be constructed later during construction when adjacent surfaces have been stabilized. Following construction of these facilities, runoff from adjacent non-stabilized surfaces will be controlled so that sediment is not transported to these facilities until permanent storm drainage systems and controls are in place. DRAFT Page | 27 3 Pollution Prevention Team Table 5 – Team Information Title Name(s) Phone Number CESCL Placeholder Placeholder Resident Engineer Placeholder Placeholder Emergency Ecology Contact Northwest Regional Office, Spill and Emergency Reporting 425-649-7000 Emergency Permittee/ Owner Contact Placeholder Placeholder Non-Emergency Owner Contact Placeholder Placeholder Monitoring Personnel Placeholder Placeholder Ecology Regional Office Northwest Regional Office 425-649-7000 4 Monitoring and Sampling Requirements Monitoring includes visual inspection, sampling for water quality parameters of concern, and documentation of the inspection and sampling findings in a site log book. A site log book will be maintained for all on-site construction activities and will include: • A record of the implementation of the SWPPP and other permit requirements • Site inspections • Stormwater sampling data A sample form can be found in Appendix D. The site log book must be maintained on-site within reasonable access to the site and be made available upon request to Ecology or the local jurisdiction. 4.1 Site Inspection Site inspections will be conducted at least once every calendar week and within 24 hours following any discharge from the site. For sites that are temporarily stabilized and inactive, the required frequency is reduced to once per calendar month. The discharge point(s) are indicated on the Site Map (see Appendix A). 4.2 Stormwater Quality Sampling Turbidity and pH sampling shall be performed at all discharge points where stormwater (or authorized non-stormwater) is discharged from the site to Puget Sound or other off-site location, before it mixes with the storm drainage system or receiving waters. The Contractor shall identify a qualified CESCL to provide turbidity and pH monitoring as required by the Construction Stormwater General Permit (CSWGP). The CESCL shall monitor and report turbidity and pH as indicated in the CSWGP. DRAFT Page | 28 4.2.1 Turbidity Sampling Requirements may include a calibrated turbidity meter or transparency tube to sample site discharges for compliance with the CSWGP. Sampling will be conducted at all discharge points at least once per calendar week, or more frequently if required by the CSWGP. Method for sampling turbidity: • Not to exceed 5 Nephelometric Turbidity Units (NTU) over upstream turbidity when upstream turbidity is 50 NTU or less; and • Not to exceed 10% above upstream turbidity when upstream turbidity is greater than 50 NTU. For construction turbidity monitoring, turbidity benchmarks of 25 and 250 NTU are used. It is presumed that turbidity of 25 NTU or less is not likely to cause an exceedance of state water quality standards under most conditions, and BMPs are thought to be functioning well. Turbidity readings above 25 NTU indicate BMPs are not functioning properly, and action must be taken to correct problems. If the discharge’s turbidity is 26 to 249 NTU, the following steps will be conducted: 1. The CESCL must immediate notify the Contractor. 2. The Contractor will make all necessary efforts to correct the condition(s) on site that are causing, or contributing to, the excess turbidity. 3. The CESCL shall review the SWPPP for compliance with Special Condition S9. Make appropriate revisions to the SWPPP within 7 days of the date the discharge exceeded the benchmark. 4. The Contractor shall immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible. Address the problems within 10 days of the date the discharge exceeded the benchmark. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when the Permittee requests an extension within the initial 10-day response period. 5. Document BMP implementation and maintenance in the site log book. If the turbidity benchmark of 250 NTU is exceeded, there is a much higher risk of exceeding standards. In this event, immediate corrective actions must be taken, and the Washington State Department of Ecology (Ecology) must be notified within 24 hours (425-649-7000). If the turbidity exceeds 250 NTU, the following steps will be conducted: 1. The CESCL must immediately notify the Contractor and appropriate Snohomish County Clearing and Grading inspector. 2. The Clearing and Grading Inspector will forward the information to the Snohomish County Clearing and Grading Supervisor, who will telephone or submit an electronic report to the applicable Ecology Region’s Environmental Report Tracking System within 24 hours. DRAFT Page | 29 • Northwest Region (King, Kitsap, Island, San Juan, Skagit, Snohomish, Whatcom): (425) 649-7000 or http://www.ecy.wa.gov/programs/spills/forms/nerts_online/NWRO_nerts_online.html 3. The Contractor shall immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible. Address the problems within 10 days of the date the discharge exceeded the benchmark. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when the Permittee requests an extension within the initial 10-day response period. 4. Document BMP implementation and maintenance in the site log book. 5. The CESCL shall continue to sample discharges daily until one of the following is true: • Turbidity is 25 NTU (or lower). • The discharge stops or is eliminated. 4.2.2 pH Sampling The Contractor shall monitor pH as required by the CSWGP. Monitoring for pH is required for “Significant concrete work” (i.e., greater than 1,000 cubic yards poured concrete over the life of the project). The use of recycled concrete or engineered soils (soil amendments including but not limited to Portland cement-treated base, cement kiln dust or fly ash) also requires pH monitoring. For significant concrete work, pH sampling will start the first day concrete is poured and continue until it is cured, typically three (3) weeks after the last pour. For engineered soils and recycled concrete, pH sampling begins when engineered soils or recycled concrete are first exposed to precipitation and continues until the area is fully stabilized. The benchmark value for pH is 8.5 standard units unless otherwise noted in the CSWGP. Values shall be within the range of 6.5 to 8.5, with a human-caused variation within the above range of less than 0.2 units. Anytime sampling indicates that pH is 8.5 or greater, the high pH water (8.5 or above) must be prevented from entering the storm drainage system or surface waters, and, if necessary, the high pH water must be adjusted or neutralized. If the measured pH is 8.5 or greater, the following measures will be taken: 1. Prevent high pH water from entering storm sewer systems or surface water. 2. Adjust or neutralize the high pH water to the range of 6.5 to 8.5 su using appropriate technology such as CO2 sparging or dry ice. 3. Written approval will be obtained from Ecology prior to the use of chemical treatment other than CO2 sparging or dry ice. Method for sampling pH: A pH meter, pH test kit, or Wide range pH indicator paper shall be used to sample pH. DRAFT Page | 30 5 Reporting and Record Keeping 5.1 Record Keeping 5.1.1 Site Log Book A site log book will be maintained for all on-site construction activities and will include: • A record of the implementation of the SWPPP and other permit requirements • Site inspections • Sample logs 5.1.2 Records Retention Records will be retained during the life of the project and for a minimum of three (3) years following the termination of permit coverage unless otherwise specified in the CSWGP. Permit documentation to be retained on-site: • CSWGP • Permit Coverage Letter • SWPPP • Site Log Book Permit documentation will be provided within 14 days of receipt of a written request from Ecology. A copy of the SWPPP or access to the SWPPP will be provided to the public when requested in writing in accordance with the CSWGP. 5.1.3 Updating the SWPPP The SWPPP will be modified if: • Found ineffective in eliminating or significantly minimizing pollutants in stormwater discharges from the site. • There is a change in design, construction, operation, or maintenance at the construction site that has, or could have, a significant effect on the discharge of pollutants to waters of the State. The SWPPP will be modified within seven (7) days if inspection(s) or investigation(s) determine additional or modified BMPs are necessary for compliance. An updated timeline for BMP implementation will be prepared. 5.2 Reporting 5.2.1 Discharge Monitoring Reports Cumulative soil disturbance is one (1) acre or larger; therefore, Discharge Monitoring Reports (DMRs) will be submitted to Ecology monthly. If there was no discharge during a given monitoring period DRAFT Page | 31 the DMR will be submitted as required, reporting “No Discharge.” The DMR due date is 15 days following the end of each calendar month. DMRs will be reported online through Ecology’s WQWeb DMR System. 5.2.2 Notification of Noncompliance If any of the terms and conditions of the permit are not met, and the resulting noncompliance may cause a threat to human health or the environment, the following actions will be taken: 1. Ecology will be notified within 24-hours of the failure to comply by calling the applicable Regional office Environmental Report Tracking System phone number (Regional office numbers listed below). 2. Immediate action will be taken to prevent the discharge/pollution or otherwise stop or correct the noncompliance. If applicable, sampling and analysis of any noncompliance will be repeated immediately and the results submitted to Ecology within five (5) days of becoming aware of the violation. 3. A detailed written report describing the noncompliance will be submitted to Ecology within five (5) days, unless requested earlier by Ecology. Specific information to be included in the noncompliance report is found in the CSWGP. Anytime turbidity sampling indicates turbidity is 250 NTUs or greater, or water transparency is 6 cm or less, the Ecology Regional office will be notified by phone within 24 hours of analysis as required by Special Condition S5.A of the CSWGP. • Central Region at (509) 575-2490 for Benton, Chelan, Douglas, Kittitas, Klickitat, Okanogan, or Yakima County • Eastern Region at (509) 329-3400 for Adams, Asotin, Columbia, Ferry, Franklin, Garfield, Grant, Lincoln, Pend Oreille, Spokane, Stevens, Walla Walla, or Whitman County • Northwest Region at (425) 649-7000 for Island, King, Kitsap, San Juan, Skagit, Snohomish, or Whatcom County • Southwest Region at (360) 407-6300 for Clallam, Clark, Cowlitz, Grays Harbor, Jefferson, Lewis, Mason, Pacific, Pierce, Skamania, Thurston, or Wahkiakum The following information shall be included: 1. Your name and Phone number 2. Permit number 3. City and County of project 4. Sample results 5. Date and Time of call 6. Date and Time of sample 7. Project name DRAFT Page | 32 In accordance with the CSWGP, the Ecology Regional office will be notified if chemical treatment other than CO2 sparging is planned for adjustment of high pH water. DRAFT Page | 33 Appendix A – Site Maps and TESC Drawings 1 2 6 3 4 5 DRAFT 0 200 Feet LEGEND: Existing Storm Drain Project Limits Flow Direction Existing Storm Structure City/County Boundary BNSF ROW Drainage Area Existing Wetlands Publish Date: 2018/03/06 4:34 PM | User: jsexton Filepath: I:\Projects\Snohomish County\Meadowdale Beach Park\Park and Habitat Design\Task 5.2 60% Design\Stormwater\CAD\0723-RP-Figure 2-3 Exist Drainage Facilities(CSWPPP).dwg Figure 2-3 Figure A Site Map & Existing Drainage Facilities Stormwater Pollution Prevention Plan Meadowdale Beach Park Recreation and Habitat Improvements Project Lund's Gulch Creek 6' x 6' Outlet Culvert Under BNSF ROW Drainage Swale Ranger Residence Picnic Shelter Drinking Fountain & Drain Portable Restroom Enclosure Nov 16, 2018 3:30pm chewett k:\Projects\0723-snohomish county\meadowdale park\construction plans\0723-PL-Cover Sheet.dwg G-1G-1 PLAN COVER SHEET 1 75 PH/BS CH/TG BS PH AS NOTED NOVEMBER 2018 PERMIT SUBMITTAL MEADOWDALE BEACH PARK AND ESTUARY DESIGN SNOHOMISH COUNTY PARKS AND RECREATION PROJECT SITE Prime Consultant Project Manager: Peter Hummel, PLA Landscape Architect: Betsy Severtsen, PLA Civil Engineer: David Rice, PE 720 Olive Way Suite 1900 Seattle WA, 98101 (206) 287-9130 VICINITY MAPSOURCE: ESRI 0 SCALE IN FEET 2000 4000 NORTH Not to Scale TACOMA VANCOUVER BELLINGHAM WASHINGTON EDMONDS EDMONDS LYNNWOOD PUGET SOUND SEATTLE APPROVED FOR CONSTRUCTION BY: R/W PERMIT NO. DATE DESCRIPTIONAPP'DDATEBY REVISIONS REV ONE INCHAT FULL SIZE, IF NOT ONEINCH SCALE ACCORDINGLYDESIGNED BY: APPROVED BY: CHECKED BY: DRAWN BY: DATE: SCALE: MEADOWDALE BEACH PARK AND ESTUARY DESIGN 18-XXXXX SHEET # OF LDA PERMIT SUBMITTAL, NOT FOR CONSTRUCTION 720 Olive Way | Suite 1900 | Seattle, WA 98101 PFN: 18-XXXXX LDA SECTION 5, TOWNSHIP 27 N., RANGE 4 E STATE OFWASHINGTON LICENSEDLANDSCAPE ARCHITECT CERTIFICATE NO. 422 PETER C. HUMMEL COUNTY EXECUTIVE: DAVE SOMERS DIRECTOR OF PARKS AND RECREATION: TOM TEIGEN COUNCIL DISTRICT 1: ROB PUTNAM COUNCIL DISTRICT 2: JULIE LANGABEER COUNCIL DISTRICT 3: JOHN BRINEY COUNCIL DISTRICT 4: STEVE YANDL COUNCIL DISTRICT 5: BOB MCCARTY SITE ADDRESS: 15433 75TH PLACE WEST EDMONDS, WA 98026 TAX PARCEL NUMBERS: 00500900000500, 27040500200100, 27040500200200 LEGAL DESCRIPTIONS: SEE DRAWING G-3 PROJECT CESCL: TO BE DETERMINED BY CONTRACTOR Owner Logan Daniels Snohomish County Parks and Recreation 6705 Puget Park Drive Snohomish, WA 89296 (425) 388-6619 logan.daniels@snoco.org EARTHWORK - APPROXIMATE GRADING QUANTITIES GRADING LIMIT OF DISTURBANCE: 191,878 SF CUT: 19,100 CY FILL: 7,800 CY SLOPES GREATER THAN 33% WITHIN PROJECT SITE AREA: 6,070 SF (0.14 AC) DRAWING INDEX SHT #DWG #TITLE 1 G-1 PLAN COVER SHEET 2 G-2 PLAN COVER SHEET 2a G-3 PLAN COVER SHEET 3 CS-1 COMPOSITE SITE PLAN (1 OF 3) 4 CS-2 COMPOSITE SITE PLAN (2 OF 3) 5 CS-3 COMPOSITE SITE PLAN (3 OF 3) 6 TA-1 TEMPORARY ACCESS AND STAGING PLAN 7 EC-1 EXISTING CONDITIONS PLAN (1 OF 3) 8 EC-2 EXISTING CONDITIONS PLAN (2 OF 3) 9 EC-3 EXISTING CONDITIONS PLAN (3 OF 3) 10 T-1 TEMPORARY EROSION AND SEDIMENT CONTROL (TESC) PLAN (1 OF 3) 11 T-2 TEMPORARY EROSION AND SEDIMENT CONTROL (TESC) PLAN (2 OF 3) 12 T-3 TEMPORARY EROSION AND SEDIMENT CONTROL (TESC) PLAN (3 OF 3) 13 D-1 CLEARING AND DEMOLITION PLAN (1 OF 3) 14 D-2 CLEARING AND DEMOLITION PLAN (2 OF 3) 15 D-3 CLEARING AND DEMOLITION PLAN (3 OF 3) 16 CV-1 LAYOUT CONTROL PLAN (1 OF 3) 17 CV-2 LAYOUT CONTROL PLAN (2 OF 3) 18 CV-3 LAYOUT CONTROL PLAN (3 OF 3) 19 C-1 GRADING PLAN (1 OF 3) 20 C-2 GRADING PLAN (2 OF 3) 21 C-3 GRADING PLAN (3 OF 3) 22 C-4 GRADING CROSS-SECTIONS (1 OF 4) 23 C-5 GRADING CROSS-SECTIONS (2 OF 4) 24 C-6 GRADING CROSS-SECTIONS (3 OF 4) 25 C-7 GRADING CROSS SECTIONS (4 OF 4) 26 CM-1 CONSTRUCTION MATERIALS PLAN (1 OF 3) 27 CM-2 CONSTRUCTION MATERIALS PLAN (2 OF 3) 28 CM-3 CONSTRUCTION MATERIALS PLAN (3 OF 3) 29 CM-4 CONSTRUCTION MATERIAL DETAILS (1 OF 6) 30 CM-5 CONSTRUCTION MATERIAL DETAILS (2 OF 6) 31 CM-6 CONSTRUCTION MATERIAL DETAILS (3 OF 6) 32 CM-7 CONSTRUCTION MATERIAL DETAILS (4 OF 6) 33 CM-8 CONSTRUCTION MATERIAL DETAILS (5 OF 6) 34 CM-9 CONSTRUCTION MATERIAL DETAILS (6 OF 6) 35 RD-1 ROADWAY PLAN AND PROFILE (1 OF 2) 36 RD-2 ROADWAY PLAN AND PROFILE(2 OF 2) 37 RD-3 TYPICAL ACCESS ROADWAY SECTIONS 36 RD-2 ROADWAY PLAN AND PROFILE(2 OF 2) DRAWING INDEX SHT #DWG #TITLE 37 RD-3 TYPICAL ACCESS ROADWAY SECTIONS 38 RD-4 TYPICAL PARKING AREA SECTIONS 39 RD-5 ROADWAY AND PARKING AREA DETAILS 40 RD-6 ROADWAY REINFORCEMENT ELEVATIONS AND SECTIONS 41 RD-7 SPIRAL NAIL ROADWAY REINFORCEMENT DETAILS 42 RD-8 PARKING AREA STRIPING PLAN 43 CU-1 UTILITY PLAN (1 OF 2) 44 CU-2 UTILITY PLAN (2 OF 2) 45 CU-3 STORM DRAIN PROFILE 46 CU-4 DRAINAGE DETAILS 47 A1.0 ARCHITECTURAL GENERAL INFORMATION 48 A1.1 ARCHITECTURAL GENERAL NOTES 49 A2.0 PORTABLE TOILET ENCLOSURE FOUNDATION AND FLOOR PLANS 50 A2.1 ROOF PLANS 51 A3.0 PORTABLE TOILET ENCLOSURE ELEVATIONS 52 A3.1 EXISTING PICNIC SHELTER ELEVATIONS 53 A7.0 PORTABLE TOILET ENCLOSURE DETAILS 54 A7.1 PORTABLE TOILET ENCLOSURE ENLARGED ELEVATION, PICNIC SHELTER COLUMN BASE DETAIL 55 S1.1 GENERAL STRUCTURAL NOTES 56 S1.2 GENERAL STRUCTURAL NOTES 57 S2.1 STRUCTURAL OVERVIEW SITE PLAN 58 S2.2 TOILET ENCLOSURE STRUCTURAL PLANS 59 S2.3 PEDESTRIAN BRIDGE ABUTMENT AND BOARDWALK PLANS 60 S3.1 TOILET ENCLOSURE STRUCTURAL TYPICAL CONCRETE DETAILS 61 S3.2 TOILET ENCLOSURE STRUCTURAL CONCRETE DETAILS 62 S3.3 PEDESTRIAN BRIDGE CONCRETE ABUTMENT DETAILS 63 S3.4 BOARDWALK DETAILS 64 S4.1 TOILET ENCLOSURE DETAILS 65 S-4 PEDESTRIAN BRIDGE DETAIL 66 E-1 ELECTRIC SITE PLAN 67 E-2 ELECTRIC NOTES, DETAILS AND SCHEDULES 68 I-1 IRRIGATION PLAN (1 OF 3) 69 I-2 IRRIGATION PLAN (2 OF 3) 70 I-3 IRRIGATION PLAN (3 OF 3) 71 I-4 IRRIGATION DETAILS 72 L-1 PLANTING PLAN (1 OF 3) 73 L-2 PLANTING PLAN (2 OF 3) 74 L-3 PLANTING PLAN (3 OF 3) 75 L-4 PLANTING DETAILS MEADOWDALE BEACH PARK 168TH ST SW 164TH ST SW INTERSTATE 575TH PL WN MEADOWDALE ROAD Architectural Consultant Salt Studio LLC 66 Bell Street Unit #1 Seattle, WA 98121 (206) 948-2104 Surveyor Duane Hartman and Associates 16928 Woodinville-Redmond Road, Suite B-107 Woodinville, WA 98072 (425) 483-5355 Structural Engineering Consultant Swenson Say Faget 2124 Third Ave, Suite 100 Seattle, WA 98121 (206) 443-6212 Mechanical Engineering Consultant Rainbow Consulting 336 NW 50th St Seattle, WA 98107 (206) 235-6002 Irrigation Consultant William Stewart Design 9220 58th Avenue SE Olympia, WA 98513 (206) 605-9863 Electrical Engineering Consultant Cross Engineers 923 Martin Luther King Jr. Way Tacoma, WA 98405 (253) 759-0118 Activity Snohomish County City of Edmonds Total New impervious surfaces 3,964 666 4,630 Replaced impervious surfaces 17,103 26,584 43,687 Removed impervious surfaces -6,562 -2,839 -9,401 Net Change Total -2,598 -2,173 -4,771 BNSF RAILWAYPUGET SOUND LUND S CREEK GUL C H LUNDS G U L C H CREEK OFF-CHANNELPOND APPROVED FOR CONSTRUCTION BY: R/W PERMIT NO. DATE DESCRIPTIONAPP'DDATEBY REVISIONS REV ONE INCHAT FULL SIZE, IF NOT ONEINCH SCALE ACCORDINGLYDESIGNED BY: APPROVED BY: CHECKED BY: DRAWN BY: DATE: SCALE: MEADOWDALE BEACH PARK AND ESTUARY DESIGN 18-XXXXX SHEET # OF LDA PERMIT SUBMITTAL, NOT FOR CONSTRUCTION 720 Olive Way | Suite 1900 | Seattle, WA 98101 PFN: 18-XXXXX LDA SECTION 5, TOWNSHIP 27 N., RANGE 4 E STATE OFWASHINGTON LICENSEDLANDSCAPE ARCHITECT CERTIFICATE NO. 422 PETER C. HUMMEL Nov 16, 2018 3:30pm chewett k:\Projects\0723-snohomish county\meadowdale park\construction plans\0723-PL-Site Context and Layout Plan.dwg 2 G-20 SCALE IN FEET 80 160 NORTH X-1 X-2 X-3 PUGET SOUND LEGEND: PROJECT BOUNDARY CITY OF EDMONDS/SNOHOMISH COUNTY BOUNDARY PARK BOUNDARY PARCEL BOUNDARY BNSF RIGHT-OF-WAY BNSF CENTERLINE EXISTING OHWM EXISTING MHHW (EL. +9.0' MLLW) EXISTING LUND GULCH CREEK THALWEG EXISTING WETLAND TO BE PROTECTED 75TH PL W.G-2 PLAN COVER SHEET 2 75 PH/BS CH/TG BS PH 1" = 80' NOVEMBER 2018 NOTES: 1.HORIZONTAL DATUM: WASHINGTON STATE PLANE NORTH ZONE, NAD 83, U.S. FEET. 2.VERTICAL DATUM: NAVD 88 3.DRAWINGS ARE INTENDED TO BE VIEWED IN COLOR. SOME INFORMATION WILL BE LOST WITH BLACK AND WHITE VIEWING. RANGER RESIDENCE Nov 16, 2018 3:30pm chewett k:\Projects\0723-snohomish county\meadowdale park\construction plans\0723-PL-Cover Sheet.dwg 2a G-3G-3 PLAN COVER SHEET 2A 75 PH/BS CH/TG BS PH AS NOTED NOVEMBER 2018 APPROVED FOR CONSTRUCTION BY: R/W PERMIT NO. DATE DESCRIPTIONAPP'DDATEBY REVISIONS REV ONE INCHAT FULL SIZE, IF NOT ONEINCH SCALE ACCORDINGLYDESIGNED BY: APPROVED BY: CHECKED BY: DRAWN BY: DATE: SCALE: MEADOWDALE BEACH PARK AND ESTUARY DESIGN 18-XXXXX SHEET # OF LDA PERMIT SUBMITTAL, NOT FOR CONSTRUCTION 720 Olive Way | Suite 1900 | Seattle, WA 98101 PFN: 18-XXXXX LDA SECTION 5, TOWNSHIP 27 N., RANGE 4 E STATE OFWASHINGTON LICENSEDLANDSCAPE ARCHITECT CERTIFICATE NO. 422 PETER C. HUMMEL GENERAL NOTES: 1.ALL EMPLOYEES MUST COMPLY WITH BNSF SAFETY REQUIREMENTS. THIS INCLUDES, BUT IS NOT LIMITED TO, PASSING A SAFETY COURSE, OBTAINING DOCUMENTATION OF SUCCESSFULLY PASSING THE COURSE, AND ADHERING TO REQUIREMENTS IDENTIFIED IN THE COURSE. THE REQUIRED BNSF SAFETY COURSE MAY BE ACCESSED AT THE FOLLOWING WEBSITE: WWW.RAILROADCOURSES.COM. 2.A BNSF FLAGGER SHALL BE PRESENT ANY TIME THE CONTRACTOR IS WORKING WITHIN 25 FEET OF THE TRACKS. THE CONTRACTOR SHALL COMMUNICATE WITH THE OWNER TO ARRANGE FOR A FLAGGER TO BE PRESENT DURING THESE TIMES. 3.DRAWINGS ARE INTENDED TO BE VIEWED IN COLOR. SOME INFORMATION WILL BE LOST WITH BLACK AND WHITE VIEWING. SURVEY NOTES: 1.SURVEY BY DUANE HARTMAN & ASSOCIATES, INC IN 2017. 2.HORIZONTAL DATUM: WASHINGTON STATE COORDINATE SYSTEM, NORTH ZONE NAD83(91), U.S. FEET UTILIZING RTK GPS FIELD PROCEDURES 3.VERTICAL DATUM: TO CONVERT ELEVATIONS SHOWN HEREON TO MEAN LOWER LOW WATER DATUM PLEASE ADD 2.05 FEET. 4.UTILITIES MAPPING: ALL EXISTING UTILITIES SHOWN HEREIN ARE TO BE VERIFIED HORIZONTALLY AND VERTICALLY PRIOR TO ANY CONSTRUCTION. ALL EXISTING FEATURES INCLUDING BURIED UTILITIES ARE SHOWN AS INDICATED BY RECORD LOCATION OR FIELD TIED AS A RESULT OF A UTILITY PAINT-OUT DURING THE COURSE OF THE FIELD SURVEY. DUANE HARTMAN & ASSOCIATES, INC. (DHA) ASSUMES NO LIABILITY FOR THE ACCURACY OF THE RECORD INFORMATION. FOR THE FINAL LOCATION OF THE EXISTING UTILITIES IN AREAS CRITICAL TO CONSTRUCTION, CONTACT THE UTILITY OWNER/AGENCY AND UTILITIES UNDERGROUND CENTER (800/424-5555). 5.TOPOGRAPHIC MAPPING: THE MAP SHOWN HEREON IS THE RESULT OF A TOPOGRAPHIC SURVEY BY DUANE HARTMAN & ASSOCIATES, INC. (DHA) COMPLETED ON OCTOBER 2016. DHA ASSUMES NO LIABILITY, BEYOND SAID DATE, FOR ANY FUTURE SURFACE FEATURE MODIFICATIONS OR CONSTRUCTION ACTIVITIES THAT MAY OCCUR WITHIN OR ADJOINING THE PERIMETER OF THIS SURVEY. CONTACT DHA (425) 483-5355 FOR SITE UPDATES AND VERIFICATIONS. 6.RAILROAD RIGHT OF WAY LINES: THE BNSF RAILWAY RIGHT OF WAY LINES SHOWN HEREON HAVE BEEN CALCULATED USING TRACK STATIONING, RAILROAD GEOMETRY AND CADASTRAL CALL OUTS AS SHOWN ON "BNSF RAILWAY RIGHT OF WAY". LEGAL DESCRIPTION: DETAIL AND SECTION REFERENCING: DETAIL REFERENCE NUMBER DRAWING ON WHICH DETAIL APPEARS "-" INDICATES TYPICAL OR ON SAME DRAWING DETAIL REFERENCE NUMBER SECTION "A" IS SHOWN ON DRAWING "C-2" INDICATES DIRECTION OF CUTTING PLAN SECTION REFERENCE NUMBER 1 C-1 SCALE: DETAIL1 -1" = 10' A C-2 SCALE: SECTIONA -1" = 10' GENERAL CONSTRUCTION NOTES: 1.UNLESS OTHERWISE INDICATED ON THE DRAWINGS OR IN THE SPECIFICATIONS, ALL MATERIALS AND WORKMANSHIP SHALL BE ACCOMPLISHED IN ACCORDANCE WITH THE CURRENT SNOHOMISH COUNTY ENGINEERING DESIGN AND DEVELOPMENT STANDARDS, THE CITY OF EDMONDS COMMUNITY DEVELOPMENT CODE, THE SNOHOMISH COUNTY DRAINAGE MANUAL, THE CITY OF EDMONDS STORMWATER MANAGEMENT CODE, THE WSDOT STANDARD SPECIFICATIONS FOR ROAD, BRIDGE, AND MUNICIPAL CONSTRUCTION (CURRENT EDITION), AND OTHER APPLICABLE CODES AND STANDARDS. 2.THE CONTRACTOR SHALL HAVE COPIES OF THE APPROVED DRAWINGS, APPLICABLE SNOHOMISH COUNTY AND CITY OF EDMONDS STANDARDS, AND THE WSDOT STANDARD SPECIFICATIONS FOR ROAD, BRIDGE, AND MUNICIPAL CONSTRUCTION (CURRENT EDITION) ON THE JOB SITE WHENEVER CONSTRUCTION IS IN PROGRESS. 3.THE CONTRACTOR SHALL VISIT THE JOB SITE PRIOR TO CONSTRUCTION AND SHALL BE RESPONSIBLE FOR VERIFYING FIELD CONDITIONS AND DIMENSIONS, AND CONFIRMING THAT THE WORK CAN BE ACCOMPLISHED AS SHOWN ON THESE DRAWINGS. ANY DISCREPANCIES BETWEEN THE EXISTING FIELD CONDITIONS AND THE DRAWINGS OR ANY INCONSISTENCIES OR AMBIGUITIES BETWEEN THE DRAWINGS AND OTHER CONTRACT DOCUMENTS SHALL BE REPORTED IN WRITING TO THE OWNER (SNOHOMISH COUNTY) PRIOR TO PROCEEDING WITH THE WORK. WORK DONE BY THE CONTRACTOR INVOLVING SUCH DISCREPANCIES WITHOUT A WRITTEN REPORT AND RESPONSE FROM THE OWNER SHALL BE DONE AT THE CONTRACTOR'S SOLE RISK AND EXPENSE. 4.THE CONTRACTOR SHALL ASSUME SOLE AND COMPLETE RESPONSIBILITY FOR JOB SITE CONDITIONS DURING THE COURSE OF CONSTRUCTION, INCLUDING THE SAFETY OF ALL PERSONS AND PROPERTY. THIS REQUIREMENT SHALL APPLY CONTINUOUSLY AND IS NOT LIMITED TO NORMAL WORKING HOURS. 5.THE CONTRACTOR SHALL BE RESPONSIBLE FOR PROVIDING ADEQUATE SAFEGUARDS, SAFETY DEVICES, PROTECTIVE EQUIPMENT, FLAGGERS, AND ANY OTHER NEEDED ACTIONS TO PROTECT THE LIFE, HEALTH, AND SAFETY OF THE PUBLIC, AND TO PROTECT PROPERTY IN CONNECTION WITH THE PERFORMANCE OF WORK COVERED BY THE CONTRACT. 6.THE CONTRACTOR SHALL PROVIDE TEMPORARY CUT SLOPES AND SHORING AS NECESSARY FOR THE CONSTRUCTION AS SHOWN ON THESE DRAWINGS. THE STABILITY OF ALL TEMPORARY SLOPES AND SHORING IS THE SOLE RESPONSIBILITY OF THE CONTRACTOR. 7.THE CONTRACTOR SHALL BE SOLELY RESPONSIBLE FOR ALL CONSTRUCTION MEANS, METHODS, TECHNIQUES, SEQUENCES, AND PROCEDURES AND FOR COORDINATING ALL PORTIONS OF THE WORK UNDER THIS CONTRACT. 8.THE CONTRACTOR SHALL MAKE ALL NECESSARY PROVISIONS TO PROTECT EXISTING STRUCTURES, SIGNS, FENCES, GATES, CURBS, ROADWAYS, DRAINAGE WAYS, CULVERTS, VEGETATION, AND OTHER IMPROVEMENTS UNLESS AND UNTIL SUCH ITEMS ARE TO BE DISTURBED OR REMOVED AS INDICATED ON THE DRAWINGS. IF SUCH ITEMS ARE DAMAGED OR NEED TO BE REMOVED OR MODIFIED TO FACILITATE CONSTRUCTION, THE CONTRACTOR SHALL FIRST NOTIFY SNOHOMISH COUNTY AND THEN REPLACE OR REPAIR THE ITEMS TO EQUAL OR BETTER CONDITION TO THE SATISFACTION OF SNOHOMISH COUNTY. 9.THE CONTRACTOR SHALL NOT DISTURB OR DESTROY ANY EXISTING SURVEY MONUMENT OR BENCHMARK. ANY SURVEY MONUMENT OR BENCHMARK DISTURBED OR DESTROYED BY THE CONTRACTOR SHALL BE REPLACED AS DIRECTED BY SNOHOMISH COUNTY AT THE CONTRACTOR'S SOLE EXPENSE. 10.THE CONTRACTOR SHALL MAINTAIN CONTINUOUS ACCESS TO THE RANGER RESIDENCE THROUGHOUT CONSTRUCTION OF THE PROJECT. ANY TEMPORARY DISRUPTION OF ACCESS TO THE RANGER RESIDENCE SHALL BE AND APPROVED BY SNOHOMISH COUNTY. 11.WHERE A CONSTRUCTION DETAIL IS NOT SHOWN OR NOTED, THE DETAIL SHALL BE THE SAME AS FOR OTHER SIMILAR WORK. 12.THE DETAILS AND NOTES PROVIDED ON THE DRAWINGS AND IN THE SPECIFICATIONS SHALL TAKE PRECEDENCE OVER THESE GENERAL NOTES. 13.DIMENSION CALL-OUTS SHALL TAKE PRECEDENCE OVER SCALES SHOWN ON THE CONTRACT DOCUMENTS. 14.ALL MATERIALS SHALL BE NEW AND UNDAMAGED, UNLESS OTHERWISE APPROVED BY SNOHOMISH COUNTY AND THE ENGINEER. THE SAME MANUFACTURER OF EACH ITEM SHALL BE USED THROUGHOUT THE WORK UNLESS OTHERWISE APPROVED BY SNOHOMISH COUNTY AND THE ENGINEER. 15.RUBBISH, DEBRIS, AND GARBAGE SHALL BE REMOVED FROM THE JOB SITE AND DISPOSED OF LEGALLY, AS ALLOWED BY THE SNOHOMISH COUNTY ENGINEERING DESIGN AND DEVELOPMENT STANDARDS AND THE WSDOT STANDARD SPECIFICATIONS FOR ROAD, BRIDGE, AND MUNICIPAL CONSTRUCTION (CURRENT EDITION). 16.THE CONTRACTOR SHALL MAINTAIN HAND DRAWN REDLINES, FIELD NOTES AND PHOTOGRAPHS ("FIELD DOCUMENTATION") OF ALL IMPROVEMENTS AS THE WORK PROGRESSES, AS REQUIRED BY THE SPECIFICATIONS. THE CONTRACTOR SHALL ALSO TAKE PHOTOGRAPHS AND VIDEO TO DOCUMENT CONDITIONS PRIOR TO CONSTRUCTION. THE CONTRACTOR'S FIELD DOCUMENTATION SHALL BE MAINTAINED ON SITE AND SHALL BE AVAILABLE FOR REVIEW BY SNOHOMISH COUNTY AND THE ENGINEER AT ALL TIMES. EXISTING UTILITY NOTES: 1.THE LOCATIONS OF EXISTING UTILITIES SHOWN ON THESE DRAWINGS ARE APPROXIMATE AND ARE BASED ON SURVEYED UTILITY MARKINGS AND FEATURES VISIBLE AT THE SURFACE, SUPPLEMENTED BY AS-BUILT INFORMATION PROVIDED BY SNOHOMISH COUNTY. 2.THE CONTRACTOR SHALL BE RESPONSIBLE FOR FIELD LOCATING ALL UTILITIES PRIOR TO CONSTRUCTION. THE CONTRACTOR SHALL CALL THE UTILITY LOCATION REQUEST CENTER (ONE-CALL CENTER) AT 811 OR 1-800-424-5555 FOR UTILITY LOCATIONS NOT LESS THAN TWO (2) BUSINESS DAYS BEFORE THE SCHEDULED DATE FOR TRENCHING OR EARTHWORK THAT MAY IMPACT EXISTING UTILITIES. 3.THE SIZE, LOCATION, AND TYPE OF UNDERGROUND UTILITIES EXPOSED OR MODIFIED BY THE CONTRACTOR SHALL BE ACCURATELY NOTED AND PLACED ON THE CONTRACTOR'S RECORD DRAWINGS. 4.THE CONDITION OF ALL ABANDONED UTILITIES THAT INTERFERE WITH EXECUTION OF THE WORK SHALL BE VERIFIED BY THE UTILITY OWNER PRIOR TO DISTURBANCE OR MODIFICATION. THE CONTRACTOR MAY ONLY TAKE ACTION AFTER WRITTEN APPROVAL HAS BEEN RECEIVED FROM THE UTILITY OWNER BY THE SNOHOMISH COUNTY. 5.THE CONTRACTOR SHALL ENSURE THAT OPERATIONS OF EXISTING SEWER, WATER, POWER, TELECOMMUNICATIONS, AND OTHER UTILITY SYSTEMS SERVING THE RANGER RESIDENCE ARE NOT DISRUPTED DURING CONSTRUCTION WITHOUT PRIOR AUTHORIZATION OF THE SNOHOMISH COUNTY. 2704050020010027040500200100 00500900000500 00500900001602 00500900001601 BNSF RAILWAYPUGET SOUND LUN D S CREEKGUL C H 100' BNSF ROW PICNIC SHELTER VOLLEYBALL COURT ASPHALTPATH CONCRETE CULVERT, SLABS,GRATING, AND CHANNEL MATERIALS CRUSHED ROCK PATH RESTROOM ENCLOSURE,FOUNDATION,AND CONC. SLAB EXISTING PEDESTRIANLIGHT WITH SECONDARYUNDERGROUND POWER CONC. PAD, PICNIC TABLE, GRILL EXTENT OF TOPOGRAPHIC SURVEY EXTENT OF TOPOGRAPHIC SURVEY CONTOURS FROM LIDAR CONTOURS FROM LIDAR EXISTING BEACHTOPOGRAPHY (SEE NOTE 5) EXISTINGINFORMAL TRAILTO GAP IN FENCE SANITARY SEWER MANHOLE JUNCTION BOX WATER METER ROCKERY STORM DRAIN CATCH BASIN(TYPE I) MONUMENT IN CASE CONIFER DECIDUOUS SIGN EDGE OF ASPHALT PLAT CENTERLINE BNSF RIGHT OF WAY PLAT LOT LINE UNDERGROUND STORM LINE UNDERGROUND SEWER GRAVITY LINE UNDERGROUND TELEPHONE LINE UNDERGROUND WATER LINE UNDERGROUND POWER LINE FENCING PVC CONC P.A. POLYVINYL CHLORIDE PIPE ABBREVIATIONS: PLANTED AREA CONCRETE YARD LIGHT POWER VAULT TREES: C CEDAR P F PINE FIR DEC DECIDUOUS HEM HEMLOCK DHA SURVEY CONTROL YARD DRAIN BOLLARD (A)APPROXIMATE PRD PER RECORD DRAWING CTN A COTTONWOOD ALDER ORN ORNAMENTAL B BIRCH WETLAND/ ORDINARY HIGH WATER FLAG WP WOOD POST SANITARY/ STORM CLEAN-OUT M MAPLE GRAVEL PATH LOG DEBRIS UNDERGROUND SEWER FORCEMAIN LINE PICNIC TABLE x 13 MONITOR WELL RD ROOF DRAIN CO CLEAN-OUT CREEK TOP CREEK TOE RAILROAD SIGNAL PARK BOUNDARY LINE ORDINARY HIGH WATER MARK WETLAND BOUNDARY BNSF CENTERLINE MEAN HIGHER HIGH WATER (EL. +9.0' MLLW) PARK BOUNDARY PROJECT BOUNDARY Nov 16, 2018 3:32pm chewett k:\Projects\0723-snohomish county\meadowdale park\construction plans\0723-PL-Existing Plan.dwg 7 EC-10 SCALE IN FEET 30 60 LEGEND: NORTH EC-1 EXISTING CONDTIONS PLAN (1 OF 3)7 75 PH/BS CH/TG BS PH 1" = 30' NOVEMBER 2018 APPROVED FOR CONSTRUCTION BY: R/W PERMIT NO. DATE DESCRIPTIONAPP'DDATEBY REVISIONS REV ONE INCHAT FULL SIZE, IF NOT ONEINCH SCALE ACCORDINGLYDESIGNED BY: APPROVED BY: CHECKED BY: DRAWN BY: DATE: SCALE: MEADOWDALE BEACH PARK AND ESTUARY DESIGN 18-XXXXX SHEET # OF LDA PERMIT SUBMITTAL, NOT FOR CONSTRUCTION PFN: 18-XXXXX LDA SECTION 5, TOWNSHIP 27 N., RANGE 4 E MATCH LINE, SEE SHEET EC-2NOTES: 1.SURVEY PROVIDED BY DHA, DATED JUNE 2017 16928 WOODINVILLE-REDMOND ROAD SUITE B-107 WOODINVILLE, WASHINGTON 98072 (425) 483-5355 2.HORIZONTAL DATUM: WASHINGTON STATE PLANE NORTH ZONE, NAD 83, U.S. FEET. 3.VERTICAL DATUM: NAVD 88 4.DRAWINGS ARE INTENDED TO BE VIEWED IN COLOR. SOME INFORMATION WILL BE LOST WITH BLACK AND WHITE VIEWING. 5.BEACH TOPOGRAPHY REPRESENTS JUNE 2016 CONDITIONS AND ARE SUBJECT TO CHANGE. CONTRACTOR IS RESPONSIBLE FOR VERIFYING GRADES AND BEACH CONDITIONS PRIOR TO GRADING. CONFIRMED LOCATIONS OF BURIED DEBRIS 27040500200100 00500900000500 00500900000500 00500900001602 27040500200100 LUN D S CREEKGUL C H LUN D S G U L C H CREE K OFF-CHANNEL POND RANGERRESIDENCE ASPHALTPARKING LOT ASPHALTROAD CONTOURS FROM LIDAR CONTOURS FROM LIDAR EXTENT OF TOPOGRAPHIC SURVEY EXTENT OF TOPOGRAPHIC SURVEY SANITARY SEWER MANHOLE JUNCTION BOX WATER METER ROCKERY STORM DRAIN CATCH BASIN(TYPE I) MONUMENT IN CASE CONIFER DECIDUOUS SIGN EDGE OF ASPHALT PLAT CENTERLINE BNSF RIGHT OF WAY PLAT LOT LINE UNDERGROUND STORM LINE UNDERGROUND SEWER GRAVITY LINE UNDERGROUND TELEPHONE LINE UNDERGROUND WATER LINE UNDERGROUND POWER LINE FENCING PVC CONC P.A. POLYVINYL CHLORIDE PIPE ABBREVIATIONS: PLANTED AREA CONCRETE YARD LIGHT POWER VAULT TREES: C CEDAR P F PINE FIR DEC DECIDUOUS HEM HEMLOCK DHA SURVEY CONTROL YARD DRAIN BOLLARD (A)APPROXIMATE PRD PER RECORD DRAWING CTN A COTTONWOOD ALDER ORN ORNAMENTAL B BIRCH WETLAND/ ORDINARY HIGH WATER FLAG WP WOOD POST SANITARY/ STORM CLEAN-OUT M MAPLE GRAVEL PATH LOG DEBRIS UNDERGROUND SEWER FORCEMAIN LINE PICNIC TABLE x 13 MONITOR WELL RD ROOF DRAIN CO CLEAN-OUT CREEK TOP CREEK TOE RAILROAD SIGNAL PARK BOUNDARY LINE ORDINARY HIGH WATER MARK WETLAND BOUNDARY BNSF CENTERLINE MEAN HIGHER HIGH WATER (EL. +9.0' MLLW) PARK BOUNDARY PROJECT BOUNDARY Nov 16, 2018 3:32pm chewett k:\Projects\0723-snohomish county\meadowdale park\construction plans\0723-PL-Existing Plan.dwg 8 EC-2LEGEND: APPROVED FOR CONSTRUCTION BY: R/W PERMIT NO. DATE DESCRIPTIONAPP'DDATEBY REVISIONS REV ONE INCHAT FULL SIZE, IF NOT ONEINCH SCALE ACCORDINGLYDESIGNED BY: APPROVED BY: CHECKED BY: DRAWN BY: DATE: SCALE: MEADOWDALE BEACH PARK AND ESTUARY DESIGN 18-XXXXX SHEET # OF LDA PERMIT SUBMITTAL, NOT FOR CONSTRUCTION PFN: 18-XXXXX LDA SECTION 5, TOWNSHIP 27 N., RANGE 4 E EC-2 EXISTING CONDITIONS PLAN (2 OF 3)8 75 PH/BS CH/TG BS PH 1" = 30' NOVEMBER 2018 0 SCALE IN FEET 30 60 NORTHMATCH LINE, SEE SHEET EC-1MATCH LINE, SEE SHEET EC-3 NOTES: 1.SURVEY PROVIDED BY DHA, DATED JUNE 2017 16928 WOODINVILLE-REDMOND ROAD SUITE B-107 WOODINVILLE, WASHINGTON 98072 (425) 483-5355 2.HORIZONTAL DATUM: WASHINGTON STATE PLANE NORTH ZONE, NAD 83, U.S. FEET. 3.VERTICAL DATUM: NAVD 88 4.DRAWINGS ARE INTENDED TO BE VIEWED IN COLOR. SOME INFORMATION WILL BE LOST WITH BLACK AND WHITE VIEWING. 00500900000500 00500900000100 ACCESS GATE CONTOURS FROM LIDAR CONTOURS FROM LIDAR EXTENT OF TOPOGRAPHIC SURVEY EX. 1-1/2" WATER METER, TO PARK SANITARY SEWER MANHOLE JUNCTION BOX WATER METER ROCKERY STORM DRAIN CATCH BASIN(TYPE I) MONUMENT IN CASE CONIFER DECIDUOUS SIGN EDGE OF ASPHALT PLAT CENTERLINE BNSF RIGHT OF WAY PLAT LOT LINE UNDERGROUND STORM LINE UNDERGROUND SEWER GRAVITY LINE UNDERGROUND TELEPHONE LINE UNDERGROUND WATER LINE UNDERGROUND POWER LINE FENCING PVC CONC P.A. POLYVINYL CHLORIDE PIPE ABBREVIATIONS: PLANTED AREA CONCRETE YARD LIGHT POWER VAULT TREES: C CEDAR P F PINE FIR DEC DECIDUOUS HEM HEMLOCK DHA SURVEY CONTROL YARD DRAIN BOLLARD (A)APPROXIMATE PRD PER RECORD DRAWING CTN A COTTONWOOD ALDER ORN ORNAMENTAL B BIRCH WETLAND/ ORDINARY HIGH WATER FLAG WP WOOD POST SANITARY/ STORM CLEAN-OUT M MAPLE GRAVEL PATH LOG DEBRIS UNDERGROUND SEWER FORCEMAIN LINE PICNIC TABLE x 13 MONITOR WELL RD ROOF DRAIN CO CLEAN-OUT CREEK TOP CREEK TOE RAILROAD SIGNAL PARK BOUNDARY LINE ORDINARY HIGH WATER MARK WETLAND BOUNDARY BNSF CENTERLINE MEAN HIGHER HIGH WATER (EL. +9.0' MLLW) PARK BOUNDARY PROJECT BOUNDARY Nov 16, 2018 3:33pm chewett k:\Projects\0723-snohomish county\meadowdale park\construction plans\0723-PL-Existing Plan.dwg 9 EC-3LEGEND: 75TH PL W.75TH PL W.APPROVED FOR CONSTRUCTION BY: R/W PERMIT NO. DATE DESCRIPTIONAPP'DDATEBY REVISIONS REV ONE INCHAT FULL SIZE, IF NOT ONEINCH SCALE ACCORDINGLYDESIGNED BY: APPROVED BY: CHECKED BY: DRAWN BY: DATE: SCALE: MEADOWDALE BEACH PARK AND ESTUARY DESIGN 18-XXXXX SHEET # OF LDA PERMIT SUBMITTAL, NOT FOR CONSTRUCTION PFN: 18-XXXXX LDA SECTION 5, TOWNSHIP 27 N., RANGE 4 E EC-3 EXISTING CONDITIONS PLAN (3 OF 3)9 75 PH/BS CH/TG BS PH 1" = 30' NOVEMBER 2018 0 SCALE IN FEET 30 60 NORTH MATCH LINE, SEE SHEET EC-2 NOTES: 1.SURVEY PROVIDED BY DHA, DATED JUNE 2017 16928 WOODINVILLE-REDMOND ROAD SUITE B-107 WOODINVILLE, WASHINGTON 98072 (425) 483-5355 2.HORIZONTAL DATUM: WASHINGTON STATE PLANE NORTH ZONE, NAD 83, U.S. FEET. 3.VERTICAL DATUM: NAVD 88 4.DRAWINGS ARE INTENDED TO BE VIEWED IN COLOR. SOME INFORMATION WILL BE LOST WITH BLACK AND WHITE VIEWING. BNSF RAILWAYPUGET SOUND LUN D S CREEKGUL C H 510467891112121 2 121 010 888992522 2324 2627152013141 6 17181915 2 0 2 5 11 12 1314 1617181818 192 1 21 21 2222 23242626 15152025121213131414 16 1617171 8 1921222324242426152 0 25131314161718181819 212223 24 2 6 2 7 2 8101010101010151520202020677788899 9 1111121213131414161617171818191921211 5 2011 1111 12 12 12 131 4 1 414 1616161616 17 1818181818 191919 212223242 4 2 5 2610 9 12 13 14 17 18 2012 13 1415 16 17 20 11 10 9 9 1 0 1112131415212122 15 2311 22251 9 16 262127242818 19 242322 1213111415161718192010 9 11 81098769 109101188 927282920191817 16 15 14 13 1211 TCTCTCTCTCTCTCTCTCTCTCTCTCTCTCTCTCTCTCTCTCTCTCIN-WATER TURBITY CURTAIN, EXTEND CURTAIN TO OUTER LIMITS OF WORK AS REQUIRED BY PERMIT 1 - TEMPORARY DIVERSION PIPE PLACE SILT FENCE AT CLEARING LIMITS C233 PLACE SILT FENCE AT CLEARING LIMITS C233 PLACE SILT FENCE AT CLEARING LIMITS C233 PLACE SILT FENCE AT CLEARING LIMITS C233 MARK CLEARING LIMITS C103 MARK CLEARING LIMITS C103C103 INTALL BULK-BAG COFFERDAM FOR TEMPORARY DIVERSION STOCKPILE AREA EX RESTROOM ENCLOSURE,FOUNDATION,AND CONC. SLAB EX VOLLEYBALLCOURT EX ASPHALT PATH CONCRETE CULVERT, SLABS,GRATING, AND CHANNEL MATERIALS EX CRUSHED ROCK PATH CONC. PAD, PICNIC TABLE, GRILL EX PICNIC SHELTER LEGEND, TESC CLEARING LIMITS SILT FENCE BULK BAG COFFERDAM STABILIZED ROCK CONSTRUCTION ENTRANCE IN-WATER TURBIDITY CURTAIN SNOHOMISH COUNTY BMP NUMBER (SEE TABLE) CATCH BASIN INLET PROTECTION STAGING AND STOCKPILE AREA EXISTING WETLAND TO BE PROTECTEDTCTC C103 1 T-1 Nov 16, 2018 3:33pm chewett k:\Projects\0723-snohomish county\meadowdale park\construction plans\0723-PL-TESC.dwg 10 T-140265&#8 +&94+%'STAT E OF WASHIN G T ONREGISTEREDPROF ESSIONAL EN G IN EERAPPROVED FOR CONSTRUCTION BY: R/W PERMIT NO. DATE DESCRIPTIONAPP'DDATEBY REVISIONS REV ONE INCHAT FULL SIZE, IF NOT ONEINCH SCALE ACCORDINGLYDESIGNED BY: APPROVED BY: CHECKED BY: DRAWN BY: DATE: SCALE: MEADOWDALE BEACH PARK AND ESTUARY DESIGN 18-XXXXX SHEET # OF LDA PERMIT SUBMITTAL, NOT FOR CONSTRUCTION 720 Olive Way | Suite 1900 | Seattle, WA 98101 PFN: 18-XXXXX LDA SECTION 5, TOWNSHIP 27 N., RANGE 4 E 0 SCALE IN FEET 30 60 NORTH BMP DESCRIPTION C103 HIGH VISIBILITY PLASTIC OR METAL FENCE C105 STABILIZED CONSTRUCTION ENTRANCE C220 STORM DRAIN INLET PROTECTION C233 SILT FENCE STANDARD TESC DETAILS LEGEND: THE FOLLOWING ARE STANDARD SNOHOMISH COUNTY TEMPORARY EROSION AND SEDIMENT CONTROL (TESC) BEST MANAGEMENT PRACTICE (BMP) DETAILS: T-1 TEMPORARY EROSION AND SEDIMENT CONTROL (TESC) PLAN (1 OF 3)10 75 PH/BS CH/TG BS PH 1" = 30' NOVEMBER 2018 NOTES: 1.HORIZONTAL DATUM: WASHINGTON STATE PLANE NORTH ZONE, NAD 83, U.S. FEET. 2.VERTICAL DATUM: NAVD 88 3.DRAWINGS ARE INTENDED TO BE VIEWED IN COLOR. SOME INFORMATION WILL BE LOST WITH BLACK AND WHITE VIEWING. 4.SEE DRAWING T-3 FOR TESC NOTES AND ADDITIONAL REQUIREMENTS. POCKET BALLAST IMPERVIOUSTURBIDITYCURTAINFLOATATION SEE NOTESNOTES: 1.AROUND PILE DRIVING AREAS AND EXISTING PILE REMOVAL AREAS, LENGTH OF CURTAIN SHALL EXTEND TO MUDLINE FOR ALL TIDELEVELS. 2.ALL OTHER AREAS, WHERE DEBRIS FROM DEMOLITION WORK MAY EXIST, LENGTH OF CURTAIN SHALL BE 6 FEET. 3.THE CONTRACTOR SHALL BE RESPONSIBLE FOR MAINTAINING THE TURBIDITY CURTAIN TO MAINTAIN FUNCTIONALITY OF THE TURBIDITY CURTAIN THROUGHOUT ALL TIDAL CONDITIONSAND WEATHER EXPECTED DURING THECONSTRUCTION PERIOD, AS REQUIRED BY THE APPROVED PROJECT PERMITS. 4.SEE SPECIFICATIONS FOR MATERIALREQUIREMENTS. SCALE: IN-WATER TURBIDITY CURTAIN1 T-1 NOT TO SCALE MATCH LINE, SEE SHEET T-2BNSF RIGHT OF WAY LUN D S CREEKGUL C H LUN D S G U L C H CREE K OFF-CHANNEL POND 252627283540 45 50 36 3738 39 414243 44 46 47 48 49 5560657075808590951001051105 2535456575859616263646667686971727374 76777879818283848687888991929394969798991011021031041061071081091111121133531 31 32 323232 33 3334 34 362 5 3035 242626 2627 28 2 9 31 32 3 3 3 4 36 253024242426272829313233 25 303 5 35 35404550 2 6 2 7 28 293132333434343637 3839 414243444647 48 49 51 25 303535354022232426 27 2727 28 2 828 292929 31 32 33343636363737 3738 39 412650454025262730292831323334353639383736 556065703527282930313233343535 34 STABILIZED ROCK CONSTRUCTION ENTRANCE, TO BE INSTALLED PRIOR TO REMOVAL OR FOLLOWING PLACEMENT OF PAVEMENT AT PARKING AREA AND DRIVEWAY STABILIZED ROCK CONSTRUCTION ENTRANCE, TO BE INSTALLED WHEN DRIVEWAY PAVEMENT IS REMOVED INSTALL FISH EXCLUSION NETTING UPSTREAM OF WORK AREA C105 C105 PLACE SILT FENCE AT CLEARING LIMITS C233 PLACE SILT FENCE AT CLEARING LIMITSC233 CATCH BASIN INLET PROTECTION C220 MARK CLEARING LIMITS C103 PLACE SILT FENCE AT CLEARING LIMITS PLACE SILT FENCE AT CLEARING LIMITS C233 C233 MARK CLEARING LIMITS C103 MARK CLEARING LIMITS C103 SOIL NAIL/ROADWAY STABILIZATION AREA STOCKPILE AREA EX RANGERRESIDENCE EX ASPHALTPARKING LOT EX ASPHALT ROAD LEGEND, TESC CLEARING LIMITS SILT FENCE BULK BAG COFFERDAM STABILIZED ROCK CONSTRUCTION ENTRANCE IN-WATER TURBIDITY CURTAIN SNOHOMISH COUNTY BMP NUMBER (SEE TABLE) CATCH BASIN INLET PROTECTION STAGING AND STOCKPILE AREA EXISTING WETLAND TO BE PROTECTEDTCTC C103 1 T-1 Nov 16, 2018 3:33pm chewett k:\Projects\0723-snohomish county\meadowdale park\construction plans\0723-PL-TESC.dwg 11 T-240265&#8 +&94+%'STAT E OF WASHIN G T ONREGISTEREDPROF ESSIONAL EN G IN EERAPPROVED FOR CONSTRUCTION BY: R/W PERMIT NO. DATE DESCRIPTIONAPP'DDATEBY REVISIONS REV ONE INCHAT FULL SIZE, IF NOT ONEINCH SCALE ACCORDINGLYDESIGNED BY: APPROVED BY: CHECKED BY: DRAWN BY: DATE: SCALE: MEADOWDALE BEACH PARK AND ESTUARY DESIGN 18-XXXXX SHEET # OF LDA PERMIT SUBMITTAL, NOT FOR CONSTRUCTION 720 Olive Way | Suite 1900 | Seattle, WA 98101 PFN: 18-XXXXX LDA SECTION 5, TOWNSHIP 27 N., RANGE 4 E T-2 TEMPORARY EROSION AND SEDIMENT CONTROL (TESC) PLAN (2 OF 3)11 75 PH/BS CH/TG BS PH 1" = 30' NOVEMBER 2018MATCH LINE, SEE SHEET T-1MATCH LINE, SEE SHEET T-3 0 SCALE IN FEET 30 60 NORTH BMP DESCRIPTION C103 HIGH VISIBILITY PLASTIC OR METAL FENCE C105 STABILIZED CONSTRUCTION ENTRANCE C220 STORM DRAIN INLET PROTECTION C233 SILT FENCE STANDARD TESC DETAILS LEGEND: THE FOLLOWING ARE STANDARD SNOHOMISH COUNTYTEMPORARY EROSION AND SEDIMENT CONTROL (TESC) BESTMANAGEMENT PRACTICE (BMP) DETAILS: NOTES: 1.HORIZONTAL DATUM: WASHINGTON STATE PLANE NORTH ZONE, NAD 83, U.S. FEET. 2.VERTICAL DATUM: NAVD 88 3.DRAWINGS ARE INTENDED TO BE VIEWED IN COLOR. SOME INFORMATION WILL BE LOST WITH BLACK AND WHITE VIEWING. 4.PATHWAY WIDENING TO 10 FEET REQUIRES WORK ON ADJACENT PROPERTY. OBTAINING AN EASEMENT FOR THIS WORK IS UNDERWAY AND WILL BE COMPLETED PRIOR TO CONSTRUCTION START DATE. 5.CONTRACTOR SHALL PROVIDE CONTINUOUS UTILITY SERVICE AND DRIVEWAY ACCESS TO RANGER RESIDENCE. 6.SEE DRAWING T-3 FOR TESC NOTES AND ADDITIONAL REQUIREMENTS. 00500900000500 00500900000100859095100105110 115 115120 12 0 125125130818283848687888991929394969798991011021031041061071081091 1 1 111112 112113 113114114116116117117118118119119121 121122 122123124124126126127127128128129129PLACE SILT FENCE AT CLEARING LIMITS C233 C103 MARK CLEARING LIMITS SOIL NAIL/ROADWAY STABILIZATION AREA SOIL NAIL/ROADWAY STABILIZATION AREA C103 EX ASPHALTROAD ACCESS GATE LEGEND, TESC CLEARING LIMITS SILT FENCE BULK BAG COFFERDAM STABILIZED ROCK CONSTRUCTION ENTRANCE IN-WATER TURBIDITY CURTAIN SNOHOMISH COUNTY BMP NUMBER (SEE TABLE) CATCH BASIN INLET PROTECTION STAGING AND STOCKPILE AREATCTC C103 1 T-1 GENERAL TEMPORARY EROSION AND SEDIMENT CONTROL (TESC) NOTES: 1.ALL CLEARING AND GRADING CONSTRUCTION MUST BE IN ACCORDANCE WITH THE SNOHOMISH COUNTY ENGINEERING DESIGN AND DEVELOPMENT STANDARDS, THE SNOHOMISH COUNTY DRAINAGE MANUAL, THE CITY OF EDMONDS COMMUNITY DEVELOPMENT CODE, THE CITY OF EDMONDS DRAINAGE ADDENDUM, AND OTHER APPLICABLE STANDARDS, CODES, AND ORDINANCES. ANY VARIANCE FROM ADOPTED EROSION CONTROL STANDARDS IS NOT ALLOWED UNLESS SPECIFICALLY APPROVED BY SNOHOMISH COUNTY. 2.THE CONTRACTOR SHALL PROVIDE A CERTIFIED EROSION AND SEDIMENT CONTROL LEAD (CESCL) TO MANAGE AND MAINTAIN TEMPORARY EROSION AND SEDIMENT CONTROL FOR THE PROJECT. THE NAMED PERSON OR FIRM SHALL BE ON-SITE OR ON-CALL AT ALL TIMES. 3.THE IMPLEMENTATION OF THESE TESC DRAWINGS AND THE CONSTRUCTION, MAINTENANCE, REPLACEMENT, AND UPGRADING OF THESE TESC FACILITIES IS THE RESPONSIBILITY OF THE CONTRACTOR UNTIL ALL CONSTRUCTION IS COMPLETED AND APPROVED AND VEGETATION/LANDSCAPING IS ESTABLISHED. 4.THE CLEARING AND DISTURBANCE LIMITS SHALL BE CLEARLY MARKED IN THE FIELD PRIOR TO CLEARING AND GRADING. WHERE SILT FENCE IS NOT SPECIFIED AT THE CLEARING AND DISTURBANCE LIMITS, THE CONTRACTOR SHALL INSTALL HIGH-VISIBILITY FENCING OR FLAGGING TO CLEARLY MARK THE CLEARING AND DISTURBANCE LIMITS. FENCES SHALL BE MAINTAINED BY THE CONTRACTOR FOR THE DURATION OF CONSTRUCTION. 5.THE TESC FACILITIES SHOWN ON THESE DRAWINGS MUST BE CONSTRUCTED IN CONJUNCTION WITH ALL CLEARING AND GRADING ACTIVITIES, AND IN SUCH A MANNER AS TO ENSURE THAT SEDIMENT AND SEDIMENT-LADEN WATER DO NOT ENTER SURFACE WATER BODIES, INCLUDING LUND'S GULCH CREEK OR PUGET SOUND. 6.THE TESC FACILITIES SHOWN ON THESE DRAWINGS ARE THE MINIMUM REQUIREMENTS FOR ANTICIPATED SITE CONDITIONS. DURING CONSTRUCTION, THESE TESC FACILITIES SHALL BE UPGRADED AS NEEDED FOR UNEXPECTED STORM EVENTS AND TO ENSURE THAT SEDIMENT AND SEDIMENT-LADEN WATER DO NOT LEAVE THE SITE. 7.THE TESC FACILITIES SHALL BE INSPECTED DAILY BY THE CONTRACTOR AND MAINTAINED, REPAIRED, OR AUGMENTED AS NECESSARY TO ENSURE THEIR CONTINUED FUNCTIONING. 8.STABILIZED CONSTRUCTION ENTRANCES SHALL BE INSTALLED AT THE BEGINNING OF CONSTRUCTION AND MAINTAINED FOR THE DURATION OF THE PROJECT. ADDITIONAL MEASURES MAY BE REQUIRED TO ENSURE THAT ALL PAVED AREAS ARE KEPT CLEAN FOR THE DURATION OF THE PROJECT. 9.FROM OCTOBER 1 THROUGH APRIL 30, NO SOILS SHALL REMAIN EXPOSED AND UNWORKED FOR MORE THAN 2 DAYS. FROM MAY 1 TO SEPTEMBER 30, NO SOILS SHALL REMAIN EXPOSED AND UNWORKED FOR MORE THAN 7 DAYS. SOILS SHALL BE STABILIZED AT THE END OF THE SHIFT BEFORE A HOLIDAY OR WEEKEND IF NEEDED BASED ON THE WEATHER FORECAST. THESE STABILIZATION REQUIREMENTS APPLY TO ALL SOILS ON SITE, WHETHER AT FINAL GRADE OR NOT. 10.SOIL AND OTHER STOCKPILES MUST BE STABILIZED AND PROTECTED WITH SEDIMENT-TRAPPING MEASURES. 11.ALL POLLUTANTS, INCLUDING WASTE MATERIALS AND DEMOLITION DEBRIS, THAT OCCUR ON SITE DURING CONSTRUCTION SHALL BE HANDLED AND DISPOSED OF IN A MANNER THAT DOES NOT CAUSE CONTAMINATION OF STORMWATER. 12.MAINTENANCE AND REPAIR OF HEAVY EQUIPMENT AND VEHICLES AND OTHER ACTIVITIES WHICH MAY RESULT IN DISCHARGE OR SPILLAGE OF POLLUTANTS TO THE GROUND OR INTO STORMWATER RUNOFF MUST BE CONDUCTED USING SPILL PREVENTION MEASURES APPROVED BY THE CONTRACTING OFFICER'S REPRESENTATIVE. REPORT ALL SPILLS TO CESCL LEAD AND DOE NW REGION: 425-649-7000. 13.WATER FROM MOST DEWATERING OPERATIONS SHALL BE DISPERSED IN AN ADJACENT OPEN SPACE, AS APPROVED BY THE OWNER'S REPRESENTATIVE. THE CONTRACTOR SHALL PROTECT PRIVATE PROPERTY FROM SCOUR AND EROSION RESULTING FROM DEWATERING OPERATIONS. HIGHLY TURBID OR CONTAMINATED DEWATERING WATER SHALL BE HANDLED SEPARATELY FROM STORMWATER AND PROPERLY DISPOSED. 14.THE CONTRACTOR SHALL PRESERVE NATURAL LANDSCAPE, AND PRESERVE AND PROTECT EXISTING VEGETATION NOT REQUIRED OR OTHERWISE AUTHORIZED TO BE REMOVED, AS OUTLINED IN THE SPECIFICATIONS. 15.THE CONTRACTOR SHALL REPAIR OR TREAT INJURED TREES AND VEGETATION AS REQUIRED BY THE SPECIFICATIONS. 16.THE CONTRACTOR SHALL REMOVE AND DISPOSE OF TREES AND VEGETATION THAT ARE INJURED OR DAMAGED BEYOND SAVING AND NOT REQUIRED OR OTHERWISE AUTHORIZED FOR REMOVAL AS REQUIRED IN THE SPECIFICATIONS. REPLACE THE INJURED TREE OR SHRUB AS DIRECTED BY THE OWNER. PROJECT SPECIFIC TESC NOTES: 1.THE TESC PLAN DRAWINGS SHOWN ARE CONCEPTUAL. THE CONTRACTOR IS REQUIRED TO SUBMIT DETAILED TESC PLANS AND ANY SUGGESTED REVISIONS TO THE APPROVED CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN (SWPPP) TO SNOHOMISH COUNTY FOR APPROVAL. 2.THE CONTRACTOR IS RESPONSIBLE FOR THE CARE AND DIVERSION OF WATER DURING CONSTRUCTION IN ACCORDANCE WITH LOCAL, STATE, AND FEDERAL WATER QUALITY STANDARDS AND PROJECT PERMIT REQUIREMENTS. 3.THE CONTRACTOR SHALL ENSURE THAT ALL NECESSARY PRECAUTIONS BE TAKEN TO PREVENT ANY CEMENT CONCRETE OR BY-PRODUCTS, ASPHALT CONCRETE OR BYPRODUCTS, OR ANY DISCHARGE FROM SAW CUTTING AND PLANING FROM BEING DISCHARGED INTO LUND'S GULCH CREEK, PUGET SOUND, OR ANY SURFACE WATER SYSTEM. 4.TESC IMPLEMENTATION AND MAINTENANCE SHALL COMPLY WITH ALL PROJECT PERMIT REQUIREMENTS. 5.THE CONTRACTOR SHALL NOT FUEL EQUIPMENT OR STORE FUEL AT ELEVATIONS LOWER THAN 5 FEET ABOVE THE ORDINARY HIGH WATER (OHW) OF THE NEAREST STREAM OR SURFACE WATER BODY. 6.WASHING OF EQUIPMENT ON THE PROJECT SITE SHALL NOT BE ALLOWED UNLESS AUTHORIZED IN WRITING BY THE CONTRACTING OFFICER. 7.THE CONTRACTOR SHALL PROVIDE, OPERATE, AND MAINTAIN EQUIPMENT NEEDED TO DIVERT AND BYPASS LUNDS GULCH CREEK FLOWS THROUGH THE SITE DURING CONSTRUCTION. THE CONTRACTOR SHALL BE RESPONSIBLE FOR TEMPORARY DIVERSION AND CONTROL OF THE FULL RANGE OF FLOWS THAT CAN BE EXPECTED DURING CONSTRUCTION. PEAK FLOWS ESTIMATED IN LUNDS GULCH CREEK THROUGH THE PROJECT SITE ARE AS FOLLOWS: ·Q (2-YEAR) = 57 CFS ·Q (5-YEAR) = 89 CFS ·Q (25-YEAR) = 106 CFS ·Q (100-YEAR) = 135 CFS Nov 16, 2018 3:34pm chewett k:\Projects\0723-snohomish county\meadowdale park\construction plans\0723-PL-TESC.dwg 12 T-3ACCES S R O A D 75TH PL W.T-3 TEMPORARY EROSION AND SEDIMENT CONTROL (TESC) PLAN (3 OF 3)12 75 PH/BS CH/TG BS PH 1" = 30' NOVEMBER 2018 MATCH LINE, SEE SHEET T-2 0 SCALE IN FEET 30 60 NORTH BMP DESCRIPTION C103 HIGH VISIBILITY PLASTIC OR METAL FENCE C105 STABILIZED CONSTRUCTION ENTRANCE C220 STORM DRAIN INLET PROTECTION C233 SILT FENCE STANDARD TESC DETAILS LEGEND: THE FOLLOWING ARE APPLICABLE STANDARD SNOHOMISHCOUNTY TEMPORARY EROSION AND SEDIMENT CONTROL(TESC) BEST MANAGEMENT PRACTICE (BMP) DETAILS, SEE SPECIFICATION APPENDIX E: CONSTRUCTION SEQUENCE: 1.SCHEDULE AND CONDUCT A PRE-CONSTRUCTION MEETING WITH SNOHOMISH COUNTY, THE CONTRACTOR'S SUPERINTENDENT AND CESCL; SUB-CONTRACTOR SUPERINTENDENTS; AND OTHER EROSION/SEDIMENT CONTROL LEADS. THIS MEETING SHALL BE HELD NO LESS THAN 48 HOURS PRIOR TO THE START OF WORK. 2.FLAG OR FENCE CLEARING LIMITS. 3.POST SIGN WITH NAME AND CONTACT NUMBER OF SUPERINTENDENT AND CESCL. 4.INSTALL CATCH BASIN INLET PROTECTION. 5.INSTALL STABILIZED CONSTRUCTION ENTRANCES. 6.INSTALL SILT FENCE, OTHER PERIMETER CONTROLS. 7.INSTALL FLOATING TURBIDITY CURTAIN. 8.INSTALL AND TEST TEMPORARY BYPASS PIPING AND PUMPS. BEGIN ROUTING STREAMFLOWS AND RUN-ON FLOWS AROUND OR THROUGH SITE. 9.GRADE AND STABILIZE ON-SITE CONSTRUCTION ACCESS ROUTES. 10.COMMENCE CLEARING, DEMOLITION, AND GRADING. 11.CONSTRUCT PERMANENT IMPROVEMENTS 12.MAINTAIN AND UPGRADE TESC BMPS, AS NEEDED TO COMPLY WITH PERMIT REQUIREMENTS AND MANUFACTURER'S RECOMMENDATIONS. 13.RELOCATE BMPS OR IMPLEMENT ADDITIONAL BMPS AS CONDITIONS CHANGE TO ENSURE THAT BMPs COMPLY WITH CONSTRUCTION STORMWATER PERMIT REQUIREMENTS. 14.COVER ALL AREAS WITHIN THE SPECIFIED TIME FRAME WITH STRAW, MULCH, COVERS, BLANKETS, PLASTIC SHEETING, OR EQUIVALENT. 15.STABILIZE EXPOSED SOILS THAT REACH FINAL GRADE BY SEEDING OR PLANTING. 16.STABILIZE ALL DISTURBED AREAS AND REMOVE ALL TEMPORARY BMPS WHEN WORK IS COMPLETE. 17.ADJUST THIS SEQUENCE AS NEEDED TO INCLUDE ADDITIONAL MEASURES REQUIRED TO MEET CONSTRUCTION STORMWATER PERMIT REQUIREMENTS. 40265&#8 +&94+%'STAT E OF WASHIN G T ONREGISTEREDPROF ESSIONAL EN G IN EERAPPROVED FOR CONSTRUCTION BY: R/W PERMIT NO. DATE DESCRIPTIONAPP'DDATEBY REVISIONS REV ONE INCHAT FULL SIZE, IF NOT ONEINCH SCALE ACCORDINGLYDESIGNED BY: APPROVED BY: CHECKED BY: DRAWN BY: DATE: SCALE: MEADOWDALE BEACH PARK AND ESTUARY DESIGN 18-XXXXX SHEET # OF LDA PERMIT SUBMITTAL, NOT FOR CONSTRUCTION 720 Olive Way | Suite 1900 | Seattle, WA 98101 PFN: 18-XXXXX LDA SECTION 5, TOWNSHIP 27 N., RANGE 4 E NOTES: 1.HORIZONTAL DATUM: WASHINGTON STATE PLANE NORTH ZONE, NAD 83, U.S. FEET. 2.VERTICAL DATUM: NAVD 88 3.DRAWINGS ARE INTENDED TO BE VIEWED IN COLOR. SOME INFORMATION WILL BE LOST WITH BLACK AND WHITE VIEWING. 4.PATHWAY WIDENING TO 10 FEET REQUIRES WORK ON ADJACENT PROPERTY. OBTAINING AN EASEMENT FOR THIS WORK IS UNDERWAY AND WILL BE COMPLETED PRIOR TO CONSTRUCTION START DATE. 5.CONTRACTOR SHALL PROVIDE CONTINUOUS UTILITY SERVICE AND DRIVEWAY ACCESS TO RANGER RESIDENCE. 6.SEE DRAWING T-3 FOR TESC NOTES AND ADDITIONAL REQUIREMENTS. DRAFT Page | 34 Appendix B – BMP Details January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 27 4.1 Source Control BMPs BMP C101: Preserving Natural Vegetation Purpose Preserving natural vegetation helps reduce erosion and surface runoff. Conditions of Use Natural vegetation should be preserved on steep slopes, near perennial and intermittent watercourses or swales, and on building sites in wooded areas. Design and Installation Specifications Phase construction to preserve natural vegetation on the project site for as long as possible during the construction period. Fence or clearly mark areas around trees that are to be saved. Where feasible, do not disturb ground within the dripline of trees that are to be saved. Do not place fill of more than six inches depth within the dripline of trees that are to be saved. If roots of plants intended to be saved must be cut due to excavations:  Cut as few roots as possible, and cut them cleanly.  Paint cut root ends with a wood dressing such as asphalt base paint.  Backfill excavations in these areas as soon as possible. Maintenance Standards Inspect flagged and/or fenced areas regularly to make sure flagging or fencing has not been removed or damaged. If the flagging or fencing has been damaged or visibility reduced, it shall be repaired or replaced immediately and visibility restored. If tree roots have been exposed or injured, “prune” cleanly with an appropriate pruning saw or loppers directly above the damaged roots and recover with native soils. Treatment of sap flowing trees (fir, hemlock, pine, soft maples) is not advised as sap forms a natural healing barrier. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 28 BMP C102: Buffer Zones Purpose Buffer zones are undisturbed areas or strips of natural vegetation or an established suitable planting that reduce soil erosion and runoff velocities. Conditions of Use Note: use of buffer zones located in critical areas requires compliance with Chapter 30.62A SCC. Natural buffer zones are used along streams, wetlands and other bodies of water that need protection from erosion and sedimentation. Vegetative buffer zones can be used to protect natural swales and can be incorporated into the natural landscaping of an area. Design and Installation Specifications Preserve natural vegetation or plantings in clumps, blocks, or strips where feasible.. Leave all unstable steep slopes in natural vegetation. Mark clearing limits with high visibility fence meeting the requirements of BMP C103, and keep all equipment and construction debris out of buffer zones. Keep all excavations outside the dripline of trees and shrubs. Do not push debris or extra soil into the buffer zone area. Maintenance Standards Inspect the area frequently to make sure flagging remains in place and the area remains undisturbed. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 29 BMP C103: High Visibility Fence Purpose High visibility fencing is intended to:  restrict clearing to approved limits;  prevent disturbance of sensitive areas, their buffers, and other areas required to be left undisturbed;  limit construction traffic to designated construction entrances or roads; and,  protect areas where marking with survey tape may not provide adequate protection. Conditions of Use See purpose. Design and Installation Specifications High visibility fence shall be either plastic or metal fence meeting the requirements of WSDOT Standard Specification 9-14.5(8) High Visibility Fencing. Fencing shall be installed in accordance with WSDOT Standard Plan I-10.10-01 High Visibility Fence. Fabric silt fence may be installed to serve as high visibility fence, provided the fence materials meet all specifications for BMP C103. Fences shall not be wired or stapled to trees. Maintenance Standards If the fence has been damaged or visibility reduced, it shall be repaired or replaced immediately and visibility restored. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 30 BMP C105: Stabilized Construction Exit Purpose Construction exits are stabilized to reduce the amount of sediment transported from construction sites onto paved roads by vehicles or equipment by constructing a stabilized pad of quarry spalls at exits to construction sites. Conditions of Use Construction exits shall be stabilized wherever traffic will be leaving a construction site if paved roads or other paved areas are within 1,000 feet of the site. For construction on single-family residential lots following plat approval, provide a stabilized construction exit for each lot at which construction is occurring, rather than only at the main subdivision exit. Stabilized surfaces shall be of sufficient length and width to provide vehicle access and parking, with a minimum length of 50 feet for construction sites less than 1 acre. Design and Installation Specifications See WSDOT Standard Plan I-80.10.01 Stabilized Construction Entrance for detail drawing and construction plan notes. Construct stabilized construction exits with a 12-inch-thick pad of 4-inch to 8-inch quarry spalls, a 4-inch course of asphalt treated base (ATB), or use existing pavement. Do not use crushed concrete, cement, or calcium chloride for construction exit stabilization. Fencing (see BMPs C103 and C104) shall be installed as necessary to restrict traffic to the stabilized construction exit. Whenever possible, the stabilized construction exit shall be constructed on a firm, compacted subgrade. Stabilized construction exits shall not cross existing sidewalks and back-of-walk drains if feasible. If such crossings cannot be avoided, the full length of the sidewalk and associated drain must be covered and protected from sediment leaving the site. Maintenance Standards Quarry spalls shall be added if the pad is no longer in accordance with the specifications. If the entrance is not preventing sediment from being tracked onto pavement, alternative measures to keep the streets free of sediment shall be used. These may include replacement or cleaning of existing quarry spalls, street sweeping, an increase in the dimensions of the entrance, or the installation of a wheel wash. Any sediment tracked onto pavement shall be removed by shoveling or street sweeping. The sediment collected by sweeping shall be removed or stabilized on site. The pavement shall not be cleaned by washing down the street, except when sweeping is ineffective and there is a threat to public safety. Street wash water shall be collected and disposed of as process wastewater, or disposed of on-site using one of the following BMPs:  BMP C236 – Pumped Vegetated Dispersion System January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 31  BMP T5.30 – Full Dispersion (see Snohomish County Drainage Manual, Volume V)  an infiltration BMP designed in accordance with Snohomish County Drainage Manual, Volume V Chapter 7. Perform street sweeping by hand or with a high-efficiency sweeper. Immediately remove quarry spalls from the roadway that have been transported from the stabilized construction entrance / exit. Upon project completion and site stabilization, all construction accesses intended as permanent access for maintenance shall be permanently stabilized. Approved equivalents The Washington State Department of Ecology has approved products as able to meet the requirements of this BMP. Snohomish County may approve these products if they are used in accordance with all requirements of this BMP and all instructions and specifications provided by the manufacturer, plus additional requirements that may be established by the County. These products are available for review at http://www.ecy.wa.gov/programs/wq/stormwater/newtech/equivalent.html. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 35 BMP C107: Construction Road/Parking Area Stabilization Purpose Stabilizing subdivision roads, parking areas, and other onsite vehicle transportation routes immediately after grading reduces erosion caused by construction traffic or runoff. Conditions of Use Permanent and temporary roads and parking areas used for construction traffic shall be stabilized. High Visibility Fencing (BMP C103) shall be installed to limit the access of vehicles to only those roads and parking areas that are stabilized. Design and Installation Specifications On areas that will receive asphalt as part of the project, install the first lift as soon as possible. A 6-inch depth of 2- to 4-inch crushed rock, gravel base, or crushed surfacing base course shall be applied immediately after grading or utility installation. A 4-inch course of asphalt treated base (ATB) may also be used, or the road/parking area may be paved. If cement or cement kiln dust is used for road base stabilization, pH monitoring and BMPs are necessary to evaluate and minimize the effects on stormwater. If the area will not be used for permanent roads, parking areas, or structures, a 6-inch depth of hog fuel may also be used. Whenever possible, construction roads and parking areas shall be placed on a firm, compacted subgrade. Temporary road gradients shall not exceed 15 percent. If road runoff is concentrated in a drainage ditch, the runoff shall be routed to a sediment control BMP acceptable for using in treating concentrated flow. If feasible, road runoff may be allowed to sheetflow into a vegetated area meeting the requirements of BMP C234 – Vegetated Strip. Storm drain inlets shall be protected to prevent sediment-laden water entering the storm drain system (see BMP C220). Maintenance Standards Inspect stabilized areas regularly, especially after large storm events. Crushed rock, gravel base, hog fuel, etc. shall be added as required to maintain a stable driving surface and to stabilize any areas that have eroded. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 36 BMP C120: Temporary and Permanent Seeding NOTE: Small projects permitted in accordance with SCC 30.63A.810 shall only use BMPs in this section that do not require the involvement of a licensed engineer. Purpose Seeding is intended to reduce erosion by stabilizing exposed soils. A well-established vegetative cover is one of the most effective methods of reducing erosion. Conditions of Use Use seeding throughout the project on disturbed areas that have reached final grade or that will remain unworked for more than 30 days. Between July 1 and August 30 seeding requires irrigation until 75 percent grass cover is established. Between October 1 and March 30 seeding requires a cover of mulch with straw or an erosion control blanket until 75 percent grass cover is established. Inspect all disturbed areas in late August to early September and complete all seeding by September 30. Design and Installation Specifications General Seed shall conform to WSDOT Standard Specification 9-14.2 Seed. Unless contradicted by information stated below, temporary and permanent seeding shall be performed in accordance with WSDOT Standard Specification 8-01.3(2) Seeding, Fertilizing, and Mulching, Sections A-F. Final seed application is restricted to the periods April 1 through June 30 and September 1 through October 1. Use of polyacrylamide (PAM) shall conform to the requirements of BMP C126. Seed and mulch all disturbed areas not otherwise vegetated at final site stabilization. Final stabilization means the completion of all soil disturbing activities at the site and the establishment of a permanent vegetative cover, or equivalent permanent stabilization measures (such as pavement, riprap, gabions or geotextiles) which will prevent erosion. Seed may be installed by hand or by hydroseeding. Hand seeding may be used for establishing temporary vegetation or for establishing permanent vegetation in areas less than one acre. Apply mulch to all seeded areas, either on top of the seed or simultaneously by hydroseeding. See BMP C121: Mulching for specifications. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 37 Seeding vegetated channels Channels that are intended to be vegetated shall be installed before other grading on the project. Hydroseed these channels with a Bonded Fiber Matrix. For vegetated channels that receive have flows capable of eroding the channel, install erosion control blankets over hydroseed. Before allowing water to flow in vegetated channels, establish 75 percent vegetation cover, or install sod in the channel bottom over hydromulch and erosion control blankets. On slopes greater than 33% use Bonded Fiber Matrix (BFM) or Mechanically Bonded Fiber Matrix (MBFM) products in accordance with the specifications set forth later in this section. Seed mixes The seed mixes listed in the tables below include recommended mixes for both temporary and permanent seeding. Snohomish County may approve other seed mixes. Select a seed mix appropriate for the location, exposure, soil type, site hydrology, need for irrigation, slope, and expected foot traffic. Alternative seed mixes approved by the local authority may be used. With the exception of the wetland mix, apply seed at a rate of 120 pounds per acre. Table 4.2 presents a seed mix appropriate for temporary vegetative cover. Table 4.2 Temporary Erosion Control Seed Mix % Weight % Purity % Germination Chewings red fescue or annual blue grass Festuca rubra var. commutata or Poa anna 40 98 90 Perennial rye - Lolium perenne 50 98 90 Redtop or colonial bentgrass Agrostis alba or Agrostis tenuis 5 92 85 White dutch clover Trifolium repens 5 98 90 Table 4.3 presents a seed mix appropriate for landscaped areas. Table 4.3 Landscaping Seed Mix % Weight % Purity % Germination Perennial rye blend Lolium perenne 70 98 90 Chewings red fescue and red fescue blend Festuca rubra var. commutata or Festuca rubra 30 98 90 January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 38 Table 4.4 presents a seed mix appropriate for dry situations where little water is required. This mix requires very little maintenance. Table 4.4 Low-Growing Turf Seed Mix % Weight % Purity % Germination Dwarf tall fescue (several varieties) Festuca arundinacea var. 45 98 90 Dwarf perennial rye (Barclay) Lolium perenne var. barclay 30 98 90 Red fescue Festuca rubra 20 98 90 Colonial bentgrass Agrostis tenuis 5 98 90 Table 4.5 presents a mix recommended for bioswales and other intermittently wet areas. Table 4.5 Bioswale Seed Mix % Weight % Purity % Germination Tall or meadow fescue Festuca arundinacea or Festuca elatior 75-80 98 90 Seaside/Creeping bentgrass Agrostis palustris 10-15 92 85 Redtop bentgrass Agrostis alba or Agrostis gigantea 5-10 90 80 Table 4.6 presents a low-growing, relatively non-invasive seed mix appropriate for very wet areas that are not regulated wetlands. Apply this mixture at a rate of 60 pounds per acre. Consult Hydraulic Permit Authority (HPA) for seed mixes if applicable. Table 4.6 Wet Area Seed Mix* % Weight % Purity % Germination Tall or meadow fescue Festuca arundinacea or Festuca elatior 60-70 98 90 Seaside/Creeping bentgrass Agrostis palustris 10-15 98 85 Meadow foxtail Alepocurus pratensis 10-15 90 80 Alsike clover Trifolium hybridum 1-6 98 90 Redtop bentgrass Agrostis alba 1-6 92 85 * Modified Briargreen, Inc. Hydroseeding Guide Wetlands Seed Mix January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 39 Table 4.7 lists a meadow seed mix appropriate for infrequently maintained areas or non- maintained areas where colonization by native plants is desirable. Seeding should take place in September or very early October in order to obtain adequate establishment prior to the winter months. Table 4.7 Meadow Seed Mix % Weight % Purity % Germination Redtop or Oregon bentgrass Agrostis alba or Agrostis oregonensis 20 92 85 Red fescue Festuca rubra 70 98 90 White dutch clover Trifolium repens 10 98 90 Roughening and Rototilling: The seedbed should be firm and rough. Roughen all soil no matter what the slope. Track walk slopes before seeding if engineering purposes require compaction. Backblading or smoothing of slopes greater than 4H:1V is not allowed if they are to be seeded. Restoration-based landscape practices require deeper incorporation than that provided by a simple single-pass rototilling treatment. Wherever practical, initially rip the subgrade to improve long-term permeability, infiltration, and water inflow qualities. At a minimum, permanent areas shall use soil amendments to achieve organic matter and permeability performance defined in engineered soil/landscape systems. For systems that are deeper than 8 inches complete the rototilling process in multiple lifts, or prepare the engineered soil system per specifications and place to achieve the specified depth. Fertilizer Use slow-release 10-4-6 N-P-K (nitrogen-phosphorus-potassium) fertilizer at a rate of 90 pounds per acre. Do not add fertilizer to the hydromulch machine, or agitate fertilizer, more than 20 minutes before use, to prevent destruction of the slow-release coating. Bonded Fiber Matrix (BFM) and Mechanically Bonded Fiber Matrix (MBFM) Apply BFM/MBFM products at a minimum rate of 3,000 pounds per acre of product with approximately 10 percent tackifier. Achieve a minimum of 95 percent soil coverage during application. Install products per manufacturer’s instructions. Most products require 24-36 hours to cure before rainfall and cannot be installed on wet or saturated soils. Maintenance Standards Reseed any seeded areas that fail to establish at least 80 percent cover (100 percent cover for areas that receive sheet or concentrated flows). If reseeding is ineffective, use an alternate method such as sodding, mulching, or nets/blankets. If winter weather prevents adequate grass growth, this time limit may be relaxed at the discretion of the local authority when sensitive areas would otherwise be protected. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 40 Approved equivalents The Washington State Department of Ecology has approved products as able to meet the requirements of this BMP. Snohomish County may approve these products if they are used in accordance with all requirements of this BMP and all instructions and specifications provided by the manufacturer, plus additional requirements that may be established by the County. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 41 BMP C121: Mulching Purpose The purpose of mulching soils is to provide immediate temporary protection from erosion, and to enhance plant establishment by conserving moisture; holding fertilizer, seed, and topsoil in place; and moderating soil temperatures. Conditions of Use As a temporary cover measure, mulch shall be used:  For less than 30 days on disturbed areas that require cover.  At all times for seeded areas, especially during the wet season and during the hot summer months.  During the wet season on slopes steeper than 3H:1V with more than 10 feet of vertical relief. Design and Installation Specifications Mulch materials and application rates shall conform to WSDOT Standard Specification 9-14.4 and subsections of that section pertaining to mulch materials and application, and to WSDOT Highway Runoff Manual BMO 6A-2.2 - Mulching. Where the option of “Compost” is selected, it should be a coarse compost that meets the following size gradations when tested in accordance with the U.S. Composting Council “Test Methods for the Examination of Compost and Composting” (TMECC) Test Method 02.02-B.  Minimum 100% passing 3” sieve openings  Minimum 90% passing 1” sieve openings  Minimum 70% passing ¾” sieve openings  Minimum 40% passing ¼” sieve openings For seeded areas mulch may be made up of cottonseed meal; fibers made of wood, recycled cellulose, hemp, kenaf; compost; or blends of these. Tackifier, if used, shall conform to WSDOT Standard Specifications 9-14.4(7), 9-14.4(7)A, and 9-14.4(7)B. Add seed and fertilizer at time of application. Apply mulch to a minimum thickness of two inches, and increase thickness as needed until ground is not visible under mulch. Mulch used within the ordinary high-water mark of surface waters should be selected to minimize potential flotation of organic matter. Composted organic materials have higher specific gravities (densities) than straw, wood, or chipped material. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 42 Maintenance Standards The design thickness of the mulch cover must be maintained. Any areas that experience erosion shall be remulched and/or protected with a net or blanket. If the erosion problem is drainage related, then the problem shall be fixed and the eroded area remulched. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 43 BMP C122: Blankets NOTE: Small projects permitted in accordance with SCC 30.63A.810 shall only use this BMP in a manner that does not require the involvement of a licensed engineer. Purpose Erosion control nets and blankets are intended to prevent erosion and hold seed and mulch in place on steep slopes and in channels so that vegetation can become well established. In addition, some nets and blankets can be used to permanently reinforce turf to protect drainage ways during high flows. Nets (commonly called matting) are strands of material woven into an open, but high-tensile strength net (for example, coconut fiber matting). Blankets are strands of material that are not tightly woven, but instead form a layer of interlocking fibers, typically held together by a biodegradable or photodegradable netting (for example, excelsior or straw blankets). They generally have lower tensile strength than nets, but cover the ground more completely. Coir (coconut fiber) fabric comes as both nets and blankets. Conditions of Use Erosion control blankets shall be used in accordance with the requirements of WSDOT Highway Runoff Manual BMP 6A-2.3 – Blankets. Design and Installation Specifications Unless specifically stated below, selection, materials, and installation of erosion control blankets shall meet the requirements of: WSDOT Standard Specification 8-01.3(3) – Placing Erosion Control Blanket WSDOT Standard Specification 9-14.5(2) – Erosion Control Blanket WSDOT Standard Plan I-60.10-00 – Erosion Control Blanket Placement on Slope WSDOT Standard Plan I-60.20-00 – Erosion Control Blanket Placement in Channel Blankets on slopes shall be installed according to manufacturer's instructions provided the instructions do not contradict the information set forth in the WSDOT documents listed above. Jute matting must be used in conjunction with mulch (BMP C121). Excelsior, woven straw blankets and coir (coconut fiber) blankets may be installed without mulch. If synthetic blankets are used, the soil shall be hydromulched first. Maintenance Standards Good contact with the ground must be maintained, and erosion must not occur beneath the net or blanket. Any areas of the net or blanket that are damaged or not in close contact with the ground shall be repaired and stapled. If erosion occurs due to poorly controlled drainage, the problem shall be fixed and the eroded area protected. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 44 Figure 4.2 –Installation of Erosion Control Blanket in Channel January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 45 Min. 2“Overlap Slope surface shall be smooth beforeplacement for proper soil contact. Stapling pattern as permanufacturer’s recommendations. Do not stretch blankets/mattings tight -allow the rolls to mold to any irregularities. For slopes less than 3H:1V, rollsmay be placed in horizontal strips. If there is a berm at thetop of slope, anchorupslope of the berm. Anchor in 6"x6" min. Trenchand staple at 12" intervals. Min. 6" overlap. Staple overlapsmax. 5" spacing. Bring material down to a level area, turnthe end under 4" and staple at 12" intervals. Lime, fertilize, and seed before installation.Planting of shrubs, trees, etc. Should occurafter installation. Figure 4.3 –Installation of Erosion Control Blanket on Slope January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 46 BMP C123: Plastic Covering NOTE: Small projects permitted in accordance with SCC 30.63A.810 shall only use this BMP in a manner that does not require the involvement of a licensed engineer. Purpose Plastic covering provides immediate, short-term erosion protection to slopes and disturbed areas. Conditions of Use Plastic covering may be used on disturbed areas that require cover measures for less than 30 days, except as stated below:  Plastic is particularly useful for protecting cut and fill slopes and stockpiles. Note: The relatively rapid breakdown of most polyethylene sheeting makes it unsuitable for long-term (greater than six months) applications.  Clear plastic sheeting can be used over newly-seeded areas to create a greenhouse effect and encourage grass growth if the hydroseed was installed too late in the season to establish 75 percent grass cover, or if the wet season started earlier than normal. Clear plastic should not be used for this purpose during the summer months because the resulting high temperatures can kill the grass.  Due to rapid runoff caused by plastic sheeting, sheeting shall not be used upslope of areas that might be adversely impacted by concentrated runoff. Such areas include steep and/or unstable slopes.  Plastic sheeting may result in increased runoff volumes and velocities, requiring additional on-site measures to counteract the increases. Creating a trough with wattles (see BMP C235) or other material can convey clean water away from these areas.  To prevent undercutting, trench and backfill rolled plastic covering products.  Whenever plastic is used to protect slopes, water collection measures must be installed at the base of the slope. These measures include plastic-covered berms, channels, and pipes used to covey clean rainwater away from bare soil and disturbed areas. Do not mix clean runoff from a plastic covered slope with dirty runoff. Plastic covering may also be used for:  Temporary ditch liner;  Pond liner in temporary sediment pond;  Liner for bermed temporary fuel storage area if plastic is not reactive to the type of fuel being stored;  Emergency slope protection during heavy rains; and,  Temporary drainpipe (“elephant trunk”) used to direct water. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 47 Design and Installation Specifications Plastic sheeting shall be selected and installed in conformance with the requirements in the following:  WSDOT Highway Runoff Manual BMP 6A-2.4 – Plastic Covering  WSDOT Standard Specification 8-01.3(5) – Placing Plastic Covering Plastic sheeting (clear and non-clear) shall conform to the requirements set forth in WSDOT Standard Specification 9-14.5(3) – Clear Plastic Covering. Clear plastic covering shall be used to promote growth of vegetation. Black plastic covering shall be used for stockpiles or other areas where vegetative growth is unwanted. Plastic slope cover must be installed as follows:  Run plastic up and down slope, not across slope;  Plastic may be installed perpendicular to a slope if the slope length is less than 10 feet;  On long or wide slopes, or slopes subject to wind, all seams should be taped;  Place plastic into a small (12-inch wide by 6-inch deep) slot trench at the top of the slope and backfill with soil to keep water from flowing underneath;  Place sand filled burlap or geotextile bags every 3 to 6 feet along seams and pound a wooden stake through each to hold them in place;  Inspect plastic for rips, tears, and open seams regularly and repair immediately. This prevents high velocity runoff from contacting bare soil which causes extreme erosion;  Sandbags may be lowered into place tied to ropes. However, all sandbags must be staked in place.  If erosion at the toe of a slope is likely, a gravel berm, riprap, or other suitable protection shall be installed at the toe of the slope in order to reduce the velocity of runoff Maintenance Standards  Torn sheets must be replaced and open seams repaired.  If the plastic begins to deteriorate due to ultraviolet radiation, it must be completely removed and replaced.  When the plastic is no longer needed, it shall be completely removed. Approved equivalents The Washington State Department of Ecology has approved products as able to meet the requirements of this BMP. Snohomish County may approve these products if they are used in accordance with all requirements of this BMP and all instructions and specifications provided by the manufacturer, plus additional requirements that may be established by the County. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 60 BMP C140: Dust Control Purpose Dust control prevents wind transport of dust from disturbed soil surfaces onto roadways, drainage ways, and surface waters. Conditions of Use In areas (including roadways) subject to surface and air movement of dust where on-site and off- site impacts to roadways, drainage ways, or surface waters are likely. Design and Installation Specifications Vegetate or mulch areas that will not receive vehicle traffic. In areas where planting, mulching, or paving is impractical, apply gravel or landscaping rock. Limit dust generation by clearing only those areas where immediate activity will take place, leaving the remaining area(s) in the original condition, if stable. Maintain the original ground cover as long as practical. Construct natural or artificial windbreaks or windscreens. These may be designed as enclosures for small dust sources. Sprinkle the site with water until surface is wet. Repeat as needed. To prevent carryout of mud onto street, refer to Stabilized Construction Entrance (BMP C105). Irrigation water can be used for dust control. Irrigation systems should be installed as a first step on sites where dust control is a concern. Spray exposed soil areas with a dust palliative, following the manufacturer’s instructions and cautions regarding handling and application. Used oil is prohibited from use as a dust suppressant. Water containing polyacrylamide (PAM) may be used in accordance with the requirements of BMP C126. Techniques that can be used for unpaved roads and lots include:  Lower speed limits. High vehicle speed increases the amount of dust stirred up from unpaved roads and lots.  Upgrade the road surface strength by improving particle size, shape, and mineral types that make up the surface and base materials.  Add surface gravel to reduce the source of dust emission. Limit the amount of fine particles (those smaller than .075 mm) to 10 to 20 percent.  Use geotextile fabrics to increase the strength of new roads or roads undergoing reconstruction.  Encourage the use of alternate, paved routes, if available.  Restrict use by tracked vehicles and heavy trucks to prevent damage to road surface and base. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 61  Apply chemical dust suppressants using the admix method, blending the product with the top few inches of surface material. Suppressants may also be applied as surface treatments.  Pave unpaved permanent roads and other trafficked areas.  Use vacuum street sweepers.  Remove mud and other dirt promptly so it does not dry and then turn into dust.  Limit dust-causing work on windy days. Maintenance Standards Respray area as necessary to keep dust to a minimum. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 62 BMP C150: Materials On Hand Purpose Quantities of erosion prevention and sediment control materials shall be kept on the project site at all times to be used for emergency situations such as unexpected heavy summer rains. Having these materials on-site reduces the time needed to implement BMPs when inspections indicate that existing BMPs are not meeting the SWPPP requirements. Conditions of Use Construction projects of any size or type can benefit from having materials on hand. A small commercial development project could have a roll of plastic and some gravel available for immediate protection of bare soil and temporary berm construction. A large earthwork project, such as highway construction, might have several tons of straw, several rolls of plastic, flexible pipe, sandbags, geotextile fabric and steel “T” posts. Materials are stockpiled and readily available before any site clearing, grubbing, or earthwork begins. A large contractor or developer could keep a stockpile of materials that are available to be used on several projects. If storage space at the project site is at a premium, the contractor may maintain the materials at their office or yard, provided that the office or yard is less than an hour from the project site. Design and Installation Specifications Depending on project type, size, complexity, and length, materials and quantities will vary. A good minimum that will cover numerous situations includes: Material Clear Plastic, 6 mil Drainpipe, 6 or 8 inch diameter Sandbags, filled Straw Bales for mulching, Quarry Spalls Washed Gravel Geotextile Fabric Catch Basin Inserts Steel “T” Posts Maintenance Standards All materials with the exception of the quarry spalls, steel “T” posts, and gravel should be kept covered and out of both sun and rain. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 63 BMP C151: Concrete Handling NOTE: Small projects permitted in accordance with SCC 30.63A.810 shall only use this BMP in a manner that does not require the involvement of a licensed engineer. Purpose Proper collection, handling and disposal of process water and slurry generated during concrete work, and of excess concrete, prevents these materials from contaminating waters of the state. Conditions of Use Any time concrete is used, these management practices shall be utilized. Concrete construction projects include, but are not limited to, the following:  Curbs  Sidewalks  Roads  Bridges  Foundations  Floors  Runways Design and Installation Specifications Wash out concrete truck chutes, pumps, and internal components at an off-site location in accordance with applicable County, state, and federal regulations, or in designated concrete washout areas (see BMP C154). Do not wash out concrete trucks onto the ground, or into storm drains, open ditches, streets, or streams. Return unused concrete remaining in the truck and pump to the originating batch plant for recycling. Do not dump excess concrete on site, except in designated concrete washout areas. Wash off hand tools including, but not limited to, screeds, shovels, rakes, floats, and trowels into formed areas only. Wash equipment difficult to move, such as concrete pavers in areas that do not directly drain to natural or constructed stormwater conveyances. Do not allow washdown from areas, such as concrete aggregate driveways, to drain directly to natural or constructed stormwater conveyances. Contain washwater and leftover product in a lined container when no formed areas are available. Dispose of wash water and contained concrete in a manner that does not violate ground water or surface water quality standards. Always use forms or solid barriers for concrete pours, such as pilings, within 15 feet of surface waters. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 64 Refer to BMPs C252 and C253 for pH adjustment to stormwater that has come into contact with fresh concrete. NOTE: These BMPs are for treatment of stormwater only. Process wastewater such as concrete wash water must be disposed of as a wastewater. Maintenance Standards Containers shall be checked for holes in the liner daily during concrete pours and repaired the same day. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 65 BMP C152: Sawcutting and Surfacing Pollution Prevention Purpose Proper collection, handling and disposal of process water and slurry generated during concrete sawcutting and surfacing work, and of excess concrete, prevents these materials from contaminating waters of the state. Conditions of Use Anytime sawcutting or surfacing operations take place, these management practices shall be utilized. Sawcutting and surfacing operations include, but are not limited to, the following:  Sawing  Coring  Grinding  Roughening  Hydro-demolition  Bridge and road surfacing Design and Installation Specifications Slurry and cuttings shall be vacuumed during cutting and surfacing operations. Slurry and cuttings shall not remain on permanent concrete or asphalt pavement overnight. Slurry and cuttings shall not drain to any natural or constructed drainage conveyance. Collected slurry and cuttings shall be disposed of in a manner that does not violate groundwater or surface water quality standards. Process water that is generated during hydro-demolition, surface roughening or similar operations shall not drain to any natural or constructed drainage conveyance and shall be disposed of in a manner that does not violate groundwater or surface water quality standards. Cleaning waste material and demolition debris shall be handled and disposed of in a manner that does not cause contamination of water. If the area is swept with a pick-up sweeper, the material must be hauled out of the area to an appropriate disposal site. Maintenance Standards Continually monitor operations to determine whether slurry, cuttings, or process water could enter waters of the state. If inspections show that a violation of water quality standards could occur, stop operations and immediately implement preventive measures such as berms, barriers, secondary containment, and vacuum trucks. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 72 BMP C160: Certified Erosion and Sediment Control Lead Purpose The project proponent designates at least one person as the responsible representative in charge of erosion and sediment control (ESC), and water quality protection. The designated person shall be the Certified Erosion and Sediment Control Lead (CESCL) who is responsible for ensuring compliance with all local, state, and federal erosion and sediment control and water quality requirements. Conditions of Use A CESCL shall be made available on projects one acre or larger that discharge stormwater to surface waters of the state. The CESCL shall: Have a current certificate proving attendance in an erosion and sediment control training course that meets the minimum ESC training and certification requirements established by Ecology (Ecology will maintain a list of ESC training and certification providers at: http://www.ecy.wa.gov/programs/wq/stormwater/cescl.html). OR Be a Certified Professional in Erosion and Sediment Control (CPESC); for additional information go to: www.cpesc.net Specification The CESCL shall have authority to act on behalf of the contractor or developer and shall be available, or on-call, 24 hours per day throughout the period of construction. A CESCL may provide inspection and compliance services for multiple construction projects in the same geographic region. Duties and responsibilities of the CESCL shall include, but are not limited to the following:  Maintaining permit file on site at all times which includes the Construction SWPPP and any associated permits and plans.  Directing BMP installation, inspection, maintenance, modification, and removal.  Updating all project drawings and the Construction SWPPP with changes made.  Completing any sampling requirements including reporting results using WebDMR.  Keeping daily logs, and inspection reports. Inspection reports should include:  Inspection date/time.  Weather information; general conditions during inspection and approximate amount of precipitation since the last inspection.  A summary or list of all BMPs implemented, including observations of all erosion/sediment control structures or practices. The following shall be noted: January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 73 o Locations of BMPs inspected. o Locations of BMPs that need maintenance. o Locations of BMPs that failed to operate as designed or intended. o Locations of where additional or different BMPs are required.  Visual monitoring results, including a description of discharged stormwater. The presence of suspended sediment, turbid water, discoloration, and oil sheen shall be noted, as applicable.  Any water quality monitoring performed during inspection.  General comments and notes, including a brief description of any BMP repairs, maintenance or installations made as a result of the inspection.  Facilitate, participate in, and take corrective actions resulting from inspections performed by outside agencies or the owner. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 74 BMP C162: Scheduling Purpose Sequencing a construction project reduces the amount and duration of soil exposed to erosion by wind, rain, runoff, and vehicle tracking. Conditions of Use  The construction sequence schedule is an orderly listing of all major land-disturbing activities together with the necessary erosion and sedimentation control measures planned for the project. This type of schedule guides the contractor on work to be done before other work is started so that serious erosion and sedimentation problems can be avoided.  Following a specified work schedule that coordinates the timing of land-disturbing activities and the installation of control measures is perhaps the most cost-effective way of controlling erosion during construction. The removal of surface ground cover leaves a site vulnerable to accelerated erosion. Construction procedures that limit land clearing provide timely installation of erosion and sedimentation controls, and restore protective cover quickly can significantly reduce the erosion potential of a site. Design Considerations Minimize construction during rainy periods. Schedule projects to disturb only small portions of the site at any one time. Complete grading as soon as possible. Immediately stabilize the disturbed portion before grading the next portion. Practice staged seeding in order to revegetate cut and fill slopes as the work progresses. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 104 BMP C220: Storm Drain Inlet Protection Purpose Storm drain inlet protection BMPs prevent coarse sediment from entering drainage systems prior to permanent stabilization of a disturbed area. Conditions of Use Use storm drain inlet protection where storm drain inlets are to be made operational before permanent stabilization of the disturbed drainage area. Provide protection for all storm drain inlets downslope and within 500 feet of a disturbed or construction area, unless the runoff that enters the catch basin will be conveyed to a sediment pond or trap. Table 4.10 lists several options for inlet protection. All of the methods for storm drain inlet protection are prone to plugging and require a high frequency of maintenance. The maximum drainage area to a single protection BMP shall be 1 acre. Emergency overflows may be required where stormwater ponding would cause a hazard. If an emergency overflow is provided, additional end-of-pipe treatment may be required. Table 4.10 Storm Drain Inlet Protection Type of Inlet Protection Emergency Overflow Applicable for Paved/ Earthen Surfaces Conditions of Use Drop Inlet Protection Excavated drop inlet protection Yes, temporary flooding will occur Earthen Applicable for heavy flows. Easy to maintain. Large area Requirement: 30’ X 30’/acre Block and gravel drop inlet protection Yes Paved or Earthen Applicable for heavy concentrated flows. Will not pond. Gravel and wire drop inlet protection No Applicable for heavy concentrated flows. Will pond. Can withstand traffic. Catch basin filters Yes Paved or Earthen Frequent maintenance required. Curb Inlet Protection Curb inlet protection with a wooden weir Small capacity overflow Paved Used for sturdy, more compact installation. Block and gravel curb inlet protection Yes Paved Sturdy, but limited filtration. Culvert Inlet Protection Culvert inlet sediment trap 18 month expected life. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 105 Design and Installation Specifications Excavated Drop Inlet Protection  Excavated drop inlet protection is an excavated impoundment around the storm drain. Sediment settles out of the stormwater prior to entering the storm drain.  Depth 1-2 ft as measured from the crest of the inlet structure.  Side Slopes of excavation no steeper than 2:1.  Minimum volume of excavation 35 cubic yards.  Shape basin to fit site with longest dimension oriented toward the longest inflow area.  Install provisions for draining to prevent standing water problems.  Clear the area of all debris.  Grade the approach to the inlet uniformly.  Drill weep holes into the side of the inlet.  Protect weep holes with screen wire and washed aggregate.  Seal weep holes when removing structure and stabilizing area.  Build a temporary dike downslope of the structure if necessary prevent bypass flow. Block and Gravel Filter  Block and gravel filter is a barrier formed around the storm drain inlet with standard concrete blocks and gravel. See Figure 4.16.  Height 1 to 2 feet above inlet.  Recess the first row 2 inches into the ground for stability.  Support subsequent courses by placing a 2x4 through the block opening.  Do not use mortar.  Lay some blocks in the bottom row on their side for dewatering the pool.  Place hardware cloth or comparable wire mesh with ½-inch openings over all block openings.  Place gravel just below the top of blocks on slopes of 2:1 or flatter.  An alternative design is a gravel donut.  Inlet slope of 3H:1V.  Outlet slope of 2H:1V.  Provide a 1-foot wide level stone area between the structure and the inlet.  Use inlet slope stones 3 inches in diameter or larger.  Use gravel ½- to ¾-inch at a minimum thickness of 1 foot for the outlet slope. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 106 Gravel and Wire Mesh Filter  A gravel and wire mesh filter is a gravel barrier placed over the top of the inlet. This structure does not provide an overflow.  Use hardware cloth or comparable wire mesh with ½-inch openings.  Use coarse aggregate.  Provide a height of 1 foot or more, 18 inches wider than inlet on all sides.  Place wire mesh over the drop inlet so that the wire extends a minimum of 1-foot beyond each side of the inlet structure.  If more than one strip of mesh is necessary, overlap the strips.  Place coarse aggregate over the wire mesh.  The depth of the gravel shall be at least 12 inches over the entire inlet opening and extend at least 18 inches on all sides. Catchbasin filters  Catchbasin filters should be designed by the manufacturer for use at construction sites. The limited sediment storage capacity increases the amount of inspection and maintenance required, which may be daily for heavy sediment loads. The maintenance requirements can be reduced by combining a catchbasin filter with another type of inlet protection. This type of inlet protection provides flow bypass without overflow and therefore may be a better method for inlets located along active rights-of-way.  A BMP for dewatering must be provided at the site.  The catch basin filter must have a high-flow bypass feature that will not clog under normal use at a construction site.  Install the catchbasin filter according to the manufacturer’s instructions. Curb Inlet Protection with Wooden Weir  Curb inlet protection with wooden weir is a barrier formed around a curb inlet with a wooden frame and gravel  Use wire mesh with ½-inch openings.  Use extra strength filter cloth.  Construct a frame  Attach the wire and filter fabric to the frame.  Pile coarse washed aggregate against wire/fabric.  Place weight on frame anchors. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 107 Block and Gravel Curb Inlet Protection  The block and gravel curb inlet protection is a barrier formed around an inlet with concrete blocks and gravel. See Figure 4.17.  Use wire mesh with ½-inch openings.  Place two concrete blocks on their sides abutting the curb at either side of the inlet opening. These are spacer blocks.  Place a 2x4 stud through the outer holes of each spacer block to align the front blocks.  Place blocks on their sides across the front of the inlet and abutting the spacer blocks.  Place wire mesh over the outside vertical face.  Pile coarse aggregate against the wire to the top of the barrier Curb and gutter sediment barrier  The curb and gutter sediment barrier is a sandbag or rock berm (riprap and aggregate) 3 feet high and 3 feet wide in a horseshoe shape. See Figure 4.18.  Construct a horseshoe shaped berm, faced with coarse aggregate if using riprap, 3 feet high and 3 feet wide, at least 2 feet from the inlet.  Construct a horseshoe shaped sedimentation trap on the outside of the berm sized to sediment trap standards for protecting a culvert inlet. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 108 Figure 4.16 – Block and Gravel Filter Ponding Height Notes: 1. Drop inlet sediment barriers are to be used for small, nearly level drainage areas. (less than 5%) 2. Excavate a basin of sufficient size adjacent to the drop inlet. 3. The top of the structure (ponding height) must be well below the ground elevation downslope to prevent runoff from bypassing the inlet. A temporary dike may be necessary on the downslope side of the structure. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 109 Figure 4.17 – Block and Gravel Curb Inlet Protection A Plan View Wire Screen or Filter Fabric Catch Basin Curb Inlet Concrete Block Ponding Height Overflow 2x4 Wood Stud(100x50 Timber Stud) Concrete Block Wire Screen orFilter Fabric Curb Inlet ¾" Drain Gravel(20mm) ¾" Drain Gravel(20mm)Section A - A Back of Curb Concrete Block 2x4 Wood Stud Catch BasinBack of Sidewalk NOTES: 1. Use block and gravel type sediment barrier when curb inlet is located in gently sloping street segment, where water can pond and allow sediment to separate from runoff. 2. Barrier shall allow for overflow from severe storm event.3. Inspect barriers and remove sediment after each storm event. Sediment and gravel must be removed from the traveled way immediately. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 110 Figure 4.18 – Curb and Gutter Barrier January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 111 Maintenance Standards Catch basin filters must be inspected frequently, especially after storm events. If the insert becomes clogged, it should be cleaned or replaced. Stone filters: If the stone filter becomes clogged with sediment, the stones must be pulled away from the inlet and cleaned or replaced. Do not wash sediment into storm drains while cleaning. Spread all excavated material evenly over the surrounding land area or stockpile and stabilize as appropriate. Approved equivalents The Washington State Department of Ecology has approved products as able to meet the requirements of this BMP. Snohomish County may approve these products if they are used in accordance with all requirements of this BMP and all instructions and specifications provided by the manufacturer, plus additional requirements that may be established by the County. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 115 BMP C233: Silt Fence Purpose A silt fence reduces the transport of coarse sediment from a construction site by providing a temporary physical barrier to sediment and reducing the runoff velocities of overland flow. See Figure 4.21 for details on silt fence construction. Conditions of Use Silt fence may be used downslope of all disturbed areas. Silt fence is not intended to treat concentrated flows, nor is it intended to treat substantial amounts of overland flow. Any concentrated flows must be conveyed through the drainage system to a sediment pond. The only circumstance in which overland flow can be treated solely by a silt fence, rather than by a sediment pond, is when the area draining to the fence is one acre or less and flow rates are less than 0.5 cfs. Silt fences should not be constructed in streams or used in V-shaped ditches. They are not an adequate method of silt control for anything deeper than sheet or overland flow. Design and Installation Specifications Use in combination with a sediment basin or other BMP. The maximum slope steepness perpendicular to the fence line) shall be 1H:1V. The maximum sheet or overland flow path length to the fence shall be 100 feet. The maximum flow the silt fence shall be 0.5 cfs. The geotextile used shall meet the standards set forth in 2008 WSDOT Standard Specifications, Section 9-33.1 Geosynthetic Material Requirements, Table 6. Standard strength fabrics shall be supported with wire mesh, chicken wire, 2-inch x 2-inch wire, safety fence, or jute mesh to increase the strength of the fabric. Silt fence materials are available that have synthetic mesh backing attached. Filter fabric material shall contain ultraviolet ray inhibitors and stabilizers to provide a minimum of six months of expected usable construction life at a temperature range of 0°F. to 120°F. 100 percent biodegradable silt fence may be left in place after the project is completed. Refer to Figure 4.21 for standard silt fence details. The following Standard Notes shall be included in the construction documents.  The contractor shall install and maintain temporary silt fences at the locations shown in the Plans.  The silt fences shall be constructed in the areas of clearing, grading, or drainage prior to starting those activities.  The minimum height of the top of silt fence shall be 2 feet and the maximum height shall be 2½ feet above the original ground surface. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 116  The filter fabric shall be sewn together at the point of manufacture, or at an approved location as determined by the Engineer, to form geotextile lengths as required. All sewn seams shall be located at a support post. Alternatively, two sections of silt fence can be overlapped, provided the contractor demonstrates to the satisfaction of the Engineer that the overlap is long enough and that the adjacent fence sections are close enough together to prevent silt laden water from escaping through the fence at the overlap.  The filter fabric shall be attached on the up-slope side of the posts and support system with staples, wire, or in accordance with the manufacturer's recommendations. The filter fabric shall be attached to the posts in a manner that reduces the potential for tearing at the staples, wire, or other connection device.  Support the filter fabric with wire or plastic mesh, dependent on the properties of the filter fabric selected for use. If wire or plastic mesh is used, the mesh shall be fastened securely to the up-slope of the posts with the filter fabric upslope of the mesh.  Mesh support, if used, shall consist of steel wire with a maximum mesh spacing of 2 inches, or a prefabricated polymeric mesh. The grab tensile strength of the mesh shall be at least 180 lbs. Polymeric mesh must have equivalent resistance to ultraviolet radiation as the filter fabric used.  The filter fabric at the bottom of the fence shall be buried in a trench to a minimum depth of 4 inches below the ground surface. The trench shall be backfilled and the soil tamped in place over the buried portion of the geotextile, such that no flow can pass beneath the fence and scouring cannot occur. If wire or polymeric back-up support mesh is used, the wire or polymeric mesh shall extend into the trench a minimum of 3 inches.  Fence posts shall be placed or driven a minimum of 18 inches, provided that a minimum depth of 12 inches is allowed if topsoil or other soft subgrade soil is not present and a minimum depth of 18 inches cannot be reached. Fence post depths shall be increased by 6 inches if the fence is located on slopes of 3H:1V or steeper and the slope is perpendicular to the fence. If required post depths cannot be obtained, the posts shall be adequately secured by bracing or guying to prevent overturning of the fence due to sediment loading.  Silt fences shall be located on contour as much as possible, except at the ends of the fence, where the fence shall be turned uphill such that the silt fence captures the runoff water and prevents water from flowing around the end of the fence.  If the fence must cross contours, with the exception of the ends of the fence, a gravel check dam placed perpendicular to the back of the fence shall be used to minimize concentrated flow and erosion along the back of the fence. The gravel check dam shall be approximately 1-foot deep at the back of the fence. The dam shall be continued perpendicular to the fence at the same elevation until the top of the dam intercepts the ground surface behind the fence. Gravel check dams shall consist of crushed surfacing base course, gravel backfill for walls, or shoulder ballast. Gravel check dams shall be located every 10 feet along the fence where the fence must cross contours. The slope of the fence line where contours must be crossed shall not be steeper than 3H:1V.  Wood, steel or equivalent posts shall be used. Wood posts shall have minimum dimensions of 2 inches by 2 inches by 3 feet minimum length, and shall be free of defects such as knots, January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 117 splits, or gouges. Steel posts shall consist of either size No. 6 rebar or larger, ASTM A 120 steel pipe with a minimum diameter of 1-inch, U, T, L, or C shape steel posts with a minimum weight of 1.35 lbs./ft. or other steel posts having equivalent strength and bending resistance to the post sizes listed. The spacing of the support posts shall be a maximum of 6 feet.  Fence back-up support, if used, shall consist of steel wire with a maximum mesh spacing of 2 inches, or a prefabricated polymeric mesh. The strength of the wire or polymeric mesh shall be equivalent to or greater than 180 lbs. grab tensile strength. The polymeric mesh must be as resistant to ultraviolet radiation as the geotextile it supports. Refer to Figure 4.22 for slicing method details. Install silt fence using the slicing method specification details follow.  The base of both end posts must be at least 2 to 4 inches above the top of the silt fence fabric on the middle posts for ditch checks to drain properly. Use a hand level or string level, if necessary, to mark base points before installation.  Install posts 3 to 4 feet apart in critical retention areas and 6 to 7 feet apart in standard applications.  Install posts 24 inches deep on the downstream side of the silt fence, and as close as possible to the fabric, enabling posts to support the fabric from upstream water pressure.  Install posts with the nipples facing away from the silt fence fabric.  Attach the fabric to each post with three ties, all spaced within the top 8 inches of the fabric. Attach each tie diagonally 45 degrees through the fabric, with each puncture at least 1 inch vertically apart. In addition, each tie should be positioned to hang on a post nipple when tightening to prevent sagging.  Wrap approximately 6 inches of fabric around the end posts and secure with 3 ties.  No more than 24 inches of a 36-inch fabric is allowed above ground level.  The installation should be checked and corrected for any deviation before compaction. Use a flat-bladed shovel to tuck fabric deeper into the ground if necessary.  Compact the soil immediately next to the silt fence fabric with the front wheel of the tractor, skid steer, or roller exerting at least 60 pounds per square inch. Compact the upstream side first and then each side twice for a total of four trips. Maintenance Standards Repair damaged or deteriorated silt fence immediately If concentrated flows are evident uphill of the fence, they must be intercepted and conveyed to a sediment pond. Check the uphill side of the fence for signs of the fence clogging and acting as a barrier to flow and causing channelization of flows parallel to the fence. If this occurs, replace the fence or remove the trapped sediment. January 2016 Snohomish County Drainage Manual Volume II - Construction Stormwater Pollution Prevention 118 Sediment deposits shall either be removed when the deposit reaches approximately one-third the height of the silt fence, or a second silt fence shall be installed. Figure 4.21 – Silt Fence DRAFT Page | 35 Appendix C – Correspondence (Placeholder) DRAFT Page | 36 Appendix D – Site Inspection Form Construction Stormwater Site Inspection Form Page 1 Project Name Meadowdale Beach Park Recreation and Habitat Restoration Improvements Project Permit # Inspection Date Time Name of Certified Erosion Sediment Control Lead (CESCL) or qualified inspector if less than one acre Print Name: Approximate rainfall amount since the last inspection (in inches): Approximate rainfall amount in the last 24 hours (in inches): Current Weather Clear Cloudy Mist Rain Wind Fog A. Type of inspection: Weekly Post Storm Event Other B. Phase of Active Construction (check all that apply): Pre Construction/installation of erosion/sediment controls Clearing/Demo/Grading Infrastructure/storm/roads Concrete pours Vertical Construction/buildings Utilities Offsite improvements Site temporary stabilized Final stabilization C. Questions: 1. Were all areas of construction and discharge points inspected? Yes No 2. Did you observe the presence of suspended sediment, turbidity, discoloration, or oil sheen Yes No 3. Was a water quality sample taken during inspection? (refer to permit conditions S4 & S5) Yes No 4. Was there a turbid discharge 250 NTU or greater, or Transparency 6 cm or less?* Yes No 5. If yes to #4 was it reported to Ecology? Yes No 6. Is pH sampling required? pH range required is 6.5 to 8.5. Yes No If answering yes to a discharge, describe the event. Include when, where, and why it happened; what action was taken, and when. *If answering yes to # 4 record NTU/Transparency with continual sampling daily until turbidity is 25 NTU or less/ transparency is 33 cm or greater. Sampling Results: Date: Parameter Method (circle one) Result Other/Note NTU cm pH Turbidity tube, meter, laboratory pH Paper, kit, meter Construction Stormwater Site Inspection Form Page 2 D. Check the observed status of all items. Provide “Action Required “details and dates. Element # Inspection BMPs Inspected BMP needs maintenance BMP failed Action required (describe in section F) yes no n/a 1 Clearing Limits Before beginning land disturbing activities are all clearing limits, natural resource areas (streams, wetlands, buffers, trees) protected with barriers or similar BMPs? (high visibility recommended) 2 Construction Access Construction access is stabilized with quarry spalls or equivalent BMP to prevent sediment from being tracked onto roads? Sediment tracked onto the road way was cleaned thoroughly at the end of the day or more frequent as necessary. 3 Control Flow Rates Are flow control measures installed to control stormwater volumes and velocity during construction and do they protect downstream properties and waterways from erosion? If permanent infiltration ponds are used for flow control during construction, are they protected from siltation? 4 Sediment Controls All perimeter sediment controls (e.g. silt fence, wattles, compost socks, berms, etc.) installed, and maintained in accordance with the Stormwater Pollution Prevention Plan (SWPPP). Sediment control BMPs (sediment ponds, traps, filters etc.) have been constructed and functional as the first step of grading. Stormwater runoff from disturbed areas is directed to sediment removal BMP. 5 Stabilize Soils Have exposed un-worked soils been stabilized with effective BMP to prevent erosion and sediment deposition? Construction Stormwater Site Inspection Form Page 3 Element # Inspection BMPs Inspected BMP needs maintenance BMP failed Action required (describe in section F) yes no n/a 5 Stabilize Soils Cont. Are stockpiles stabilized from erosion, protected with sediment trapping measures and located away from drain inlet, waterways, and drainage channels? Have soils been stabilized at the end of the shift, before a holiday or weekend if needed based on the weather forecast? 6 Protect Slopes Has stormwater and ground water been diverted away from slopes and disturbed areas with interceptor dikes, pipes and or swales? Is off-site storm water managed separately from stormwater generated on the site? Is excavated material placed on uphill side of trenches consistent with safety and space considerations? Have check dams been placed at regular intervals within constructed channels that are cut down a slope? 7 Drain Inlets Storm drain inlets made operable during construction are protected. Are existing storm drains within the influence of the project protected? 8 Stabilize Channel and Outlets Have all on-site conveyance channels been designed, constructed and stabilized to prevent erosion from expected peak flows? Is stabilization, including armoring material, adequate to prevent erosion of outlets, adjacent stream banks, slopes and downstream conveyance systems? 9 Control Pollutants Are waste materials and demolition debris handled and disposed of to prevent contamination of stormwater? Has cover been provided for all chemicals, liquid products, petroleum products, and other material? Has secondary containment been provided capable of containing 110% of the volume? Were contaminated surfaces cleaned immediately after a spill incident? Were BMPs used to prevent contamination of stormwater by a pH modifying sources? Construction Stormwater Site Inspection Form Page 4 Element # Inspection BMPs Inspected BMP needs maintenance BMP failed Action required (describe in section F) yes no n/a 9 Cont. Wheel wash wastewater is handled and disposed of properly. 10 Control Dewatering Concrete washout in designated areas. No washout or excess concrete on the ground. Dewatering has been done to an approved source and in compliance with the SWPPP. Were there any clean non turbid dewatering discharges? 11 Maintain BMP Are all temporary and permanent erosion and sediment control BMPs maintained to perform as intended? 12 Manage the Project Has the project been phased to the maximum degree practicable? Has regular inspection, monitoring and maintenance been performed as required by the permit? Has the SWPPP been updated, implemented and records maintained? 13 Protect LID Is all Bioretention and Rain Garden Facilities protected from sedimentation with appropriate BMPs? Is the Bioretention and Rain Garden protected against over compaction of construction equipment and foot traffic to retain its infiltration capabilities? Permeable pavements are clean and free of sediment and sediment laden- water runoff. Muddy construction equipment has not been on the base material or pavement. Have soiled permeable pavements been cleaned of sediments and pass infiltration test as required by stormwater manual methodology? Heavy equipment has been kept off existing soils under LID facilities to retain infiltration rate. E. Check all areas that have been inspected. All in place BMPs All disturbed soils All concrete wash out area All material storage areas All discharge locations All equipment storage areas All construction entrances/exits Construction Stormwater Site Inspection Form Page 5 F. Elements checked “Action Required” (section D) describe corrective action to be taken. List the element number; be specific on location and work needed. Document, initial, and date when the corrective action has been completed and inspected. Element # Description and Location Action Required Completion Date Initials Attach additional page if needed Sign the following certification: “I certify that this report is true, accurate, and complete, to the best of my knowledge and belief” Inspected by: (print) (Signature) Date: Title/Qualification of Inspector: DRAFT Page | 37 Appendix E – Construction Stormwater General Permit (Placeholder) DRAFT Page | 38 Appendix F – 303(d) List Waterbodies / TMDL Waterbodies Information (Placeholder) DRAFT Page | 39 Appendix G – Contaminated Site Information (No Contamination Known at Site) DRAFT Page | 40 Appendix H – Engineering Calculations (Placeholder) Appendix E Hydrologic Model Input and Results ————————————————————————————————— MGS FLOOD PROJECT REPORT Program Version: MGSFlood 4.46 Program License Number: 200510001 Project Simulation Performed on: 02/02/2018 9:26 AM Report Generation Date: 02/02/2018 9:59 AM ————————————————————————————————— Input File Name: Meadowdale.fld Project Name: Meadowdale Analysis Title: Stormwater Drainage Basins Comments: ———————————————— PRECIPITATION INPUT ———————————————— Computational Time Step (Minutes): 15 Extended Precipitation Time Series Selected Climatic Region Number: 2 Full Period of Record Available used for Routing Precipitation Station : 95003605 Puget West 36 in_5min 10/01/1939-10/01/2097 Evaporation Station : 951036 Puget West 36 in MAP Evaporation Scale Factor : 0.750 HSPF Parameter Region Number: 1 HSPF Parameter Region Name : USGS Default ********** Default HSPF Parameters Used (Not Modified by User) *************** ********************** WATERSHED DEFINITION *********************** Predevelopment/Post Development Tributary Area Summary Predeveloped Post Developed Total Subbasin Area (acres) 27.792 27.780 Area of Links that Include Precip/Evap (acres) 0.000 0.012 Total (acres) 27.792 27.792 ----------------------SCENARIO: EXISTING Number of Subbasins: 6 ---------- Subbasin : Area 1 - Road ---------- -------Area (Acres) -------- Till Forest 5.038 Till Grass 0.020 ROADS/FLAT 0.659 ---------------------------------------------- Subbasin Total 5.717 ---------- Subbasin : Area 2 - Ranger Residence ---------- -------Area (Acres) -------- Till Forest 0.746 Till Grass 0.125 ROADS/FLAT 0.137 ---------------------------------------------- Subbasin Total 1.008 ---------- Subbasin : Area 3 - West of Ranger Residence ---------- -------Area (Acres) -------- Till Forest 2.781 Till Grass 1.342 ROADS/FLAT 0.326 ---------------------------------------------- Subbasin Total 4.449 ---------- Subbasin : Area 4 - North of Creek ---------- -------Area (Acres) -------- Till Forest 11.518 ROADS/FLAT 0.279 ---------------------------------------------- Subbasin Total 11.797 ---------- Subbasin : Area 5 - Railroad Berm and Beach ---------- -------Area (Acres) -------- Outwash Pasture 1.005 ROADS/FLAT 0.574 ---------------------------------------------- Subbasin Total 1.579 ---------- Subbasin : Area 6 - Off-site Area ---------- -------Area (Acres) -------- Till Forest 3.111 ROADS/FLAT 0.131 ---------------------------------------------- Subbasin Total 3.242 ----------------------SCENARIO: PROPOSED Number of Subbasins: 7 ---------- Subbasin : Area 1 - Road ---------- -------Area (Acres) -------- Till Forest 5.029 Till Grass 0.011 ROADS/FLAT 0.677 ---------------------------------------------- Subbasin Total 5.717 ---------- Subbasin : Area 2 - Ranger Residence ---------- -------Area (Acres) -------- Till Forest 0.980 Till Grass 0.300 ROADS/FLAT 0.219 ---------------------------------------------- Subbasin Total 1.499 ---------- Subbasin : Area 3B - West of Ranger Not Draining to Rock Swale ---------- -------Area (Acres) -------- Till Forest 1.115 Till Grass 0.505 ROADS/FLAT 0.063 ---------------------------------------------- Subbasin Total 1.683 ---------- Subbasin : Area 4 - North of Creek ---------- -------Area (Acres) -------- Till Forest 11.563 ROADS/FLAT 0.234 ---------------------------------------------- Subbasin Total 11.797 ---------- Subbasin : Area 5 - Railroad Berm and Beach ---------- -------Area (Acres) -------- Outwash Pasture 1.005 ROADS/FLAT 0.574 ---------------------------------------------- Subbasin Total 1.579 ---------- Subbasin : Area 6 - Off-site Area ---------- -------Area (Acres) -------- Till Forest 3.111 ROADS/FLAT 0.131 ---------------------------------------------- Subbasin Total 3.242 ---------- Subbasin : Area 3A - West of Ranger Draining to Rock Swale ---------- -------Area (Acres) -------- Till Forest 1.271 Till Grass 0.826 ROADS/FLAT 0.166 ---------------------------------------------- Subbasin Total 2.263 ************************* LINK DATA ******************************* ----------------------SCENARIO: EXISTING Number of Links: 8 ------------------------------------------ Link Name: Area 1 Link Link Type: Copy Downstream Link Name: Creek DS of Area 2 ------------------------------------------ Link Name: Area 2 Link Link Type: Copy Downstream Link Name: Creek DS of Area 2 ------------------------------------------ Link Name: Area 3 Link Link Type: Copy Downstream Link Name: Creek US of Berm ------------------------------------------ Link Name: Area 4 Link Link Type: Copy Downstream Link Name: Creek US of Berm ------------------------------------------ Link Name: Area 5 Outfall Link Type: Copy Downstream Link: None ------------------------------------------ Link Name: Area 6 Outfall Link Type: Copy Downstream Link: None ------------------------------------------ Link Name: Creek DS of Area 2 Link Type: Copy Downstream Link Name: Creek US of Berm ------------------------------------------ Link Name: Creek US of Berm Link Type: Copy Downstream Link: None ************************* LINK DATA ******************************* ----------------------SCENARIO: PROPOSED Number of Links: 11 ------------------------------------------ Link Name: Area 1 Link Link Type: Copy Downstream Link Name: Swale ------------------------------------------ Link Name: Area 2 Link Link Type: Copy Downstream Link Name: Swale ------------------------------------------ Link Name: Area 3B Link Link Type: Copy Downstream Link Name: Creek US of Berm ------------------------------------------ Link Name: Area 4 Link Link Type: Copy Downstream Link Name: Creek US of Berm ------------------------------------------ Link Name: Area 5 Outfall Link Type: Copy Downstream Link: None ------------------------------------------ Link Name: Area 6 Outfall Link Type: Copy Downstream Link: None ------------------------------------------ Link Name: Creek DS of Area 2 Link Type: Copy Downstream Link Name: Rock Swale ------------------------------------------ Link Name: Creek US of Berm Link Type: Copy Downstream Link: None ------------------------------------------ Link Name: Swale Link Type: Bioretention Facility Downstream Link Name: Creek DS of Area 2 Base Elevation (ft) : 21.60 Riser Crest Elevation (ft) : 21.77 Storage Depth (ft) : 0.17 Bottom Length (ft) : 180.0 Bottom Width (ft) : 3.0 Side Slopes (ft/ft) : L1= 2.00 L2= 2.00 W1= 2.00 W2= 2.00 Bottom Area (sq-ft) : 540. Area at Riser Crest El (sq-ft) : 665. (acres) : 0.015 Volume at Riser Crest (cu-ft) : 175. (ac-ft) : 0.004 Infiltration on Bottom only Selected Soil Properties Biosoil Thickness (ft) : 0.67 Biosoil Saturated Hydraulic Conductivity (in/hr) : 2.00 Biosoil Porosity (Percent) : 20.00 Maximum Elevation of Bioretention Soil : 22.60 Native Soil Hydraulic Conductivity (in/hr) : 0.25 Riser Geometry Riser Structure Type : Rectangular Riser Length (ft) : 2.00 Riser Width (ft) : 1.67 Common Length (ft) : 2.000 Riser Crest Elevation : 21.77 ft Hydraulic Structure Geometry Number of Devices: 0 ------------------------------------------ Link Name: Area 3A Link Link Type: Copy Downstream Link Name: Rock Swale ------------------------------------------ Link Name: Rock Swale Link Type: Copy Downstream Link Name: Creek US of Berm **********************FLOOD FREQUENCY AND DURATION STATISTICS******************* ----------------------SCENARIO: EXISTING Number of Subbasins: 6 Number of Links: 8 ********** Subbasin: Area 1 - Road ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.300 5-Year 0.408 10-Year 0.500 25-Year 0.613 50-Year 0.714 100-Year 0.739 200-Year 0.752 ********** Subbasin: Area 2 - Ranger Residence ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 6.578E-02 5-Year 9.474E-02 10-Year 0.115 25-Year 0.163 50-Year 0.166 100-Year 0.176 200-Year 0.180 ********** Subbasin: Area 3 - West of Ranger Residence ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.241 5-Year 0.408 10-Year 0.520 25-Year 0.669 50-Year 0.806 100-Year 0.870 200-Year 0.887 ********** Subbasin: Area 4 - North of Creek ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.312 5-Year 0.487 10-Year 0.641 25-Year 0.791 50-Year 0.946 100-Year 0.968 200-Year 1.036 ********** Subbasin: Area 5 - Railroad Berm and Beach ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.207 5-Year 0.274 10-Year 0.300 25-Year 0.351 50-Year 0.449 100-Year 0.518 200-Year 0.542 ********** Subbasin: Area 6 - Off-site Area ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 9.563E-02 5-Year 0.149 10-Year 0.191 25-Year 0.230 50-Year 0.286 100-Year 0.293 200-Year 0.309 ********** Link: Area 1 Link ********** Link Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.300 5-Year 0.408 10-Year 0.500 25-Year 0.613 50-Year 0.714 100-Year 0.739 200-Year 0.752 ********** Link: Area 1 Link ********** Link Outflow 1 Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.300 5-Year 0.408 10-Year 0.500 25-Year 0.613 50-Year 0.714 100-Year 0.739 200-Year 0.752 ********** Link: Area 2 Link ********** Link Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 6.578E-02 5-Year 9.474E-02 10-Year 0.115 25-Year 0.163 50-Year 0.166 100-Year 0.176 200-Year 0.180 ********** Link: Area 2 Link ********** Link Outflow 1 Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 6.578E-02 5-Year 9.474E-02 10-Year 0.115 25-Year 0.163 50-Year 0.166 100-Year 0.176 200-Year 0.180 ********** Link: Area 3 Link ********** Link Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.241 5-Year 0.408 10-Year 0.520 25-Year 0.669 50-Year 0.806 100-Year 0.870 200-Year 0.887 ********** Link: Area 3 Link ********** Link Outflow 1 Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.241 5-Year 0.408 10-Year 0.520 25-Year 0.669 50-Year 0.806 100-Year 0.870 200-Year 0.887 ********** Link: Area 4 Link ********** Link Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.312 5-Year 0.487 10-Year 0.641 25-Year 0.791 50-Year 0.946 100-Year 0.968 200-Year 1.036 ********** Link: Area 4 Link ********** Link Outflow 1 Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.312 5-Year 0.487 10-Year 0.641 25-Year 0.791 50-Year 0.946 100-Year 0.968 200-Year 1.036 ********** Link: Area 5 Outfall ********** Link Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.207 5-Year 0.274 10-Year 0.300 25-Year 0.351 50-Year 0.449 100-Year 0.518 200-Year 0.542 ********** Link: Area 5 Outfall ********** Link Outflow 1 Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.207 5-Year 0.274 10-Year 0.300 25-Year 0.351 50-Year 0.449 100-Year 0.518 200-Year 0.542 ********** Link: Area 6 Outfall ********** Link Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 9.563E-02 5-Year 0.149 10-Year 0.191 25-Year 0.230 50-Year 0.286 100-Year 0.293 200-Year 0.309 ********** Link: Area 6 Outfall ********** Link Outflow 1 Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 9.563E-02 5-Year 0.149 10-Year 0.191 25-Year 0.230 50-Year 0.286 100-Year 0.293 200-Year 0.309 ********** Link: Creek DS of Area 2 ********** Link Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.368 5-Year 0.502 10-Year 0.611 25-Year 0.777 50-Year 0.879 100-Year 0.915 200-Year 0.929 ********** Link: Creek US of Berm ********** Link Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.866 5-Year 1.368 10-Year 1.693 25-Year 1.982 50-Year 2.630 100-Year 2.730 200-Year 2.746 ********** Link: Creek US of Berm ********** Link Outflow 1 Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.866 5-Year 1.368 10-Year 1.693 25-Year 1.982 50-Year 2.630 100-Year 2.730 200-Year 2.746 ----------------------SCENARIO: PROPOSED Number of Subbasins: 7 Number of Links: 11 ********** Subbasin: Area 1 - Road ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.305 5-Year 0.413 10-Year 0.507 25-Year 0.627 50-Year 0.720 100-Year 0.745 200-Year 0.759 ********** Subbasin: Area 2 - Ranger Residence ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.110 5-Year 0.163 10-Year 0.197 25-Year 0.273 50-Year 0.290 100-Year 0.303 200-Year 0.311 ********** Subbasin: Area 3B - West of Ranger Not Draining to Rock Swale ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 7.199E-02 5-Year 0.132 10-Year 0.174 25-Year 0.206 50-Year 0.274 100-Year 0.298 200-Year 0.302 ********** Subbasin: Area 4 - North of Creek ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.303 5-Year 0.474 10-Year 0.627 25-Year 0.782 50-Year 0.923 100-Year 0.945 200-Year 1.016 ********** Subbasin: Area 5 - Railroad Berm and Beach ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.207 5-Year 0.274 10-Year 0.300 25-Year 0.351 50-Year 0.449 100-Year 0.518 200-Year 0.542 ********** Subbasin: Area 6 - Off-site Area ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 9.563E-02 5-Year 0.149 10-Year 0.191 25-Year 0.230 50-Year 0.286 100-Year 0.293 200-Year 0.309 ********** Subbasin: Area 3A - West of Ranger Draining to Rock Swale ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.132 5-Year 0.227 10-Year 0.287 25-Year 0.379 50-Year 0.449 100-Year 0.485 200-Year 0.496 ********** Link: Area 1 Link ********** Link Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.305 5-Year 0.413 10-Year 0.507 25-Year 0.627 50-Year 0.720 100-Year 0.745 200-Year 0.759 ********** Link: Area 1 Link ********** Link Outflow 1 Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.305 5-Year 0.413 10-Year 0.507 25-Year 0.627 50-Year 0.720 100-Year 0.745 200-Year 0.759 ********** Link: Area 2 Link ********** Link Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.110 5-Year 0.163 10-Year 0.197 25-Year 0.273 50-Year 0.290 100-Year 0.303 200-Year 0.311 ********** Link: Area 2 Link ********** Link Outflow 1 Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.110 5-Year 0.163 10-Year 0.197 25-Year 0.273 50-Year 0.290 100-Year 0.303 200-Year 0.311 ********** Link: Area 3B Link ********** Link Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 7.199E-02 5-Year 0.132 10-Year 0.174 25-Year 0.206 50-Year 0.274 100-Year 0.298 200-Year 0.302 ********** Link: Area 3B Link ********** Link Outflow 1 Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 7.199E-02 5-Year 0.132 10-Year 0.174 25-Year 0.206 50-Year 0.274 100-Year 0.298 200-Year 0.302 ********** Link: Area 4 Link ********** Link Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.303 5-Year 0.474 10-Year 0.627 25-Year 0.782 50-Year 0.923 100-Year 0.945 200-Year 1.016 ********** Link: Area 4 Link ********** Link Outflow 1 Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.303 5-Year 0.474 10-Year 0.627 25-Year 0.782 50-Year 0.923 100-Year 0.945 200-Year 1.016 ********** Link: Area 5 Outfall ********** Link Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.207 5-Year 0.274 10-Year 0.300 25-Year 0.351 50-Year 0.449 100-Year 0.518 200-Year 0.542 ********** Link: Area 5 Outfall ********** Link Outflow 1 Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.207 5-Year 0.274 10-Year 0.300 25-Year 0.351 50-Year 0.449 100-Year 0.518 200-Year 0.542 ********** Link: Area 6 Outfall ********** Link Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 9.563E-02 5-Year 0.149 10-Year 0.191 25-Year 0.230 50-Year 0.286 100-Year 0.293 200-Year 0.309 ********** Link: Area 6 Outfall ********** Link Outflow 1 Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 9.563E-02 5-Year 0.149 10-Year 0.191 25-Year 0.230 50-Year 0.286 100-Year 0.293 200-Year 0.309 ********** Link: Creek DS of Area 2 ********** Link Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.411 5-Year 0.565 10-Year 0.679 25-Year 0.896 50-Year 0.993 100-Year 0.998 200-Year 1.039 ********** Link: Creek US of Berm ********** Link Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.860 5-Year 1.358 10-Year 1.689 25-Year 1.984 50-Year 2.637 100-Year 2.727 200-Year 2.737 ********** Link: Creek US of Berm ********** Link Outflow 1 Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.860 5-Year 1.358 10-Year 1.689 25-Year 1.984 50-Year 2.637 100-Year 2.727 200-Year 2.737 ********** Link: Swale ********** Link Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.420 5-Year 0.573 10-Year 0.693 25-Year 0.919 50-Year 1.002 100-Year 1.048 200-Year 1.063 ********** Link: Swale ********** Link Outflow 1 Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.411 5-Year 0.565 10-Year 0.679 25-Year 0.896 50-Year 0.993 100-Year 0.998 200-Year 1.039 ********** Link: Swale ********** Link WSEL Stats WSEL Frequency Data(ft) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) WSEL Peak (ft) ====================================== 1.05-Year 21.816 1.11-Year 21.821 1.25-Year 21.827 2.00-Year 21.840 3.33-Year 21.851 5-Year 21.856 10-Year 21.868 25-Year 21.886 50-Year 21.895 100-Year 21.895 ********** Link: Area 3A Link ********** Link Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.132 5-Year 0.227 10-Year 0.287 25-Year 0.379 50-Year 0.449 100-Year 0.485 200-Year 0.496 ********** Link: Area 3A Link ********** Link Outflow 1 Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.132 5-Year 0.227 10-Year 0.287 25-Year 0.379 50-Year 0.449 100-Year 0.485 200-Year 0.496 ********** Link: Rock Swale ********** Link Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.523 5-Year 0.782 10-Year 0.977 25-Year 1.298 50-Year 1.438 100-Year 1.482 200-Year 1.532 ********** Link: Rock Swale ********** Link Outflow 1 Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.523 5-Year 0.782 10-Year 0.977 25-Year 1.298 50-Year 1.438 100-Year 1.482 200-Year 1.532 ***********Groundwater Recharge Summary ************* Recharge is computed as input to Perlnd Groundwater Plus Infiltration in Structures Total Predeveloped Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: Area 1 - Road 773.329 Subbasin: Area 2 - Ranger Resi 128.014 Subbasin: Area 3 - West of Ran 574.152 Subbasin: Area 4 - North of Cr 1762.945 Subbasin: Area 5 - Railroad Be 293.814 Subbasin: Area 6 - Off-site Ar 476.170 Link: Area 1 Link 0.000 Link: Area 2 Link 0.000 Link: Area 3 Link 0.000 Link: Area 4 Link 0.000 Link: Area 5 Outfall 0.000 Link: Area 6 Outfall 0.000 Link: Creek DS of Area 2 0.000 Link: Creek US of Berm 0.000 _____________________________________ Total: 4008.424 Total Post Developed Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: Area 1 - Road 770.956 Subbasin: Area 2 - Ranger Resi 183.194 Subbasin: Area 3B - West of Ra 226.540 Subbasin: Area 4 - North of Cr 1769.833 Subbasin: Area 5 - Railroad Be 293.814 Subbasin: Area 6 - Off-site Ar 476.170 Subbasin: Area 3A - West of Ra 285.936 Link: Area 1 Link 0.000 Link: Area 2 Link 0.000 Link: Area 3B Link 0.000 Link: Area 4 Link 0.000 Link: Area 5 Outfall 0.000 Link: Area 6 Outfall 0.000 Link: Creek DS of Area 2 0.000 Link: Creek US of Berm 0.000 Link: Swale 157.121 Link: Area 3A Link 0.000 Link: Rock Swale 0.000 _____________________________________ Total: 4163.563 Total Predevelopment Recharge is Less than Post Developed Average Recharge Per Year, (Number of Years= 158) Predeveloped: 25.370 ac-ft/year, Post Developed: 26.352 ac-ft/year ***********Water Quality Facility Data ************* ----------------------SCENARIO: EXISTING Number of Links: 8 ********** Link: Area 1 Link ********** Basic Wet Pond Volume (91% Exceedance): 10147. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 15221. cu-ft 2-Year Discharge Rate : 0.300 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.15 cfs Off-line Design Discharge Rate (91% Exceedance): 0.08 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 650.79 Inflow Volume Including PPT-Evap (ac-ft): 650.79 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 650.79 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00% ********** Link: Area 2 Link ********** Basic Wet Pond Volume (91% Exceedance): 1845. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 2767. cu-ft 2-Year Discharge Rate : 0.066 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.03 cfs Off-line Design Discharge Rate (91% Exceedance): 0.02 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 133.17 Inflow Volume Including PPT-Evap (ac-ft): 133.17 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 133.17 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00% ********** Link: Area 3 Link ********** Basic Wet Pond Volume (91% Exceedance): 8159. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 12238. cu-ft 2-Year Discharge Rate : 0.241 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.11 cfs Off-line Design Discharge Rate (91% Exceedance): 0.06 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 573.73 Inflow Volume Including PPT-Evap (ac-ft): 573.73 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 573.73 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00% ********** Link: Area 4 Link ********** Basic Wet Pond Volume (91% Exceedance): 20244. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 30367. cu-ft 2-Year Discharge Rate : 0.312 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.26 cfs Off-line Design Discharge Rate (91% Exceedance): 0.14 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 989.37 Inflow Volume Including PPT-Evap (ac-ft): 989.37 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 989.37 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00% ********** Link: Area 5 Outfall ********** Basic Wet Pond Volume (91% Exceedance): 2924. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 4386. cu-ft 2-Year Discharge Rate : 0.207 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.09 cfs Off-line Design Discharge Rate (91% Exceedance): 0.05 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 229.71 Inflow Volume Including PPT-Evap (ac-ft): 229.71 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 229.71 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00% ********** Link: Area 6 Outfall ********** Basic Wet Pond Volume (91% Exceedance): 5540. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 8310. cu-ft 2-Year Discharge Rate : 0.096 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.07 cfs Off-line Design Discharge Rate (91% Exceedance): 0.04 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 289.46 Inflow Volume Including PPT-Evap (ac-ft): 289.46 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 289.46 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00% ********** Link: Creek DS of Area 2 ********** Basic Wet Pond Volume (91% Exceedance): 12022. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 18033. cu-ft 2-Year Discharge Rate : 0.368 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.18 cfs Off-line Design Discharge Rate (91% Exceedance): 0.10 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 783.96 Inflow Volume Including PPT-Evap (ac-ft): 783.96 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 783.96 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00% ********** Link: Creek US of Berm ********** Basic Wet Pond Volume (91% Exceedance): 39964. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 59946. cu-ft 2-Year Discharge Rate : 0.866 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.53 cfs Off-line Design Discharge Rate (91% Exceedance): 0.29 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 2347.06 Inflow Volume Including PPT-Evap (ac-ft): 2347.06 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 2347.06 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00% ----------------------SCENARIO: PROPOSED Number of Links: 11 ********** Link: Area 1 Link ********** Basic Wet Pond Volume (91% Exceedance): 10191. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 15286. cu-ft 2-Year Discharge Rate : 0.305 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.15 cfs Off-line Design Discharge Rate (91% Exceedance): 0.08 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 655.74 Inflow Volume Including PPT-Evap (ac-ft): 655.74 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 655.74 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00% ********** Link: Area 2 Link ********** Basic Wet Pond Volume (91% Exceedance): 2839. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 4258. cu-ft 2-Year Discharge Rate : 0.110 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.04 cfs Off-line Design Discharge Rate (91% Exceedance): 0.02 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 213.96 Inflow Volume Including PPT-Evap (ac-ft): 213.96 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 213.96 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00% ********** Link: Area 3B Link ********** Basic Wet Pond Volume (91% Exceedance): 3054. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 4581. cu-ft 2-Year Discharge Rate : 0.072 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.04 cfs Off-line Design Discharge Rate (91% Exceedance): 0.02 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 197.27 Inflow Volume Including PPT-Evap (ac-ft): 197.27 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 197.27 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00% ********** Link: Area 4 Link ********** Basic Wet Pond Volume (91% Exceedance): 20159. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 30238. cu-ft 2-Year Discharge Rate : 0.303 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.26 cfs Off-line Design Discharge Rate (91% Exceedance): 0.14 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 974.81 Inflow Volume Including PPT-Evap (ac-ft): 974.81 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 974.81 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00% ********** Link: Area 5 Outfall ********** Basic Wet Pond Volume (91% Exceedance): 2924. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 4386. cu-ft 2-Year Discharge Rate : 0.207 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.09 cfs Off-line Design Discharge Rate (91% Exceedance): 0.05 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 229.71 Inflow Volume Including PPT-Evap (ac-ft): 229.71 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 229.71 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00% ********** Link: Area 6 Outfall ********** Basic Wet Pond Volume (91% Exceedance): 5540. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 8310. cu-ft 2-Year Discharge Rate : 0.096 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.07 cfs Off-line Design Discharge Rate (91% Exceedance): 0.04 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 289.46 Inflow Volume Including PPT-Evap (ac-ft): 289.46 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 289.46 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00% ********** Link: Creek DS of Area 2 ********** Basic Wet Pond Volume (91% Exceedance): 13788. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 20681. cu-ft 2-Year Discharge Rate : 0.411 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.21 cfs Off-line Design Discharge Rate (91% Exceedance): 0.11 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 718.48 Inflow Volume Including PPT-Evap (ac-ft): 718.48 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 718.48 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00% ********** Link: Creek US of Berm ********** Basic Wet Pond Volume (91% Exceedance): 41280. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 61920. cu-ft 2-Year Discharge Rate : 0.860 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.54 cfs Off-line Design Discharge Rate (91% Exceedance): 0.30 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 2196.25 Inflow Volume Including PPT-Evap (ac-ft): 2196.25 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 2196.25 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00% ********** Link: Swale ********** Basic Wet Pond Volume (91% Exceedance): 13033. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 19549. cu-ft 2-Year Discharge Rate : 0.411 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.19 cfs Off-line Design Discharge Rate (91% Exceedance): 0.11 cfs Time to Infiltrate 91% Treatment Volume, (Hours): 1046.14 Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 869.71 Inflow Volume Including PPT-Evap (ac-ft): 874.90 Total Runoff Infiltrated (ac-ft): 157.12, 17.96% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 718.48 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 17.96% ********** Link: Area 3A Link ********** Basic Wet Pond Volume (91% Exceedance): 4223. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 6335. cu-ft 2-Year Discharge Rate : 0.132 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.06 cfs Off-line Design Discharge Rate (91% Exceedance): 0.03 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 305.70 Inflow Volume Including PPT-Evap (ac-ft): 305.70 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 305.70 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00% ********** Link: Rock Swale ********** Basic Wet Pond Volume (91% Exceedance): 18020. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 27029. cu-ft 2-Year Discharge Rate : 0.523 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.26 cfs Off-line Design Discharge Rate (91% Exceedance): 0.14 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 1024.17 Inflow Volume Including PPT-Evap (ac-ft): 1024.17 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 1024.17 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00% ***********Compliance Point Results ************* Scenario Existing Compliance Link: Creek DS of Area 2 Scenario Proposed Compliance Link: Creek DS of Area 2 *** Point of Compliance Flow Frequency Data *** Recurrence Interval Computed Using Gringorten Plotting Position Predevelopment Runoff Postdevelopment Runoff Tr (Years) Discharge (cfs) Tr (Years) Discharge (cfs) ---------------------------------------------------------------------------------------------------------------------- 2-Year 0.368 2-Year 0.411 5-Year 0.502 5-Year 0.565 10-Year 0.611 10-Year 0.679 25-Year 0.777 25-Year 0.896 50-Year 0.879 50-Year 0.993 100-Year 0.915 100-Year 0.998 200-Year 0.929 200-Year 1.039 ** Record too Short to Compute Peak Discharge for These Recurrence Intervals **** Flow Duration Performance **** Excursion at Predeveloped 50%Q2 (Must be Less Than or Equal to 0%): 24.3% FAIL Maximum Excursion from 50%Q2 to Q2 (Must be Less Than or Equal to 0%): 53.7% FAIL Maximum Excursion from Q2 to Q50 (Must be less than 10%): 99999.0% FAIL Percent Excursion from Q2 to Q50 (Must be less than 50%): 100.0% FAIL ------------------------------------------------------------------------------------------------- FLOW DURATION DESIGN CRITERIA: FAIL ------------------------------------------------------------------------------------------------- **** LID Duration Performance **** Excursion at Predeveloped 8%Q2 (Must be Less Than 0%): -3.0% PASS Maximum Excursion from 8%Q2 to 50%Q2 (Must be Less Than 0%): 24.3% FAIL ------------------------------------------------------------------------------------------------- LID DURATION DESIGN CRITERIA: FAIL ------------------------------------------------------------------------------------------------- Appendix F Hydraulic Analysis and Facility Sizing Calculations Wet Biofiltration Swale Sizing (Per Dept of Ecology Stormwater Management Manual for Western Washington (SMMWW), Volume 5, Chapter 9) Project: Meadowdale Beach Park Recreation and Habitat Improvement Project Engineer: David Rice PRELIMINARY STEPS blue-user input red-calculated value P-1:Q2-YR=0.411 CFS (From Model) Q WQ =Q 2-YR X Ratio (Based on Effective Impervious Area (EIA) EIA= 15% Ratio= 0.33 (15 Min Data, Table 4.1) QWQ=0.136 CFS (15 Min Data, Using Factor From Table 4.1) QWQ=0.190 CFS (From Model with WWHM) QWQ=0.190 CFS - USE THIS VALUE P-2:Slope (s)=0.020 ( 0.02 max for wet bioswale) P-3:Cover:Grass Mixture, Infrequently Mowed DESIGN STEPS D-1:Depth (y)=4.0 IN (4" Max for wet bioswale) D-2:n =0.30 (per Table V-9.4.1) D-3:Shape:Trapezoidal D-4:Bottom Width (b) (From Manning's Equation) Q=1.49(A)(R)2/3(S)0.5/n Where: y=4.0 IN b=3.0 FT Sideslope (Z)=2.5 FT/FT D-5:Area (A)=1.278 FT2 Hyd. Rad. (R)=0.266 FT Q>or=QWQ=0.371 CFS (Make equal to or greater than QWQ by adjusting y, b, s, or Z) D-6:Velocity (V)=0.29 FT/S (V=Q/A, 1 FPS max per Table 9.1, if more increase b or y) D-7:Length (L)=157.0 FT (L=V x t, t=9 min. Adjust y, b, s or Z to optimize L) CHECK FOR CHANNEL STABILITY (FOR FLOWS GREATER THAN Q WQ ) SC-1:Q100-YR=0.998 CFS (From WWHM) QSC=1.597 CFS (Q100-YR x 1.6) SC-2:Vegetation:8-inch mowed height, fair coverage SC-3:Retardance:C (per Table V-9.4.2) SC-4:Trial "n":0.055 (per Table V-9.4.1 for mowed infrequently) SC-5:VRapprox=2 FT2/S (per Figure V-9.4.7) SC-6:Vmax=3 FT/S (per Table V-9.4.2) R=0.667 R=VRapprox/Vmax SC-7:VRactual=1.9 FT2/S (per manning's formula using R from above) SC-8:Difference=3%(Adjust n and VRapprox until VRactual is within 5% of Vrapprox, 0.033 min) SC-9:Vactual=2.92 FT/S SC-10:ASC=0.55 FT2 SC-11:ASC<ACAP?TRUE (ASC should be less than ACAP=area calc'd for D-5) SC-12:ySC=1.95 IN ASC=0.55 (Adjust ysc until this equals the area calc'd in SC-10) SC-13:Freeboard=2.30 FEET yTOTAL=31.60 IN SC-14:RTOTAL=1.47 FT ATOTAL=25.24 FT2 SC-15:QTOTAL=22.93 CFS (Should be greater thank QSC) Biofiltration Swale Sizing(Per DOE Stormwater Management Manual for Western Washington (SMMWW), Volume 5, Chapter 9)Project: Meadowdale Beach Park Recreation and Habitat Improvement ProjectEngineer: David RiceBed Width:3.0ftSlope:0.02ftSide Slopes:2.5ft/ftTable Calculates Overall Swale Width Based on User Input Top of Slope Elevations:Distance - Ctr to Top of Slope Top of Slope Elev.StationBed Elev.(ft)Left(ft)Right(ft)Left(ft)Right(ft)X Section Area (ft^2)Inc. Volume (ft^3)0276.50 6.5029.00 29.00 16.001026.80 5.75 5.7528.50 28.50 12.33 141.632026.60 5.00 5.0028.00 28.00 9.10 107.133026.40 4.25 4.2527.50 27.50 6.32 77.124026.20 4.12 4.1227.25 27.25 5.91 61.165026.00 4.00 4.0027.00 27.00 5.50 57.036025.80 3.25 3.2526.50 26.50 3.32 44.127025.60 3.12 3.1226.25 26.25 3.01 31.668024.40 5.50 5.5026.00 26.00 11.20 71.039024.20 4.75 4.7525.50 25.50 8.13 96.6310024.00 4.63 4.6325.25 25.25 7.66 78.9111023.80 4.50 4.5025.00 25.00 7.20 74.2812023.60 3.75 3.7524.50 24.50 4.72 59.6213023.40 3.62 3.6224.25 24.25 4.36 45.4114023.20 5.37 5.3724.75 24.75 10.66 75.0615022.00 5.25 5.2523.50 23.50 10.13 103.9116021.80 5.13 5.1323.25 23.25 9.61 98.6617021.60 4.38 4.3822.75 22.75 6.76 81.8118021.55 3.88 3.8822.50 22.50 5.11 59.3118521.50 3.38 3.3822.25 22.25 3.66 21.911,386 10,371 gallons0.03acre-ft51.35 cu-yd Standard Step Backwater Analysis System: Meadowdale Beach Park Design Event: High Flow (100-year event) Outlet Inlet Identification Rock Swale A1 Normal Depth (ft) 0.55 Rim/Overflow Elev. (ft) 12.00 21.10 Critical Depth (ft) 0.64 Invert Elevation (ft)11.00 11.88 Froude No. 1.36 Water Surf. Elev. (ft)12.00 12.94 Avg. Velocity (fps) 4.26 Min. Velocity (fps) 2.86 Discharge (cfs) 2.25 Max. Velocity (fps) 5.11 Diameter (inches) 12 Normal Velocity (fps) 5.11 Ineffective Depth( ft) 0.00 Crit. Velocity (fps) 4.23 Length (feet) 88 Manning n 0.012 Entrance Vel. (fps) 0.00 Entrance Loss (Ke) 0.50 Slope 0.01 10.5 11.0 11.5 12.0 12.5 13.0 13.5 -20 0 20 40 60 80 100 Elevation (feet)Horizontal Distance (feet)HGL Normal Depth Critical Depth Pipe Outlet Inlet Standard Step Backwater Analysis System: Meadowdale Beach Park Design Event: High Flow (100-year event) Outlet Inlet Identification A2 A1 Normal Depth (ft) 0.20 Rim/Overflow Elev. (ft) 21.10 19.75 Critical Depth (ft) 0.23 Invert Elevation (ft)16.18 16.75 Froude No. 1.35 Water Surf. Elev. (ft)16.51 17.11 Avg. Velocity (fps) 2.71 Min. Velocity (fps) 1.43 Discharge (cfs) 0.25 Max. Velocity (fps) 2.89 Diameter (inches) 8 Normal Velocity (fps) 2.89 Ineffective Depth( ft) 0.00 Crit. Velocity (fps) 2.33 Length (feet) 57 Manning n 0.012 Entrance Vel. (fps) 0.00 Entrance Loss (Ke) 0.50 Slope 0.01 16.0 16.2 16.4 16.6 16.8 17.0 17.2 17.4 17.6 -10 0 10 20 30 40 50 60 70 Elevation (feet)Horizontal Distance (feet)HGL Normal Depth Critical Depth Pipe Outlet Inlet Standard Step Backwater Analysis System: Meadowdale Beach Park Design Event: High Flow (100-year event) Outlet Inlet Identification A1 A3 Normal Depth (ft) 0.42 Rim/Overflow Elev. (ft) 21.10 23.57 Critical Depth (ft) 0.60 Invert Elevation (ft)16.96 18.80 Froude No. 2.02 Water Surf. Elev. (ft)17.46 19.78 Avg. Velocity (fps) 6.42 Min. Velocity (fps) 6.42 Discharge (cfs) 2.00 Max. Velocity (fps) 6.42 Diameter (inches) 12 Normal Velocity (fps) 6.42 Ineffective Depth( ft) 0.00 Crit. Velocity (fps) 4.04 Length (feet) 92 Manning n 0.012 Entrance Vel. (fps) 0.00 Entrance Loss (Ke) 0.50 Slope 0.02 16.5 17.0 17.5 18.0 18.5 19.0 19.5 20.0 -20 0 20 40 60 80 100 120 Elevation (feet)Horizontal Distance (feet)HGL Normal Depth Critical Depth Pipe Outlet Inlet Standard Step Backwater Analysis System: Meadowdale Beach Park Design Event: High Flow (100-year event) Outlet Inlet Identification A3 Bioswale Outlet Normal Depth (ft) 0.51 Rim/Overflow Elev. (ft) 23.57 22.21 Critical Depth (ft) 0.60 Invert Elevation (ft)18.82 18.88 Froude No. 1.38 Water Surf. Elev. (ft)19.78 19.86 Avg. Velocity (fps) 2.61 Min. Velocity (fps) 2.58 Discharge (cfs) 2.00 Max. Velocity (fps) 2.65 Diameter (inches) 12 Normal Velocity (fps) 4.97 Ineffective Depth( ft) 0.00 Crit. Velocity (fps) 4.04 Length (feet) 6 Manning n 0.012 Entrance Vel. (fps) 0.00 Entrance Loss (Ke) 0.50 Slope 0.01 18.6 18.8 19.0 19.2 19.4 19.6 19.8 20.0 -101234567Elevation (feet)Horizontal Distance (feet)HGL Normal Depth Critical Depth Pipe Outlet Inlet Standard Step Backwater Analysis System: Meadowdale Beach Park Design Event: High Flow (100-year event) Outlet Inlet Identification Bioswale Inlet B1 Normal Depth (ft) 0.51 Rim/Overflow Elev. (ft) 29.00 30.50 Critical Depth (ft) 0.60 Invert Elevation (ft)27.70 27.94 Froude No. 1.38 Water Surf. Elev. (ft)28.70 28.92 Avg. Velocity (fps) 2.69 Min. Velocity (fps) 2.55 Discharge (cfs) 2.00 Max. Velocity (fps) 2.91 Diameter (inches) 12 Normal Velocity (fps) 4.97 Ineffective Depth( ft) 0.00 Crit. Velocity (fps) 4.04 Length (feet) 24 Manning n 0.012 Entrance Vel. (fps) 0.00 Entrance Loss (Ke) 0.50 Slope 0.010 27.6 27.8 28.0 28.2 28.4 28.6 28.8 29.0 29.2 -5 0 5 10 15 20 25 30 Elevation (feet)Horizontal Distance (feet)HGL Normal Depth Critical Depth Pipe Outlet Inlet Standard Step Backwater Analysis System: Meadowdale Beach Park Design Event: High Flow (100-year event) Outlet Inlet Identification B1 B2 Normal Depth (ft) 0.39 Rim/Overflow Elev. (ft) 30.50 35.22 Critical Depth (ft) 0.60 Invert Elevation (ft)27.97 30.57 Froude No. 2.27 Water Surf. Elev. (ft)28.92 31.55 Avg. Velocity (fps) 6.80 Min. Velocity (fps) 2.59 Discharge (cfs) 2.00 Max. Velocity (fps) 6.97 Diameter (inches) 12 Normal Velocity (fps) 6.97 Ineffective Depth( ft) 0.00 Crit. Velocity (fps) 4.04 Length (feet) 104 Manning n 0.012 Entrance Vel. (fps) 0.00 Entrance Loss (Ke) 0.50 Slope 0.025 27.5 28.0 28.5 29.0 29.5 30.0 30.5 31.0 31.5 32.0 -20 0 20 40 60 80 100 120 Elevation (feet)Horizontal Distance (feet)HGL Normal Depth Critical Depth Pipe Outlet Inlet Standard Step Backwater Analysis System: Meadowdale Beach Park Design Event: High Flow (100-year event) Outlet Inlet Identification B2 B3 Normal Depth (ft) 0.45 Rim/Overflow Elev. (ft) 35.22 36.21 Critical Depth (ft) 0.60 Invert Elevation (ft)30.60 32.31 Froude No. 1.73 Water Surf. Elev. (ft)31.55 33.29 Avg. Velocity (fps) 5.41 Min. Velocity (fps) 2.59 Discharge (cfs) 2.00 Max. Velocity (fps) 5.78 Diameter (inches) 12 Normal Velocity (fps) 5.78 Ineffective Depth( ft) 0.00 Crit. Velocity (fps) 4.04 Length (feet) 114 Manning n 0.012 Entrance Vel. (fps) 0.00 Entrance Loss (Ke) 0.50 Slope 0.015 30.0 30.5 31.0 31.5 32.0 32.5 33.0 33.5 -20 0 20 40 60 80 100 120 140 Elevation (feet)Horizontal Distance (feet)HGL Normal Depth Critical Depth Pipe Outlet Inlet Standard Step Backwater Analysis System: Meadowdale Beach Park Design Event: High Flow (100-year event) Outlet Inlet Identification B3 B4 Normal Depth (ft) 0.18 Rim/Overflow Elev. (ft) 36.21 36.60 Critical Depth (ft) 0.23 Invert Elevation (ft)32.33 32.81 Froude No. 1.66 Water Surf. Elev. (ft)33.29 33.17 Avg. Velocity (fps) 0.74 Min. Velocity (fps) 0.72 Discharge (cfs) 0.25 Max. Velocity (fps) 0.90 Diameter (inches) 8 Normal Velocity (fps) 3.35 Ineffective Depth( ft) 0.00 Crit. Velocity (fps) 2.33 Length (feet) 32 Manning n 0.012 Entrance Vel. (fps) 0.00 Entrance Loss (Ke) 0.50 Slope 0.0150 32.2 32.4 32.6 32.8 33.0 33.2 33.4 33.6 -5 0 5 10 15 20 25 30 35 Elevation (feet)Horizontal Distance (feet)HGL Normal Depth Critical Depth Pipe Outlet Inlet Standard Step Backwater Analysis System: Meadowdale Beach Park Design Event: High Flow (100-year event) Outlet Inlet Identification B3 B5 Normal Depth (ft) 0.42 Rim/Overflow Elev. (ft) 36.21 37.28 Critical Depth (ft) 0.56 Invert Elevation (ft)32.33 33.25 Froude No. 1.75 Water Surf. Elev. (ft)33.29 34.16 Avg. Velocity (fps) 4.70 Min. Velocity (fps) 2.25 Discharge (cfs) 1.75 Max. Velocity (fps) 5.59 Diameter (inches) 12 Normal Velocity (fps) 5.59 Ineffective Depth( ft) 0.00 Crit. Velocity (fps) 3.84 Length (feet) 61 Manning n 0.012 Entrance Vel. (fps) 0.00 Entrance Loss (Ke) 0.50 Slope 0.0151 32.0 32.5 33.0 33.5 34.0 34.5 -10 0 10 20 30 40 50 60 70 Elevation (feet)Horizontal Distance (feet)HGL Normal Depth Critical Depth Pipe Outlet Inlet Standard Step Backwater Analysis System: Meadowdale Beach Park Design Event: High Flow (100-year event) Outlet Inlet Identification B5 B6 Normal Depth (ft) 0.18 Rim/Overflow Elev. (ft) 37.28 38.10 Critical Depth (ft) 0.23 Invert Elevation (ft)33.28 33.73 Froude No. 1.66 Water Surf. Elev. (ft)34.16 34.09 Avg. Velocity (fps) 0.78 Min. Velocity (fps) 0.72 Discharge (cfs) 0.25 Max. Velocity (fps) 1.03 Diameter (inches) 8 Normal Velocity (fps) 3.35 Ineffective Depth( ft) 0.00 Crit. Velocity (fps) 2.33 Length (feet) 30 Manning n 0.012 Entrance Vel. (fps) 0.00 Entrance Loss (Ke) 0.50 Slope 0.0150 33.2 33.4 33.6 33.8 34.0 34.2 34.4 34.6 -5 0 5 10 15 20 25 30 35 Elevation (feet)Horizontal Distance (feet)HGL Normal Depth Critical Depth Pipe Outlet Inlet Standard Step Backwater Analysis System: Meadowdale Beach Park Design Event: High Flow (100-year event) Outlet Inlet Identification B5 B7 Normal Depth (ft) 0.26 Rim/Overflow Elev. (ft) 37.28 41.00 Critical Depth (ft) 0.52 Invert Elevation (ft)33.28 36.95 Froude No. 3.84 Water Surf. Elev. (ft)34.16 37.78 Avg. Velocity (fps) 9.34 Min. Velocity (fps) 9.34 Discharge (cfs) 1.50 Max. Velocity (fps) 9.34 Diameter (inches) 12 Normal Velocity (fps) 9.34 Ineffective Depth( ft) 0.00 Crit. Velocity (fps) 3.64 Length (feet) 52 Manning n 0.012 Entrance Vel. (fps) 0.00 Entrance Loss (Ke) 0.50 Slope 0.0706 33.0 34.0 35.0 36.0 37.0 38.0 39.0 -10 0 10 20 30 40 50 60 Elevation (feet)Horizontal Distance (feet)HGL Normal Depth Critical Depth Pipe Outlet Inlet Standard Step Backwater Analysis System: Meadowdale Beach Park Design Event: High Flow (100-year event) Outlet Inlet Identification B7 B8 Normal Depth (ft) 0.25 Rim/Overflow Elev. (ft) 41.00 44.26 Critical Depth (ft) 0.52 Invert Elevation (ft)36.98 40.34 Froude No. 4.09 Water Surf. Elev. (ft)37.78 41.17 Avg. Velocity (fps) 9.77 Min. Velocity (fps) 9.77 Discharge (cfs) 1.50 Max. Velocity (fps) 9.77 Diameter (inches) 12 Normal Velocity (fps) 9.77 Ineffective Depth( ft) 0.00 Crit. Velocity (fps) 3.64 Length (feet) 42 Manning n 0.012 Entrance Vel. (fps) 0.00 Entrance Loss (Ke) 0.50 Slope 0.0800 37.0 37.5 38.0 38.5 39.0 39.5 40.0 40.5 41.0 41.5 42.0 -5 0 5 10 15 20 25 30 35 40 45 50 Elevation (feet)Horizontal Distance (feet)HGL Normal Depth Critical Depth Pipe Outlet Inlet Standard Step Backwater Analysis System: Meadowdale Beach Park Design Event: High Flow (100-year event) Outlet Inlet Identification B8 B9 Normal Depth (ft) 0.23 Rim/Overflow Elev. (ft) 44.60 51.00 Critical Depth (ft) 0.52 Invert Elevation (ft)40.37 46.12 Froude No. 4.88 Water Surf. Elev. (ft)41.17 46.95 Avg. Velocity (fps) 11.11 Min. Velocity (fps) 11.11 Discharge (cfs) 1.50 Max. Velocity (fps) 11.11 Diameter (inches) 12 Normal Velocity (fps) 11.11 Ineffective Depth( ft) 0.00 Crit. Velocity (fps) 3.64 Length (feet) 50 Manning n 0.012 Entrance Vel. (fps) 0.00 Entrance Loss (Ke) 0.50 Slope 0.1150 40.0 41.0 42.0 43.0 44.0 45.0 46.0 47.0 48.0 -10 0 10 20 30 40 50 60 Elevation (feet)Horizontal Distance (feet)HGL Normal Depth Critical Depth Pipe Outlet Inlet Appendix G BMP Selection and Treatment Menus January 2016 Snohomish County Drainage Manual Volume I - Minimum Technical Requirements 18 List #2: On-site Stormwater Management BMPs for Projects Triggering Minimum Requirements 1 through 9 For each surface, consider the BMPs in the order listed for that type of surface. Use the first BMP that is considered feasible. Feasibility shall be determined according to specific criteria set forth for each BMP as described in Volumes III and V of this manual, and based in part on the information in the Soils Report prepared as part of the required Stormwater Site Plan described Chapter 3 of this volume. If a BMP is determined to be feasible for a surface, no other on-site stormwater management BMP is necessary for that surface. An on-site stormwater management BMP shall not be required for a surface if it is determined that no BMP is feasible for that surface. In addition, Snohomish County may remove or reduce the requirement for a BMP if its implementation will conflict with any of the following:  Historic Preservation Laws and Archaeology Laws as listed at http://www.dahp.wa.gov/learn-and-research/preservation-laws;  Federal Superfund or Washington State Model Toxics Control Act;  Federal Aviation Administration requirements for airports;  Americans with Disabilities Act;  special zoning district design criteria adopted and being implemented pursuant to a community planning process;  Public health and safety standards;  Transportation regulations to maintain the option for future expansion or multi-modal use of public rights-of-way; or  Tree species protection standards in Chapter 30.62A SCC. Lawn and landscaped areas: 1. Post-Construction Soil Quality and Depth in accordance with BMP T5.13 in Volume V, Chapter 5 of this manual Roofs: 1. Full Dispersion in accordance with BMP T5.30 in Volume V, Chapter 5 of this manual, or, for single-family residential roofs and commercial roofs determined by Snohomish County to have similar runoff pollution characteristics to single-family residential roofs, Downspout Full Infiltration Systems in accordance with BMP T5.10A in Volume III, Chapter 3 of this manual 2. Bioretention in accordance with Volume V, Chapter 7 of this manual. 3. For single-family residential roofs and commercial roofs determined by Snohomish County to have similar runoff pollution characteristics to single-family residential roofs, Downspout Dispersion Systems in accordance with BMP T5.10B in Volume III, Chapter 3 of this manual 4. For single-family residential roofs and commercial roofs determined by Snohomish County to have similar runoff pollution characteristics to single-family residential roofs, January 2016 Snohomish County Drainage Manual Volume I - Minimum Technical Requirements 19 Perforated Stub-out Connections in accordance with BMP T5.10C in Volume III, Chapter 3 of this manual. Other Hard Surfaces: 1. Full Dispersion in accordance with BMP T5.30 in Volume V, Chapter 5 of this manual. 2. Permeable pavement in accordance with BMP T5.15 in Volume V, Chapter 5 of this manual. NOTE: This is not a requirement to pave these surfaces. Where pavement is proposed, it must be permeable to the extent feasible unless full dispersion is employed. 3. Bioretention in accordance with Volume V, Chapter 7 of this manual. 4. Sheet Flow Dispersion in accordance with BMP T5.12, or Concentrated Flow Dispersion in accordance with BMP T5.11 in Volume V, Chapter 5 of this manual. 2.5.6 Minimum Requirement 6: Runoff Treatment Stormwater treatment facilities shall be provided for each threshold discharge area in which the hard and pervious surfaces subject to this minimum requirement (see SCC 30.63A.300 through 30.63A.310) meet the following criteria:  the total of pollution-generating hard surface (PGHS) in the threshold discharge area is 5,000 square feet or more; or  the total of pollution-generating pervious surfaces (PGPS) in the threshold discharge area, excluding permeable pavement, and from which stormwater will be discharged in a natural or man-made conveyance system from the site, is three-quarters (3/4) of an acre or more. Stormwater from multiple threshold discharge areas can be treated in a single stormwater facility designed on the basis of the combined flows. If stormwater treatment is required, use the procedures set forth in Volume I, Chapter 4, Section 4.2, Step 5 of this manual to determine the specific type of stormwater treatment facility required for the project. Design requirements for specific stormwater treatment facilities are set forth in Volume V of this manual. Volume V, Chapter 4, Section 4.1 provides requirements for design storm volumes and flow rates. 2.5.7 Minimum Requirement 7: Flow Control Flow control is required as set forth below. If the discharge is to a stream that leads to a wetland, or to a wetland that has an outflow to a stream, both Minimum Requirement #7 and Minimum Requirement #8 apply. Thresholds for requiring flow control The requirements of this section apply to projects that discharge stormwater directly or indirectly through a conveyance system into a fresh water system. Unless excepted in this section, flow control shall be provided for applicable threshold discharge areas of projects as determined by the requirements of Chapter 2 of this volume. Flow control shall be provided for projects that meet any of the following thresholds: Edmonds Chapter 18.30 STORM WATER MANAGEMENT Page 16/23 FINAL Version: August 23, 2016 For projects that elect to use List No. 2 to comply with ECDC 18.30.060.D.b (iii), for each surface, consider the BMPs in the order listed for that type of surface. Use the first BMP that is considered feasible. No other On-site Stormwater Management BMP is necessary for that surface. Feasibility shall be determined by evaluation against design criteria, limitations, and infeasibility criteria identified for each BMP in the SWMMWW; and Competing Needs Criteria listed in Chapter 5 of Volume V of the SWMMWW. Lawn and landscaped areas: i. Post-Construction Soil Quality and Depth in accordance with BMP T5.13 in Chapter 5 of Volume V of the SWMMWW. Roofs: i. Full Dispersion in accordance with BMP T5.30 in Chapter 5 of Volume V of the SWMMWW, or Downspout Full Infiltration Systems in accordance with BMP T5.10A in Section 3.1.1 of Volume III of the SWMMWW. ii. Bioretention (See Chapter 7 of Volume V of the SWMMWW) facilities that have a minimum horizontally projected surface area below the overflow which is at least 5 percent of the total surface area draining to it. iii. Downspout Dispersion Systems in accordance with BMP T5.10B in Section 3.1.2 of Volume III of the SWMMWW. iv. Perforated Stub-out Connections in accordance with BMP T5.10C in Section 3.1.3 of Volume III of the SWMMWW. v. Detention vaults or pipes in accordance with the Edmonds Stormwater Addendum. Note that if the project is required to construct a flow control facility to comply with Minimum Requirement No. 7 (per ECDC 18.30.060.D.7), a detention vault is not required to be installed to meet Minimum Requirement No. 5. In addition, the City may waive the requirement to install a detention vault if the downstream analysis in Minimum Requirement #4, or available City data, indicate that peak flow control is not beneficial. Other Hard Surfaces: i. Full Dispersion in accordance with BMP T5.30 in Chapter 5 of Volume V of the SWMMWW. ii. Permeable pavement in accordance with BMP T5.15 in Chapter 5 of Volume V of the SWMMWW. iii. Bioretention (See Chapter 7 of Volume V of the SWMMWW) facilities that have a minimum horizontally projected surface area below the overflow which is at least 5 percent of the total surface area draining to it. iv. Sheet Flow Dispersion in accordance with BMP T5.12, or Concentrated Flow Dispersion in accordance with BMP T5.11 in Chapter 5 of Volume V of the SWMMWW. v. Detention vaults or pipes in accordance with the Edmonds Stormwater Addendum. Note that if the project is required to construct a flow control facility to comply with Minimum Requirement No. 7 (per ECDC 18.30.060.D.7), a detention vault is not required to be installed to meet Minimum Requirement No. 5. In addition, the City may waive the requirement to install a detention vault if the downstream analysis in Minimum Requirement #4, or available City data, indicate that peak flow control is not beneficial. January 2016 Snohomish County Drainage Manual Volume I - Minimum Technical Requirements 36 The first option is to infiltrate through rapidly draining soils that meet the site characterization and Site Suitability Criteria set forth in Volume III, Chapter 3 of this manual for providing flow control, but do not meet Site Suitability Criterion (SSC) 6 – Soil Physical and Chemical Suitability for treatment. If the site is suitable for flow control using infiltration but SSC 6 is not met, flow control can be accomplished using infiltration provided the requirements for treatment set forth in Step 5 below are met. The infiltration facility must provide adequate volume such that the flow duration standard of Minimum Requirement 7 will be achieved. The second option is to infiltrate through soils that meet the site characterization and site suitability criteria in Volume III, Chapter 3. The facility would be designed to meet the requirements for treatment and flow control. If infiltration facilities for flow control are planned, the flow control requirement has been met; proceed to Step 5. If infiltration facilities are not planned, proceed to Step 4b. Step 4b: Use the Western Washington Hydrology Model to size a detention facility. Refer to Volume III, Chapter 2, for an explanation of the use of the Western Washington Hydrology Model. Note that reducing the level of site disturbance reduces the size of the required flow control facility. Step 5: Select Stormwater Treatment Facilities For each threshold discharge area in which stormwater treatment is required per Step 3 above, select an appropriate treatment system using the following procedure. The requirements set forth in Volume III, Chapter 3 and Volume V shall be used to size and design the selected facilities. Volume V, Chapter 12 of this manual includes information about stormwater treatment BMPs to which the Washington State Department of Ecology has given a use-level designation for pretreatment, oil, phosphorous, enhanced, or basic treatment. Snohomish County will approve the use of the subset of those BMPs to which Ecology has given a General Use-Level Designation (GULD). NOTE: Only basic treatment is required for landscaped areas of industrial, commercial, and multi-family project sites, and parking lots of industrial and commercial project sites, dedicated solely to parking of employees’ private vehicles, which do not involve any other pollution- generating sources (e.g., industrial activities, customer parking, storage of erodible or leachable material, wastes or chemicals). Step 5a: Determine the receiving waters and pollutants of concern based on offsite analysis. Determine the natural receiving waters (e.g., ground water, wetland, lake, stream, salt water) for the stormwater drainage from the project site. If the discharge is to the Snohomish County storm drainage system, the receiving waters for the drainage system must be determined. January 2016 Snohomish County Drainage Manual Volume I - Minimum Technical Requirements 37 Step 5b: Determine if an oil control facility is required Oil control facilities are required for projects that have “high-use sites.” High-use sites are those that typically generate high concentrations of oil due to high traffic turnover or the frequent transfer of oil. High-use sites include:  An area of a commercial or industrial site subject to an expected average daily traffic (ADT) count equal to or greater than 100 vehicles per 1,000 square feet of gross building area. Note: Snohomish County will consider fueling stations, with or without small convenience stores, to be a high-use site unless the applicant demonstrates, to the County’s satisfaction and through the stormwater site planning process, that the ADT threshold will not be met.  An area of a commercial or industrial site subject to petroleum storage and transfer in excess of 1,500 gallons per year, not including routinely delivered heating oil.  An area of a commercial or industrial site subject to parking, storage or maintenance of 25 or more vehicles that are over 10 tons gross weight (trucks, buses, trains, heavy equipment, etc.).  A road intersection with a measured ADT count of 25,000 vehicles or more on the main roadway and 15,000 vehicles or more on any intersecting roadway, excluding projects proposing primarily pedestrian or bicycle use improvements. The traffic count can be estimated using information from “Trip Generation,” published by the Institute of Transportation Engineers, or from a traffic study prepared by a professional engineer or transportation specialist with experience in traffic estimation. January 2016 Snohomish County Drainage Manual Volume I - Minimum Technical Requirements 38 Figure 1.4 Treatment Facility Selection Flow Chart Step 5a: Determine receiving waters and pollutants of concern through off-site analysis Step 5b: Determine if an Oil Control Facility is required Select Oil Control Facility API Separator CP Separator Linear Sand Filter Step 5c: Determine if infiltration for pollution is practicable Select Pretreatment: Presettling Basin Any Basic treatment BMP AND Select Infiltration Infiltration Basin Infiltration Trench Bioretention Step 5d: Determine if Phosphorus Control is required Select Phosphorus Control Facility Large Sand Filter Large Wetpond Two Facility Treatment Train Step 5e: Determine if Enhanced Treatment is required Select Enhanced Treatment Facility (see note 1) Large Sand Filter Treatment wetland Compost-Amended Filter Strip Two facility Treatment Train Bioretention WSDOT Media Filter Drain Step 5f: Select Basic Treatment Facility Biofiltration Swale Infiltration Treatment Filter Strip Basic Wetpond Wet Vault Treatment Wetlands Combined Detention Wetpool Sand Filter Bioretention WSDOT Media Filter Drain Yes Yes To step 5b No Yes Yes To step 5c No No January 2016 Snohomish County Drainage Manual Volume I - Minimum Technical Requirements 39 Some land use types require the use of a spill control (SC-type) oil/water separator. Those situations are described in Volume IV and are separate from this treatment requirement. While a number of activities may be required to use spill control (SC-type) separators, only a few will necessitate American Petroleum Institute (API) or coalescing plate (CP)-type separators for treatment. The following urban land uses are likely to have areas that fall within the definition of “high-use sites” or have sufficient quantities of free oil present that can be treated by an API or CP-type oil/water separator.  Industrial Machinery and Equipment, and Railroad Equipment Maintenance  Log Storage and Sorting Yards  Aircraft Maintenance Areas  Railroad Yards  Fueling Stations  Vehicle Maintenance and Repair  Construction Businesses (paving, heavy equipment storage and maintenance, storage of petroleum products) Oil control facilities are to be placed upstream of other stormwater facilities and as close as is feasible to the oil source. For high-use sites located within a larger commercial center, only the impervious surface associated with the high-use portion of the site is subject to treatment requirements. If common parking for multiple businesses is provided, treatment shall be applied to the number of parking stalls required for the high-use business only. However, if the treatment collection area also receives runoff from other areas, the treatment facility must be sized to treat all water passing through it. High-use roadway intersections shall treat lanes where vehicles accumulate during the signal cycle, including left and right turn lanes and through lanes, from the beginning of the left turn pocket. If no left turn pocket exists, the treatable area shall begin at a distance equal to three car lengths from the stop line. If runoff from the intersection drains to more than two collection areas that do not combine within the intersection, treatment may be limited to any two of the collection areas. If an oil control facility is required, select one of the options below.  API-Type Oil/Water Separator – See Volume V, Chapter 11  Coalescing Plate Oil/Water Separator – See Volume V, Chapter 11  Linear Sand Filter – See Volume V, Chapter 8  Any BMP for which Ecology has issued a General Use Level Designation for oil control The linear sand filter is used in the basic, enhanced, and phosphorus treatment menus also. If used to satisfy one of those treatment requirements, the same facility shall not also be used to satisfy the oil control requirement unless quarterly maintenance is assured. January 2016 Snohomish County Drainage Manual Volume I - Minimum Technical Requirements 40 Step 5c: Determine whether infiltration for pollutant removal is practicable If the evaluation in Step 4a determines the site is unsuitable to provide flow control using infiltration, the site is also unsuitable for stormwater treatment using infiltration. If so, proceed to Step 5d. If the site is suitable for flow control using infiltration, determine whether native soils are suitable for treating stormwater by infiltration in accordance with Site Suitability Criterion SSC- 6 in Volume III, Chapter 3.3.7. Infiltration treatment facilities must be preceded by a pretreatment facility (see Volume V, Chapter 6), which may be a presettling basin, an oil control facility, or a basic treatment facility. If an oil/water separator is used for pretreatment, more frequent facility inspections may be necessary to determine when accumulated solids exceed the sediment depth at which maintenance is required (See Volume V, Chapter 4). If infiltration treatment is practicable, select an infiltration facility and an appropriate pretreatment facility. If infiltration treatment is not practicable, proceed to Step 5d. Step 5d: Determine if a phosphorus control facility is required. Control of phosphorus in new development or redevelopment is required prior to:  surface discharge to waters reported under section 305(b) of the Clean Water Act and designated as not supporting beneficial uses due to phosphorus;  surface discharge to water bodies those waters listed in Washington State's Nonpoint Source Assessment required under section 319(a) of the Clean Water Act because of nutrient concentrations;  surface discharge to wetlands categorized as Category I or Category II by the Washington State Wetland Rating System of Western Washington; or  stormwater infiltrated within one-quarter mile of a phosphorus-sensitive receiving water or a tributary to that water in soils that do not meet the soil suitability criteria for infiltration treatment in Chapter 3 of Volume III. If phosphorus control is not required, proceed to Step 5e. If phosphorus control is required, select one of the facilities below.  Large sand filter  Large wetpond  Treatment train for phosphorus removal – see Table 1.2  Any other treatment system for which the Washington State Department of Ecology has issued a General Use Level Designation for phosphorus treatment. January 2016 Snohomish County Drainage Manual Volume I - Minimum Technical Requirements 41 Table 1.2 – Treatment Trains for Phosphorus Removal First Basic Treatment Facility Second Treatment Facility Biofiltration Swale Basic Sand Filter or Sand Filter Vault Filter Strip Linear Sand Filter (no presettling needed) Linear Sand Filter Filter Strip Basic Wetpond Basic Sand Filter or Sand Filter Vault Wetvault Basic Sand Filter or Sand Filter Vault Stormwater Treatment Wetland Basic Sand Filter or Sand Filter Vault Basic Combined Detention and Wetpool Basic Sand Filter or Sand Filter Vault Proceed to Step 5e to determine whether enhanced treatment is required. Projects for which phosphorus control is required may be subject to requirements for enhanced treatment as well, in which case a facility or treatment train must be selected that that satisfies both requirements. Step 5e: Determine if enhanced treatment is required. Unless excepted as stated below, enhanced treatment is required for the following project sites or portions of sites that discharge to fresh waters designated for aquatic life or that have existing aquatic life use, to conveyance systems tributary to such waters, or to stormwater infiltration systems that are not designed and constructed to provide treatment in accordance with the requirements of this manual and that are within ¼ mile of such waters:  Industrial project sites;  Commercial project sites;  Multi-family project sites; and  High ADT roads as follows: o Within Urban Growth Areas: - Fully controlled and partially controlled limited access roads with Average Daily Traffic (ADT) counts of 15,000 or more - All other roads with an ADT of 7,500 or greater o Outside of Urban Growth Areas: - Roads with an ADT of 15,000 or greater unless discharging to a 4th Strahler order stream or larger; - Roads with an ADT of 30,000 or greater if discharging to a 4th Strahler order stream or larger (as determined using 1:24,000 scale maps to delineate stream order). January 2016 Snohomish County Drainage Manual Volume I - Minimum Technical Requirements 42 Exceptions For threshold discharge areas with more than one land use or activity, the enhanced treatment requirement shall apply to a threshold discharge area if 50 percent or more of the total runoff within that threshold discharge area is subject to the enhanced treatment requirements set forth above. Projects or portions of projects meeting the descriptions above do not need enhanced treatment if the stormwater discharges directly or indirectly through a municipal storm sewer system to a water body listed in Volume I, Appendix I-C If enhanced treatment is required, select one of the treatment systems below.  Large sand filter  Stormwater treatment wetland  Compost-amended filter strip  Bioretention  WSDOT media filter drain - see the 2014 Washington State Department of Transportation Highway Runoff Manual for design and construction requirements.  Treatment train for dissolved metals removal – See Table 1.3  Any other treatment system for which the Washington State Department of Ecology has issued a General Use Level Designation for enhanced treatment. &KDSWHU 9 7UHDWPHQW )DFLOLW\ 0HQXV 7KLV FKDSWHU LGHQWLILHV FKRLFHV WKDW FRPSULVH WKH WUHDWPHQW IDFLOLW\ PHQXV UHIHUUHG WR LQ &KDSWHU 97UHDWPHQW )DFLOLW\6HOHFWLRQ 3URFHVV S 7KH PHQXV LQ WKLV FKDSWHU DUH GLVFXVVHG LQ WKH RUGHU 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