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20060553 & 20060554 05-446 Emerson-Culver4.doc City of Edmonds TH 121 5 AVENUE NORTH • EDMONDS, WA 98020 • (425) 771-0220 FAX(425) 771-0221 Website: www.ci.edmonds.wa.us DEVELOPMENT SERVICES DEPARTMENT Planning • Building • Engineering Plan Review Corrections Application : Date: # bld20061302 & bld20061303 ( April 17, 2007 bld20060553 & bld20060554) Project Name/Address: Emerson & Culver / 7211 & 7217 Mead Bch Road Contact Person/Address/Fax: Michael Painter / fax: 425-672-4323 Reviewer: Jeanie McConnellDivision:Engineering This completes the 4th review from the Engineering Division on this project. The previous submittal included 2 civil sheets, the current submittal includes 4 civils sheets. New and additional information has been provided which has also spurred new plan corrections. Please address each individual item and review plans for accuracy and clarity prior to resubmittal. Review comments noted pertain to both SFR’s – Emerson and Culver – and corrections shall be made to individual plan sets for 7211 and 7217 Mead Bch Road ** For clarity in the plan set, please revise the submitted civil sheets as follows. Examples of what should be shown on each sheet includes, but is not limited to: Sheet 1 – Plot Plan, Including Frontage improvements.  Wetland and steep slope buffers  Clearly delineate areas of disturbance from those to be preserved, consistent with the Hearing Examiner requirements.  Location of split rail fence and signage as required.  Required frontage improvements and provide reference to details. Sheet 2 – Utility Improvement Plan  Water, Sewer and Storm improvements. Sheet 3 – TESC and Grading Plan  TESC requirements  Exisitng and proposed contours (dark lines this sheet, greyed out on other sheets) and legend.  Grading calcs  All proposed rockeries, top and bottom elevations, distance from structures, etc. Sheet 4 – Easement Plan - This plan can be eliminated from the civil set.  Easement areas to be delinieated on sheet 1 - Plot Plan. Bearings for the easements are to be provided with the easement legal documents. PROVIDED TO CONTACT 4/18/07 5 PAGES 1. ok 2. 10/31/05 - Provide bottom of footing elevations for each home on the grading plan. The bottom of footing elevation will be used to verify gradings quantities. Over 500 cy of grading, on either site, will require SEPA. ok  ok   12/20/06 – A SEPA packet has been submitted, however the cubic yards of grading noted understates the amount of grading to be done on site. Using the bottom of footing elevation provided for each home, I have calculated the cubic yards of grading for both foundations to be about 900cy. In addition to this, there will be additional cuts made to construct the driveway as well as for the interceptor drain system. 4/17/07 – The SEPA checklist states 750cy fill and 750cy cut for both of the homes. The plans submitted 2/26/07 state 1147cy cut for lot 1 and 854cy cut for lot 2. Separate grading calculations were submitted 3/1/07 which state 945cy cut for lot 1 and 729cy cut for lot 2. Please refer to comment #2 from the Planning Division. SEPA will need to be revised accordingly and the plans and associated documents need to provide accurate information.  12/20/06 – It is understood that 12’ trench depths will be required for the interceptor drain system. Please indicate on the plans how the interceptor system will be constructed and the actual amount of disturbance required to install the perf pipe at 12’ depths. Actual trench width is required. 4/17/07 – Clarification as requested in response letter. The plans need to clearly show the area of disturbance and the quantity of material to be excavated. This is critical as there are limits of disturbance placed on the project. 3. ok 4. ok 5. ok 6. 10/31/05 - Pursuant to Edmonds Community Development Code (ECDC) 18.90 sidewalks are required as a condition of development approval. Revise the site plan to include 5’ sidewalks along the property frontage. The face of curb shall be placed a minimum of 12’ from the road centerline. 10/12/06 – Please revise the sidewalk cross section to reference standard detail E2.8 for curb and gutter, not vertical curb.  Also add reference to standard detail E2.13 for the sidewalk and revise the sidewalk thickness to be 5 ½” and 6” in the driveway.  ok  ok  ok 4/17/07 - Reference to City of Edmonds standard details has not been made on the plan set. 7. ok 8. ok 9. ok 10. ok 11. ok 12. ok 13. 10/31/05 - Indicate how the driveway surface runoff will be collected and distributed to the drainage detention system. ok   12/20/06 – The drainage calcs provided for each home include a portion of the driveway, but the strip drain across the driveway ties into one detention system. If each detention system is designed to accommodate a portion of the driveway surface runoff then two separate drains will be required and placement of the drains will need to be consistent with the amount of impervious area to be collected and distributed to the detention system. Also, in looking at the elevations of the detention system and the topos across the driveway, it appears as though the strip drain can be located further down the driveway in order to collect the maximum amount of impervious runoff. 4/17/07 – For clarity on this issue, indicate on the plans the amount of impervious area runoff that will flow to each detention system. A “split” strip drain has been proposed, but there is no guarantee of how much impervious area would flow to each separate detention system. It would be cleaner to place two separate strip drains in different areas along the driveway, one of which would drain to lot #1 detention and one of which would drain to lot #2 detention. The strip drain for lot #2 detention PROVIDED TO CONTACT 4/18/07 5 PAGES could be placed at the lower end of the driveway serving only lot #2. The strip drain for lot #1 detention could be placed at the lowest possible point in the driveway portion that serves both lots, to collect runoff from the remaining area. 4/17/07 – The proposed strip drain can be located further down the driveway if it is connected to the detention system for lot #1. It needs to be placed in a location that will collect the maximum amount of impervious runoff. 14. ok 15. 10/31/05 - Detention Pipe Detail: Both detention systems shall have an upstream structure.   12/20/06 – upstream MH is no longer shown in plan view. Also, RIM elevations for all structures is to be provided. 4/17/07 – Response letter states there is not enough room to show downstream or upstream San Sewer manholes. This review correction pertains to STORM not sanitary. Please show the upstream manhole in plan view as requested. 16. ok 17. ok 18. ok 19. 10/31/05 - The sanitary sewer lines are shown in two different locations on the plans. Please clarify which location is accurate. ok  ok   ok  12/20/06 – It appears as though the side sewers cross other utilities and therefore a cross section shall be provided. Please also provide invert elevations at the sewer cleanouts. 4/17/07 – A cross section of utilities has been provided, however it is not clear where this cross section is taken. Please clarify. 20. ok 21. ok 22. ok 23. ok 24. 10/31/05 - Provide easements for the following: 4/17/07 - Easements have been provided, however the following corrections need to be made: The Hearing Examiner Decision dated 8/14/06 for the Reasonable Use Exception and Critical Areas o Variances states storm system is to be privately owned and maintained. Therefore, the recording document for the storm easement shall include maintenance responsibility language. All easements shall state Property owner and address. o Review all tax parcel numbers for accuracy. An error has been found in at least one of the o documents. A legal description of each parcel shall be included. o Easements shall be written as Grantor and Grantee. Do not “combine” easements under one o document. Review easement bearings to ensure consistency between the easement document and the plan. Also, o the easement bearings shall be written so the legal description of the easement can be followed from point of beginning to the end. Errors have been found in at least one document. Easements shall be recorded with Snohomish County and a copy of the recorded easements shall be o provided to the City. 25. ok 26.4/17/07 - Hydraulics Analysis for Emerson, submitted 2/26/07. Review comments as follows:  Need to follow the ECDC 18.30.060 and the DOE 1992 Stormwater Management Manual for Western Washington when designing the detention system for the Emerson lot.  All development sites less than one acre that discharge directly or indirectly to a stream shall be required to limit the peak rate of runoff to the predeveloped condition two-year, 24-hour design storm, while PROVIDED TO CONTACT 4/18/07 5 PAGES maintaining the predeveloped condition peak runoff rate for the 10-year, 24-hour and 100-year, 24-hour storms.  Need predevelopment conditions peak flows and hydrographs for the 2-year, 24-hour design storm, 10- year, 24-hour design storm, and 100-year, 24 hour design storm. The predevelopment condition for all cases other than open water bodies shall be considered meadows or young second growth forest.  Need development conditions peak flows and hydrographs for the 2-year, 24-hour design storm, 10-year, 24-hour design storm, and 100-year, 24 hour design storm.  R/D facility needs to be designed with multiple orifices to maintain the predeveloped condition for the 2- yr, 10-yr, and 100-yr, 24-hr storms. 4/17/07 – Sheet 1 – Plot Plan, Corrections required. 27.  Two different RIM elevations have been provided for the sanitary sewer manhole shown on this sheet, which is also stated to be the datum point. Please clarify and ensure consistency with the height calcs.  It appears as though a sewer manhole has been shown along the north property line, in the City right-of- way. This location however is not consistent with the surveyed location of the sanitary sewer main. Revise plans accordingly.  The driveway approach shall be constructed per City of Edmonds standard detail E2.26. This detail shall be referenced on the plans. 4/17/07 – Sheet 2 – Utility Plan, Corrections required. 28.  Number each of the details provided and reference the detail number in the pertinent location on the plans.  A cross section of the roadway, sidewalk and back of walk has been provided, but not labeled as A-A. A portion of this cross section shows 12” perf pipe that is to be installed at the back of walk. A detail for the perf pipe installation is provided in a different location on the plans and labeled as section A-A. Another detail, the driveway profile, includes elevations for the sidewalk and curb which should be provided as part of the A-A cross section. Cross sections and details shall be properly labeled, provide the necessary information and be referred to in plan view.  With regards to the sidewalk and curb elevations provided in the profile, the elevations need to be labeled as to what is being represented. Back of walk? Bottom of curb?  The proposed driveway slope as shown in the profile needs to be labeled.  There are various proposed elevations (spot elevations and RIM and IE elevation) on this plan sheet that do not state what the elevation pertains to. Please clarify. Also, verify proposed elevations are consistent with proposed topography contours.  Indicate where the rockery drains will connect to the storm system. This information is part of the drainage/utility plan.  During a field visit to the site it was found there is an existing drain pipe crossing Meadowdale Beach Rd, in the vicinity of the proposed new CB to be set with this project. This crossing needs to be shown on the plans and shall not be eliminated with this project. This crossing essentially creates a break in the existing ditch system, diverting the upstream flows across Mead. Bch Rd at this point. The crossing needs to be taken into account with the design of the proposed culvert system and placement of the new CB. Also, the level of the existing ditch on the downhill side of this crossing is higher than the invert elevation of the crossing which further provides for a break in the system. The new pipe elevations shall be consistent with existing conditions. Show both existing and proposed invert elevations.  The sanitary sewer manhole shown on the plans submitted 2/26/07 was not shown on previous submittals. The proposed sanitary side sewer lateral should tie into the manhole instead of tapping into the main due to the close proximity of the manhole. The manhole shall be core drilled and re-channeled per City of Edmonds standard detail E6.1. This detail shall be referenced on the plans. PROVIDED TO CONTACT 4/18/07 5 PAGES  Interceptor Drain Detail Notes: Item Number 5 – Revise notes to include both Lots 1 and 2 Item Number 6 – Revise “tow trench drains” to read “two trench drains”. A separate detail shall be provided for the requirement to bed the connection with a clay check dam. The detail shall be referenced in these notes and on the plans. Item Number 7 – For clarification, the second sentence should be revised to read “A separate 6” slotted line . . .” therefore it is understood the two perf systems do not tie into each other. st 4/17/07 – Sheet 2 – Recharging of the Wetland, 1 proposal provided in 2/26/07 submittal. 29.  The Hearing Examiner Decision states the wetland shall be recharged by the interceptor drains. The proposed drawings indicate recharging of the wetland from the detention systems. Please confirm with the City Planning Division that this is acceptable.  If the wetlands can be recharged by the detention system then the following adjustments to the system will be required: a.The wetland watering spreader trench as proposed will fill with silt and is not maintainable. This line shall be a minimum of 4” in diameter instead of the proposed 1” pvc. b.Each detention system shall have two outlets. The first outfall and initial release of storm water shall be to the wetland spreader through a tee and specified size orifice as required by the detention system design. The second outfall shall be an emergency overflow that will be tied to the City storm system and bypass the wetland area. Elevations shall be provided for both and shown on the plans and details.  For clarity, the wetland watering line (spreader trench) shall be labeled in plan view and a detail with pertinent construction information shall be referenced. Do not provide the details of construction in plan view.  The wetland watering spreader detail shall provide minimum required trench dimensions. 4/17/07 – Sheet 3 – TESC and GRADING PLAN 30.  The catch basin protection detail provided is out of date. Please include the most current City standard detail, which shows the requirement for overflow holes.  Bottom of footing elevations shall be shown on this plan, the grading plan.  Separate rockery details shall be provided on the civil plans, which show construction requirements, setbacks from structures, drainage requirements, etc. Proposed rockeries should be shown in bold line type on Sheet 3 and details shall be referenced.  Proposed topography contours shall tie into rockeries. Please resubmit 3 copies of the revised plans/documents for each Single Family Residence to a Development Services Coordinator. JoAnne Zulauf is your City contact for this project. Please contact me at 425-771-0220 or by e-mail at mcconnell@ci.edmonds.wa.us if you have specific questions regarding these plan corrections. PROVIDED TO CONTACT 4/18/07 5 PAGES