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8354 OLYMPIC VIEW DR.PDF8354 OLYMPIC VIEW DR Inc. 1890 CITY OF EDMONDS 121 5TH AVENUE NORTH • EDMONDS, WA98020 • (425) 771-0220 • FAX (425) 771-0221 Websile: www.d.edmonds.wa.us DEVELOPMENT SERVICES DEPARTMENT Planning • Building • Engineering August 16, 2007 MEMO TO: Edmonds School District Verizon Northwest SNOCOM Police and Fire Dispatch SNOPAC Snohomish County E911 U.S. Post Office Snohomish County Assessor's Office Snohomish County Information Services Snohomish County P.U.D. Puget Sound Energy Edmonds Fire Department Edmonds Police Department Edmonds Utility Billing Edmonds Public Works Edmonds Building/Street File Edmonds Address Files Lynnwood Disposal Comcast Cable Waste Management Northwest GARY HAAKENSON MAYOR Please be advised that the attached address has been added to the Edmonds address system: 8344 Olympic View Dr. (Lot B) and 8354 Olympic View Dr (Lot A) Previously one parcel split to three addressed 8364 Olympic View Dr (Lot C) on which original house will remain. Occupancy: R3 Tax ID Number: 27041800101000 If you have any questions regarding this letter, please contact a permit coordinator at 425-771-0220. Please contact us if you wish to be removed from this list. Respectfully, Permit Coordinator Edmonds Building Department Cc: William Ritter 8364 Olympic View Dr Edmonds, WA 98026 L\Temp\DST'sWaster Letters\New Address8/16/2007 • Incorporated August 11, 1890 • Sister Citv - Hekinan, Jaoan %J1 ful IvI I WWI T9 • Coun ty y Park 0 �,A 11h 3. 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Geotechnical Engineering Engineering Geology Earth Science i September 26, 2005 Mr. Bill Ritter 8364 Olympic View Drive Edmonds, WA 98026 Dear Mr. Ritter: Subject: Geotechnical Engineering Study Proposed 3-Lot Short Plat 8364 Olympic View Drive Edmonds, Washington L&A Job No. 5A112 INTRODUCTION We have completed a geotechnical engineering study for the subject plat site, located at the above address in Edmonds, Washington. The general location of the project site is shown on Plate I — Vicinity Map. We understand that the proposed development for the site is to plat it into three single-family residential building lots. The purpose of this study is to characterize the subsurface conditions of the site and provide geotechnical recommendations for grading, slope stabilization, erosion mitigation, surface and ground water drainage control, foundation design and construction, etc., for the proposed development. Presented in this report are our findings and recommendations. PROJECT DESCRIPTION For our use in this study, we were provided with an undated plat . plan of the proposed development for the site. According to this plan, the proposed development for the site is to plat it into three single-family residential lots. The existing house on the new Southern Lot will remain, and a new residence will be constructed on each of the two remaining new lots (the Northeast and Northwest lots). The Northeast and Northwest Lots are on a moderate to steep 19213 Kenlake Place NE - Kenmore, Washington 98028 Phone (425) 483-9134 - Fax (425) 486-2746 September26, 2005 Proposed 3-Lot Short Plat L&A Job No. 5A 112 Page 2 1 _ hillside. Although design plans for the new residences to be constructed on these lots are not yet available, we anticipate the buildings will be wood -framed structures supported on concrete - walled basement and interior bearing walls, columns and footing foundations. The footprint excavation for these buildings will probably require cuts from a couple to 15 feet deep and possibly less significant fill. SCOPE OF SERVICES Our scope of services for this study comprises specifically the following: 1 Review the geologic and soil conditions at the site based on a published geologic map. 2. Explore the site for subsurface conditions with backhoe. test pits to a firm bearing soil . stratum or to the maximum depth (about 12 feet) capable by the backhoe used for excavating the test pits, whichever occurs first. 3. Perform necessary geotechnical analyses, and provide geotechnical recommendations for site grading, erosion abatement, slope stabilization, surface and ground water control, and foundation design and construction, based on subsurface conditions encountered in the test pits and results of our geotechnical analyses. 4. Prepare a written report to present our findings, conclusions, and recommendations. SITE CONDITIONS SURFACE CONDITIONS The site is an irregularly -shaped tract of land. It is bounded by Olympic View Drive and.an undeveloped city park land to the north, and adjoined by residential developments to the south, east and west. The site is situated on the mid -slope of a broad, moderate to steep, northwesterly - declining hillside. The southern portion of the site where the new South Lot is located has been previously graded into a relatively level bench. The terrain within the new Northeast and LIU & ASSOCIATES, INC. September. 26, 2005 .Proposed 3-Lot Short Plat L&A Job No. 5 A 112 Page 3 Northwest Lots of the site generally slopes down northerly to northwesterly at about 15 to 83 percent grade. The steeper portions are mostly along the south sides of these two lots and.the eastern half of the Northwest lot. The existing residence on the South Lot is accessed by a.paved driveway along the east side of the site. The unpaved area around this existing residence is mostly landscaped with shrubs. The area of the Northeast and Northwest Lots is heavily wooded, dotted by tall, mature evergreen and deciduous trees and covered by dense underbrush. GEOLOGIC SETTING The Geologic Map of the Eastern Half and Part of the Western Half Quadrangles, Washington, by James P. Minard, published by U. S. Geological Survey in 1983, was referenced for the geologic and soil conditions of the lot. According to this publication, the surficial soil units at and in the vicinity of the lot are mapped as Vashon Till (Qvt) underlain by Advance Outwash (Qva)• , The geology of the Puget Sound Lowland has been modified by the advance and retreat of several glaciers in the past and subsequent deposits and erosion. The latest glacier advanced to the Puget Sound Lowland is referred to as the Vashon Stade of the Fraser Glaciation, which has occurred during the later stages of the Pleistocene Epoch and retreated from the region some 14,500 years ago. The Vashon till soil unit is a very dense mixture of unsorted clay, silt, sand, gravel, and scattered cobbles and boulders, often referred to as "hard pan". The Vashon till over the top two to four feet is normally weathered to a medium -dense state, and is moderately permeable and compressible. The underlying fresh till is very dense and practically impervious to stormwater LIU & ASSOCIATES, INC. SeptembeC26, 2005 Proposer 3-Lot Short Plat L&A Job No. 5A 112 Page 4 2, infiltration. The Vashon till soil unit, however, was not encountered by the test pits excavated on the site. The advance outwash soil unit underlying the Vashon till is composed of stratified sand and gravel with minor amounts of silt and clay, deposited by the meltwater of advancing glacial ice. Due to its generally granular composition, the advance outwash is of moderate permeability and generally drains well. The advance outwash is glacially overridden and is generally dense to very dense in its natural, undisturbed state, except the top 3 to 5 feet where exposed on slopes which may be eroded and weathered to a loose to medium -dense state. The advance outwash deposits can stand in steep cuts or natural slopes for extended period of time when undisturbed. Where exposed on slopes of poor vegetation cover and subjected to storm runoff, the advance outwash deposits can be .gradually eroded and may slough to a flatter inclination. The advance outwash deposits in their native, undisturbed state can provide very good foundation support with little settlement expected for light to moderate residential structures. SOIL CONDITIONS Subsurface conditions of the subject site were explored on September 6, 2005, with six test pits. The test pits were excavated with a track -mounted backhoe to depths from 8.0 to 10.0 feet. The approximate locations of the test pits are shown on Plate 2 - Site and Exploration Location Plan. The test. pits were located with either a tape measure or by visual reference to existing topographic features in the field and on the topographic survey map, and their locations should be considered only accurate to the measuring method used. A geotechnical engineer from our office was present during subsurface exploration, who examined the soil and geologic conditions encountered and completed the logs of test pits. Soil samples obtained from each soil unit in the test pits were visually classified in general LIU & ASSOCIATES, INC. Selltember•26, 2005 Proposed 3-Lot Short Plat L&A Job No. 5A112 Page 5 accordance with United Soil Classification System, a copy of which is presented on' Plate 3. Detailed descriptions of soil units encountered during site exploration are presented in the test pit logs on Plates 4 through 6. The test pits revealed that the site is mantled by a layer of loose, organic topsoil, from 0.8 to 2.7 feet thick. The topsoil is underlain by a layer of weathered soils of light -brown, loose to medium -dense, silty fine sand with a trace of gravel, from 1.6 to 3.5 feet thick. Underlying this layer of weathered soils is a brown -gray to light -brown to light -gray advance outwash deposit of medium -dense, gravelly, clean to slightly silty, fine to medium sand with occasional cobble, from 1.8 to 3.2 feet thick. This medium -dense advance outwash deposit is underlain to the depths explored by a light -gray advance outwash deposit of dense, gravelly, fine to coarse sand. GROUNDWATER CONDITION Groundwater was not encountered in any of the test pits. The advance outwash deposits underlying the site are of moderately high permeability, and would allow stormwater to seep through. Stormwater infiltrating into the advance outwash deposits would perch and accumulate over an underlying impervious silt and clay layer at greater depth. We expect little impact on the proposed development by this deeper groundwater. DISCUSSION AND RECOMMENDATIONS GENERAL Based on the soil conditions encountered in our subsurface explorations, it is our opinion that the site is suitable for the proposed development from the geotechnical engineering, viewpoint, provided that the recommendations in this report are fully implemented and observed during construction. The topsoil, loose weathered soils and soils in the root zone should be completely stripped within the driveways, the building pads and where the subgrade soils are to support LIU & ASSOCIATES, INC. a • September 26, 2005 Proposed 3-Lot Short Plat L&A Job No. 5A 112 Page 6 structural or traffic load. The medium -dense to dense advance outwash soils are of fair to moderately high shear strength and can provide good foundation support to the driveways and the new buildings to constructed on the site. Conventional footing foundations placed on or into the underlying medium -dense to dense advance outwash soils may be used for supporting the new buildings to be constructed on the site. Structural fill, if required for site grading, should be constructed over the underlying medium -dense to dense advance outwash soils following the stripping of surficial unsuitable soils. GRADING SEASON Due to the sensitive nature of the steep slopes within the site, we recommend that grading and foundation construction work for the residence be carried out and completed in the dryer period from April 1 to October 30 of the year. The site should be stabilized with proper drainage and erosion control measures in place beyond this dry season grading period. GEOLOGIC HAZARDS AND REMEDIATION Landslide Hazards The subject site is underlain at shallow depth by medium -dense to dense advance. outwash soils of fair to moderately -high shear strength. The advance outwash deposits are quite permeable, and the impervious silty soils normally underlying the advance outwash soil unit is not exposed within the site. Therefore, seepage of groundwater out of slopes from the interface of the advance outwash deposits and the underlying silty soil unit should not occur within the site. The competent advance outwash soils underlying the site and little potential of groundwater seepage within the site would make it unlikely for deep-seated landslide to occur within the site. LIU & ASSOCIATES, INC. September*26, 2005 Proposed 3-Lot Short Plat L&A Job No. 5A112 Page 7 Erosion Hazard The surficial topsoil and loose weathered soils over the steeper portion of the site can be easily eroded when stripped of vegetation cover and overly saturated. Prolonged erosion can lead to soil sloughing and shallow, skin -type mudflows on the steeper portion of the site. To mitigate erosion potential, the vegetation cover outside of construction limits should not be disturbed. Concentrated stormwater should not be discharged onto the ground anywhere within the site. Spoil soils and yardwaste should not be disposed of within the site. Storm runoff over impervious surfaces, such as roofs and paved driveways, should be captured with underground drain line systems tied to roof downspouts and by catch basins installed in driveways, and should be tightlined to discharge collected water into a storm sewer or a suitable stormwater disposal facility. Unpaved, disturbed ground within the site should be re -vegetated as soon as possible to provide erosion protection. Once the drainage control measures for the roadway and houses are in place after the completion of the proposed development, the amount of surface runoff and near -surface groundwater flow will be reduced, which would further reduce soil erosion and enhance site stability. Seismic Hazard The Puget Sound region is in an active seismic zone. The lot is underlain by medium -dense to dense advance outwash soils of fair to moderately high shear strength. There is a lack of continuous, extensive, static groundwater table at shallow depth under the lot. Therefore the potential for seismic hazards, sucfi as deep-seated landslides, liquefaction, lateral soil spreading, to occur on the site should be minimal. The proposed building, however, should be designed for e seismic forces induced by strong earthquakes. Based on the soil conditions encountered by the test pits, it is our opinion that Seismic Use Group I and Site Class D should be used in the seismic design of the proposed residences in accordance with the 2003 international Building Code (IBC). LIU & ASSOCIATES, INC. September'26, 2005 Proposed 3-Lot Short Plat L&A Job No. 5A 112 Page 8 SITE PREPARATION AND GENERAL GRADING Site preparation for the proposed development should include clearing and grubbing within construction limits. Topsoil, loose weathered soils, and unsuitable soils in the root zone should be completely stripped within the driveways, the building pads of the proposed buildings and in other areas subject to traffic and structural loads. The exposed soils should be compacted to a non -yielding state with a vibratory compactor and proof -rolled with a piece of heavy earthwork equipment operated on the site. The on -site soils contain a high percentage of fines and are sensitive to moisture. A layer of clean quarry spalls should be placed over excavated areas and areas of frequent traffic, as required, to protect the subgrade soils from disturbance by construction traffic. Silt fences should be erected along the downslope boundaries of the site to prevent sediments being transported by storm runoff onto adjoining properties or the street. The bottom edge of the silt fence should be embedded in a trench and ballasted with crushed rock or gravel. EXCAVATION AND FILL SLOPES Under no circumstance should excavation slopes be steeper than the limits specified by local, state and federal safety regulations if workers have to perform construction work in excavated areas. Unsupported temporary cuts greater than 4 feet in height should be no steeper than I - 1 /4H:1 V in the surficial topsoil and loose weathered soils, and no steeper than 1 H:1 V in the underlying medium -dense to dense advance outwash soils. Permanent cuts should be no steeper than 21/2H:1 V in the surficial topsoil and loose weathered soils, and no steeper than 2H:1 V in the underlying medium -dense to dense advance outwash soils. The soil units and the stability of cut slopes should be observed and verified by a geotechnical engineer during excavation. LIU & ASSOCIATES, INC. September"26, 2005 Proposed 3-Lot Short Plat L&A Job No. 5A 112 Page 9 i.. Permanent fill embankments required to support structural or traffic loads should be constructed with compacted structural fill placed over proof -rolled, undisturbed, medium -dense to dense advance outwash soils after the unsuitable surficial soils are stripped. Permanent fill to be placed on slopes steeper than 20 percent grade should be retained structurally. Sloping ground exceeding 15 percent grade over which fill is to be placed should be benched with vertical steps no more than 4 feet high after stripping of unsuitable surficial soils. The slope of permanent fill embankments should be no steeper than 2H:1 V. Upon completion, the sloping face of permanent fill embankments should be thoroughly compacted to a non -yielding state with a hoe -pack. The above recommended cut and fill slopes are under the assumption that groundwater seepage will not be encountered during construction. if encountered, the construction work should be immediately halted and the slope stability re-evaluated. The slopes may have to be flattened and other measures taken to stabilize the slopes. Storm runoff should not be allowed to flow uncontrolled over the top of cut or fill slopes. Permanent cut slopes or fill embankments should be seeded and vegetated as soon as possible for erosion protection and long-term stability, and should be covered with clear plastic sheets, as required, to protect them from erosion by stormwater until the vegetation is fully established. STRUCTURAL FILL Structural fill is the fill that supports structural or traffic load. Structural fill should consist of clean soils free of organic and other deleterious substances and with particles not larger than four inches. Structural fill should have a moisture content within one percent of its optimum moisture content at the time of placement. The optimum moisture content is the water content in the soils that enable the soils to be compacted to the highest dry density for a given compaction effort. LIU & ASSOCIATES, INC. September" 26, 2005 Proposed 3-Lot Short Plat L&A Job No. 5A 112 Page 10 The on -site advance outwash soils contain a high percentage of fines, and may be used as structural fill only under fair weather condition when their moisture content can be controlled to close to optimum moisture content. Imported material for structural fill should be clean, free - draining, granular soils containing no more than 5% by weight finer than the No. 200 sieve based on the fraction of the material passing No. 4 sieve, and should have individual particles not larger than four inches. Imported structural fill should be stockpiled and covered separately from the on -site soils. Structural fill should be placed in lifts no more than 10 inches thick in loose state, with each lift compacted to a minimum percentage of the maximum dry density determined by ASTM D1557 (Modified Proctor Method) as follows: Application Within building pads Roadway/driveway subgrade Retaining wall backfill Utility trench backfill BUILDING SETBACK % of Maximum Dry Density 95% 95% for top 2 feet and 90% below 90% 95% for top 4 feet and 90% below The purpose of building setback from the top or toe or an overly steep portion of a slope is to establish a safe buffer such that if a slope failure should occur the stability of the structure can be maintained and damages to the structure minimized. To maintain stability of the. buildings to be construction on the new Northeast and Northwest Lots, we recommend that the buildings be set back at least 20 feet from the crest or toe or any portion of 40% or steeper slopes. Reinforced concrete or soldier pile retaining walls may be used to regrade the ground and enhance stability LIU & ASSOCIATES, INC. September026, 2005 Proposed 3-Lot Short Plat L&A Job No. 5A 112 Page l 1 of 40% or steeper slopes. If retaining walls are used, the proposed building should be set back no less than 10 feet from the retaining walls. The buildings should be also be set back sufficiently such that an imaginary plane drawing from the edge of the footing foundations to the toe of slopes 40% or steeper should be no steeper than 3HA V. Also, the footing foundations within 30 feet of the toe or top or any portion of 40% or steeper slopes should be embedded at least 1.5 foot into the medium -dense to dense advance outwash soils. The footprint bearing soils should be verified by a geotechnical engineer after the excavation of the building footprints are completed. DEBRIS WALLS If retaining walls are not constructed to enhance the stability of the steep slopes uphill of the proposed new buildings, we recommend that the uphill -side basement walls of the buildings be extended at least 3 feet above their adjacent finish grade to serve as debris blocking walls in case a mudflow should occur on the uphill steep slope. The combined basement/debris walls should be designed in accordance with the recommendations in the BASEMENT AND RETAINING WALLS section of this report. BUILDING FOUNDATIONS Conventional footing foundations may be used for supporting the buildings to be constructed on the site. The footing foundations should be placed on or into the underlying, medium -dense to dense advance outwash soils, or on structural fill constructed over these undisturbed competent basal soils. Water should not be allowed to accumulate in excavated footing trenches. Disturbed soils in footing trenches should be completely removed down to firm native soils prior to pouring concrete for the footings. The sandy advance outwash soils can be easily disturbed by construction traffic. To protect the footing bearing soils, a 6-inch-minimum layer of 2-inch- minus compacted crushed rock should be placed over the bearing soils. The footing foundations may then be poured over the crushed rock base. LIU & ASSOCIATES, INC. September'26, 2005 Proposed 3-Lot Short Plat L&A Job No. 5A 112 Page 12 If the above recommendations are followed, our recommended design criteria for footing foundations are as follows: • The allowable soil bearing pressure for footing foundations, including dead and live loads, should be no greater than 2,500 psf if supported on undisturbed medium -dense to dense native soils and no greater than 2,000 psf if supported on structural fill placed over firm undisturbed soils. The footing bearing soils. should be verified on -site by a geotechnical engineer after the footing trenches are.excavated and before the footings poured. • The minimum depth to bottom of perimeter footings below adjacent final exterior grade should be no less than 18 inches. The minimum depth to bottom of the interior footings below top of floor slab should be no less than 12 inches. • . The minimum width should be no less than 16 inches for continuous footings, and no less than 24 inches for individual footings. A one-third increase in the above recommended allowable soil bearing pressure may be used when considering short-term, transitory, wind or seismic loads. For footing foundations designed and constructed per recommendations above, we estimate that the maximum total post - construction settlement of the buildings should be 3/4 inch or less and the differential settlement across building width should be 1 /2 inch or less. Lateral loads on buildings can be resisted by the friction force between the foundations and the subgrade soils or the passive earth pressure acting on the below -grade portion of the foundations. For the latter, the foundations must be poured "neat" against undisturbed soils or backfilled with a clean, free -draining, compacted structural fill. We recommend that an equivalent fluid density (EFD) of 300 pcf (pounds per cubic foot) for the passive earth pressure be used for lateral resistance. The above passive pressure assumes that the backfill is level or inclines upward away LIU & ASSOCIATES, INC. September*26, 2005 Proposed 3-Lot Short Plat L&A Job No. 5A 112 Page 13 ,. from the foundations for a horizontal distance at least twice the depth of the foundations below the final grade. A coefficient of friction of 0.60 between the foundations and the subgrade soils may be used. The above soil parameters are unfactored values, and a proper factor, of safety should be used in calculating the resisting forces against lateral loads on the buildings. BASEMENT AND RETAINING WALLS Basement walls restrained horizontally at the top are considered unyielding and should be designed for a lateral soil pressure under the at -rest condition; while retaining walls free to move at the top should be designed for active lateral soil pressure. We recommend that a lateral soil pressure of 45 and 70 pcf EFD be used for the design of foundation walls with level/descending backslope and rising backslope, respectively; and 35 and 55 pcf EFD for retaining walls with level/descending backslope and rising backslope, respectively. To counter the active soil or at - rest pressure, a passive lateral soil pressure of 350 pcf EFD may be used, except that the passive pressure within the top 12 inches of the finish subgrade should be ignored. The above passive pressure assumes that the backfill is level or inclines upward away from the walls. The above lateral soil pressures are under the assumption that groundwater behind the walls is fully drained. To resist against sliding, the friction force between the footings and the subgrade soils may be calculated based on a coefficient of friction of 0.60. The above soil parameters are ultimate values, and proper factors of safety should be used in the design of the basement and retaining walls against sliding and overturning failures. Basement walls or retaining walls may be supported on footing foundations seated on or into the underlying very -dense fresh till or very - hard transitional beds soils, with an allowable soil bearing pressure not to exceed 3,000 psf. A vertical drainage blanket consisting of at least 12-inch-thick free -draining pea gravel or washed 'gravel should be placed against foundation and retaining walls to prevent accumulation of groundwater behind and buildup of hydrostatic pressure against the walls. The remaining LIU & ASSOCIATES, INC. September°26, 2005 Proposed 3-Lot Short Plat L&A Job No. 5A 112 Page 14 �. backfill should consist of structural fill constructed per recommendations in the STRUCTURAL FILL section of this report. The top 12 inches of backfill should consist of compacted, clean, on - site soils. The backfill material for the foundation and retaining walls should be compacted with A hand -operated compactor. Heavy compaction equipment should not be allowed closer to the walls than a horizontal distance equal to the wall heights. A footing drain, as recommended in the DRAINAGE CONTROL section of this report, should also be provided for foundation and retaining walls. SLAB -ON -GRADE FLOORS Slab -on -grade floors, if used, should be placed on firm subgrade prepared as outlined in the SITE PREPARATION AND GENERAL EARTHWORK and the STRUCTURAL FILL sections of this report. Where moisture control is critical, the slab -on -grade floors should be placed on a capillary break which is in turn placed on the compacted subgrade. The capillary break should consist of a minimum four -inch -thick layer of clean, free -draining, 7/8-inch crushed rock, containing no more than 5 percent by weight passing the No. 4 sieve. A vapor barrier, such as a 6-mil plastic membrane, may be placed over the capillary break, as required, to keep moisture from migrating upwards. PAVED DRIVEWAYS Performance of paved driveways is critically related to the conditions of the underlying subgrade soils. We recommend that the subgrade soils within the driveways be treated and prepared as described in the SITE PREPARATION AND GENERAL EARTHWORK section of this report. Prior to placing base material, the subgrade soils should be compacted to a non -yielding state with a vibratory roller compactor and proof -rolled with a piece of heavy construction equipment, such as a fully -loaded dump truck. Any areas with excessive weaving or deflection should be over -excavated and re -compacted or replaced with a structural fill or crushed rock placed and LIU & ASSOCIATES, INC. September"26.2005 Proposed 3-Lot Short Plat L&A Job No. 5A 112 Page 15 compacted in accordance with the recommendations provided in the STRUCTURAL FILL section of this report. We recommend that an 4-inch-thick minimum, compacted, crushed rock base (CRB), consisting of 7/8-inch-minus crushed rock, be used for the roadways. The crushed rock or subgrade base should be topped with 2-inch asphalt treated base (ATB) topped by 1-1/2-inch-thick Class B asphalt concrete (AC). DRAINAGE CONTROL Building Footprint Excavation Groundwater is not expected within depth of excavation for the construction of the proposed buildings. If encountered, the bottom of building footprint excavation should be sloped and ditches excavated along the bases of the cut banks to direct runoff and groundwater into a sump pit from which water can be pumped into a nearby storm sewer. The inlet of the storm sewer should be covered by a filter sack to keep sediments from entering the storm sewer system. A layer of 2-inch crushed rock should be placed. over undisturbed subgrade soils supporting footings and on -grade slabs, as required, to protect the soils from disturbance by construction traffic. Surface Drainage Water should not be allowed to stand in any areas where footings, slabs, or pavement is to be constructed. Final site grades should allow storm runoff to flow away from the building. We recommend the finish ground be sloped at a gradient of 3 percent minimum for a distance of at least 10 feet away from the building, except in the areas to be paved. LIU & ASSOCIATES, INC. a , September 26, 2005 Proposed 3-Lot'Short Plat L&A Job No. 5A 112 Page 16 j. Runoff over Impervious Surfaces Storm runoff over impervious surfaces, such as roofs and paved driveways, should be collected by underground drain line systems connected to downspouts and by catch basins installed in the driveways. Stormwater thus collected should be tightlined to discharge into a storm sewer or a suitable stormwater disposal facility. Sufficient numbers of cleanouts at strategic locations should be provided to the underground drain line systems to allow for periodical cleaning of the drain lines. Footing Drains A subdrain should be installed around the perimeter footings of the proposed houses and along the base of retaining walls. The subdrains should consist of a 4-inch-minimum-diameter, perforated, rigid, drain pipe, laid a few inches below bottom of the building perimeter footings or retaining wall footings. The trenches and the drain lines should have a sufficient gradient to generate flow by gravity. The drain lines should be embedded in washed gravel completely wrapped in non -woven filter fabric to within about 12 inches of finish grade. The remaining trenches may be backfilled with clean on -site soils. Sufficient numbers of cleanouts at strategic locations should be provided to the footing drain lines to allow for their periodical cleaning and maintenance. Water collected by the footing drains should be tightlined, separately from the roof. and surface stormwater drain systems, to discharge into a storm sewer. RISK EVALUATION STATEMENT The site is underlain by medium -dense to dense advance outwash soils at shallow depth. These soils are of fair to moderately -high shear strength and have good resistance against deep-seated slope failures. The key to maintain stability of the site is to maintain stable temporary cut slopes and to have proper and adequate erosion and drainage control during and after construction_ It is our opinion that if the recommendations in the report are fully implemented and observed during construction and after the completion of the development, the areas disturbed by construction LIU & ASSOCIATES, INC. A September 26, 2005 Proposed 3-Lot Short Plat L&A Job No. 5A112 Page 17 will remain stable and will not increase the potential for soil movement. In our opinion, the risk of damage to the proposed development and from the development to adjacent properties from soil instability should be minimal. LIMITATIONS This report has been prepared for the specific application to this project for the exclusive use by Mr. Bill Ritter, and his associates, representatives, consultants and contractors. We recommend that this report, in its entirety, be included in the project contract documents for the information of the prospective contractors for their estimating and bidding purposes. The conclusions and interpretations in this report, however, should not be construed as a warranty of the subsurface conditions. The scope of this study does not include services related to construction safety precautions and our recommendations are not intended to direct the contractor's methods, techniques, sequences or procedures, except as specifically described in this report for design considerations. Our recommendations and conclusions are based on the geologic and soil conditions encountered in the test borings, and our experience and engineering judgment. The conclusions and recommendations are professional opinions derived in a manner consistent with the level of care and skill ordinarily exercised by other members of the profession currently practicing under similar conditions in this area. No warranty, expressed or implied, is'made. The actual subsurface conditions of the site may vary from those encountered by the test pits. The nature and extent of such variations may not become. evident until construction starts. If variations appear then, we should be retained to re-evaluate the recommendations of this report, and to verify or modify them in writing prior to proceeding further with the construction. LIU• & ASSOCIATES, INC. �t + September 26, 2005 Proposed 3-Lot Short Plat L&A Job No. 5A 112 Page 18 j. CLOSURE We are pleased to be of service to you on this project. Please feel free to call us if you have any questions regarding this report or need further consultation. 27588 � h 1 EXPIRES 7 / l7 /'7 0 0'7 1 Six plates attached Yours very truly, LIU & ASSOCIATES, INC. J. S. (Julian) Liu, Ph.D., P.E. Consulting Geotechnical Engineer LIU & ASSOCIATES, INC. '4FC, V - --LAW & ASSOCIAT'ES, INC. AP-fF0 Geotechnica[ Engineering Geol ogy Engineering — ---- — — - - -- ------ - --- -- ----- ---- ----- - - Earth Science April ! 4 2006 PLA/ft - - — -- - �'i Mr. Bill Ritter 8364 Olympic View Drive Edmonds, WA 98026 Dear ,Mr. Ritter: Subject: Addendum No. 1 to 9/26/2005 Geotechnical Report On -Site Stormwater lnfiltrat;on 1'renches Proposed 3-Lot Short Plat 8364 Olympic View Drive Edmonds, Washington L&A Job No. 5A 112 Six test pits were excavated on the subject plat site. The test pits encountered 0.8 to 2.7 feet of loose organic topsoil underlain by a laver of weathered soils of light -brown. loose to medium - dense. silty fine sand with a trace of gravel, fi•om 1.6 to 3.5 feet thick. Underlying this layer of weathered soils are advance outwash sand deposits of brown -gray to fight -brown to light -gray medium -dense, gravelly. clean to s{ighrly s;Ity, tine to medium sand with occasional cobble, from 1.8 to 3.2 teci thick, and light -gray advance outwash deposit of dense, gravelly, tine to coarse sand. Groundwater was not encountered by any of the test pits excavated up to 10 feet deep. advance :outwash deposit of clean. fine to coarse stand. vvith various an—ount of grave!, underlying the site at depths from 3.2 to 6.0 ieet below existing ground surface is of high permeability. The Soil Survey of Snohomish County Area of Washington, published by in U. S. Department of Agriculture in cooperat;on with Washington State Department of Natural Resources and Washington State University Agriculture Research Center, was also referenced for the surficial soil unit at the subject site. According to this publication, the advance outwash sand deposit at the subject site is also classified as Everett Gravelly Sandy Loam with the Soil 19213 Kenlake Place NE • Kenmore, Washington 98028 Phone (425) 483-9134 • Fax (425) 486-2746 Attachment 6A April 14,-2006 Addendum No.. 1 to 9/26/2005 Geotechnical Report Proposed ;-1,0t Short Plat L&A .lob No. 5A 112 Page 2 Conservation Services (SCS) Classification System. Table 14 of the above publication lists the Permeability of this soil unit at a depth from 6 to 60 inches below grade to be from 6 to 20 iph (inches per hour). Our experience of this soil unit in the neighborhood of the sub _.eet site indicates its in -situ. infiltration rate to be in the range from 20 to 40 iph. It is, therefore, feasible to use infiltration trenches to dispose stormwater into the ground on site. We recommend a design infiltration rate of =.0 iph (including a factor of safety of at least 4.0) be used for the design of infiltration trenches. Infiltration trenches should be located on the downhill of the houses to be constructed on the lots. They should be setback at least 10 feet from the houses and 5 feet from property lines. Our recommendations for design and construction of the infiltration trenches are shown on Plate attached hereto. The bottom of infiltration tI'e1lelleS should he excavated at least 6 inches into the underlying. clean, light -brown to light -gray, advance outwash sand deposit. The soils at bottom of infiltration trenches should be verified by a (,eotechnical engineer. The side walls of the trenches should be lined with a layer of non -woven filter fabric, and the trenches backfilled with clean washed gravel to within about 12 inches of the finished grade. A 4-inch perforated PVC pipe through which stonrtwater is to be dispersed into the (,round should be set level in the gravel fill of each infiltration trench. The perforated PVC pipes should be set as high as possible in the trenches to have maximum separation from the winter high groundwater table, but should have at least 18 inches of soil/gravel cover over the perforated pipes. The top of the gravel fill should also be covered with filter fabric. The remaining trenches may be backfilled with on -site clean soils. • We are pleased to he of service to you on this project. Please feel free to call us if you have any questions regarding this report or need further consultation. ICI U & ASSOCIATES, INC. I Alfril 14, 2006 Addendum No.J to 9/26,12005 Geotechnicai Report Proposed 3-Lot Short Plat L&A .lob No. SA 112 Page 3 One plate attached Yours eery truly, L1U & ASSOCIATES, INC. J.. S. (Julian) Liu, Ph.D., P.E. Consulting Geotechnical Engineer LIU & ASSOCIATES, INC. I G QL � = �Y la o 4 �� -xo — Q� z �> 7:1: d v NI J 3otl j v� VII 0 7 0. �•O •o .'•O, p• � •o 00 'f • 3 00 \•p0 tee• o 10 Z "Z V • (I - oP .?f a9 i o 0 7'P I Z ; oo 0 �O' O 9s e '4 I • �O '-�o°.o Ono . � OJ p )� o o� �� nu+•� ro � Cd •Qje O� O + -P P q •+ O, • •• f OO O O. J J� O. O O _' 11� I �1 11 Iil Ii I ti:u •Nlw ,t81 S� �yvA LIU & ASSOCIATES, INC. Geotechnical Engineering - Engineering Geology . Earth Science 7 ..i _1 _O s v Z Q -w v --1 z V <'o Z J p k--- 0 3,9 s !�- 0~�' Z �wS YPICAL SECTION - INFILTRATION TRENCHES BILL RITTER 3-LOT SHORT PLAT 8364 OLYMPIC VIEW DRIVE EDMONDS, WASHINGTON JOB NO. 5A112 DATE 4/14/2006 1 PLATE 1 LIU - ASSOCIATES, INC. Geotechnical Engineering Engineering Geology Earth Science October 5, 2006 Mr. Bill Ritter 8364 Olympic View Drive Edmonds, WA 98026 Dear Mr. Ritter: � RA,9lT COI J 'C)� Subject: Feasibility of Shoring Wall for Grading and Building Support Proposed 3-Lot Short Plat 8364 Olympic View Drive Edmonds, Washington L&A Job No. 5A 112 We understand that a permanent shoring wall is being contemplated for grading and building support for a new residence to be constructed on the northwestern lot of the subject 3-lot plat. The shoring wall is to be located along the back (uphill side) of the house. It will be used for retention of building footprint excavation and for foundation support of the house. It is our opinion that such a shoring wall will be feasible in achieving its intended purposes. We will be glad to present the design and construction recommendations for this shoring wall if you decided to proceed with it. Yours very truly, LIU SSOCIA , INC. J. S. (Julian) Liu, Ph.D., P.E. Consulting Geotechnical Engineer 7l171 19213 Kenlake Place NE - Kenmore, Washington 98028 Phone (425) 483-9134 • Fax (425) 486-2746 Attachment 6B CITY OF EDMONDS ENGINEERING REQUIREMENTS FOR SHORT PLATS i Name: RITTER File No.: S-06-44 Reviewed by: Lyle Chrisman Vicinity: 8364 Olympic V;eu-a OrWe Engineering ineerm mvtston aate Req'd prior to recording Req'd w/bldg. Permit Bond posted Complete 1. Rights -of -way for public streets: _...__._No dedication required...----- -- ------ ----- ---- --- - _ —_ _ _ _ ---_ --- ------- -- X 2. Easements(City utilities, private access, other utilities): Provide all easements as needed. X_— Obtain Access easement rights from Snohomish County for access across property along Olympic View Dr in order to provide additional easement width between Olympic View Dr. _—and subject.property line - --- Private access easement shall be a minimum of 20' feet in width. ^ X ----------..... _..—_ X ---... -- = --------- — --- --- 3. Street improvements ACP with curb and utter Construct 18" curb & gutter along property frontagewith the face of curb located 12' from the painted centerline_ _ Private access road serving all lots shall be paved a minimum of _........__16:0' in width, plus W' asphalt thickened edge. Slope of private access road/driveway shall not exceed 14% X X — X 4. Street turnaround: Provide on -site turn around for lot A. — — X 5. Sidewalks and/or walkways:. - Construct 5 _wide sidewalkalong�roperty frontage_---__......___.._...__..__.__.._..____..-._X..._.---.._....._...._._................___._......._..__..__.......-_.. ...................----.-.-.--.----.._.:...___--..._......__._.... 6. Street lights: _ .. N/A _ ...--.----._...._. _------..__._ X -----__.___ 7. Planiin strip: _ N/A X 8. Waters stem improvements Install 4" storz adapter on the existing hydrant . Provide new water service to each lot. X X Connect to public water system. X X hitp:Hedmondspmtweb/permittrax/PermitTraxMain/Attachments/Live/PERMIT/PMT-54236/3132007113224807.doc for Attachment 7 9. Sanitary sewer system Improvements Provide new sewer service to each lot Connect to public sewer system 10. Storm sewer system improvements _ Provide new storm sewer service to all proposed lots Construct storm detention system sized to provide adequate capacity for all proposed single family dwellings and access _ _ improvements in accordance with ECDC 18.30._— Connect to Public Storm system 11. On -site drainage (plan per Ord. 3013): — Connect all new impervious surfaces to detention system. 12. Underground wiring (per Ord.1387): ____Required for all new services 13. Excavation and grading (per IBC, appendix j (2003 edition)) Submit.a grading plan as�4 of engineered site_plan_ Grading for foundations to be included with building permit i 14. Signage (per City Engineer): _.._ Provide fire and aid address signage_._...__....._.._.__._....._.__._...._.___.___._.._. Provide "Access Ends" 15. Survey monumentation (per Ord., Section 12.10.120): N/A 16. As -built drawings (per City Engineer): Required for all utility -construction. 17. Other requirements: a1 Plat showing lots, easements, legals, survey information b� Legal documents for each lot _.._ - ....... ------------ - - c) -.-Field stake lot corners (by professional surveyor) _ _ Field stake utility stubs at propS5y_lines_ _.. ---- — e) Clustered mailbox location per Postmaster. f) Maintenance agreements Req'd prior Req'd Bond Complete to w/bldg. posted recording Permit X X X X X X X X X I X .......... __._. .......... ._..X._....__._._...._..---_._..---.___. -_--..__._.---- ........ _____._X._._ X X X X - X X X .. __ X .-........_....._._..._._..._.__...._..... .. X _.__.._..._---.._ ___......__ ._....__._._.-_......_._—_._._..._. X X X --- — -- —.... -- ---- — — X http://edmondspmtweblpermittraxlPermitTraxMainlAttachments/Live/PERMIT/PMT-5423613132007113224807.doc form revised: 1/2/07 Req'd prior Req'd Bond Complete to w/bldg. posted recording Permit 18. Engineering fees: a Storm development charge access on�� $ ...._._ _. X._._-- _-- — bZ Storm drainage connection fee (sfr) -- $428/lot _ X —X c Sewer connection fee: d) Water connection fee: X ..... --.---.�__._..-. ._.....-.----_.._.__—._-..__..._.._.....---........____..—_--.._._._..__...-----_._.____._..__..__._......-.--.--._-._-..-_......__._.._...--.---.--..__....._..__.__.........__.--__._....-._._-._..._... e Water meter fee - 3/4" meter: X ___.....-.---..._....__....._._ .__ _ f) Traffic mitigation fee $840.72/ new lot $ — _ — X — _ — review fee (short plat ----- - ----- $860 — — _X_-- __.—..g1...Plat _ _per h) Short plat inspection fee(2.2% of improvement costs)$ TBD X A.L. Chrisman 13 Mar 07 ENGINEERING PROGRAM MANAGER, CITY OF EDMONDS DATE The Engineering requirements have been completed and the subdivision can be recorded. Authorized for recording by: Date: http://edmondspmtweblpermittrax[PermitTraxMain/Attachments/Live/PERMIT/PMT-5423613132007113224807.doc form revised: 1/2/07 RECEIVED November 27, 2006 NOV 2 7 2006 EDMONDS CITY CLERK To: City of Edmonds Development Services Department 12 15'"Ave. N. Edmonds, WA 98020 From Erie and Connie Falk. 8310 01mpic View Dr. (nailing address P. O. Box 661, Edmonds, WA) Edmonds, WA 98026 425 672-7620 RE: Notice of Development File # S-06044 (subdivision at 8364 Olynnpic View Dr..) We have reviewed. the listed application and. have some concerns. We obtained. four documents associated with the developers (Mr. Ritter) application. One of the documents is a copy of the Snohomish County Parks and Recreation Special Use Permit # 072704- 0001. The next was a map of the proposed short plat that had a date stamp -of " October 12, 2006 Permit Countcr" The next was a letter from the City of Edtnends dated November 1, 2006 titled " Subject of complete Application" and signed by Yen Machuga, and last document was a City of Edmonds email t1W. written by Lyle Chrisman and sent to Jen Maehuga. It was a surprise to see the county issued a permit without notifying neighboring property owners. I phoned the Snohomish County Parks and recreation otiice and spoke with Dianne Bailey about the permit_ She confirmed that the permit wets issued on July 31, 2006. She said the permit allowed Mr. Ritter to install a ten -foot wide road, which he could pave, for ingress and egress purposes to meet compliance for the City of Edmonds Planning Department, Diane said the permit didn't authorize.1W Ritter to place any uti 1 ities (spedf ic§Aly a 4" storm dry) within or under the am otdimr d in the permit or designated on the short plat/ grading drainage magi on file in this application. Diane said a request to place utilities within the area was never discussed with the parks department and to do so would lye a violation of the existingpermit. We also nodced the mtraly didn't show a road or driveway leading- to the new house (on the east lot) from Olympic View Dr. The map showed access to the new house on the east lot is an angled driveway off the existing private driveway. Tf that is the case then what is the purpose of needing the special use permit to cross the existing county park.? . Another area of concernis the discrepancy between. the above listed letter and email. The letter. indicates the land use application submitted by Mr. Ritter is complete but, the email indicates -there is a sight distance issue that needs to be addressed. Lyle told Jen that Mr_ Ritter would need to reshape the hillside and remove some trees all within the County Page: 1 cif 7 Attachment 8 Park. I couldn't find anything within the file that indicated Mr. Ritter was notified of this or that he met the mquest. Diane Badey said the Snohomish. County Parks and Recreation has not received ft►rther requests from Mr. Ritter to do anything within the park other than what it listed in the above special use permit, which was dated approximately threes months Were the email from Lyle to 3en-. Our other concern is the impact that the excavation of the two lots and construction of the house will have on our property and the private driveway used by us and the other two homeowners (excluding Mr. Ritter) for daily ingress and egress= We don't feel we should be burdened with repairingthe private driveway when it is damaged by construction equipment or unreasonable delays to access our property during development and construction; We have no desire to stop Mr. Ritter from developing his property. We want to make scare our personal and public interests am protected and that his dealing with the City and County are with guideliires. I have some questiom aboutthe placetnertCall the utilities but -I wasn't -able to get the answers before the end of the comment period. I will also tell you that Mane )bailey of the Snohomish County Parks and Recreation office wW surprised. when .I described the drainage map to her and informed her there would be two new houses built on the existing property. She said Mr. Ritter told her he was dividing the lot and building one more house; not two. She asked me to send her a copy of the map and said she would mvicw it and adddms the permit if n=ssary. Please keep us apprised of the situation and call if you have further questions. Thanks for your time. Sincerely, 9��05�� --"7 Eric M. Fa Connie. A.'Falk Pam 2 of 2, juawqaejlV v V. � Q® 0®`a❑pa®; i l 12 i7 Q q O CID �0 N 0 4" . m �J N «NCI NHill LLNN �AAA�`Q�Q`jj � cSRR$� a ail 0 N 0