The URL can be used to link to this page

9202 OLYMPIC VIEW DR.PDFiiiiiiiiiiiiii14310 9202 OLYMPIC VIEW DR PROJECT REVIEW CHECKLIST PROJECT NAME: P PLAN CHECK #: PROJECT ADDRESS: q2JC)2_ N �4 J-Q AA,) -Lc RECEIPT DATE: �/)Lj 01_W j . ...................................... ............. ........ . . . . . . .. .. . .... ... . .... . . ............... . ............ ................. .... ......... ........ ........... ...... . ...................... .................... X ....... .............. ................ ........ ...... . .......... ............. ...... ...... . ..... . .. . ... 0 ................................ M ..................... . . . . . . . . . . . . . . . . . .. .. .. . ......................... Setbacks/Variance/Setback Adjustment MINA* N Conditional Use Permit ADB Requirements . . . . . . . . . . ........... Other Zoning Requirements . Underground Wiring Required .... ..... Lot Slope 15% SEPA Environmental Checklist/Hydraulics Permit Tree Cutting Plan Al 199 Plat/Subdivision Requirements Legal Description Verification .......... .......... Quit Claim/Street Dedications X.- A ... Easements - Public/Private Engineering Storm Drain Review Fee . . . . . . . . . . Engineering 2.2 Inspection Fee . . . . . . . . . . . . . . . . . . p Drainage Plan (On-Site ... PL) Setback - To of Bank, Stream, Water Courses Setback -Storm Drain Line Open Ditch - Existing .... ....... Culvert Required . ...... Culvert Size . . . . Shoulder Drainage/Shale Open Runoff . . . . . . . . . . Catch Basin Required V - Driveway Slope & Vehicle Access ---- ---- --- Sidewalk Required .................................. Curb & Gutter Required --- ------- .............. ..... Curb Cut For Driveway Required . . . . . . . . . . . . . . . . . . . . -Z. Street Paving Required Right -Of -Way Construction Permit Required ............ Street Name Sign Required ............... ........... Other Signing Required Bond Required For Public Improvements FEMA- .Map Ch ck/Water Table 0 A — Side .9eAier Availability Calculate Sewer Connection Fee If No LID # . . . . . ..................... Create Street File L".10 ... Existing Water Main Size Water Meter Size Service Line Size if Water Meter Charge Required Hydrant Required Hydrant Size Existing ---------- Fire Line Charge Required - Sprinkler .......... Street Cut ........... Miscellaneous Reviewed By: FIRE RECEIVED RF-CU'J'aW MAR uk, PLANNING E N RING PORKS A -U I BLIC VVOR MR, N Fr 1-+ 1-+ N+ H H H 1.+ 1-+ ►-� W . N O w co V C1 m A W N ..-i D a o v z z m m f7 A m m v v v v a n m m V W N N N N N O t0 OW T Ul p W N O to CO V N N N N 01 Vl .A W N r m N � E --IN m z m rn N 3 3 m -m a m m CA CA c CA m c m v m v W O!� m m v N N I= m 0 0 z M 0 z n 7 C z r O z ;;� 0 x o �T1 s c� 0 m CL 0 H R r- 9 C7 > z rm o h z z 0 .a z Rio _ . PiERMEX ,al 9v L )oy5 CITY OF EDMOND SIDE SEWER PERMIT EDMONDS E:r J89 9q'° 4 aO��,D jiREATIVI,ERT PIS PERMIT _ o., N0- 8982 ,R0Y 6 I9513 Address of ConsP6&jt: �Awww �� DEP1 Property Legal Description (Include all easements): _ 0 n Owner and/or Contractor: ��11 / • /y/ f fZ �--�/v �y State License No. O/��14 4:9:7C C� g . �> Building Permit No. 6) L/ L'S`ingle Family ❑ Multi -Family (No. of Units ) ❑ Commercial ❑ Public aN Invasion into City Right -of -Way:'®" No ❑ Yes RW Construction Permit No. Cross other Private Property: Er —No ❑ Yes Attach legal description and copy of recorded easement I certify that I have read and shall comply with all city requirements as indicated on the back of the Permit Card. Date * CALL DIAL -A -DIG (1-800-424-5555) BEFORE ANY EXCAVATION ** PERMIT MUST BE POSTED ON JOB SITE ** White Copy: File Green Copy: Inspector- Buff Copy: Applicant Revised 3'90 4- -z RON 12 0 eo n. %I — - "%...z-0 cbc_•w o M 0 d d 0 z z 0 z q 0 z 94, a cD cD cD v co 17311-135th Avenue NE, A-500 Woodinville, WA 98072 (425) 486-1669 • Fax 481-2510 November 24, 1997 City of Edmonds Planning Department 250 — 5th Avenue Edmonds, Washington 98020 Supplemental Letter Four Lot Short Plat Edmonds, Washington NCA File No. 178096 Dear Sirs: NELSON-COUVRETTE & ASSOCIATES, INC. CONSULTING GEOTECHNICAL ENGINEERS, GEOLOGISTS AND ENVIRONMENTAL SCIENTISTS Snohomish County (425) 337-1669 Wenatchee/Chelan (509) 784-2756 Fr l�,' f t KA.tiv'Y This is a supplemental letter to our preliminary geological investigation letter for this site, dated July 11, 1996 (NCA File No 178096). The purpose of this letter is to clarify our use of the term "buffer zone" in the Building Setback subsection of our report. We have been requested to provide this clarification by Jeff Vehrs of the Emerald Coast Group. In our report, we recommended a minimum building setback of 10 feet for structures on Lots 3 and 4, to establish a "buffer zone" between dwelling areas and the slope margin. We did not intend the word "buffer" to be used as referenced and defined by the City of Edmonds in their Development Code. We understand that these definitions were provided in the new code which was enacted after our report was prepared. The City of Edmonds defines "buffer" as the area immediately next to and part of a steep slope. The buffer is intended to protect the stability of the slope. A 15-foot setback is required from the edge of the buffer. The topographic map provided corresponds with our field measurements taken at the time of our explorations. The topographic map of the steep slope area shows that the slope the maximum slope Supplemental Letter f Edmonds Short Plat November 24, 1997 NCA File No. 178096 Page 2 inclination is about 58 percent for a total height of 8 to 10 feet. The portion of the slope with an average slope above 40 percent is less than 20 feet in vertical height. Therefore, this slope does not qualify as a steep slope hazard area under the City of Edmonds Code. It is our opinion that a building setback of 10 feet from the toe of the slope is appropriate. This allows for maintenance of the area in the event a slough event occurs. The term "buffer" used in our original report was not intended to be used as defined in the code, but was intended to be used as a setback of the structure from the toe of the slope. In the event that the steep slope hazard is still applied, it is our opinion that moving the buffer onto the slope and having the standard building setback start at the toe of the slope would be appropriate. - We trust this letter provides you with the information you requested and appreciate the opportunity to be of continued service to you on this project. If you have any questions concerning this letter, do not hesitate to call. Sincerely, NELSON-COUVRETTE & ASSOCIATES, INC. Charles P. Couvrette, PE Principal Engineer LMH:CPC:nt Three Copies Submitted NELSON-COUVRETTE & ASSOCIATES, INC. GEOTECHNICAL INVESTIGATION REPORT FOUR LOT SHORT PLAT EDMONDS, WASHINGTON FOR THE CITY OF EDMONDS AND LOVELL-SAUERLAND & ASSOCIATES, INC. C/TV Cp*pY NELSON-COUVRETTE & ASSOCIATES, INC. CONSULTING GEO TECHNICAL ENGINEERS, GEOLOGISTS AND ENVIRONMENTAL SCIENTISTS 17311.135th Avenue NE, A-500 Snohomish County (206) 337.1669 Woodinville, WA 98072 (206) 486.1669 • Fax 481-2510 Wenatchee/Chelan (509) 784.2756 July 11, 1996 City of Edmonds Planning Department 250 - 5th Avenue Edmonds, Washington 98020 Geotechnical Investigation Report Four Lot Short Plat Edmonds, Washington NCA File No. 178096 INTRODUCTION This report presents the results of our geotechnical investigation for the planned LSA/Echelbarger four lot short plat in Edmonds, Washington. The site is located on the south side of Olympic View Drive near the 9200 block. We have been retained to evaluate a critical area and provide recommendations for site development. For our use in preparing this report, we have been provided with a copy of the plans, dated May 1996, prepared by Lovell- Sauerland & Associates, Inc. (LSA). The project will consist of four residential lots that will be accessed along the western property line. The access road will have a few feet of fill with a planned rockery as high as 4 feet on the downhill side. An existing slope will be regraded on the east side of Lot 3. A rockery 4 to 6 feet in height is planned at the base of this slope. The excavated material from the slope regrading will be used as fill to raise the road grades and to fill a low area on the west side of Lots 1 and 2. A steep slope located in the southeast corner of the site is to remain undisturbed. The steep slope will be.within Lots 3 and 4, and we have been requested to provide setbacks from the toe of slope for these lots. Existing structures will be removed from the site during project development. The grading required to develop the lot areas will need to be accomplished during plat development as it incorporates building and roadway areas. .J ' Geotechnical Investigation Report Four Lot Short Plat NCA File No. 178096 July 11, 1996 Page 2 i SCOPE The purpose of this study is to explore the subsurface conditions and to provide recommendations for project development. Specifically, our scope of services includes the following: 1. Review the geologic map for the area. 2. Explore the subsurface conditions with backhoe excavated test pits. 3. Evaluate the ground water conditions. 4. Provide recommendations for site preparation, grading and structural fill. 5. Provide recommendations for foundation design and setbacks from steep slopes. 6. Provide general information for on -site drainage considerations. 7. Prepare a written report to document our findings and recommendations. 3 j SITE CONDITIONS Surface The site is over 1.3 acres in size and has a residence, garage, shed, and fallout shelter. The site is accessed in the middle of the north property line from Olympic View Drive. A couple. of short retaining •' walls and hedges exist along side of the driveway. The site slopes generally to the northwest with a total vertical relief of approximately 50 feet. We measured the slopes on site with a clinometer. These measurements were compared to the site plan provided to us. Our slope angles are similar to the grades shown on the topography map provided to us. A steep slope exists in southeastern portion of the site. The steep slope has angles up to 30 degrees (58 percent) with a. vertical relief of approximately 15 feet. Near the top of the steep slope, the neighboring property owner has been using the area as a garden. Debris has been placed on the steep slope, in the approximate area shown on the site plan, creating a pile approximately 3 to 4 feet in height. A low area exists in the northwest portion of the site. The lowest point is approximately 5 to 6 feet below the road elevation. The area is covered with tall grass. We suspect that the area was previously used as a borrow pit. Vegetation consists of a few large evergreen and deciduous trees with a dense undergrowth in the southern portion of the site. The developed portion of the site is covered with grass, trees and small i j NELSON-COUVRETTE & ASSOCIATES, INC. Geotechnical Investigation Report Four Lot Short Plat j NCA File No. 178096 July 11, 1996 Page 3 i underbrush or shrubs. Tall strands of hedges occur along side the existing driveway. Vegetation on the steep slope consists of brush, bevy vines, and scattered deciduous trees. The trees on the steep slope range up to 22 inches in diameter. Geologic Conditions Landforms within this region comprise a system of glacially sculptured features, which have been exposed by post -glacial erosion. Locally, the terrain of this area is interpreted to have been glacially modified, and to have been placed during the latest glaciation of the Puget Lowland area. Glacial ice is thought to have last occupied the region during the late Pleistocene Epoch, some 11,000 to 13,000 years before present. The latest glacial advance over the area is referred to as the Vashon Stade of the Fraser Glaciation, of which the geologic materials on site are believed composed. The general stratigraphy within this area was observed and found to consist of advance glacial outwash, referred to as Esperance Sand (Qva/Qe). Advance outwash in this area is composed of a dense, fine sand, with trace silt and occasional gravel, which has been overridden and compacted by the weight of the thick glacial ice. The advance sands were observed in all of the test pits. It is not uncommon for more gravelly and/or silty zones to occur in these deposits. Washington by James P. Minard, published by U.S. Geological Survey in 1975, was referenced for the geologic and soil conditions at the site. The soil unit mapped at this site is classified as a Whidbey Formation (Qw), with glacial till (Qvt) and Esperance Sand in the near vicinity.. We did not encounter the Qw or Qvt in the subsurface conditions of the site. The Esperance Sand deposit is the geological unit which commonly lies between the Whidbey and till deposits. Subsurface Conditions The subsurface conditions at the site were explored on June 8, 1996 by excavating ten test pits with .a tire -mounted backhoe. The depths of the backhoe test pits range from 4.0 to 7.5 feet. The approximate locations of the test pits are shown on the Site Plan in Figure 2. A representative from our firm was present during the explorations. He examined the soils and geologic conditions encountered and maintained logs of the test pits. The soils were visually classified in general accordance with the Unified j Soil Classification System, a copy of which is presented as Figure 3. The logs of the test pits are presented in Figures 4 through 6. , NELSON-COUVRETTE & ASSOCIATES, INC. i Geotechnical Investigation Report Four Lot Short Plat NCA File No. 178096 July 11, 1996 Page 4 i Subsurface conditions found on site consist mostly of a fine sand with silt or trace silt that varied from loose at the surface, to medium dense to dense with depth. We have interpreted these soils to be the Esperance Sands. Test Pit 9, located on the east portion of Lot 2, encountered 4 feet of fill. The fill consists of similar native material with some organics and bottles. We also expect localized fills in areas behind structures and/or retaining walls. The site is covered with a thin layer of topsoil. The topsoil ranged up to 0.8 feet in depth. Hydrologic Conditions No obvious evidence of ground water, perched ground water or outcropping ground water along the slopes was observed within this site. The advance outwash is considered fairly permeable and water is expected to infiltrate vertically in the deposit until it encounters a less permeable layer, such as the Whidbey Formation. We do not know the depths of these less permeable layers. The site appears to be well drained with the advance sands. SENSITIVE AREA EVALUATION Seismic Hazard The Puget Sound Region is classified as a Zone 3 by the Uniform Building Code. Seismic considerations for this type of site includes liquefaction potential and attenuation of ground motions by soft soil i deposits. The liquefaction potential is highest for loose sand and silty sand with a high ground water table: The sand deposits at the site below a few feet were at least medium dense or better. These soils have a low potential of liquefaction. Seismically sensitive soft soils were not observed at this site. Erosion Hazard The erosion hazard criteria used for determination of affected areas include soil type, slope gradient, vegetation cover, and ground water conditions. The erosion sensitivity is related to vegetative cover and the specific surface soil types (group classification), which are related to the underlying geologic .soil units. The soils have been classified in accordance with the Soil Conservation Service (SCS) classification system and have been grouped with respect to the corresponding geologic unit. The geologic unit is Esperance Sand which corresponds to the SCS classification of Everett soils. The ' erosion hazard is greatest when the on -site soils have been stripped of vegetation. Provided the surface water flowing over the exposed sandsare properly controlled during construction, and vegetation is re- established after development, we do not expect a significant erosion concern. I NELSON- COU VRETTE & ASSOCIATES, INC. Geotechnical Investigation Report Four Lot Short Plat NCA File No. 178096 July 11, 1996 Page 5 -i Landslide Hazard An evaluation of potential landslide hazard was performed for this site. This evaluation includes soil type, underlying stratigraphy, slope gradient, ground water conditions, and vegetation cover. The soil conditions at the site commonly have high strengths and the slope angles are not excessively steep for these types of soils. We also did not observe any signs of instability such as shallow or deep-seated failures. Accordingly, it is our opinion that the native site slopes are stable and large scale failures are not expected.. Localized slough events may occur in the steep portions depending on the area specific conditions. These would be expected to be shallow, involving the near -surface soils. The garden debris placed on the top of the steep slope is considered unstable may cause shallow sloughs of the steep slope. CONCLUSIONS AND RECOMMENDATIONS General The site is suitable for the planned residential short plat. The underlying sand deposits have moderately high strength, and the existing slopes are considered stable with respect to deep-seated landslides or failures. Surficial sloughing and erosion can occur, however, we did not observe evidence of slope failures. The risk of these sloughs can be minimized by maintaining vegetation on the slopes and controlling any surface water that may exist. We consider that minimum setbacks from the toe of slope are considered appropriate to reduce the risk of future effects from surface sloughing. The outwash sand deposits should provide a good subgrade for support of the structure's foundations. { The soil to be used as structural fill will be obtained from the east side of Lots 1, 2 and 3. Excavating these soils to be used as fill, will cause a portion of the trees and the existing structures to be removed during the initial development activities. The fill soil will be placed in the roadway area and also the low depression on the west side of Lot 1. Building Setbacks Uncertainties related to building along steep slopes are typically addressed by the use of building setbacks. The purpose of the setback is to establish a "buffer zone" between the dwelling areas and the slope margin so that ample room is allowed for normal slope regression, or if a slope failure were to occur, the likelihood of dwelling involvement would be minimized. In a general sense, the greater the setback, the lower the risk. From a geological standpoint, the setback dimension is usually based on the slope's physical characteristics, e.g., slope height, surface angle, material composition, hydrology, etc. Other factors such as historical slope activity, rate of regression, type, and desired life span of the development are important considerations as well. :I NELSON-COUVRETTE & ASSOCIATES, INC. .S i r (` Geotechnical Investigation Report Four Lot Short Plat j NCA File No. 178096 i July 11, 1996 Page 6 Based upon our explorations, slope evaluation and observations, we recommend a minimum building setback of 10 feet for structures on Lots 3 and 4. Setbacks are not necessary on the other lots from the toe of the steep slope. Specifically, we recommend that the setback area not be used for placement or storage of fill materials, including "temporary" excavation spoils from building area preparation and excavation. The landscape debris on the upper portion of the steep slope should be removed.. The area should be re-established with vegetation if the soil is exposed. Any development or encroachment into the setback areas should be evaluated by a specific geotechnical evaluation and report. Site Preparation and Grading Site preparation and grading should consist of stripping the vegetation and topsoil layer to the planned subgrade. The exposed surface should be compacted to a non -yielding condition using a steel -drum vibratory compactor. The subgrade should be observed for indication of disturbance of the lower soils both during excavation and compaction. If the subgrade shows signs of disturbance, we should be retained to provide recommendations for repair or potentially alternate construction techniques. The on -site soil is expected to be only somewhat moisture sensitive with a uniform grain size, and may be difficult to work and compact during periods of wet weather. Earthwork should be suspended during rainfall and for a period of time afterward. The actual ability to work the site during the wet time of the year will be dependent on the performance of the soils under load when wet. These conditions should be observed and the site work adjusted accordingly. We recommend that all soil stock piles that are intended to be used as backfill be covered with plastic during rainy weather to help maintain a moisture content suitable for compaction. Sometimes a layer of crushed gravel or 2- to 4-inch spalls is used to provide wet season access and to improve pavement and foundation subgrade. The use of the gravel and spalls should be based on conditions observed in the field. Excavation Slopes Temporary slopes greater than 4 feet in height should be sloped at an inclination no steeper than 1.5H:1V for the loose to medium dense sands, and 1H:1V for dense sands for cuts up to 12 feet in height. These slopes should be protected from rain by well secured plastic sheeting. If ground water or seepage is encountered, we should be retained to comment on the stability of the slopes in the excavation. The above cut slope angles should be considered preliminary in nature. The contractor should be ultimately responsible for the stability of the cut slopes, as he is continuously at the site and can observe the performance on a daily basis. All state and federal standards should be followed with respect to cut slopes and workman safety. NELSON-COUVRETTE & ASSOCIATES, INC. a ' Geotechnical Investigation Report Four Lot Short Plat NCA File No. 178096 July 11, 1996 Page 7 Structural Fill General: Fill will be placed with the current design. Fill to be placed beneath buildings, pavements or other settlement sensitive features, should be placed as structural. fill. Structural fill, by definition, is soil placed in`accordance with prescribed methods and standards described in this report, and is monitored by an experienced geotechnical professional or soils technician. Field monitoring procedures would include a representative number of in -place density tests to document the attainment of the desired degree of relative compaction. Materials: Imported structural fill should consist of a good quality free draining granular soil, free of organic and other deleterious material, and be well graded to a maximum size of about 3 inches. Imported all weather fill should contain no more than about 5 percent fines (soil finer than a U.S. No. 200 sieve) based on that fraction passing the U.S. 3/4-inch sieve. The on -site outwash soil can be used as structural fill but these soils contain some fine-grained particles and are considered slightly moisture sensitive. The use of the soils as fill should be limited to extended periods of dry weather. These soils have a uniform grain size and are sometimes more difficult to compact than well graded soils. Depending on the moisture content of the soil, adding water may be necessary to achieve compaction. Soils with a high organic content should not be used as structural fill. Fill Placement: Following subgrade preparation, placement of the structural fill may proceed. All backfilling should be accomplished in 8- to 10-inch thick uniform lifts. Each lift should be spread evenly 5 and be thoroughly compacted prior to placement of subsequent lifts. All structural fill underlying building areas, and within 2 feet of pavement subgrade, should be compacted to a minimum of 95 percent of its maximum dry density. Maximum dry density in this report refers to that density as determined by the ASTM D 1557 compaction test procedure. Fills more than 2 feet beneath sidewalks and pavement subgrades should be compacted to at least 90 percent of their maximum dry density. The moisture content of the soils to be compacted should be within about 2 percent of optimum, so that a readily compactable condition exists. It may be necessary to overexcavate and remove wet soils in cases where drying to a compactable condition is not feasible. All compaction should be accomplished by equipment of a type and size sufficient to attain the desired degree of compaction. Care should be taken when compacting the soil condition near to adjacent houses. A photo documented survey of the neighboring structures is suggested prior to any heavy equipment arriving at the site. Sometimes the use of smaller compaction equipment and thinner lifts is better if adjacent structures are being impacted. NELSON-COUVRETTE & ASSOCIATES, INC. Geotechnical Investigation Report Four Lot Short Plat NCA File No. 178096 July 11, 1996 Page 8 Foundations The foundations should be placed either on undisturbed medium dense or dense native sand or structural fill extending to these soils. If footings are to bear on structural fill, the fill zone should extend outside of the footing a distance equal to the depth of fill beneath the footing. The soil conditions should be evaluated for appropriate density and disturbance at the time of construction. Exterior footings should extend a minimum of 18. inches below the adjacent outside ground surface, with interior column footings a minimum of 12 inches below the bottom of the adjacent slab. All loose or disturbed soil should be removed from the foundation excavation prior to placing concrete. Standing water should not be allowed to accumulate in the building pad or footing trenches. For foundations constructed as outlined above, we recommend an allowable design bearing pressure of not more than 2,500 pounds per square foot-(psf) be used. Higher bearing values may be available based on specific soil conditions, footing size and settlement tolerance. This can be reviewed at the time that the structure is designed and foundation loads are determined. A .one-third increase in the above allowable bearing pressure may be used when considering short-term transitory wind or seismic loads. Although structural loading information was not available at the time of this study, based on our experience with similar structures supported on similar soil conditions and for the above allowable soil bearing pressures, we estimate that the maximum total post -construction settlement for medium dense sands should be 3/4 of an inch or less, and that the differential settlement across the building width should be 1/2 inch or less. We expect larger differential settlements may occur if the building is constructed part on fill and part on native soils. Lateral Pressures The lateral pressure acting on retaining walls is dependent on the nature and density of the soil behind the wall, the amount of lateral wall movement which can occur as backfill is placed and the inclination of the backfill. Soil pressures will be less for walls that are free to yield at the top at least one -thousandth of the height of the wall, than if movement is limited by such factors as wall stiffness or bracing. We recommend that yielding walls supporting horizontal backfill be .designed using an equivalent fluid density of 35 pounds per cubic foot (pcf). Non -yielding walls should be designed using an equivalent fluid density of 50 pcf. These lateral soil pressures do not include the effects of surcharges such as traffic loads or other surcharge loads. Surcharge effects should be considered, if appropriate. If desired, we can provide recommendations for surcharge loads as they become apparent. NELSON-COUVRETTE & ASSOCIATES, INC. Geotechnical Investigation Report Four Lot Short Plat NCA File No. 178096 July 11, 1996 Page 9 All backfill for subgrade walls that will, not act as structural fill should be compacted to between 90 and 92 percent of the maximum dry density as determined in accordance with ASTM D 1557. Care should be taken to prevent the buildup of excess lateral soil pressures due to overcompaction of the backfill behind the wall. This can be accomplished by placing the backfill within 18 to 24 inches of the wall in lifts not exceeding 8 inches in loose thickness, and compacting this zone with hand -operated vibrating plate compactors. Lateral loads can be resisted by friction between the foundation and subgrade or the passive earth pressure acting on the below -grade foundation. For the latter, the foundation must be placed "neat" against the undisturbed soil, or backfilled with a clean, free draining, compacted structural fill. We recommend that lateral passive resistance be calculated by using an equivalent fluid weight of 250 pcf. An allowable coefficient of'friction between footings and the subgrade of 0.40 may be used. These values include a factor of safety of 2.0 for lateral resistance and 1.5 for the coefficient of friction. The wall pressures, listed above, are based on the assumption that the soil directly behind the wall is free draining or a drainage composite is used. All of the on -site surface soils are not free draining. Some free draining soil may exist at depth. Wall drains are discussed in the Subsurface Drainage sub -section of this report. Site Drainage Surface Drainage: The finished ground surface should be graded such that storm water is directed off of the site. Water should not be allowed to stand in any area where footings, slabs or pavements are to be constructed. Final site grades should allow for drainage away from the building. We suggest that the finished ground be sloped at a gradient of 3 percent minimum for a distance of at least 10 feet away from the building. Surface water should be collected by permanent catch basins and drain lines, and be discharged into a storm drain system. The surficial soils are loose to medium dense, fine sand. These soil types erode easily, especially when directly exposed to precipitation and runoff. Surface water should be diverted away from the steep to moderate slopes. Stripped areas should be revegetated to improve the stability of the near -surface slope soils. The vegetation should be maintained until it is established. Subsurface Drainage: Where slabs are located below the surrounding grades, a system of perimeter footing drains should be included in the design. The perimeter footing drains should consist of 4-inch diameter perforated smooth -walled PVC pipe surrounded by pea gravel. The footing drains should. be NELSON-COUVRETTE & ASSOCIATES, INC. Geotechnical Investigation Report Four Lot Short Plat j NCA File No..178096 i July 11, 1996 Page 10 1 . located at the elevation of the footing. The drains should be tightlined to the storm drain system. We do not consider foundation drains necessary for standard foundations construction. A drainage system should be planned behind all retaining walls. The drainage system should consist of an 18-inch wide blanket of free draining material. Pea gravel would be a suitable material. If 0.5-inch or larger washed rock is used, filter fabric may be required ,to surround the rock. A drainage composite approved by geotechnical engineer could be used in place of the rock blanket. A 4-inch diameter perforated pipe should be placed along the base of the wall within the free draining material. The drains should be routed to an appropriate discharge point. Slabs -on -Grade Slabs should be supported on native subgrade soils or structural fill prepared as described in the Site Preparation and Grading and Structural Fill sub -sections of this report. Where moisture control is important, we recommend that the floor slabs be underlain by 6 inches of free draining granular material, for use as a capillary break. A suitable vapor barrier, such as heavy plastic sheeting, should be placed over the capillary break material. A 2-inch thick sand blanket may be placed over the vapor barrier to protect it during placement of the concrete and to help the concrete cure. Rockeries Rockeries are used in the Puget Sound region to face stable soil exposures to reduce weathering and slough type failures. Although it is not always common to consider a rockery as a retaining wall, in reality, the rockery can act as a gravity wall. The problems associated with using the rockery as a retaining wall is the quality of the rockery construction and the compacted backfill. There is some risk associated with rockeries since the rocks are not tied together. Therefore, the methods in which they are stacked are very important. Rockeries should be designed and constructed in accordance with Association of Rockery Contractors (ARC) guidelines, unless otherwise recommended in this report. Inspection of the rockery construction by the geotechnical consultant is recommended. We consider the rockery at the base of the cut slope to be appropriate. However, we recommend that the rock sizes be increased to H/2 instead of the H/3 as recommended in the ARC manual. We recommend that the same standards be used for the rockery that retains the driveway fill. However, since the wall could be exposed to unknown wheel and traffic loads, it may be prudent to design it as a reinforced soil wall. The reinforcement could consist of either fabric or geogrid. NELSON-COUVRETTE & ASSOCIATES, INC. Geotechnical Investigation Report Four Lot Short Plat 1 NCA File No. 178096 July 11, 1996 Page 11 USE OF THIS REPORT We have prepared this report for The City of Edmonds, Lovell- Sauerland & Associates, Inc. and their agents, for use in planning and design of this project. The data and report should be provided to prospective contractors for their bidding or estimating purposes, but our report, conclusions and interpretations should not be construed as a warranty of the subsurface conditions. The scope of our services 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 consideration in design. There are possible variations in subsurface conditions between the explorations and also with time. A contingency for unanticipated conditions should be included in the budget and schedule. We should be retained to provide monitoring and consultation services during construction to confirm that 'the conditions encountered are consistent with those indicated by the explorations, to provide recommendations for design changes should the conditions revealed during the work differ from those anticipated, and to evaluate whether or not earthwork and foundation installation activities comply with contract plans and specifications. Within the limitations of scope, schedule and budget for our services, we have strived to take care that our work has been completed in accordance with generally accepted practices followed in this area at the time this report was prepared. No other conditions, expressed or implied, should be understood. NELSON-COUVRETTE & ASSOCIATES, INC. Geotechnical Investigation Report Four Lot Short Plat NCA File No. 178096 July 11, 1996 Page 12 We appreciate the opportunity to be of service to you. If there are any questions concerning this report or if we can provide additional services, please call. Sincerely, NELSON-COUVRETTE & ASSOCIATES, INC. C3L� Rick B: Powell, PE Project Engineer EXPIRES to •l�• mot$ Charles P. Couvrette, PE. Principal Engineer Three Copies Submitted Six Figures cc: Mr. Jurgen Sauerland - Love ll-Sauerland & Associates, Inc. NELSON-COUVRETTE & ASSOCIATES, INC. LOG OF EXPLORATION DEPTH USC SOIL DESCRIPTION TEST PIT ONE 0.0 - 1.3 SM DARK BROWN SILTY FINE SAND WITH ORGANICS (LOOSE TO MEDIUM DENSE, WET) (TOPSOIL) 1.3 - 4.0 SP-SM RED -BROWN FINE SAND WITH SILT (MEDIUM DENSE, MOIST) (WEATHERED Qva) 4.0 - 6.5 SP-SM GRAY -BROWN FINE SAND WITH SILT (MEDIUM DENSE TO DENSE, MOIST TO WET) (Qva) SAMPLE WAS COLLECTED AT 6.0 FEET GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 6.5 FEET ON 6/15/96 TEST PIT TWO 0.0 - 0.4 SM DARK BROWN SILTY FINE SAND WITH SOME ORGANICS (LOOSE TO MEDIUM DENSE, WET) 0.4 - 4.0 SP-SM GRAY -BROWN FINE SAND WITH SILT AND ORGANICS (MEDIUM DENSE, MOIST TO WET) (Qva) SAMPLES WERE NOT COLLECTED GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 4.0 FEET ON 6/15/96 TEST PIT THREE 0.0 - 0.2 TOPSOIL 0.2 - 2.0 SP LIGHT BROWN FINE SAND (MEDIUM DENSE TO DENSE, MOIST) IFILLI 2.0 - 3.5 SP-SM/SM BROWN TO DARK BROWN FINE SAND WITH SILT TO SILTY FINE SAND (LOOSE TO MEDIUM DENSE, MOIST) (OLD TOPSOIL) 3.5 - 5.0 SP LIGHT BROWN FINE SAND (MEDIUM DENSE TO DENSE, MOIST TO WET) (Qva) SAMPLES WERE NOT COLLECTED GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 5.0 FEET ON 6115/96 TEST PIT FOUR 0.0 - 0.2 TOPSOIL 0.2 - 2.0 SP-SM BROWN TO DARK BROWN FINE SAND WITH SILT AND SOME ORGANICS (MEDIUM DENSE, MOIST) (TOPSOIUQva) 2.0 - 4.0 SP LIGHT BROWN TO BROWN FINE SAND (MEDIUM DENSE, MOIST) (Qva) SAMPLES WERE COLLECTED AT 1.5 AND 4.0 FEET GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 4.0 FEET ON 6/15/96 NELSON-COUVRETTE & ASSOCIATES, INC. FILE NO. 178096 FIGURE 4 ;Q (D (D D 0 (D OL (n 60 C, 0 J OL 0 0 (D OL CT 0 a (D r- Z 0 C: 0 >, m 5;u M z 0g z 50 0 --I > m -U Z 0 X En U) cc) m 1-01 0 O nn ; j - 3-i m 0 O O or 'I* SOIL CLASSIFICATION SYSTEM GROUP MAJOR DIVISIONS SYMBOL GROUP NAME COARSE GRAVEL CLEAN GRAVEL GW WELL -GRADED GRAVEL, FINE TO COARSE GRAVEL GRAVEL GP POORLY -GRADED GRAVEL GRAINED SOILS MORE THAN50%OFCOARSE FRACTION RETAINED ON WITH FINES GM SILTY GRAVEL NO., SIEVE GC CLAYEY GRAVEL MORE THAN sm RETAINED ON NO.2W SIEVE SAND CLEAN SAND SW WELL -GRADED SAND, FINE TO COARSE SAND SP POORLY -GRADED SAND MORE THAN s0% OF COARSE FRACTION PASSES NO.4 SIEVE SAND SM SILTY SAND SC CLAYEY SAND. WITH FINES FINE SILT AND CLAY INORGANIC ML SILT CL CLAY GRAINED LIQUID LJMR LESS THAN 50% ORGANIC OL ORGANIC SILT, ORGANIC CLAY . SOILS SILT AND CLAY INORGANIC MH SILT OF HIGH PLASTICITY, ELASTIC SILT CH CLAY OF HIGH PLASTICITY, FAT CLAY MORE THAN SO% PASSES NO. 2W SIEVE uOUIDuMTT50%ORMORE ORGANIC OH ORGANIC CLAY, ORGANIC SILT HIGHLY ORGANIC SOILS PT PEAT NOTES: SOIL MOISTURE MODIFIERS 1) Field classification is based on Dry- Absence of moisture, dusty, dry visual examination of soil in general to the touch accordance with ASTM D 2488 - 83. Moist - Damp, but no visible water 2) Soil classification using laboratory tests is based on ASTM D 2487 - 83. Wet - Visible free water or saturated, usually soil is obtained from 3) Descriptions of soil density or below water table consistency are based on Interpretation of blowcount data, visual appearance, of soils, and/or test data. NELSON- COUVRETTE&ASSOCIATES, INC. SOIL CLASSIFICATION SYSTEM CONSULTING ENGINEERS, GEOLOGISTS GEOTECIHNICAL AND ENVIRONMENTAL SCIENTISTS FIGURE 3 LOG OF EXPLORATION DEPTH USC SOIL DESCRIPTION TEST PIT ONE 0.0 -1.3 SM DARK BROWN SILTY FINE SAND WITH ORGANICS (LOOSE TO MEDIUM DENSE, WET) (TOPSOIL) 1.3 - 4.0 SP-SM RED -BROWN FINE SAND WITH SILT (MEDIUM DENSE, MOIST) (WEATHERED Ova) 4.0 - 6.5 SP-SM GRAY -BROWN FINE SAND WITH SILT (MEDIUM DENSE TO DENSE, MOIST TO WET) (Ova) SAMPLE WAS COLLECTED AT 6.0 FEET GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 6.5 FEET ON 6/15/96 TEST PIT TWO 0.0 - 0.4 SM DARK BROWN SILTY FINE SAND WITH SOME ORGANICS (LOOSE TO MEDIUM DENSE, WET) 0.4 - 4.0 SP-SM GRAY -BROWN FINE SAND WITH SILT AND ORGANICS (MEDIUM DENSE, MOIST TO WET) (Ova) SAMPLES WERE NOT COLLECTED GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 4.0 FEET ON 6/15/96 TEST PIT THREE 0.0 - 0.2 TOPSOIL 0.2 - 2.0 SP LIGHT BROWN FINE SAND (MEDIUM DENSE TO DENSE, MOIST) (FILL) 2.0 - 3.5 SP-SM/SM BROWN TO DARK BROWN FINE SAND WITH SILT TO SILTY FINE SAND (LOOSE TO MEDIUM DENSE, MOIST) (OLD TOPSOIL) 3.5 - 5.0 SP LIGHT BROWN FINE SAND (MEDIUM DENSE TO DENSE, MOIST TO WET) (Ova) SAMPLES WERE NOT COLLECTED GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 5.0 FEET ON 6/15/96 TEST PIT FOUR 0.0 - 0.2 TOPSOIL 0.2 - 2.0 SP-SM BROWN TO DARK BROWN FINE SAND WITH SILT AND SOME ORGANICS (MEDIUM DENSE, MOIST) (TOPSOIL/Qva) 2.0 - 4.0 SP LIGHT BROWN TO BROWN FINE SAND (MEDIUM DENSE, MOIST) (Ova) SAMPLES WERE COLLECTED AT 1.5 AND 4.0 FEET GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 4.0 FEET ON 6/15/96 NELSON-COUVRETTE & ASSOCIATES, INC. FILE NO. 178096 FIGURE 4 LOG OF EXPLORATION DEPTH USC SOIL DESCRIPTION TEST PIT FIVE 0.0 - 0.4 0.4 - 4.0 TEST PIT SIX 0.0 - 0.5 0.5 - 4.0 TEST PIT SEVEN 0.0 - 0.5 0.5 - 2.0 2.0 - 7.5 TEST PIT EIGHT 0.0 - 0.4 0.4 - 3.0 3.0 - 5.5 TOPSOIL SP LIGHT BROWN WITH SLIGHT RUST STAINING FINE SAND WITH TRACE SILT (MEDIUM DENSE TO DENSE, MOIST) (Qva) SAMPLES WERE NOT COLLECTED GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 4.0 FEET ON 6/15/96 TOPSOIL SP-SM LIGHT BROWN TO BROWN FINE SAND WITH SILT (MEDIUM DENSE TO DENSE, MOIST TO WET) (Qva) SAMPLES WERE COLLECTED FROM 3.0 - 4.0 FEET GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 4.0 FEET ON 6/15/96 TOPSOIL SP-SM/SM BROWN TO RED -BROWN FINE SAND WITH SILT TO SILTY FINE SAND (MEDIUM DENSE, MOIST) (WEATHERED Qva) SP LIGHT BROWN TO BROWN FINE SAND WITH TRACE SILT (MEDIUM DENSE TO DENSE, MOIST) (Qva) SAMPLE WAS COLLECTED AT 6.0 FEET GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 7.5 FEET ON 6/15196 TOPSOIL SP-SM TAN -BROWN FINE SAND WITH SILT (MEDIUM DENSE, MOIST TO WET) (WEATHERED Qva) SP-SM GRAY -BROWN FINE TO MEDIUM SAND WITH SILT (MEDIUM DENSE TO DENSE, MOIST TO WET) (Qva) SAMPLES WERE COLLECTED FROM 4.0 - 5.0 FEET GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 5.5 FEET ON 6/15/96 NELSON-COUVRETTE & ASSOCIATES, INC. FILE NO. 178096 FIGURE 5 LOG OF EXPLORATION 1 DEPTH USC SOIL DESCRIPTION i TEST PIT NINE 0.0 - 0.7 TOPSOIL 0.7 - 4.0 SM/SP-SM BROWN TO DARK BROWN SILTY FINE SAND TO FINE SAND WITH SILT, ORGANICS AND A BOTTLE (LOOSE, MOIST) LMU 4.0 - 5.0 SP-SM BROWN FINE SAND WITH SILT (MEDIUM DENSE, MOIST) (Qva) SAMPLES WERE NOT COLLECTED GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS. COMPLETED AT 5.0 FEET ON 6/15/96 TEST PIT TEN 0.0 - 0.8 TOPSOIL 0.8 - 4.0 SP-SM RED -BROWN TO LIGHT BROWN FINE SAND WITH SILT AND OCCASIONAL COBBLES (MEDIUM DENSE TO DENSE, MOIST TO WET) (Qva) SAMPLES WERE NOT COLLECTED GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 4.0 FEET ON 6/15/96 NELSON-COUVRETTE & ASSOCIATES, INC. FILE NO. 178096 FIGURE 6 9�2o;2 o,z V. Vvie, rAO 4.01 rs 7-X7,e%,Al 1�5 aeiz S//0 /�7— 7- 5-9 5 - P-o ,P- er -' _ FrLL s ag &Ae. F7" e.N. Yas. - ' � Co•viNG" — N��(Qo�1.%Uf � NT L=.tiE SG. IeUt� LZNF� gullbot TAR = 1"- WS CITY C-Qpy. 05 06 98 12:42 FAX 1-425-481-6149 BDZ DEVELOPERS .-.. LSA Z 01 Sky Valley P.O. Box 835 Monroe, WA. 98272 Testing (360) 794-4555 (206) 788-6600 December 4, 1996 DEC 1 0 1996 Project No. 6854 BDZ Developers, Inc. 19400 33rd Ave W, suite 200 Lynnwood, Wa. 98036 Reference: Olympic View S.P. 92 Ave W. & Olympic view Dr. Edmonds, Wa. To Whom It May Concern: The Above referenced site was monitored by observing fill placement arid the taking of density tests as fill was placed and compacted. These were taken in the fill area located in the west portion of lots 1 & 2. Results are enclosed along with (proctor) maximum density. we trust this information is of value and if you have any questions please call. incere� Jerry Boyd Soil Consultant SKY VALLEY TESTING P. O. Box 835 Monroe, WA 98212 (360) 7944555 (206) 788-6600 DAILY FIELD REPORT Soils tab — Drainfleld Design TRAVEUPREP. TrhfE / Q JOB No. f J fiSW� G� Tims ON srrE LAMES MMOFF SrrE FAGS OF WEATHER P �Guoy �v��a VISrTORS CLMWT/OWNER REPORT SEO. NO. rw� mm s�r�rs�r��►rr��i�� ftw� rrwwrw��r��r ww��r■►w�■r�.rAo s�Mrlrrrar+w��a� ■�r�r��t`�www �rr��rN►rr•�� 05/ 0 6.,,98 12: 4 2 FAX 1-425-481-6146 BDZ . DtVELO , PtRS ... LSA SKY VALLEY TESTING TRAVEUPRIEF, TrME JOB NO. P. 0. Box 835 VRE ON srm MILES Monroe, WA 98272 (360) 7944555 (206) 788-6600. TDAE OFF ME PAGE OF DAILY FIELD REPORT WEATHER 4�0057 VISITORs CUUNT/OwKER REPORT SEQ- NO. Z02 Joe 0011,lvvox JOB LOCATION nAY OF WEEK CONTRACTOR 64) z FOREMAN J IRS. CIIARGED Test Point No. Location Fill Depth Ft. Elev. Ft. Moisture Content % Dry Dre-rasity Pd Max. Dry Density PCf 17,Z-5 Percent Compaction 17 7— Z 0 4r- -)ILZ?. 12-v -7-J M�7 &-e ,44 M457 '01'aF /Or /xz- J*Zso 05, 06. 98 12: 42 FAX 1=425-481-6149 BDZ DE17ELOPERS 444 LSA Z 03 SKY VALLEY TESTING TRAVIIJPREP.TIAS / d JOB No. P. O. Box 835 Monroe, WA 98272 r TIME ON SffE Z J � MRES (360) 794-4555 (206) 788-6600 T EOFFSrM PAGE OF DAILY FIELD PORT' WEATHER PW7ZZJ eZ4W /Sy/i�,VY VISITORS CLIENT/OWNER REPORT SEQ. NO. OB JD6-/ TION JOHZpTf�G iIli aw 04 J)ATE I1�(/f� I I DAYWEEK I CONTRACTOR FOREMAN HRS. CHARGED Test Location Fill Elev. Moisture Dry Max. Dry Percent Point Depth Ft, Content. Density Density Compaction No. Ft. % pcf pcf 13 1`/ �5�-- /3: zr / 7 /02-5 96 NOTES: 9L E M6—f 41 7h�73�� 'maw - f89a.-19�0 City of Edmonds t +� ;r ,y DEC 7 1995 a : PERMIT COUNTER - .Y� J Critical Areas Checklist The Critical Areas Checklist contained on and submit.] KWilie"City. The City will this form is to be filled out by- any person , review the checklist, make a precursory site ' ... preparing a Development Permit • -visit, and make a determination of the Application for the City of Edmonds prior..;;; .: `" . subsequent steps necessary to complete_ a_ to his/her submittal of a development,; `..,:-:f development permit application. permit to the City. Arth a signed copy.,of this form; the - The purpose of the Checklist is to. enable applicant should also submit a vicinity map City staff to determine -whether any - • -- ----- or plot -plan for individual lots ofthe•par+cel potential Critical Areas are or may be•with enough detail that City staff can find- present on the subject property: The ::and identify the subject pareel(s).i,7 information needed to complete the r ty ad&don, the applicant shall include Checklist should be easily available.froiii'•;` - other pertinent information (e.g. site,:`:":; - observations of the site or data available at _ . •.: . P1ax4 topography map, etc.):ur studies. • s'm l City Hall (Critical Areas inventories; maps, •' cogjunction with this Checkl stio assist or soil surveys). :�;:A� staff in completing their preliminary.. '. y,• assessment of the site. An applicant, or his/her" representative, must fill out the checklist, sign and date it, I have completed the attached Critical Area Checklist and attest that the answers provided are factual, to th4est of my knowledge (fill out the appropriate column below). -^ - Owner / Applicant: Applicant Representative: N. V� Cu tJN b w 6 O&M Cv Name Name `t2c° w R 61 Street Address ' Street Address 11T City, State, ZIP City, State, ZIP ti,. {� p ty �Phoae c.�, Z b 95 s� 9,Sta• Signature Date Signature Date _ i ,�, h }. x i`>� •!31 f � err sz � 1, i � 2 +ti Ft;d��J m.A7h y, ; ��,pa:�. . c.•,' S t}�Jr4M.Y .ry, 4 •S'�� It i L�ti�tt ,�, i � �a;t t� �' F^�'f-�'�p y�C , •(..r �, 'r •. �f' 't L� h .Y $ CA FILE NO.�5�� Critical Areas Checklist Site Information`(soils/topography/hydrology/vegetation) 1. Site Address/Location: 9.20H 01 wto lc- -Tw► o 2. Property Tax Account Number: 5 10 ' ba - O (5 - U 00% S'r `S� �0O b" oa 3. Approximate Site Size (acres or square feet): ' S 9 oca o s J�4 a 1(,00c, CS,�S.E,- Oct -0J3 -V 4. Is this site currently developed? K yes; no.R ` If yes; how is site developed? < % vw e ' C 4 R-es c e 5. Describe the general site topography. Check all that apply. Flat: less than 5-feet elevation change over entire site. _. Rolling: slopeFon site generally less than 15% (a vertical rise of 10-feet over a horizontal distance of 66-feet). Hilly: slopes present on site of more than 15% and less than 30% ( a vertical rise of 10-feet over a horizontal distance of 33 to 66-feet). Steep: grades of greater than 30% present on site (a vertical rise of 10-feet over a horizontal distance of less than 33-feet). Other (please describe): 6. Site contains areas of year-round standing water: VL0IN ; Approx. Depth: 7. Site contains areas of seasonal standing water. 110"C ; Approx. Depth: What season(s) of the year? �1 a 8. Site is in the floodway nd floodplain ✓W of a water course. 9. Site contains a creek or an area where water flows across the grounds surface? Flows are year- round? h o.% Flows are seasonal? 41:5_ (What time of year? A . ). 10. Site is primarily: forested ; meadow ; shrubs ; mixed urban. landscaped (lawn,shrubs etc) )C 11. Obvious wetland is present on site: no t4@. R"0004% ti 9�2 D ;2 4�0100vN G- e-7— Sr'a G�,ET-,�,vrrry�cl SA5 T7�! -t/i = //, Ad S B0. G1�3�9'q°v ' M Y _ Fri_7T-=0u 7, V-P - - ----- 1 FILL_ NT L�tiE. �UILDIN� MAR - � 1998 GEOTECHNICAL INVESTIGATION REPORT FOUR LOT SHORT PLAT EDMONDS, WASHINGTON FOR THE CITY OF EDMONDS AND LOVELL-SAUERLAND & ASSOCIATES, INC. STREET FILE I NELSON-COUVRETTE & ASSOCIATES, INC. CONSULTING GEOTECHNICAL ENGINEERS, GEOLOGISTS AND ENVIRONMENTAL SCIENTISTS 17311.135th Avenue NE, A-500 Woodinville, WA 98072 (206) 486-1669 • Fax 481.2510 July 11, 1996 City of Edmonds Planning Department 250 - 5th Avenue Edmonds, Washington 98020 Geotechnical Investigation Report Four Lot Short Plat Edmonds, Washington NCA File No. 178096 Snohomish County (206) 337.1669 Wenatchee/Chelan (509) 784.2756 INTRODUCTION This report presents the results of our geotechnical investigation for the planned LSA/Echelbarger four lot short plat in Edmonds, Washington. The site is located on the south side of Olympic View Drive near the 9200 block. We have been retained to evaluate a critical area and provide recommendations for site development. For our use in preparing this report, we have been provided with a copy of the plans, dated May 1996, prepared by Lovell-Sauerland & Associates, Inc. (LSA). The project will consist of four residential lots that will be accessed along the western property line. The access road will have a few feet of fill with a planned rockery as high as 4 feet on the downhill side. An existing slope will be regraded on the east side of Lot 3. A rockery 4 to 6 feet in height is planned at the base of this slope. The excavated material from the slope regrading will be used as fill to raise the road grades and to fill a low area on the west side of Lots 1 and 2. A steep slope located in the southeast corner of the site is to remain undisturbed. The steep slope will be .within Lots 3 and 4, and we have been requested to provide setbacks from the toe of slope for these lots. Existing structures will be removed from the site during project development. The grading required to develop the lot areas will need to be accomplished during plat development as it incorporates building and roadway areas. ' Geotechnical Investigation Report Four Lot Short Plat NCA File No. 178096 July 11, 1996 Page 2 SCOPE The purpose of this study is to explore the subsurface conditions and to provide recommendations for project development. Specifically, our scope of services includes the following: 1. Review the geologic map for the area. 2. Explore the subsurface conditions with backhoe excavated test pits. 3. Evaluate the ground water conditions. 4. Provide recommendations for site preparation, grading and structural fill. 5. Provide recommendations for foundation design and setbacks from steep slopes. 6. Provide general information for on -site drainage considerations. 7. Prepare a written report to document our findings and recommendations. 1 j SITE CONDITIONS Surface The site is over 1.3 acres in size and has a residence, garage, shed, and fallout shelter. The site is accessed in the middle of the north property line from Olympic View Drive. A couple of short retaining walls and hedges exist along side of the driveway. The site slopes generally to the northwest with a total vertical relief of approximately 50 feet. We measured the slopes on site with a clinometer. These measurements were compared to the site plan provided to us. Our slope angles are similar to the grades shown on the topography map provided to us. A steep slope exists in southeastern portion of the site. The steep slope has angles up to 30 degrees (58 percent) with a vertical relief of approximately J 5 feet. Near the top of the steep slope, the neighboring property owner has been using the area as a garden. Debris has been placed on the steep slope, in the approximate area shown on the site plan, creating a pile approximately 3 to 4 feet in height. A low area exists in the northwest portion of the site. The lowest point is approximately 5 to 6 feet below the road elevation. The area is covered with tall grass. We suspect that the area was previously used as a borrow pit. Vegetation consists of a few large evergreen and deciduous trees with a dense undergrowth in the southern portion of the site. The developed portion of the site is covered with grass, trees and small 3 NELSON-COUVRETTE & ASSOCIATES, INC. Geotechnical Investigation Report Four Lot Short Plat NCA File No. 178096 July 11, 1996 Page 3 underbrush or shrubs. Tall strands of hedges occur alongside the existing driveway. Vegetation on the steep slope consists of brush, bent' vines, and scattered deciduous trees. The trees on the steep slope range up to 22 inches in diameter. Geologic Conditions Landforms within this region comprise a system of glacially sculptured features, which have been exposed by post -glacial erosion. Locally, the terrain of this area is interpreted to have been glacially modified, and to have been placed during the latest glaciation of the Puget Lowland area. Glacial ice is thought to have last occupied the region during the late Pleistocene Epoch, some 11,000 to 13,000 years before present. The latest glacial advance over the area is referred to as the Vashon Stade of the Fraser Glaciation, of which the geologic materials on site are believed composed. The general stratigraphy within this area was observed and found to consist of advance glacial outwash, referred to as Esperance Sand (Qva/Qe). Advance outwash in this area is composed of a dense, fine sand, with trace silt and occasional gravel, which has been overridden and compacted by the weight of the thick glacial ice. The advance sands were observed in all of the test pits. It is not uncommon for more gravelly and/or silty zones to occur in these deposits. The Geologic Map of the Edmonds East and Edmonds West Quadrangle Snohomish and King Counties Washington by James P. Minard, published by U.S. Geological Survey in 1975, was referenced for the geologic and soil conditions at the site. The soil unit mapped at this site is classified as a Whidbey Formation (Qw), with glacial till (Qvt) and Esperance Sand in the near vicinity. We did not encounter F the Qw or Qvt in the subsurface conditions of the site. The Esperance Sand deposit is the geological unit which commonly lies between the Whidbey and till deposits. Subsurface Conditions The subsurface conditions at the site were explored on June 8, 1996 by excavating ten test pits with .a tire -mounted backhoe. The depths of the backhoe test pits range from 4.0 to 7.5 feet. The approximate locations of the test pits are shown on the Site Plan in Figure 2. A representative from our firm was present during the explorations. He examined the soils and geologic conditions encountered and maintained logs of the test pits. The soils were visually classified in general accordance with the Unified i Soil Classification System, a copy of which is presented as Figure 3. The logs of the test pits are presented in Figures 4 through 6. f NELSON-COUVRETTE & ASSOCIATES, INC. fi Geotechnical Investigation Report Four Lot Short Plat NCA File No. 178096 July 11, 1996 Page 4 i Subsurface conditions found on site consist mostly of a fine sand with silt or trace silt that varied from loose at the surface, to medium dense to dense with depth. We have interpreted these soils to be the Esperance Sands. Test Pit 9, located on the east portion of Lot 2, encountered 4 feet of fill. The fill consists of similar native material with some organics and bottles. We also expect localized fills in areas behind structures and/or retaining walls. The site is covered with a thin layer of topsoil. The topsoil ranged up to 0.8 feet in depth. Hydrologic Conditions No obvious evidence of ground water, perched ground water or outcropping ground water along the slopes was observed within this site. The advance outwash is considered fairly permeable and water is expected to infiltrate vertically in the deposit until it encounters a less permeable layer, such as the Whidbey Formation. We do not know the depths of these less permeable layers. The site appears to be well drained with the advance sands. SENSITIVE AREA EVALUATION Seismic Hazard The Puget Sound Region is classified as a Zone 3 by the Uniform Building Code. Seismic considerations for this type of site includes liquefaction potential and attenuation of ground motions by soft soil i deposits. The liquefaction potential is highest for loose sand and silty sand with a high ground water table. The sand deposits at the site below a few feet were at least medium dense or better. These soils have a low potential of liquefaction. Seismically sensitive soft soils were not observed at this site. Erosion Hazard The erosion hazard criteria used for determination of affected areas include soil type, slope gradient, vegetation cover, and ground water conditions. The erosion sensitivity is related to vegetative cover and the specific surface soil types (group classification); which are related to the underlying geologic soil units. The soils have been classified in accordance with the Soil Conservation Service (SCS) classification system and have been grouped with respect to the corresponding geologic unit. The geologic unit is Esperance Sand which corresponds to the SCS classification of Everett soils. The erosion hazard is greatest when the on -site soils have been stripped of vegetation. Provided the surface water flowing over the exposed sands are properly controlled during construction, and vegetation is re- established after development, we do not expect a significant erosion concern. NELSON-COUVRETTE & ASSOCIATES, INC. w r.. ' Geotechnical Investigation Report Four Lot Short Plat NCA File No. 178096 July 11, 1996 Page 5 i Landslide Hazard An evaluation of potential landslide hazard was performed for this site. This evaluation includes soil type, underlying stratigraphy, slope gradient, ground water conditions, and vegetation cover. The soil conditions at the site commonly have high strengths and the slope angles are not excessively steep for these types of soils. We also did not observe any signs of instability such as shallow or deep-seated failures. Accordingly, it is our opinion that the native site slopes are stable and large scale failures are not expected.. Localized slough events may occur in the steep portions depending on the area specific conditions. These would be expected to be shallow, involving the near -surface soils. The garden debris placed on the top of the steep slope is considered unstable may cause shallow sloughs of the steep slope. CONCLUSIONS AND RECOMMENDATIONS General The site is suitable for the planned residential short plat. The underlying sand deposits have moderately high strength, and the existing slopes are considered stable with respect to deep-seated landslides or failures. Surficial sloughing and erosion can occur, however, we did not observe evidence of slope failures. The risk of these sloughs can be minimized by maintaining vegetation on the slopes and controlling any surface water that may exist. We consider that minimum setbacks from the toe of slope are considered appropriate to reduce the risk of future effects from surface sloughing. The outwash sand deposits should provide a good subgrade for support of the structure's foundations. The soil to be used as structural fill will be obtained from the east side of Lots 1, 2 and 3. Excavating these soils to be used as fill, will cause a portion of the trees and the existing structures to be removed during the initial development activities. The fill soil will be placed in the roadway area and also the low depression on the west side of Lot 1. ' Building Setbacks Uncertainties related to building along steep slopes are typically addressed by the use of building setbacks. The purpose of the setback is to establish a "buffer zone" between the dwelling areas and the slope margin so that ample room is allowed for normal slope regression, or if a slope failure were to occur, the likelihood of dwelling involvement would be minimized. In a general sense, the greater the setback, the lower the risk. From a geological standpoint, the setback dimension is usually based on the slope's physical characteristics, e.g., slope height, surface angle, material composition, hydrology, etc. Other factors such as historical slope activity, rate of regression, type, and desired life span of the development are important considerations as well. ;I NELSON-COUVRETTE & ASSOCIATES, INC. Geotechnical Investigation Report Four Lot Short Plat . j NCA File No. 178096 j July 11, 1996 i Page 6 Based upon our explorations, slope evaluation and observations, we recommend a minimum building setback of 10 feet for structures on Lots 3 and 4. Setbacks are not necessary on the other lots from the toe of the steep slope. Specifically, we recommend that the setback area not be used for placement or storage of fill materials, including "temporary" excavation spoils from building area preparation and excavation. The landscape debris on the upper portion of the steep slope should be removed. The area should be re-established with vegetation if the soil is exposed. Any development or encroachment into the setback areas should be evaluated by a specific geotechnical evaluation and report. Site Preparation and Grading Site preparation and grading should consist of stripping the vegetation and topsoil layer to the planned subgrade. The exposed surface should be compacted to a non -yielding condition using a steel -drum vibratory compactor. The subgrade should be observed for indication of disturbance of the lower soils both during excavation and compaction. If the subgrade shows signs of disturbance, we should be retained to provide recommendations for repair or potentially alternate construction techniques. The on -site soil is expected to be only somewhat moisture sensitive with a uniform grain size, and may be difficult to work and compact during periods of wet weather. Earthwork should be suspended during rainfall and for a period of time afterward. The actual ability to work the site during the wet time of the year will be dependent on the performance of the soils under load when wet. These conditions should be observed and the site work adjusted accordingly. We recommend that all soil stock piles that are intended to be used as backfill be covered with plastic during rainy weather to help.maintain a moisture content suitable for compaction. Sometimes a layer of crushed gravel or 2- to 4-inch spalls is used to provide wet season access and to improve pavement and foundation subgrade. The use of the gravel and spalls should be based on conditions observed in the field. Excavation Slopes Temporary slopes greater than 4 feet in height should be sloped at an inclination no steeper than 1.5H:1 V for the loose to medium dense sands, and 1H:1V for dense sands for cuts up to 12 feet in height. These slopes should be protected from rain by well secured plastic sheeting. If ground water or seepage is encountered, we should be retained to comment on the stability of the slopes in the excavation. The above cut slope angles should be considered preliminary in nature. The contractor should be ultimately responsible for the stability of the cut slopes, as he is continuously at the site and can observe the performance on a daily basis. All state and federal standards should be followed with respect to cut slopes and workman safety. NELSON-COUVRETTE & ASSOCIATES, INC. ' Geotechnical Investigation Report Four Lot Short Plat NCA File No. 178096 July 11, 1996 Page 7 Structural Fill General: Fill will be placed with the current design. Fill to be placed beneath buildings, pavements or other settlement sensitive features, should be placed as structural. fill. Structural fill, by definition, is soil placed in accordance with prescribed methods and standards described in this report, and is monitored by an experienced geotechnical professional or soils technician. Field monitoring procedures would include a representative number of in -place density tests to document the attainment of the desired degree of relative compaction. Materials: Imported structural fill should. consist of a good quality free draining granular soil, free of organic and other deleterious material, and be well graded to a maximum size of about 3 inches. Imported all weather fill should contain no more than about 5 percent fines (soil finer than a U.S. No. 200 sieve) based on that fraction passing the U.S. 3/4-inch sieve. The on -site outwash soil can be used as structural fill but these soils contain some fine-grained particles and are considered slightly moisture sensitive. The use of the soils as fill should be limited to extended periods of dry weather. These soils have a uniform grain size and are sometimes more difficult to compact than well graded soils. Depending on the moisture content of the soil, adding water may be necessary to achieve compaction. Soils with a high organic content should not be used as structural fill. Fill Placement: Following subgrade preparation, placement of the structural fill may proceed. All backfilling should be accomplished in 8- to 10-inch thick uniform lifts. Each lift should be spread evenly and be thoroughly compacted prior to placement of subsequent lifts. All structural fill underlying building areas, and within 2 feet of pavement subgrade, should. be compacted to a minimum of 95 percent of its maximum dry density. Maximum dry density in this report refers to that density as determined by the ASTM D 1557 compaction test procedure. Fills more than 2 feet beneath sidewalks and pavement subgrades should be compacted to at least 90 percent of their maximum dry density. The moisture content of the soils to be compacted should be within about 2 percent of optimum, so that a readily compactable condition exists. ' It may be necessary to overexcavate and remove wet soils in cases where drying to a compactable condition is not feasible. All compaction should be accomplished by equipment of a type and size sufficient to attain the desired degree of compaction. Care should be taken when compacting the soil condition near to adjacent houses. A photo documented survey of the . neighboring structures is suggested prior to any heavy equipment arriving at the site. Sometimes the use of smaller compaction equipmen't and thinner lifts is better if adjacent structures are being impacted. NELSON-COUVRETTE & ASSOCIATES, INC. Geotechnical Investigation Report Four Lot Short Plat NCA File No. 178096 July l 1, 1996 . Page 8 Foundations The foundations should be placed either on undisturbed medium dense or dense native sand or structural fill extending to these soils. If footings are to bear on structural fill, the -fill zone should extend outside of the footing a distance equal to the depth of fill beneath the footing. The soil conditions should be evaluated for appropriate density and disturbance at the time of construction. Exterior footings should extend a minimum of 18. inches below the adjacent outside ground surface, with interior column footings a minimum of 12 inches below the bottom of the adjacent slab. All loose or disturbed soil should be removed from the foundation excavation prior to placing concrete. Standing water should not be allowed to accumulate in the building pad or footing trenches. For foundations constructed as outlined above, we recommend an allowable design bearing pressure of not more than 2,500 pounds per square foot•(psf) be used. Higher bearing values may be available based on specific soil conditions, footing size and settlement tolerance. This can be reviewed at the time that the structure is designed and foundation loads are determined. A .one-third increase in the above allowable bearing pressure may be used when considering short-term transitory wind or seismic loads. Although structural loading information was not available at the time of this study, based on our experience with similar structures supported on similar soil conditions and for the above allowable soil bearing pressures, we estimate that the maximum total post -construction settlement for medium dense sands should be 3/4 of an inch or less, and that the differential settlement across the building width should be 1/2 inch or less. We expect larger differential settlements may occur.if the building is constructed part on fill and part on native soils. Lateral Pressures The lateral pressure acting on retaining walls is dependent on the nature and density of the soil behind the wall, the amount of lateral wall movement which can occur as backfill is placed and the inclination of the backfill. Soil pressures will be less for walls that are free to yield at the top at least one -thousandth of the height of the wall, than if movement is limited by such factors as wall stiffness or bracing. We recommend that yielding walls supporting horizontal backfill be .designed using an equivalent fluid density of 35 pounds per cubic foot (pcf). Non -yielding walls should be designed using an equivalent fluid density of 50 pcf. These lateral soil pressures do not include the effects of surcharges such as traffic loads or other surcharge loads. Surcharge effects should be considered, if appropriate. If desired, we can provide recommendations for surcharge loads as they become apparent. NELSON-COUVRETTE & ASSOCIATES, INC. Geotechnical Investigation Report Four Lot Short Plat NCA File No. 178096 July 11, 1996 Page 9 All backfill for subgrade walls that will, not act as structural fill should be compacted to between 90 and 92 percent of the maximum dry density as determined in accordance with ASTM D 1557. Care should be taken to prevent the buildup of excess lateral soil pressures due to overcompaction of the backfill behind the wall. This can be accomplishedby placing the backfill within 18 to 24 inches of the wall in lifts not exceeding 8 inches in loose thickness, and compacting this zone with hand -operated vibrating plate compactors. Lateral loads can be resisted by friction between the foundation and subgrade or the passive earth pressure acting on the below -grade foundation. For the latter, the foundation must be placed "neat" against the undisturbed soil, or backfilled with a clean, free draining, compacted structural fill. We recommend that lateral passive resistance be calculated by using an equivalent fluid weight of 250 pcf. An allowable coefficient of friction between footings and the subgrade of 0.40 may be used. These values include a factor of safety of 2.0 for lateral resistance and 1.5 for the coefficient of friction. The wall pressures, listed above, are based on the assumption that the soil directly behind the wall is free draining or a drainage composite is used. All of the on. -`site surface soils are not free draining. Some free draining soil may exist at depth. Wall drains are discussed in .the Subsurface Drainage sub -section of this report. Site Drainage Surface Drainage: The finished ground surface should be graded such that storm water is directed off of the site. Water should not be allowed to stand in any area where footings, slabs or pavements are to be constructed. Final site grades should allow for drainage away from the building. We suggest that the finished ground be sloped at a gradient of 3 percent minimum for a distance of at least 10 feet away from the building. Surface water should be collected by permanent catch basins and drain lines, and be discharged into a storm drain system. The surficial soils are loose to medium dense, fine sand. These soil types erode easily, especially when directly exposed to precipitation and runoff. Surface water should be diverted away from the steep to moderate slopes. Stripped areas should be revegetated to improve the stability of the near -surface slope soils. The vegetation should be maintained until it is established. Subsurface Drainage: Where slabs are located below the surrounding grades, a system of perimeter footing drains should be included in the design. The perimeter footing drains should consist of 4-inch diameter perforated smooth -walled PVC pipe surrounded by pea gravel. The footing drains should be NELSON-COUVRETTE & ASSOCIATES, INC. Geotechnical Investigation Report Four Lot Short Plat j NCA File No..178096 i July 11, 1996 Page 10 1 located at the elevation of the footing. The drains should be tightlined to the storm drain system. We do not consider foundation drains necessary for standard foundations construction. A drainage system should be planned behind all retaining walls. The drainage system should consist of an 18-inch wide blanket of free draining material. Pea gravel would be a suitable material. If 0:5-inch or larger washed rock is used, filter fabric may be required to surround the rock. A drainage composite approved by geotechnical engineer could be used in place of the rock blanket. A 4-inch diameter perforated pipe should be placed along the base of the wall within the free draining material. The drains should be routed to an appropriate discharge point. Slabs -on -Grade Slabs should be supported on native subgrade soils or structural fill prepared as described in the Site Preparation and Grading and Structural Fill sub -sections of this .report. Where moisture control is important, we recommend that the floor slabs be underlain by 6 inches of free draining granular material, for use as a capillary break. A suitable vapor barrier, such as heavy plastic sheeting, should be placed over the capillary break material. A 2-inch thick sand blanket may be placed over the vapor barrier to protect it during placement of the concrete and to help the concrete cure. Rockeries Rockeries are used in the Puget Sound region to face stable soil exposures to reduce weathering and slough type failures. Although it is not always common to consider a rockery as a retaining wall, in reality, the rockery can act as a gravity wall. The problems associated with using the rockery as a retaining wall is the quality of the rockery construction and the compacted backfill. There is some risk associated with rockeries since the rocks are not tied together. Therefore, the methods in which they are stacked are very important. Rockeries should be designed and constructed in accordance with Association of Rockery Contractors (ARC) guidelines, unless otherwise recommended in this report. Inspection of the rockery construction by the geotechnical consultant is recommended. We consider the rockery at the base of the cut slope to be appropriate. However, we recommend that the rock sizes be increased to H/2 instead of the 1-1/3 as recommended in the ARC manual. We recommend that the same standards be used for the rockery that retains the driveway fill. However, since the wall could be exposed to unknown wheel and traffic loads, it may be prudent to design it as a reinforced soil wall. The reinforcement could consist of either fabric or geogrid. NELSON- COU VRETTE & ASSOCIATES, INC. Geotechnical Investigation Report Four Lot Short Plat . i NCA File No. 178096 i July 11, 1996 Page 11 USE OF THIS REPORT We have prepared this report for The City of Edmonds, Lovell- Sauerland & Associates, Inc. and their agents, for use in planning and design of this project. The data and report should be provided to prospective contractors for their bidding or estimating purposes, but our report, conclusions and interpretations should not be construed as a warranty of the subsurface conditions. The scope of our services 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 consideration in design. There are possible variations in subsurface conditions between the explorations and also with time. A contingency for unanticipated conditions should be included in the budget and schedule. We should be retained to provide monitoring and consultation services during construction to confirm that the conditions encountered are consistent with those indicated by the explorations, to provide recommendations for design changes should the conditions revealed during the work differ from those anticipated, and to evaluate whether or not earthwork and foundation installation activities comply with contract plans and specifications. Within the limitations of scope, schedule and budget for our services, we have strived to take care that our work has been completed in accordance with generally accepted practices followed in this area at the time this report was prepared. No other conditions, expressed or implied, should be understood. NELSON-COUVRETTE & ASSOCIATES, INC. Geotechnical Investigation Report Four Lot Short Plat NCA File No. 178096. July 11, 1996 Page 12 f We appreciate the opportunity to be of service to you. If there are any questions concerning this report or if we can provide additional services, please call. Sincerely, NELSON-COUVRETTE & ASSOCIATES, INC. C7UX Rick B. Powell, PE Project Engineer EXPIRES (e . t-+. �jg Charles P. Couvrette, PE Principal Engineer Three Copies Submitted Six Figures s cc: Mr. Jurgen Sauerland - Lovell-Sauerland & Associates, Inc. 1 NELSON-COUVRETTE & ASSOCIATES, INC. LOG OF EXPLORATION DEPTH USC SOIL DESCRIPTION TEST PIT ONE 0.0 -1.3 SM DARK BROWN SILTY FINE SAND WITH ORGANICS (LOOSE TO MEDIUM DENSE, WET) (TOPSOIL) 1.3 - 4.0 SP-SM RED -BROWN FINE SAND WITH SILT (MEDIUM DENSE, MOIST) (WEATHERED ova) 4.0 - 6.5 SP-SM GRAY -BROWN FINE SAND WITH SILT (MEDIUM DENSE TO DENSE, MOIST TO WET) (Ova) SAMPLE WAS COLLECTED AT 6.0 FEET GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 6.5 FEET ON 6/15/96 TEST PIT TWO 0.0 - 0.4 SM DARK BROWN SILTY FINE SAND WITH SOME ORGANICS (LOOSE TO MEDIUM DENSE, WET) 0.4 - 4.0 SP-SM GRAY -BROWN FINE SAND WITH SILT AND ORGANICS (MEDIUM DENSE, MOIST TO WET) (Ova) SAMPLES WERE NOT COLLECTED. GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 4.0 FEET ON 6/15/96 TEST PIT THREE 0.0 - 0.2 TOPSOIL 0.2 - 2.0 SP LIGHT BROWN FINE SAND (MEDIUM DENSE TO DENSE, MOIST) IFILLI 2.0 - 3.5 SP-SM/SM BROWN TO DARK BROWN FINE SAND WITH SILT TO SILTY FINE SAND (LOOSE TO MEDIUM DENSE, MOIST) (OLD TOPSOIL) 3.5 - 5.0 SP LIGHT BROWN FINE SAND (MEDIUM DENSE TO DENSE, MOIST TO WET) (Ova) SAMPLES WERE NOT COLLECTED GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 5.0 FEET ON 6/15/96 TEST PIT FOUR 0.0 - 0.2 TOPSOIL 0.2 - 2.0 SP-SM BROWN TO DARK BROWN FINE SAND WITH SILT AND SOME ORGANICS (MEDIUM DENSE, MOIST) (TOPSOIUQva) 2.0 - 4.0 SP LIGHT BROWN TO BROWN FINE SAND (MEDIUM DENSE, MOIST) (Ova) SAMPLES WERE COLLECTED AT 1.5 AND 4.0 FEET GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 4.0 FEET ON 6/15/96 NELSON-COUVRETTE & ASSOCIATES, INC. FILE NO. 178096 FIGURE 4 Approximzis Location of Debris * ....... TP-8 . ................................................................... i.- .... . % A N % TP- 101 TP-5 TP-7 Al \ \ •�l ;1 •:e�� =tit.:- \ 2 - ----- IS 7 C I'VE L TP-2 TP-3 T 1-6 0 TP-4 �N Z- TP-1 7 - - - - - - - - - - - - - - - - V LEGEND TP- NUMBER AND APPROXIMATE LOCATION OF TEST PITS 2 rV-T SE?XCK AT PL NELSON- COUVRETTE &ASSOCIATES, INC. Reference: Site Plan was created from a drawing provided by Lovell-Sauerland & Associates, Inc., CoNsuLrNa GEOTECHNIC44 ENGINEERS. GEOLOGISTS dated May 16,1996 AND ENVIRONMENTAL SCIENTISTS !-9 Site Plan 0 40 80 Scale 1" = 40' FIGURE LSA/Echelbarger 2 FILE NO. DATE 178096 June 1996 SOIL CLASSIFICATION SYSTEM GROUP MAJOR DIVISIONS SYMBOL GROUP NAME COARSE GRAVEL CLEAN GRAVEL GW WELL -GRADED GRAVEL, FINE TO COARSE GRAVEL GRAVEL GP POORLY -GRADED GRAVEL GRAINED SOILS MORE TI"W%OF COARSE FRACTIONRETANEDON WITH FINES GM SILTY GRAVEL NO.4 SIEVE GC CLAYEY GRAVEL MORE THAN 5M RETANED ON NO.200 SIEVE SAND CLEAN SAND SW WELL -GRADED SAND, FINE TO COARSE SAND SP POORLY -GRADED SAND MORE THAN 50% OF COARSE FRAC M PASSES NO.4 SIEVE SAND SM SILTY SAND SC CLAYEY SAND WITH FINES FINE SILT AND CLAY INORGANIC ML SILT CL CLAY GRAINED uOVio IJMR LESS THAN So% ORGANIC OL ORGANIC SILT, ORGANIC CLAY . SOILS SILT AND CLAY INORGANIC MH SILT OF HIGH PLASTICITY, ELASTIC SILT CH CLAY OF HIGH PLASTICITY, FAT CLAY MORE 71-AN Sax PASSES NO. 200 SIEVE UOM UMIT sax OR MORE ORGANIC OH ORGANIC CLAY, ORGANIC SILT HIGHLY ORGANIC SOILS PT PEAT NOTES: SOIL MOISTURE MODIFIERS 1) Field classirication is based on Dry - Absence of moisture, dusty, dry visual examination of soil In general to the touch accordance with ASTM D 2488 - 83. Moist - Damp, but no visible water 2) Soil classification using laboratory tests is based on ASTM D 2487 - 83. Wet - Visible free water or saturated, usually soil is obtained from 3) Descriptions of soil density or below water table consistency are based on Interpretation of blowcount data, visual appearance, of soils, and/or test data. NELSON-COUVRETTE & ASSOCIATES, INC. SOIL CLASSIFICATION SYSTEM CONSULTING GEOTECHNICAL ENGINEERS, GEOLOGISTS AND ENVIRONMENTAL SCIENTISTS - FIGURE 3 LOG OF EXPLORATION DEPTH USC SOIL DESCRIPTION TEST PIT ONE 0.0 -1.3 SM DARK BROWN SILTY FINE SAND WITH ORGANICS (LOOSE TO MEDIUM DENSE, WET) (TOPSOIL) 1.3 - 4.0 SP-SM RED -BROWN FINE SAND WITH SILT (MEDIUM DENSE, MOIST) (WEATHERED ova) 4.0 - 6.5 SP-SM GRAY -BROWN FINE SAND WITH SILT (MEDIUM DENSE TO DENSE, MOIST TO WET) (Ova) SAMPLE WAS COLLECTED AT 6.0 FEET GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 6.5 FEET ON 6/15/96 TEST PIT TWO 0.0 - 0.4 SM DARK BROWN SILTY FINE SAND WITH SOME ORGANICS (LOOSE TO MEDIUM DENSE, WET) 0.4 - 4.0 SP-SM GRAY -BROWN FINE SAND WITH SILT AND ORGANICS (MEDIUM DENSE, MOIST TO WET) (Ova) SAMPLES WERE NOT COLLECTED GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 4.0 FEET ON 6/15/96 TEST PIT THREE 0.0 - 0.2 TOPSOIL 0.2 - 2.0 SP LIGHT BROWN FINE SAND (MEDIUM DENSE TO DENSE, MOIST) (FILL1 2.0 - 3.5 SP-SM/SM BROWN TO DARK BROWN FINE SAND WITH SILT TO SILTY FINE SAND (LOOSE TO MEDIUM DENSE, MOIST) (OLD TOPSOIL) 3.5 - 5.0 SP LIGHT BROWN FINE SAND (MEDIUM DENSE TO DENSE, MOIST TO WET) (Ova) SAMPLES WERE NOT COLLECTED GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 5.0 FEET ON 6/15/96 TEST PIT FOUR 0.0 - 0.2 TOPSOIL 0.2 - 2.0 SP-SM BROWN TO DARK BROWN FINE SAND WITH SILT AND SOME ORGANICS (MEDIUM DENSE, MOIST) (TOPSOIUQva) 2.0 - 4.0 SP • LIGHT BROWN TO BROWN FINE SAND (MEDIUM DENSE, MOIST) (Ova) SAMPLES WERE COLLECTED AT 1.5 AND 4.0 FEET GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 4.0 FEET ON 6/15/96 NELSON-COUVRETTE & ASSOCIATES, INC. FILE NO. 178096 FIGURE 4 LOG OF EXPLORATION DEPTH USC SOIL DESCRIPTION TEST PIT FIVE 0.0 - 0.4 0.4 - 4.0 TEST PIT SIX 0.0 - 0.5 0.5 - 4.0 TEST PIT SEVEN 0.0 - 0.5 0.5 - 2.0 2.0 - 7.5 TEST PIT EIGHT 0.0 - 0.4 0.4 - 3.0 3.0 - 5.5 TOPSOIL SP LIGHT BROWN WITH SLIGHT RUST STAINING FINE SAND WITH TRACE SILT (MEDIUM DENSE TO DENSE, MOIST) (Ova) SAMPLES WERE NOT COLLECTED GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 4.0 FEET ON 6/15/96 TOPSOIL SP-SM LIGHT BROWN TO BROWN FINE SAND WITH SILT (MEDIUM DENSE TO DENSE, MOIST TO WET) (Ova) SAMPLES WERE COLLECTED FROM 3.0 - 4.0 FEET GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 4.0 FEET ON 6/15/96 TOPSOIL SP-SM/SM BROWN TO RED -BROWN FINE SAND WITH SILT TO SILTY FINE SAND (MEDIUM DENSE, MOIST) (WEATHERED Ova) SP LIGHT BROWN TO BROWN FINE SAND WITH TRACE SILT (MEDIUM DENSE TO DENSE, MOIST) (Ova) SAMPLE WAS COLLECTED AT 6.0 FEET GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST.PIT WAS COMPLETED AT 7.5 FEET ON 6115/96 TOPSOIL SP-SM TAN -BROWN FINE SAND WITH SILT (MEDIUM DENSE, MOIST TO WET) (WEATHERED Ova) SP-SM GRAY -BROWN FINE TO MEDIUM SAND WITH SILT (MEDIUM DENSE TO DENSE, MOIST TO WET) (Ova) SAMPLES WERE COLLECTED FROM 4.0 - 5.0 FEET GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 5.5 FEET ON 6/15/96 NELSON-COUVRETTE & ASSOCIATES, INC. FILE NO. 178096 FIGURE 5 LOG OF EXPLORATION DEPTH USC SOIL DESCRIPTION TEST PIT NINE 0.0 - 0.7 TOPSOIL 0.7 - 4.0. SM/SP-SM BROWN TO DARK BROWN SILTY FINE SAND TO FINE SAND WITH SILT, ORGANICS AND A BOTTLE (LOOSE, MOIST) Fj ILL) 4.0 - 5.0 SP-SM BROWN FINE SAND WITH SILT (MEDIUM DENSE, MOIST) (Qva) SAMPLES WERE NOT'COLLECTED GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 5.0 FEET ON 6/15/96 TEST PIT TEN 0.0 - 0.8 TOPSOIL 0.8 - 4.0 SP-SM RED -BROWN TO LIGHT BROWN FINE SAND WITH SILT AND OCCASIONAL COBBLES (MEDIUM DENSE TO DENSE, MOIST TO WET) (Qva) SAMPLES WERE NOT COLLECTED GROUND WATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 4.0 FEET ON 6/15/96 NELSON-COUVRETTE & ASSOCIATES, INC. FILE NO. 178096 FIGURE 6 PLANNING DATA NAME: & *�6m SITE ADDRESS: /per OVp DATE: �8 ZONING: F-S I2 PLAN CHK#: 9� - 7✓ PROJECT DESCRIPTION:_�� j�f f off' 5- 95 - -20y. CORNER LOT (Yes/No) FLAG LOT 1W (Yes/No) SETBACKS: Required Setbacks: Front: �" Left Side:" ZO Right Side: Id Rear: Actual Setbacks: Front:�Left Side:2,1Right Side: 10 Rear . A Street map checked for additional setback required? (Yes/No) LEGAL NONCONFORMING LAND USE DETERMINATION ISSUED (Y/N) LOT COVERAGE: 2/�,� e� Maximum Allowed: o A al: A n BUILDING HEIGHT: ° Maximum Allowed: �d'1 S Actual Hei9 ht: ktr, S Datum Point: Na4" Datum Elevation: 17 (5, y`i A.D.U. CREATED?: ND SUBDIVISION: UUVWydW41i SW/- � 5-- ZO 1- CRITICAL AREAS #: 95 � 21- SEPA DETERMINATION: NIA LOT AREA: `'5r 0 v OTHER: c:uue3spertn1trp1anaaL000 I 17311-135th Avenue NE, A-500 Woodinville, WA 98072 (425) 486-1669 • Fax 481-2510 November 24, 1997 City of Edmonds Planning Department 250 — Sth Avenue Edmonds, Washington 98020 Supplemental Letter Four Lot Short Plat Edmonds, Washington NCA File No. 178096 Dear Sirs: NELSON-COUVRETTE & ASSOCIATES, INC. CONSULTING GEOTECHNICAL ENGINEERS, GEOLOGISTS AND ENVIRONMENTAL SCIENTISTS Snohomish County (425) 337-1669 Wenatchee/Chelan (509) 784-2756 STREET FILE This is a supplemental letter to our preliminary geological investigation letter for this site,'dated July 11, 1996 (NCA File No 178096). The purpose of this letter is to clarify our use of the term "buffer zone" in the Building Setback subsection of our report. We have been requested to provide this clarification by Jeff Vehrs of the Emerald Coast Group. In our report, we recommended a minimum building setback of 10 feet for structures on Lots 3 and 4, to establish a "buffer zone" between dwelling areas and the slope margin. We did not intend the word "buffer" to be used as referenced and defined by the City of Edmonds in their Development Code. We understand that these definitions were provided in the new code which was enacted after our report was prepared. The City of Edmonds defines "buffer" as the area immediately next to and part of a steep slope. The buffer is intended to protect the stability of the slope. A 15-foot setback is required from the edge of the buffer. The topographic map provided corresponds with our field measurements taken at the time of our explorations. The topographic map of the steep slope area shows that the slope the maximum slope Supplemental Letter Edmonds Short Plat November 24, 1997 NCA File No. 178096 Page 2 inclination is about 58 percent for a total height of 8 to 10 feet. The portion of the slope with an average slope above 40 percent is less than 20 feet in vertical height. Therefore, this slope does not qualify as a steep slope hazard area under the City of Edmonds Code. It is our opinion that a building setback of 10 feet from the toe of the slope is appropriate. This allows for maintenance of the area in the event a slough event occurs. The term "buffer" used in our original report was not intended to be used as defined in the code, but was intended to be used as a setback of the structure from the toe of the slope. In the event that the steep slope hazard is still applied, it is our opinion that moving the buffer onto the slope and having the standard building setback start at the toe of the slope would be appropriate. We trust this letter provides you with the information you requested and appreciate the opportunity to be of continued service to you on this project. If you have any questions concerning this letter, do not hesitate to call. Sincerely, NELSON-COUVRETTE & ASSOCIATES, INC. Charles P. Couvrette, PE Principal Engineer LMH:CPC:nt Three Copies Submitted NELSON-COUVRETTE & ASSOCIATES, INC. �1 I%I • i P f A1UM a Mo�G I i 3.2 �\ _ I . + I Gur WA.-15�� T ` ej voA 2 IN M c rJ 77} ItJ eo&b A) VA ACCEPTABLE' i:TUNEhWAl j.=.MNL N-12 ADS d Fr SCh 40 PVC �h,yr, �.• q �, SDR 35 (ASTM D3034) ::::b ::.f. T L ?3 L \ I —APPROVED A 6,j' O �. :t Wit; � CDINO ► .( Mk - � CITY COPY - • , 1 .�. , , � �/1 t lei .U/�' . A ED Y PUNNING loll A tyI 'f I /f I /fin . I I � �o 'S � �✓E N/Dej I ' tom. . I `•. .. , : ,.1. s o - I i ► , 69 1 }1 i Oki r � v u I A 01, I y?ry w ~ J J i o R w M c� N t'2o c T� �T i� I �• T I �, � .. DS ' 1 •1' 1 i Ov it VA AC PTABLE TIQY1'L'INE N.�11TEIIFl,.,ol� N-12. ADS Sch 40 PVC , ,ti ► A , DR 35 AStM D303) i APPROVED AS 7, ti.�7 G� 3 9 9�' i � .. •• i I n AR STREET FILE CITY OF EDMONDS CONSTRUCTION PERMIT APPL OWNPNAM /NE OF �ISINES NAME ADDRESS } CITY NAME ) 4. ADDRESS q CITY r USE PERMIT ZONE ! 8y''+�/0 4 ..- NUMBER L,/f�-,:f�' TION roe i ONENUMBER NUMBER W/ C- ZIP. ITELEPHONE NUM ST TE LICENSE NUMBER PIRA Tom ,06, -t� f Legal Description of Property - include all easements' Z 0 T— r a Lu it furl t7 Property Tax Account) f ADDRESS / T -- PIL)IC- a -EGAL DESCRIPTION CHECK SUBDIVISION NO. LID NO- S 9t5 - zcfz N/A PUBLIC RIGHT OF WAY PER OFFICIAL STREET MAP. EXISTING 10' REQUIRED DEDICATION _ TESCP Approved ❑ RW Permit Required ❑ Street Use Permit Req'd PROPOSED F✓T �f1 Inspection Required ❑ Sidewalk Required ❑ cc M T R SIZE LINE SIZE NO. OF FIXTURES PRV REQUIRED Q "/ „ YES NO ❑ 3 0 TEMARKS Z till 1 Z IA1 j Z F-C,.2 (� - /= ��iI�TQ 1% Ei�GSr[ , Z • .q% DATED REVJEN/FD BY VARIANCE OR CU ADB It SHORELINE q SEPA REVIEW SIGN AREA HEIGHT COMPLETE I EXEMPT ALLOWED I PROPOSED ALLOWED PROPOSED EXP � - t� LOT COVERAGE fY �JY�jfREQUIREDSETBACKS ETBACKS (Fr.) PROPOSED SETBACKS (FT) ALL IPROPOSED FRONTDE REAR I//5_/J/o5-I0 Parcel Na ,, �`_^ ' t j) ! / _f _� " •- % ( r NRLI EW ADDITION REMODEL REPAIR ❑ ® RESIDENTIAL COMMERCIAL APT. BLDG. j GR 'DyN CYDS. WOODSTOVE ♦ PLUMBING/MECH COMPLIANCE OR CI CHANGE OF USE SIGN FENCE (x_FT► SWIM POOL REMARKS CHECKED BY TYPE SPECIAL INSPECTOR DEMOLISH L_j INSERT HOT TUB/SPA Z 6,77 %�L4-07' CARPORT ROCKERY REQUIRED ❑ YES 'M 7 `® CGARAGE RETAINING WALL/ RENEWAL REMARKS (TYPE OF USE, BUSINESS OR ACTI •ITY) EXPLAIN: U¢ W NUMBER NUMBER OF CRITICAL O OF R DWELLING ( AREAS qr- m STORIES UNITS rrr NUMBER 1 j DESCRIBE W046 TO BE DONE (gTT.QCH PLq`r PLAN) J: = " PROGRESS INSPECTIONS PER. UBC 108 FINAL INSPECTION REQUIRED VALUATION FEE OCCUPANT LOAD PLAN CHECK FEE - BUILDING HEAT SOURCE: GLAZING fC�1 PLUMBING Plan Check No. o MECHANICAL GRADINGIFILL This Permit covers work to be done on private properly ONLY. Any construction on the public domain (curbs, sidewalks, driveways, marquees, etc.) will require separate permission. STATE SURCHARGE Permit Application: 180 Days Permit Limit: 1 Year - Provided Work Is Started Within 180 Days STORM DRAINAGE FEE i "Applicant, on behalf of his or her spouse, heirs, assigns and ENG. INSPECTION FEE 0— ,n successors in interest, agrees to indemnify, defend and hold w harmless the City of. Edmonds, Washington, its officials, I employees, and agents from any and all claims for damages of a z whatever nature, arising directly or indirectly from the issuance be deemed to PLAN CHECK DEPOSIT q- of this permit. Issuance of this permit shall not �. omodify, waive or reduce any requirement of any city ordinance = nor Iimit In any way the City's ability to enforce any ordinance TOTAL AMOUNT DUE provision." I hereby acknowledge tfiat I have read this application; that the informationgiven is coirect; and that I am the owner, or the duly ATTENTION APPLICATION APPROVAL authorized agent of the -owner. I agree_to comply with city and state laws regulating construction; and in doing the work authoriz- THIS PERMIT AUTHORIZES This application is not a permit until ed thereby, no person will be employed in violation of the Labor ONLY THE signed by the Building Official or his/her Code of ttte State of Washington relating to Workmen's Compensa- WORK NOTED Deputy; and fees are paid, and receipt is tion Insur nce aria RCW 18.27. INSPECTION acknowledged in space provided. SIGNAT7E ( WNER OR GENT) DATE S GNE e^ DEPARTMENT CITY OF OFFI ?1 'S ATURE D TE r EDMONDS �- UA CALL FOR RELEASE6. D ATTENTION INSPECTION - IT IS UNLAWFUL TO USE OR OCCUPY A BUILDING OR STRUCTURE UNTIL A FINAL INSPECTION HAS BEEN MADE AND APPROVAL OR O�wO 7711 ORIGINAL — File YELLOW Inspector A CERTIFICATE OF OCCUPANCY HAS BEEN GRANTED. UBC — SECTION 109 3141, PINK — Owner GOLD — Assessor