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REVIEWED BLD2021-0035 Geotech with Attachments,...................... REVIE E CITY OF E BUILDING D CONSULTANTS,GEOSPECTRUM G;eafeohniccil Engineering ........ :WED Y :DMONDS PARTMENT September 28, 2012 Mr. Rob Michel Soundview Lane LLC P. O. Box 1483 Edmonds, WA 98020 SUBJECT: OEOTECLINICAL EVALUATION Proposed 3-Lot Short Plat 7231 Soundview Lane Edmonds, Washington Project No. 12-127-01 IT: :no RECEIVED Nov 19 2013. DEVELOPMENT SERVICE COUNTER This report presents our geotechnical evaluations and recommendations for development of the subject property as a 3-Lot short plat. Our services were provided i in accordance with the scope and conditions of our proposal dated July 27, 2012. We have been provided a site topographic survey and the proposed lot lines within the property which includes an existing residence located in the southern portion of the j property. We understand that two new lots will be created in the western and northern portions of the property and that residential development on the two new lots will likely be two-story structures with daylight basements. Access will be provided from the east side of the property by a new driveway north of the existing residence. I _ We have not. been provided_ any structural load information, but based on our experience we expect that bearing wall loads. will be on the order of 2 to 3 kips per foot and column loads are expected to range from about 10 to 20 kips. If actual structural loads exceed the above values by more than 25%, this office should be notified. ]we P , Box 2z 6, Isscrquoh, IR/A 980 °✓-0276 © hone; (25) 397- 2.2-8 FOP. (425) 397--4228 Soundview Lane LLC September 28, 2012 SCOPE OF WORK Our work has included site reconnaissance, subsurface explorations, engineering evaluations and the preparation of this report. The scope of work included the following specific tasks: o Review of published geologic mapping and Edmonds ECA Inventory Maps of geologically hazardous Areas maps for the site vicinity. o (Performed a site reconnaissance to observe conditions on the site and on the slopes within the property. o Observed existing and new test pit excavations to explore the subsoil conditions within the proposed new residential lots. Approximate locations of the test pits are shown on Figure 2 and logs of the test pits are included in Appendix A. o Performed engineering evaluations of the surface and subsurface conditions observed and developed geotechnical recommendations for foundation design and construction including foundation slope setbacks plus geotechnical recommendations general site development. o Prepared this geotechnical report summarizing our findings and geotechnical recommendations for site development including foundation design and construction, subgrade preparation, erosion control and drainage control. Surface Conditions Our site observations and explorations were made on 8/7/12 The property is located in northeastern Edmonds near the top of the west facing coastal bluff. The property is situated on the west side of Soundview Lane north of its intersection with Sound View Drive. Topographically the site includes the point of a broad ridge that is bordered on the north by a small 'ravine as shown in Figures 2 and 3. The proposed new lots will be located within the moderate to steeply sloped areas north and west of the existing house and will be bordered on the north and west by neighboring residential property as shown in Figures 2 and 3. The proposed new Lot 2 in the southwestern area of the property includes two terrace areas with gradients of 10 percent or less bordered on the west sides by two existing rockeries that range from about 2 to 6 feet in height. The area below (west of) the lower rockery slopes down to the adjoining residential property at moderate to steep (Project No. 12-127-01 page 2 Soundview Lane LLC September 28, 2012 gradients ranging from about 30 to 40 percent. The upper terrace areas within Lot 2 are vegetated with grass and occasional fruit trees and a hedge (arbor vita?) along the upper side of the lower rockery. In addition the northwestern area of Lot 2 below the terraces is wooded with maple and fir trees from about 2 to 2.5 feet in diameter along with understory vegetation as well. We observed no evidence of past instability within the proposed Lot 2. The proposed new Lot 3 in the northwestern area of the property is moderately to steeply sloped with gradients that range from about 15 percent up to 65 percent and is bordered on the north by a dry ravine that included a primitive road along the bottom of the ravine. The Lot 3 area was also well vegetated with alder, maple, pine, cedar and fir trees ranging up to about 3 feet in diameter and also includes understory vegetation such as blackberry, ferns, ivy, vine maple and filbert trees. We observed no evidence of past instability within the proposed Lot 3. Subsoil Conditions Subsoil conditions were observed in five test pit explorations at the approximate locations shown on Figure 3. Detailed logs of the our test pits are presented in Appendix A. Subsoils observed in the explorations included localized areas of fill and weathered natural soils overlying very dense/hard natural soils. Fill soils were encountered along the lower side of an existing graded road (TP-2), above the existing rockeries (TP-4) and we noted a debris fill deposit at the southwest corner of the site (south of TP-3) and the fill soils were consistently loose at all locations. Weathered natural soils were typically loose to medium dense silty very fine sand and ranged in thickness from about 2.5 to 4 feet thick at the test pit locations. The underlying less weathered natural soils were generally silty very fine sand with occasional gravel with the exception of a very fine sandy silt encountered at TP-1. The natural soils became very dense to hard at depths of about 2.5 to 4 feet below the natural ground surface (6 to 7 feet below the existing fill surfaces). Ground Water Conditions No ground water was encountered in any of the test pits: The subsoils at all locations were field classified as moist with measured moisture contents of the soil samples typically ranging from about 7 to 10 percent with the exception of the 18 percent moisture of the sandy silt sample from TP-1 and the 5.5 percent moisture of the cemented soil sample from TP-5. Project No. 12-127-01 Page 3