223 PECKS DR 2016-01-01 MF Import

. • c'"� !"i subso�is Our evaluation of the subsurface conditions ;aas based on our observations of four exploratory testpi�s exacavated on the site. Fill soils were encountered in al.l of the testpits to depths ranging from about 5 to 11 feet. Existing fill soils appeared to ha -e been olaced in two or more episodes. The most recent fills placed during pad construction . were found to overlie an apparent older fill surface where small alders and other vegetation had been recently growing. Fill soils were generally brown, moist to wet, silty sand and sandy silt soils with varying amounts of organic debris, asphalt and concrete. In testpits TP-1 and TP-2, located along the north side of the pad, the fill soils had an organic odor. Natural soils underlying the fill were found to be a sequence of dark brown to black topsoil, underlain by a thin layer of stiff gray sandy silt over dense to very dense brown to red-brown silty sand with gravel. Based on review of a published geologic map of the area, it appears that the site is near a boundary between a Vashon glacial till and an area of alluvial deposits. The map indicates that the area to the northeast of the site has been mined as a gravel pit . Ground WatFL During excavation of the testpits, no ground water was encountere:d to the depths of the testpits. However we did note that the soils encountered in testpit TP-2 were very moist to wet. S��hcnrface Variations Based on our experience, it is our opinion that some variation in the continuity and depth of subsoil deposits and ground water conditions should be anticipated. Due to the depositional characteristics of the natural soils and seasonal ground water variations, care should be exercised when interpolating or extrapolating subsurface soils and ground water conditions between or beyond our testpits . Fill depths are expected to vary over the site, depending on the original natural ground surface, previous grading and previous onsite structures .