11632 EVERGREEN WAY BASE FILE 2018-01-01 MF Import

Proposed Retail Dcvelopmeat J-1443 112'�Street and Hwy.99 Febcuery 26,2004 CEvcrett;Washington Page 8 spalis and medium dense silty sand fill. Elsewh;re across the building pad, as well as below the fill soils and pcat, ihe borings encountered medium dense to very dense silty sand with some gravcl that was intcrproted to be weathered and unweathered glacial till. These soils were cncountered to the full depths explored. Parking.0.rcas,Outlots and 5tormwaler Managcment Area Soil conditions varied greatly in these areas. The topographically lugher portions of the main pazking area, as well as portions of Outlots #1 and #2 appeaz lo be underlain primarily by medium dense to dense silty sand to gravelly silty sand interpreted U� be glacial till. Elsewhere, one to 8 feet of soil intcrpreted to bc undo::umentcd fill was interpretcd to be prescnt above native soils that varied from soft peat to loose silty sand to very dense glacial till soils. The United Slates Departmen� of Agriculture Sor! 5urvey for Snohomish County, Washing�on (1983) indicates that the site is underlain by lhe Alderwood-Urban land complex. Alderwood soils are generatly described as glacially-derived gravelly sandy loam while Urban land is considered lo be covered with strcets, buildings, parking lots, and other stmctures that obscure or alter the soils so that identification is not feasible. Bascd on the results of our , evaluation,the majority of the site is considered to ba underlain by glacial titl soils that match thc descriptions of the Alderwood gravelly sandy loam. This soil is described by the USDA tc� have the following characteristics: � A(derwood gravelly sandy loam: • Low shrink-swell potential • pH range of 5.1 —6.5 • Permeability range of 2.0 to 6.0 in/hr in the upper 30 inches,negligible below 30 inches • Soil Hydrologic Group C • Slow runoff potential • Slight erosion hazard . Seasona] high perched groundwatcr betwccn 1% to 3 fcet below the gtound surFace between January and March • Low potential for frost action • Itisk of corrosion to uncoated steel and concrete is moderate • Unified Soil Classification Systcm classification of GM. Groundwater Conditions Slight to moderate groundwater sccpage was oUserved in 24 of the 32 borings completed as par[of this cvsluatioa. Additionally, slight lo heavy groundwater seepage was observed in 12 of the 21 tcst pits completed as part of this evaluation. The seepage observed was genetally interpreted to be perched groundwater abovc the dense to very dense glacial ti(1 soils. The depths to groundwater varied from I Y: to 9 feet below existing gades. Perched groundwater is likely to I bc more prevalent across the site during and after winter rains and aftcr winter rains and � / J-1443,022604 8 �