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Underwood Gartland Everett, LLC ES-2232.02 <br /> February 6, 2015 Page 3 <br /> Fill <br /> As previously described, the subject property had historically been mined for sand and gravel, <br /> and subsequently filled. Based on the subsurface investigation, fill throughout the reclaimed <br /> areas of the gravel pit site is comprised largely of silty fine to medium sand with varying <br /> amounts of gravel. Limited zones of silt and clay fill were also identified at-depth in three of the <br /> ten borings drilled as part of the 2011 investigation. The fill extends to depths ranging between <br /> roughly 20 to 75 feet. The deepest areas of fill were identified primarily throughout the central <br /> and south regions of the site. Relative density of the silty sand fill generally ranges from loose <br /> to medium dense. Concrete rubble and occasional wood debris where also identified (primarily <br /> near surface) at some locations. Much of the rubble, however, was either removed or <br /> redistributed and placed as compacted fill during the 2012 grading activities. <br /> Native Soil <br /> Native deposits underlying the area of existing fill are comprised primarily of dense to very <br /> dense advance outwash sand and gravel (Qva). All of the borings drilled as part of the 2011 <br /> investigation were advanced through the upper fills and into these native soil deposits. <br /> Geologic Setting <br /> The referenced geologic map of the area identifies glacial till (Qvt) and advance outwash (Qva) <br /> deposits throughout the site and surrounding areas. Glacial till was likely the predominant <br /> deposit along the original ground surface prior to the historic sand and gravel mining activities. <br /> Groundwater <br /> Zones of perched groundwater seepage were observed at some locations within the existing fill <br /> deposits during the 2011 investigation. This groundwater seepage condition is likely comprised <br /> of discrete and discontinuous zones of perched water that fluctuates seasonally within the fill <br /> deposits. Groundwater seepage of this nature fluctuates depending on many factors, including <br /> precipitation duration and intensity, the time of year, and soil conditions. In general, <br /> groundwater seepage levels and flow rates will be higher during the wetter, winter months. <br /> Groundwater seepage zones should be expected in the deeper excavations related to the <br /> planned development. <br /> Earth Solutions NK LLC <br />