905 80TH ST SW MTORRES AMERICA 2018-09-18

February 22,2016 Project No. T-7364 3.2 Soils The site soils are weathered and unweathered glacial till deposits comprised primarily of silty sand with varying amounts of gravel: The unweathered till is dense to very dense and moist, and was typically observed below depths of about five to seven feet. The overlying weathered till is generally medium dense to dense,moist to wet, and mottled. We observed approximately 2.5 feet of fill consisting of loose silty sand with gravel in Test Pit TP - 5 in the northwestern portion of the site. The Geologic map of the Everett 7.5-minute quadrangle, Snohomish County, Washington, by J.P. Minard(1985) shows the vast majority of the site mapped as Vashon till (Qvt), which is consistent with the soils observed in the test pits. The lower northern portion of the site is mapped as Vashon advance outwash (Qva). We did not observe soils consistent with outwash deposits in any of the test pits. The preceding,discussion is intended to be a brief review of the soil conditions observed in the site explorations. Detailed descriptions are presented on the Test Pit Logs attached in Appendix A. 33 Groundwater We observed groundwater seepage in all five of the test pits excavated at the site. The observed seepage was generally light and was perched above the dense to very dense till between depths,of about one and five feet. The occurrence of shallow perched groundwater is typical for sites underlain by till and till-like soils: We expect that perched groundwater levels and flow rates will fluctuate seasonally with the highest levels occurring during and shortly following the wet winter months(October through May). 3.4 Geologic Hazards We evaluated site conditions for the presence of geologic hazards as designated in the Everett Municipal Code (EMC). Chapter 37.080 (Geologically hazardous areas) of the EMC defines geologically hazardous areas as erosion hazard areas,landslide hazard areas,and seismic hazard areas. 3.4.1 Erosion Hazard Areas Chapter 37.080.3 of the EMC defines erosion hazard areas as follows: a. Those areas defined as high and very high/severe risk of erosion in the Dames and Moore Methodology for the Inventory,Classification and Designation of Geologically Hazardous Areas,City of Everett,Washington: July 1, 1991: i. High erosion hazard areas include slopes of 25 to 40 percent in Qva and Qal geologic units; and slopes of greater than 40 percent in other(not Qva or Qal)geologic units. Very high/severe erosion hazard areas include slopes of greater than 40 percent in Qva and Qal geologic units. Page No.3