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Pacific Ridge — DRH, LLC ES-8528.01 <br /> July 18, 2022 Page 4 <br /> Groundwater <br /> Groundwater seepage was observed within three of seven test pits, generally in a perched <br /> condition atop the transition to unweathered glacial till deposits. In our opinion, perched <br /> groundwater is likely to develop atop the unweathered glacial till deposits encountered across <br /> the site when subjected to significant rainfall events and periods of extended wet weather. <br /> Groundwater seepage rates and elevations fluctuate depending on many factors, including <br /> precipitation duration and intensity, time of year, and soil conditions. <br /> Geologically Hazardous Areas Review <br /> ESNW reviewed Chapter 19.37.080 "Geologically Hazardous Areas" of the City of Everett (City) <br /> municipal code, along with the referenced mapping resources, to evaluate the presence of <br /> geologically hazardous areas at and surrounding the subject site. Geologically hazardous areas <br /> within the City include areas susceptible to Iandsliding, seismicity, or erosion. Based on our <br /> review, the subject site does not contain areas meeting City definitions of geologically hazardous <br /> areas. <br /> DISCUSSION AND RECOMMENDATIONS <br /> General <br /> Based on the results of our investigation, construction of the proposed residential development <br /> is feasible from a geotechnical standpoint. Our field observations indicate the subject site is <br /> underlain by about one to five feet of existing fill and topsoil. Underlying the fill and topsoil, <br /> medium dense to very dense glacial till deposits extend to depths of at least 10 feet below existing <br /> grades. <br /> Topsoil present below the existing fill will need to be removed from structural areas, and existing <br /> fill will need to be removed and/or reworked to the specifications of structural fill. New structural <br /> fill should be placed on competent native soil or reworked existing fill. <br /> After completing earthwork activities in accordance with recommendations in this report, the <br /> proposed structures can be supported on conventional spread and continuous foundations <br /> bearing on undisturbed, competent native soil, recompacted native soil, or new structural fill. <br /> Where loose or unsuitable soil conditions are encountered at foundation subgrade elevations, <br /> compaction of the soils to the specifications of structural fill, or overexcavation and replacement <br /> with suitable structural fill will likely be necessary. A representative of ESNW should confirm <br /> suitability of foundation subgrades at the time of construction. <br /> Due to the high moisture sensitivity of the site soils, foundation subgrade areas should be <br /> protected from wet weather or areas of remediation should be anticipated; a layer of crushed rock <br /> can be considered to protect foundation subgrade areas. If structural building pads are disturbed <br /> during wet weather, remediation measures such as cement treatment or overexcavation and <br /> replacement with rock may be necessary in some areas. Additionally, perched groundwater <br /> seepage may create unsuitable soil conditions above the hardpan which would require aeration, <br /> cement treatment, or replacement with crushed rock. <br /> Earth Solutions NW, LLC <br />