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•; Earth <br /> Solutions <br /> NW«c <br /> April 26,2017 <br /> ES-5168 <br /> Earth Solutions NW LLC <br /> Habitat for Humanity of Snohomish County <br /> 16929 Highway 99, Suite 100 • Geotechnical Engineering <br /> Lynnwood, Washington 98037 • Construction Monitoring <br /> • Environmental Sciences <br /> Attention: Mr. Chris Anderson <br /> Dear Mr. Anderson: <br /> Earth Solutions NW, LLC (ESNW) is pleased to present this report titled "Geotechnical <br /> Engineering Study, Twin Creeks Village, 925, 925 '/2 A/B, C/D, E, AND 917 — 112th Street <br /> Southeast, Everett, Washington". Based on the results of our investigation, the proposed <br /> residential development is feasible from a geotechnical standpoint. Our study indicates the site <br /> is underlain primarily by firm glacial till deposits. During our subsurface exploration completed <br /> on March 29, 2017, groundwater seepage was identified at the test pit locations between about <br /> three to five feet below existing grades. The contractor should be prepared to control zones of <br /> groundwater seepage likely to be encountered during construction. <br /> In our opinion, the proposed residential structures may be constructed on conventional <br /> continuous and spread footing foundations bearing on competent native soil, recompacted <br /> native soil, or new structural fill. In general, competent native soil suitable for support of <br /> foundations will likely be encountered beginning within the upper two to three feet of existing <br /> grades. Where loose or unsuitable soil conditions are exposed at foundation subgrade <br /> elevations, compaction of soils to the specifications of structural fill, or overexcavation and <br /> replacement with suitable structural fill, will be necessary. <br /> Construction of the proposed stormwater detention vault within the northern portion of the site is <br /> feasible from a geotechnical standpoint. Based on our field observations, grade cuts for the <br /> vault are likely to expose very dense, unweathered glacial till. It is our opinion the native glacial <br /> till should not be considered an ideal geologic feature for accommodation of infiltration facilities, <br /> especially when encountered in a dense, compact state. In general, the glacial till should be <br /> considered impervious for practical design purposes. <br /> Pertinent geotechnical recommendations are provided in this study. We appreciate the <br /> opportunity to be of service to you on this project. If you have questions regarding the content <br /> of this geotechnical engineering study, please call. <br /> Sincerely, <br /> EARTH SOLUTIONS NW, LLC <br /> . .,:Adam Z. Shier, G.I.T. <br /> Staff Geologist <br /> 1805 -136th Place N.E.,Suite 201 • Bellevue,WA 98005 • (425)449-4704 • FAX(425)449-4711 <br />