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1 <br /> June 6,2008 <br /> Serenity Meadows <br /> L&A Job No. 8A017 <br /> Page 7 <br /> and structural damage. Therefore, we recommend that the fill and relic topsoil under the <br /> backyard and other places within the site be excavated out and regraded. In areas of roadways,. <br /> the unsuitable surficial soils should stripped down to the medium-dense weathered soils,while in <br /> areas of building lots the unsuitable surficial soils should be stripped down to the dense to very- <br /> dense,fresh,advance outwash or till soils. Conventional footing foundations placed on the dense <br /> to very-dense, fresh, advance outwash and/or till soils or on structural fill constructed over such <br /> competent basal soils may be used to support the residences to be constructed on the site. <br /> The onsite surficial soils contain a high percentage of fines, and are sensitive to moisture. They <br /> ' can also be saturated quickly and easily disturbed during and after extended periods of heavy <br /> rainstorms. Interceptor trench drains or ditches should be installed along the uphill boundaries of <br /> the site, as required, to intercept and drain surface runoff and near-surface perched groundwater <br /> away from construction areas to minimize soil erosion and to facilitate grading and foundation <br /> construction work. <br /> GEOLOGIC HAZARDS <br /> Landslide Hazard <br /> The site is mostlygentlyto moderatelysloped. The dense to very-dense,fresh, advance outwash <br /> Pe rY' <br /> and till soils underlying the site at shallow depth are of moderately-high to very-high shear <br /> strength and have good resistance against slope failures. Therefore, it is our opinion that the <br /> potential for deep-seated landslides to occur on the site should be minimal. <br /> Erosion Hazard <br /> The surficial fill,topsoil and weathered soils are of low resistance against erosion. Erosion may <br /> occur in such weak surficial soils over the steeper areas of the site if they are devoid of <br /> vegetation cover and overly saturated. Prolonged erosion may result in shallow, skin-type <br /> mudflows. The generally gentle to moderate terrain will greatly reduce the erosion hazard of the <br /> ■ LIU & ASSOCIATES, INC. <br />