4107 OLIVE ST 2018-01-02 MF Import

JRN-22-9E_ JTRI 14:2.0 If ` DAVID L. NELSON AND ASSOCIATES, INC. Consulting Engineering Geology October 10, 1990 "out No. 9490 " 4 the site is stable with respect to deep seate4 slides. The steeper gradients on site could be susceptible to shallow sloughing failures da+nelope, if ground water seepage (springs) Nara to occur in this vicinity. provisions for maintaining existing slope stability, including drainage control, earthwork (filling and grading) control and structure placemwit, are presented herein to reduce potential risk of slope failures. Landslide hazard within this area is eoosidered low, particularly if the leaxmmendatiens presented in the previous geotecWcal evaluation report are followed. Springs!tiround water Seepage Areas Phase two elements mentioned in the new ordinance are similar conditions, which are discvmaed together in this letter. During our &valuation of the site, we obaerved the surface areas for springs and seeps, and observed our backhoe exploration (test) pits for grvund water seepage conditions. We did not encounter any evidence of springs or soaps within the site slap the easterly slope. we did observe evidence of seepage along the northerly steep cut slope of Teeple Drive, and donmslope of the site to the east. this would indicate that ground water does occur within the area, but as interflow and perched water within the surf icial sandy soils and above the relatively impermeable glacial till and/or interglacial silts. where excavations occur (such as Teeple Drive) and they intersect this perched water, ground water seepage, or springs, may occur. Our discussions and recvmemdations in the prnevioun gooterhnical report present methods of mitigation of any perched or seepage waters encountered during conslxvction. Springs are not observed within the easterly, sloping portion of the property perhaps due to reduced perched water, or that no excavations occur within this area. The springs noted downelope of the s9te are expected to be the clevatiena at which the perched water intersects the ground surface. Steep slopes Associated with The Above Elements 7!e new ordinance states that steep slopes are those at 25 pervent or greater.