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Storm outfall arese occur along the slope at approxiruate locatione <br /> as ahown on the location map. These outfalls transmit eurface <br /> watere irom the upslope areas o�er the top-of-slope and into small <br /> swales down the slooe toward the toe-of-slope. These outfall <br /> areas genei•ally have large diameter pipes which have been broken <br /> or separated part way down the slope and thus flow upon native <br /> soil from the break dovm to the toe-of-slope . These waters are <br /> then transmitted out to Possession Souad through a s�ries of <br /> burried culverts under the railroad tracks. Some erosion has <br /> occurred within the areae of the outfalls. particularly below <br /> the areas of the broken pipe. We observed these areas and fcund <br /> that the soils a•re quite dense and that erosion appeare minimal. <br /> Near the top-of-slope where the soils are less clense and sandier� <br /> the slope is more Busceptible to erosion. �Some� drainage pipes <br /> :rom the residences outfalJ. near or along the top-of-slope areas. <br /> Erosion and surface failures due to the�e drain pipea were observed <br /> and appear to be more active than the pipe outfall areas within <br /> the lower elevation soils� <br /> The drainage areas o£ Powder Mill Gulch and Edgewater Creek <br /> appear to significantly influence ground water occurrences within <br /> the stu3y area. It appears most ground water and sur£ace water <br /> is directed into these drainage areas, contributing to the minimal <br /> amounts of ground water observed outcrcpping alor.g the slope . I <br /> The depression area and general surface drainage noted on the air <br /> I <br /> photo interpretation map appear to be the most influential drain- � <br /> age and hydrologic conditions within the site arear in addition I <br /> to the storm drainage . <br /> SLOPE STABILITY <br /> In general. we would consider the subject study area to be rela- <br /> tively stable, with areas of local surficial instability. It <br /> appears that the majority of recent failures observed are surficial <br /> ir. nature, generally less than 5-10 feet deep, or are erosional <br /> in nature and have been created over a longer length of time. <br /> We believe the slope area can be divided into two main areas I <br /> of activity� The easterly larger scale and older activity area, <br /> and the westerly smaller scale and younger activi.ty area. The ' <br /> geologic setting and the cunstruction of the rai:lroad track/sea � <br /> wall toe contribute greatly to the over,�ll stability observed. <br /> -6- <br />