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- 8 - <br />• The overburden soils at shal:.ow depths typically exhibit low <br /> to moderate change potential and mx7erate shear strength when loaded <br />at existing ~misture and density conditions. The silt and fine sands <br />within the valley bottaa also exhibit tendencies to compress <br />moderately when wetted. Moist upper clays encountered within the <br />plateau area do not exhibit significant swell potential. However, if <br />allowed to dry, moderate to high swell potential would be anticipated <br />such as exhibited by some of the lower dry clays (see Figs. 18 <br />and 22). Swell pressures between approximately 2,000 to 10,000 psf <br />were measured. <br />Permeability tests performed on rertelded samples of the clays and <br />sandy silts, presented in Table II, irrlicate minor seepage potential. <br />Natural clay soils within the upper plateau area would also be <br />• relatively impervious. Organic matter tests were conducted on the <br />topsoil layer (Table III). <br />Moisture contents were generally described as being rtuist to very <br />moist for near surface soils. Within most of the plateau area, soils <br />became only slightly iroist with. dapth, whereas in the lower area near <br />the river, free water was encountered at depths 3 to 10 feet. Ground <br />water levels encountered at the boring locations are presented on <br />Figs. 4 through 9. Seasonal fluctuations to these general trends <br />should be anticipated, especially during spring runoff when perched <br />water conditions can develop. <br />' Foundations: Based on anticipated construction and soil conditions <br />• <br />