Laserfiche WebLink
Geobgkat ncicnks I" Page 3 <br /> Groundwater Monitoring Report <br /> Project No 425 2 <br /> November 8,2005 <br /> batholithic and metamorphic rocks are poorly transmissive, however the overlying <br /> ' sedimentary layers are often quite permeable These unconsolidated layers include <br /> Pliocene/Pleistocene age continental deposits, Pleistocene age lacustrine and marsh deposits, <br /> and Holocene older and younger alluviums and flood-basin deposits <br /> 1 1.2 Regional Stratigraphy <br /> ' The following information comes from the United States Department of Agriculture — Soil <br /> Conservation Service (USDA) Soil Survey of San Joaquin County, California (McElhiney, <br /> M A , 1992), indicates the area surrounding the site is predominately made up of one general <br /> ' soil type <br /> • Capay— Stomar — Zacharias A gentle 0 to 2 percent slope, moderately well drained and <br /> well drained, moderately fine textured, gravelly moderately fine textured, and fine <br /> ' textured soils that are very deep, in interfan basins and on alluvial fans and stream <br /> terraces <br /> ' • The USDA Soil Survey of San Joaquin County, California (McElhiney, M A , 1992), <br /> states the soils beneath and adjacent to ST are categorized as <br /> o Capay clay Wet 0 to 2 percent slope, very deep, moderately well drained, nearly <br /> level soil is in interfan basins It formed in alluvium derived from nixed rock <br /> sources Typically the surface layer is grayish brown and dark grayish brown clay <br /> about 20 inches thick and the next 60-inches is typically pale brown silty clay loam <br /> ' and clay loam Slow permeability, high shrink-swell potential, low strength, and <br /> high water table <br /> ' 1.3 Lithology and Soil Characteristics <br /> The following section discusses the subjective field observations and geology documented <br /> 1 during this investigation based on the interpretations of the field geologist Cross sectional <br /> views are included in GTIs Additional Site Characterization and P Quarter 2004 <br /> Groundwater Monitoring Report dated March 22, 2004 <br /> ' In Summary <br /> • The lithology of the site is basically, alternating layers of clay-sand mixtures and sand- <br /> gravel mixtures <br /> ' 8 The lithology between the surface and 20-feet bgs is predominately clays and sands <br /> ® The lithology between 20 and 40-feet bgs is predominately sands and gravels <br /> e The lithology between 40 and 80-feet bgs is comprised of alternating layers of clay-sand <br /> ' mixtures and sand-gravel mixtures approximately 2 to 8 feet in thickness <br /> i <br />