Laserfiche WebLink
December lb, 1992 � WAWALAFAM <br /> • Unocal Service Station No 6981, Stockton, California Working To Restore Nature <br /> percent The production well exhibited non-linear head losses resulting in a low to <br /> moderate efficiency The limit of capture zone downgradient of the pumping test well is 18 <br /> feet <br /> SITE CONDITIONS <br /> Site Geol & <br /> I <br /> Sediments beneath the site consist primarily of clay, silt, and fine- to medium-grained sand <br /> Three generalized cross-sections A-A', B-B', and C-C' (Plates 5, 6, and 7) were constructed <br /> 1 using the Logs of Barings The surface trace of these cross-sections is shown on Plate 2 <br /> Cross section A-A' shows our interpretation of the soil stratigraphy beneath the site in the <br /> east-west direction, and cross section B-B' shows our interpretation of the soil stratigraphy <br /> 1 <br /> in the north-south direction Cross section C-C' is an enlargement of the area bisecting the <br /> tank pit and the dispenser islands The site is predominantly underlain by silt Lenses of <br /> poorly graded sand were encountered in borings B-1, B-3, B-5, B-14, and B-15 from <br /> approximately 22 to 65 feet below grade Lenses of silty sand were encountered in these <br /> borings and borings B-2, B-8, B-10, B-18, and B-19 The occurrence of these lenses are <br /> shown on Plates 5, 6, and 7 <br /> 1 <br /> Site Hydrogeology <br /> The depth to water beneath the site has dropped from approximately 50 feet below grade <br /> in February 1990 to approximately 56 feet below grade in September 1992 The direction <br /> of ground-water flow has been consistently to the northeast The ground-water gradient has <br /> • <br /> 38032-10 10 <br /> r <br />