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11 December 2003 AGE-NC Project No. 03-1109 Page 2 of 5 Range and the Sierra Nevada,respectively.Rocks composing the basement complex of the province have not been completely defined but are believed to be metamorphic and igneous in origin. The northern and southern portions of the Great Valley Province have been designated the Sacramento and San Joaquin Valleys,respectively. Based on the General Soil Map from the San Joaquin County Soil Survey,published by the United States Department ofAgriculture Soil Conservation Service in 1992,the site area is within the Delhi- Veritas-Tinnin(DVT)association.The DVT soils are located within dunes,alluvial fans and stream terraces along the Stanislaus River,and generally consist of well drained coarse textured soils. The soils are generally derived from both marine and non-marine sediment, and are generally formed in alluvium derived from granitic and mixed rock sources. 2.2. GROUND WATER DEPTH AND GRADIENT The estimated depth to ground water at the site is approximately 20 feet below surface grade(bsg) based on information from Lines of Equal Depth of Water Wells Fall 1997, published by the San Joaquin County Flood Control District and Water Conservation District(SJCFCD).Based on review of a regional ground water elevation map published by the SJCFCD, the prevailing ground water flow direction in Manteca is generally toward the northwest, although flow directions may be both locally and seasonably variable. Based on data collected from wells located on the immediately adjacent (Rainwater) site, first observed saturated soil was between 15 feet bsg and 20 feet bsg. 3.0. SCOPE OF WORK Perchloroethene(PCE)has been detected in ground water samples collected from monitoring wells at the Rainwater site. Based upon the detection of PCE, the CVRWQCB is requesting the implementation of a soil gas vapor survey around the French Cleaners property.In a letter dated 10 November 2003,the CVRWQCB stated that"at a minimum,vapor samples from the vicinity of the sewer lateral connection of the building, and from the front and rear of the property." The proposed assessment activities will consist of the following tasks: • Permitting and pre-field work activities; • Geoprobe advancement and soil gas vapor sample collection; • Soil gas vapor sample analysis; Advanced GeoEnvironnlental,Inc.