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z •� � i Chevron U.S.A. - Page 2 water conditions. The report concluded that shallow soil at the subject property were predominantly comprised of clay and sands underlain by interbedded silts and clays to the maximum depth of the exploration. Ground water was not encountered during the course of subsurface exploration. Minor levels of petroleum cons s were reported in one of the — I 0 L A F 1 LE �}C soil borings (C-D) at approximate depths of 20 and 30 feet below existing grade. The report summarized that the chemical quality of the ground water at the subject property was not known, and that at least 22 ground water monitoring wells were situated within a 1/2 mile radius of the subject property. One monitoring well was described as existing at the ^ - �,�e subject property. � U A letter prepared by the San Joaquin Local Health District dated February 1, 1989 was received by Chevron U.S.A. on February 8, 1989, which directed Chevron to conduct further assessment of the subject property. As a result of that request, Chevron has requested that Dames & Moore prepare a workplan for the installation of three ground water monitoring wells at the subject property. The following proposed preliminary site characterization workplan summarizes the details of our proposed investigation at the subject property. PURPOSE AND SCOPE OF SERVICES The purpose of the proposed investigation will be to install three ground water monitoring wells at the subject property in order to obtain ground water samples. Additionally, se soil samples obtained from the soil borings advanced to install the monitoring wells will be analyzed for petroleum hydrocarbons presence and concentrations. The ground water samples obtained from the monitoring wells installed would be analyzed to determine if petroleum hydrocarbons contamination has impacted ground water resources beneath the subject property. The investigation will be accomplished by exploratory soil boring and soil sampling, installation of ground water monitoring wells, and chemical analysis of soil and ground water samples. The data obtained from the field and laboratory investigation, coupled with review of previous site investigations and published data regarding the geologic and hydrogeologic conditions in the vicinity of the subject property will be used to help identify the presence and concentration of contamination in subsoils and ground water resources. The proposed scope of services will include the following tasks: o Research and review of pertinent, readily available geologic and hydrologic literature; o Obtain necessary permits prior to the commencement of the field portion of the investigation; o Drilling and sampling of subsoils for chemical analysis; o Installation, development and sampling of a ground water monitoring wells; o Chemical analysis of ground water samples to detect the presence and concentration of petroleum constituents; o Preparing a report to present our findings, conclusions and.recommendations.