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Y Woodward-Clyde Appendix A. WCC submitted the Preliminary Report to the RWQCB on June 23, 1986. While waiting for RWQCB review, Placer Tractor under contract to Caltrans remove the underground storage tanks in February 1989. On September 14, 1989 (letter attached in Appendix A) after review of the Preliminary Report, the RWQCB directed OSA to proceed with a site investigation and complete the Problem Assessment Report. The object of this work was to further define the limits of subsurface contamination and idenliiy applicable remedial alternatives. The results of this work and a review of applicable remedial alternatives are described below. A checkiisi of the items required by the RWQCB's Guidelines for a Problem Assessment Report is described below. A copy of the RWQCB's March guidelines used for the preparation of this report and a copy of WCC's 1988 Problem Assesement Report Is provided In Appendix A. 1.2 Report Content This report contains the information required in RWQCB's Guidelines 24 March 1987 to complete a Problem Assessment Report, The information required on pages 3 and 4 of these guidolinesare presented as follows: 1) tables 1 through 5 present raw laboratory and well survsy data, 2) Figures 4 through 8, and Figure 10, show the limits of vapor, W� soil, and groundwater phase contamination, 3) Table 3 and Figure 8 shows the depth to first groundwater, 4) Figure 9 shows the direction of groundwater flow with calculations of the horizontal groundwater gradient in section 2.6 of the text, 5) Figure 8 shows the soil stratigraphy in cross section using the boring logs provided In Appendix A and those from WCC's 1987 report, 6) Figure 2 shows the locations of buildings within the area of the subsurface hydrocarbon spill that may be Impacted by soil gas vapors (WCC's 1988 Preliminary Report summarizes the locations of wells within 112 mile of the site which may be impacted at some future date by subsurface migraf€on of the plume), 7) Figure 10 shows the estimated limits of contamination with projections of the "zero line", 8) there Is no discussion of floating product because it was not observed at the site, 9) section 6 evaluates remedial action alternatives.,iapplicable to the site, and section 7 evaluates their cost effectiveness and recommends a preferred remedial alternative. In addition, all data and maps are presented with north arrows and scales. Figure 3 shows the locations of utNitfes, buried lines, and other pertinent subsurface features, and all logs have been reviewed and approved by a registered California geologist. This work does not identify the depth to the second groundwater, or delineate the extent of the horizontal or vertical plume beyond the projections provided on Figure 9. Recommendations to complete this work is presented in section 8 and is required to fulfill the RWQCB's guidelines for completing a Problem Assessment Report. z ; y