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Background <br /> Kaprealian Engineering's July 15, 1992 Report (KEI-P88-1013.R2) <br /> addressed to UNOCAL Corporation, provides site description and back- <br /> ground, and a description of their recent field activities at the site <br /> which need not be repeated in this report. <br /> Well Damage During Excavation <br /> As stated in KEI's July 15, 1992 Report, three of the four subject <br /> monitoring wells (MW4, MW5, and MW9) "suffered various amounts of <br /> wellhead damage" during the excavation of the site by UNOCAL's con- <br /> tractor. The contractor used backhoes and frontend loaders to do the <br /> excavation, constructing a ramp in the northeast corner of the excava- <br /> tion for access, and then stockpiling the excavated materials around <br /> the north, east, and south sides of the excavation. As near as we can <br /> tell, a large amount of stockpiled excavated soil was placed directly <br /> on top of MW3, MW4, and MW5. Whether any precautions were taken by <br /> UNOCAL, KEI, or the contractor to mark or protect the wells is unknown <br /> to the owner. <br /> According to KEI's July 15, 1992 Report, an attempt was made to sample <br /> MW3, MW4, and MW5 on November 29, 1988 during the excavation project. <br /> KEI's report stated that these wells had been "damaged during the soil <br /> excavation" and "were in need of repair. " <br /> Backfilling and grading of the site was completed by UNOCAL's contrac- <br /> tor on or about December 12, 1988. At turnover, there was no marking <br /> or other identification on-site of MW3, MW4, Mw5, or MW9. UNOCAL was <br /> asked on December 14, 1988 to obtain a statement of site release from <br /> the appropriate environmental health officials so the owner could <br /> proceed with construction of the new commercial building for which a <br /> building permit had been issued by the City of Stockton the preceding <br /> June. <br /> Site Turnover <br /> Soil remediation was reportedly complete in December 1988, and the <br /> site returned to the owner to proceed with the construction of his <br /> new commercial building. According to one of the owners Mr. Max <br /> Stone, and our Construction Manager Mr. Robert Romero, when the site <br /> was returned by UNOCAL, there were no markers or anything on-site to <br /> indicate where any of the remaining wells were. The site had been <br /> graded and leveled to the point that additional grading for the new <br /> building was unnecessary. <br /> Building Construction <br /> The owner completed work on storm drains and parking lot extension <br /> north of the site, toward Chili's Restaurant in the Spring of 1989. <br /> This would be in the general area of MW9 according to Figure 2 of the <br /> b:\mwj-#12\Site-Rep.ort <br /> Printed: September 22, 1992 Page 2 <br />