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Wright Environmental ' .. September 15, 1997 NORCAL Page 5 Contour Maps, Plate 7, have localized contour closures that appear to be caused by surface metal sources as well as the utilities mentioned above. These surface sources include the billboard and debris to the south. There are a few localized contour closures elsewhere within this parcel, however they are of low magnitude and probably represent limited amounts of scattered debris. Many of the magnetic variations shown on the VMG Contour Map, Plate 7, also appear to be caused by the underground utility alignments described above. There are two zones of high magnitude magnetic variations, and a smaller localized zone that are labeled A, B, and C, respectively, on Plate 7. Zones A, and B are probably due to unknown subsurface debris. The GPR data collected over these zones revealed discontinuous reflection patterns that we interpret to be caused by scattered debris. We did not observe the characteristic large parabolic reflection patterns that are typical of UST's. Zone C is located near a utility alignment, however, the contour closures are laterally offset from this alignment, therefore it may be caused by an additional source. Parcel 6 The EMLL scan did not reveal the presence of underground utilities at this parcel. The lack of closely spaced contours on the TC and IP Contour Maps indicates that there is very little subsurface material variation. The TC Contour Map shows linear contours along the survey perimeter, and a few localized contour closures in the southern portion of the site. The linear contours probably represent the effects of the nearby fence. The localized closures to the south probably represent limited, scattered, non-metallic debris. The VMG Contour Map also shows linear contours along the survey perimeter. As described above, we interpret the linear contours to be caused by the fence. There is one significant variation, labeled A on Plate 8, near the southern limit of the survey area. This variation is located near the metal plate described above. It is not clear whether this magnetic variation caused solely by the metal plate or an additional buried object. The remainder of this area appears to be free of any significant buried sources. STANDARD CARE AND WARRANTY The scope of NORCAL's services for this project consisted of using geophysical methods to explore for UST's, and other buried debris. The accuracy of our findings is subject to specific site conditions and limitations inherent to the techniques used. We performed our services in a manner consistent with the level of skill ordinarily exercised by members of the profession currently employing similar methods. No warranty, with respect to the performance of services or products delivered under this agreement, expressed or implied, is made by NORCAL.