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Wright Environmental <br /> September 15, 1997 NORCAL <br /> Page 4 <br /> GPR Analy, <br /> We examined the GPR records for large parabolic reflection patterns indicative of <br /> UST's and discontinuous reflection patterns that can indicate the presence of buried <br /> debris or former excavations. <br /> SURVEY RESULTS <br /> The results of our investigations are described below and are shown on the Vertical <br /> Magnetic Gradient, Terrain Conductivity, and In-Phase Contour Maps presented on <br /> Plates 4-8. <br /> Parcels 1 , and 2 <br /> The EMLL scan indicated that several utility alignments exist. These alignments were <br /> detected trending north-south in the eastern and northern portions, and east-west <br /> through the southern and central portions of the area. The approximate locations are <br /> shown on Plate 1 . <br /> The underground utilities have a pronounced effect on the TC and IP Contour Maps <br /> shown on Plates 4 and 5, respectively. The linear contour trends and other localized <br /> variations defined on the TC and IP contour maps appear to be associated with the <br /> underground utilities described above. There appears to be minimal effects from <br /> above ground sources and there are no localized variations that are considered <br /> anomalous. <br /> The VMG Contour Map, Plate 6, shows more variability than the EM Contour Maps <br /> described above. There are two localized contour closures, labeled A, and B on Plate <br /> 6, that have no known source and are considered anomalous. Both of these <br /> variations are of moderate magnitude and may be caused by an object or mass of <br /> metal that is no greater than a small UST. The most significant variations occur <br /> within the three hatched zones shown on Plate 6. We detected utility alignments in <br /> all of these zones, however due to the strength of the magnetic variations, there may <br /> be buried metal in addition to the utilities. The contour closures within the remainder <br /> of the site appear to be caused by the underground utilities, and surface sources <br /> shown on Plate 1 . <br /> Parcel 5. <br /> The EMLL survey revealed several utility alignments traversing the survey area. The <br /> approximate locations of these alignments are shown on Plate 2. The TC and IP <br />