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I. Kleinfelder December 10, 2003 Page 3 SURVEY RESULTS The results of the geophysical survey are shown on the Geophysical Survey Map (Plate 1). This map shows the locations of aboveground and detected subsurface features. The locations of the GPR traverses are also included. We interpreted four GPR anomalies, labeled A-D, that could possibly represent USTs. We also identified numerous other GPR anomalies, one MD anomaly and 9 utilities/utility segments. A more detailed discussion regarding these features follows below. GPR Anomalies Based on our analysis of the GPR data, we have identified localized GPR reflections that may be caused by buried objects and/or subsurface material changes. These areas with localized reflections are referred to as anomalies and are shown on Plate 1 as either diagonally-shaded areas or double- headed arrows where they were observed along the GPR traverses. Some of the shaded anomalies are shown as enclosed areas (with a solid perimeter line) since they are defined on each side on both north-south and east-west profiles. Other shaded zones were only observed along profiles in one orientation and therefore the areal extent can not be determined in all directions, and a solid perimeter line is not shown.. Our interpretation of the GPR records indicates that only four of these anomalies, labeled A-D, have subtle characteristics typical of a UST. These characteristics include high amplitude localized reflections in the upper four feet that 1) exhibit some aspects of the reflection curvature of a UST, and 2) cover an area large enough to represent the response from at least a small UST. Anomaly A is semi-coincident with a patched area in the concrete. Certain types of non-UST sources can also cause similar GPR anomalies. The sources may include subsurface objects such as pipes/utilities and debris, or even changes in material properties, such as a change from native soils to backfill in a previously excavated area. The GPR anomalies marked with the double-headed arrows are typical of small, localized objects/debris, or in some cases can represent a short segment of a pipe. The remaining unlabeled areal GPR anomalies also did not exhibit reflection characteristics of a UST and therefore may represent a different type of buried object, or some change in subsurface materials. Based on our interpretation of the GPR data, these features are most likely insignificant with regard to the presence of USTs, but are shown to provide an indication of the variability in subsurface conditions that may be encountered at the site. The metal detector is typically used to verify the existence of coincident large metal objects such as USTs at the GPR anomaly locations. However, this was ineffective at A due to interference from the reinforcement in the concrete. At B-D, we did not observe a significant metal response. Although this may indicate the lack of metal at these locations and therefore the potential absence I.