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• Bureau Veritas November 25, 2008 Page 2 GPR data along these same traverses and analyzed the data for reflection patterns characteristic of UST's, utilities,and other subsurface features. In addition,the MD and GPR methods were used to investigate the boring locations for detectable utility alignments and potential drilling obstructions. Results The results of the MD survey defined the location of several utility alignments and one buried near surface metal object. The utilities trend throughout the site and consist of electric, storm drain, and undifferentiated utilities. The buried metal object is located on the west side of the survey area in line with an undifferentiated utility. The MD response over this object is consistent with effects typically associated with a utility vault or possible buried man-way cover. The results of the GPR survey defined reflection patterns typical of utilities and shallow fill horizons associated with the pavement. Over the MD anomaly, the GPR did not exhibit large reflection pattems typical of a utility vault or man-way cover. Therefore,this object is probably buried beyond the detection capabilities of the GPR. The results of the borehole site surveys are shown on the enclosed copies of the field diagram(BV- 1 through BV-4) and Borehole Site Survey Logs (BV-5 and 6). During the course of this investigation,we detected electric and undifferentiated utilities. The surface trace of the utilities,and the proposed boring locations, were marked with spray paint on the ground surface. Limitations Geophysical methods have limitations that may not allow for the detection of certain subsurface features. These limitations may be related to targets being deeper than instrument detection capabilities; targets not providing sufficient contrast with the surrounding materials, such as non- metallic pipes; and other objects or structures causing instrument interference that masks the detection of a target of interest. Therefore, it is possible that not all subsurface objects or features may be located or characterized. Also,the depth of detection of the GPR is dependent on site specific conditions. These conditions include the electrical properties of the subsurface soils, and the surface conditions over the suspected target. Typically, the GPR depth of detection will be reduced as the clay content in the subsurface increases. In some cases, the depth of detection will also be affected by the degree of soil saturation. We estimate the GPR depth of detection at this site to be about 2 to 3 tet. Standard Care and Warranty The scope of NORCAL's services for this project consisted of using geophysical methods to characterize the shallow subsurface. 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.