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NORCAL COONSULTANTS , INC . • November 25, 2008 Mr. Don Ashton Bureau Veritas 6920 Koll Center Parkway, Suite 216 Pleasanton, CA 94566 Subject: Geophysical Investigation Walgreens, 15 West Harding Way, Stockton, CA NORCAL Project#08-304.30 Dear Mr. Ashton: The purpose of this letter is to confirm the findings of the geophysical investigation performed by NORCAL Geophysical Consultants, Inc. on the subject property.The field survey was performed on November 11,2008 by NORCAL Professional Geophysicist Donald J. Kirker. Logistical support was provided by Allison Florence of Bureau Veritas. Site information, provided by Bureau Veritas, indicates that this property was formerly occupied by a gas station. However, records are incomplete as to whether or not the underground storage tanks(UST's)were removed when the gas station was decommissioned. Therefore, the purpose of the geophysical investigation is to obtain subsurface information that will aid in determining if USTs exist within the designated limits of the survey area. In addition to the UST survey,subsurface investigations were conducted at 6 proposed boring sites. The purpose of these investigations was to locate detectable utilities in the vicinity of each proposed drilling location. The survey area, as specified by Bureau Veritas, is shown on the enclosed copy of a NORCAL produced field diagram. It is located in the southeast corner of the subject property and covers a 75 by 75 foot portion of the asphalt covered parking lot. Four of the proposed boring sites are located within this area. The remaining two are located inside the Walgreens Store and near the loading dock (not shown on the field diagram). Geophysical Methods and Field Survey For this survey,we used the metal detection(MD)and ground penetrating radar(GPR)techniques. The MD was used to detect shallow subsurface metal objects that may represent a UST. The GPR was used to aid in further characterizing the source of any detected MD anomalies. Typically, the magnetic (MAG) method is used in conjunction with the MD and GPR methods to investigate for UST's. However, interference caused by vehicles continuously passing through the survey area precluded the use of the MAG at this site. We obtained MD scans along both south-north and west-east trending traverses spaced approximately 5 feet apart over the survey area. The locations of buried metal objects (MD anomalies)and detected utilities were marked on the ground surface with spray paint. We obtained 321A BLODGETT STREET • COTATI, CA 94931 • TELEPHONE (707) 796-7170 • FAX (707) 796-7175 www.norcalgeophysical.com