SITE INFORMATION AND CORRESPONDENCE

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NORCALCOONSULTANAIS . INC . • January 3, 2012 Mr. Daniel Villanueva Advanced GeoEnvironmental, Inc 837 Shaw Road Stockton, CA 95215 Subject: Geophysical Survey 520 N. EI Dorado, Stockton, CA NORCAL Job No. 11-492.04 Dear Mr. Villanueva: This letter presents the findings of a geophysical investigation performed by NORCAL Geophysical Consultants, Inc. on a portion of the subject property in Stockton, CA. The field survey was conducted on December 21, 2011 by NORCAL California Professional Geophysicist Donald J. Kirker. Logistical support was provided by Daniel Villanueva of Advanced GeoEnvironmental, Inc. 1.0 SITE DESCRIPTION AND PURPOSE The subject property comprises a vacant bank building and asphalt covered parking lot. The area of investigation, as specified by Advanced GeoEnvironmental, measures 70- by 80-ft and covers the southwest corner of the parking lot adjacent to North Eldorado and East Fremont Streets. As shown on Plate 1, it is generally free from above ground objects, except for a narrow planter to the north and a wrought iron fence along the west and south borders. Site information, provided by Advanced GeoEnvironmental, indicates that the survey area was formerly occupied by a gas station. However, it is not known if the underground storage tanks (USTs) used to store gasoline were removed when the station was decommissioned. Therefore, the purpose of the geophysical investigation is to obtain subsurface information that will aid in determining if LISTS exist within the designated limits of the survey area. 2.0 FIELD INVESTIGATION Prior to proceeding with the geophysical survey, we established a horizontal control grid using a fiberglass measuring tape and marking paint. The marking paint was used to mark the grid nodes every 10- by 10-ft on the ground. These grid nodes were then used to guide the field survey. The limits of the respective survey area are shown on Plate 1. The use of a particular geophysical method is typically dictated by the character of the subsurface target and its proximity to above ground objects. Subsurface targets, such as USTs, utility vaults, utilities, and debris, are often both metallic and nonmetallic in nature. These features can produce subsurface magnetic and electrical contrasts that can be delineated by certain geophysical methods. These include, but are not limited to, vertical magnetic gradient (VMG), metal detection (MD), electromagnetic line locating (EMLL), and ground penetrating radar (GPR) methods. 321A BLODGETT STREET - COTATI. CA 94931 • TELEPHONE (707) 796-7170 • FAX (707) 796-71.75 www.norcalgeoPhys,cal.com