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• TERRAX Environmental Engineering and Consulting Terrax's review of historical aerial photographs records, and information obtained from the EDR database report indicate that the subject site was historically occupied by a used car dealership from at least 1935 until at least 1972. Historic records indicate that this dealership had both gasoline and waste oil underground storage tanks (USTs). Terrax conducted a Site Investigation as reported in November 17, 2016. On November 1, 2016 Terrax subcontracted with Environmental Control Associates, Inc. (ECA, State of California C57 Water Well Drilling Contractor License Number 695970) to provide and operate drilling equipment. ECA, under the direction of Terrax, advanced 2-inch soil borings B1 through B6 with a truck-mounted Geoprobe Model 5410 direct push rig. Each boring was completed with soil vapor probes (1 /4 -inch) installed at 5 and 15 feet bgs The wells were completed with flush mounted well boxes. 2.0 Local Geology and Hydrogeology The subject property is located in the Eastern San Joaquin Subbasin of the San Joaquin Valley Groundwater Basin in the southern part of the Great Valley of Central California (also known as the Central Valley). The Eastern San Joaquin Subbasin is defined by the areal extent of unconsolidated to semi-consolidated sedimentary deposits that are bounded by the Mokelumne River on the north and northwest; San Joaquin River on the west; Stanislaus River on the south; and consolidated bedrock on the east. Water bearing formations consist of the Alluvium and Modesto/Riverbank Formations, Flood Basin Deposits, Laguna Formation and Mehrten Formation. The Alluvium and Modesto/Riverbank Formations are exposed in the area of the subject property. These deposits are Recent to Late Pleistocene in age and consist primarily of sand and gravel in the fan areas while clay, silt and sand are dominant in the interfan areas. These units range in thickness from a thin veneer on the east side of the basin to over 150 feet near the center of the basin. Because of overdraft of groundwater resources, groundwater levels in the area have declined as much as 100 feet in the past 40 years. The presence of an overdraft-induced groundwater depression northeast of the subject property causes groundwater flow beneath the subject property to trend to the northeast. According to the State Water Resources Control Board (SWRCB) GeoTracker Website, there are several nearby Leaking Underground Storage Tank (LUST) sites. Available monitoring data for these sites indicate that depth to first observed groundwater is approximately 20 feet bgs. Page 2 • CaXikorciva, 92649