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Interim Corrective Action Plan—Tosco(76)Service Station No. 111.95,Lathrop,California August 28,2002 Wetlands There are no wetlands in the vicinity of the site. Per the Basin Plan and topographic maps,the closest wetlands are approximately 3.25 miles southwest of the site, where the Paradise Cut drains to the San Joaquin River. The Paradise Cut is backed up into a wetland due to the presence of the Paradise Dam. Groundwater Per the Basin Plan, the existing and potential beneficial uses applicable to groundwater in the San Joaquin Basin include municipal and domestic water supply, industrial process water supply,industrial service water supply, and agricultural water supply. 4. The potential effects of residual contamination on nearby surface water, wetlands, and groundwater: In September of 1998,Alisto Engineering Group(Alisto)performed a'/2-mile radius water well search by reviewing water well driller reports on file at the California Department of Water Resources(DWR). Alisto's well search identified seven water wells within the 1/2-mile search area, however, Alisto reported that locations of the wells could not be determined from the information provided by DWR. A visual reconnaissance of the search area did not identify the locations of any water wells. In August, 2002, GR reviewed unpublished data and the GeoTracker website database for water wells within a '/2-mile radius of the site. Two wells were identified by GR as being within the search area. GeoTracker reported a municipal well as being located 504 feet from the site. Due to potential terrorist threat, all well location information has been temporarily removed from the GeoTracker database. Therefore, GR could not determine the location of the municipal well. Additionally, GeoTracker reported up to 11,000 feet of estimated error in the location of the municipal well. The second reported well within'/2-mile of the site is a destroyed municipal well owned by the City of Lathrop, originally located approximately 1,800 feet south of the site. Based on the information presented in subsections 2 and 3 above, the potential effects of residual contamination on nearby surface water and wetlands is considered to be minimal. However,based on the analytical results of the groundwater samples collected from the monitoring wells to date,the first aquifer beneath the site has been impacted by petroleum hydrocarbons. Although GR has identified one municipal well that is potentially located within.500 feet of the site,the distance to the municipal well and the fact that municipal wells typically have a screened interval depth below several hundred feet, make it unlikely that groundwater from beneath the site will reach the municipal well.The well name is listed on GeoTracker as Acampo Water System Well No. 2. GR contacted the County of San Joaquin Department of Public Works regarding the location of this municipal well and was informed that the Acampo Water System is in the City of Acampo, located approximately 25 miles north of the site_ 140193.13 7