Laserfiche WebLink
17 January 2020 AdvancedGeo <br /> Project No. 19-4964 AnEmp/oyee-OwnedCompany <br /> Page <br /> g <br /> of the fresh groundwater in the Central Valley is contained in the post-Eocene-aged <br /> continental rocks and deposits and in the Holocene-aged river deposits consisting of <br /> gravel, sand, silt, and minor amounts of clay. In general, these geologic materials <br /> comprise a major widespread aquifer extending hundreds of feet deep and occasionally <br /> containing individual confining layers. The Modesto, Riverbank, Turlock Lake Formations <br /> and overlying recent alluvium are the principal source of domestic groundwater in the <br /> 13,500-square mile San Joaquin Valley Groundwater Basin (Basin 5-22). This basin is <br /> drained primarily by the San Joaquin River, which is approximately 2 miles west of the <br /> property and is the nearest surface water feature near the site. <br /> 4.1. GROUNDWATER DESCRIPTION FOR THE GENERAL AREA <br /> According to the San Joaquin County Flood Control and Water Conservation District's <br /> Lines of Equal Depth to Groundwater Fall 2018 and the Department of Water Resources <br /> (DWR) Water Data Library, depth to groundwater at the site is approximately 20 to 25 <br /> feet below surface grade (bsg). Groundwater flow direction locally appears to be toward <br /> the northeast. Groundwater was not encountered in the 42-inch deep percolation test hole <br /> advanced on 09 January 2020. <br /> 4.2. GROUNDWATER CONTAMINATION IN THE AREA OF THE SITE <br /> The immediately adjacent and outlying land use for the parcel is governmental, residential <br /> and agricultural. Potential groundwater contamination can occur from several sources <br /> including leaking underground storage tanks, septic systems, agricultural activities, <br /> dairies, and stormwater infiltration. <br /> A review of the California Department of Toxics and Substance Control (DTSC) <br /> EnviroStor Database and the Geotracker Web site revealed one (1) leaking fuel <br /> underground storage tank (LUST) site just slightly outside a half-mile radius of the subject <br /> property. However, the site has been closed for over 20 years. Based on the status of the <br /> investigation and its distance and direction from the subject property, the closed <br /> investigation should not impact the subject property. The review did not reveal any other <br /> sites of environmental concern within a 0.5-mile radius of the site. <br /> 4.3. ON-SITE EXISTING WELL DESCRIPTION <br /> There is one existing domestic water supply well on the property. The installation date <br /> and construction specifications of the well are unknown. There is one permit on record at <br /> EHD (SR0058508) dated October 2009 for pump replacement. The permit states that the <br /> pump was set to 100 feet bsg and standing water was located at 45 feet bsg. AGI <br /> reviewed files using the Department of Water Resources (DWR) online database and <br /> could not locate any additional information about the well. Currently, the well provides <br />