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13 August 2021 <br />Project No. 21-6530 <br />Page 5 of 14 <br />Advanced <br />An Stoyee-Ownrd0or , <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 eight miles southwest <br />of the subject property. The nearest surface water feature to the site is the Calaveras <br />River, which is approximately 0.4 miles northwest of the subject property. <br />4.1. GROUNDWATER DESCRIPTION FOR THE GENERAL AREA <br />According to the State of California Department of Water Resources (DWR) Sustainable <br />Groundwater Management Act (SGMA) Data Viewer, Seasonal Report for Spring 2020, <br />depth to groundwater at the site is approximately 70 feet below surface grade (bsg). <br />Between 2011 and 2019, depth to groundwater at the site has fluctuated between 70 and <br />95 feet bsg. Groundwater flow direction locally appears to be to the northeast. <br />Groundwater was not encountered in the 42 -inch -deep percolation test hole advanced on <br />12 August 2021. <br />4.2. GROUNDWATER CONTAMINATION IN THE AREA OF THE SITE <br />The immediately adjacent and outlying land use for the parcel is residential. Potential <br />groundwater contamination can occur from several sources including leaking <br />underground storage tanks, septic systems, agricultural activities, dairies, and stormwater <br />infiltration. <br />A review of the California Department of Toxics and Substance Control (DTSC) <br />EnviroStor Database and the Geotracker Web Site did not reveal any Leaking <br />Underground Storage Tank (LUST) sites within 0.5 miles of the site. <br />4.3. ON-SITE EXISTING WELL DESCRIPTION <br />There are no wells on the subject property. A domestic well will be constructed on the <br />subject property during site redevelopment to serve as the potable water source. <br />5.0. SOIL PROFILE <br />An OWTS Permit was issued for the property by the EHD on 02 August 2021 to perform <br />a percolation test (Appendix B). On 12 August 2021, a 4 -inch diameter hand auger was <br />