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28 September 2022 Project No. 22-6994 Page 10 of 15 AdvancedGeo An Employee Owned Company information provided by the United States Department of Agriculture's Soil Geographic Database (USDASGD). The USDASGD soil survey indicates the soil type for the property is predominantly composed of the Madera -Alamo complex having 0 to 1 percent slopes (#195). The Madera -Alamo complex is composed of alluvium derived from granitic rock sources. Soils are described as moderately well drained, with very high runoff, and salinity ranging from 0.0 to 2.0 millimhos per centimeter (mmhos/cm). The Madera -Alamo complex typically features sandy loam from 0 to 10 inches bsg; clay from 10 to 20 inches bsg; and indurated soils from 20 to 60 inches bsg. 7.2. MASS TRANSPORT PROPERTIES OF UNDERLYING SITE SOILS The percolation test and dominant soil type at the site indicates that the soils are semi- permeable and have moderate water storage. These soils will allow moderate infiltration of water through the surface soils. The longer the effluent remains near the surface, the more treatment is enhanced due to natural processes within the soil. If the permeable soils exist to the depth of the groundwater table, it is possible that surface contaminants may be transported fairly rapidly. 8.0. GROUNDWATER ANALYSIS The subject property is supplied with potable water by the onsite domestic water well located to the south of the existing residence (Figure 2). A groundwater sample was collected from the well and analyzed for nitrates as part of this study. 8.1. DESCRIPTION OF LOCAL GROUNDWATER According to the DWR SGMA Data Viewer for Spring 2021, depth to groundwater at the site is approximately 90 to 95 feet bsg. Between 2011 and 2021, depth to groundwater at the site has fluctuated between 70 and 100 feet bsg. Groundwater flow direction locally appears to be toward the northwest. Groundwater was not encountered in the 118 -inch - deep percolation test hole advanced on 26 September 2022. 8.2. EXISTING OR POTENTIAL GROUNDWATER CONTAMINATION The immediately adjacent and outlying land use for the parcel is residential and agricultural. Potential groundwater contamination can occur from several sources including leaking underground storage tanks, septic systems, agricultural activities, dairies, and stormwater infiltration. A review of the DTSC EnviroStor Database and the Geotracker Web site did not reveal any LUST sites within a half -mile radius of the site. The review did not reveal any other sites of environmental concern within a half -mile radius of the site. Based on the