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Nitrate Loading Study Irerracon Guillermo Ramirez Property Ripon, California April 29, 2019 n Terracon Project No. NA197019 rapid permeability and slow runoff. The rate of water in-take in irrigated areas is anticipated at 3.0 inches per hour. For homesite development with septic tank absorption fields, the main limitations are rapid permeability and poor filtration. A tillage pan may form if soil is tilled when wet; however, the pan may be broken up by chiseling or ripping. Chuloak coarse sandy loam soils comprise approximately 16% of soils near the eastern portion of the site and have moderately slow permeability. For homesite development with septic tank absorption fields, the main limitation is slow to moderate permeability which can be overcome by increasing the size of the leach field. Terracon searched the Department of Water Resources online Well Completion Records for additional information regarding soil lithology up to 0.5 miles of the site. The following two water supply wells were identified nearest the site. Well Number Latitude Longitude Depth Approximate Feet Distance/Direction from Site WCR2016-011554 37.783889 -121.070556 295.00 Adjacent/East WCR2014-014092 37.782778 -121.070556 260.00 Adjacent/Southeast Based on a review of the Well Completion records for the adjoining eastern and southeastern properties, the soils within the vadose zone (0 to 45 feet bgs) are comprised of alternating sand gravel, and/or clay strata which extend to depths of 295 feet bgs. Copies of the Well Completion records are included in Appendix C. Refer to Section 2.1 for further discussion regarding regional groundwater information. The longer effluent remains near the surface, the more treatment is enhanced due to natural processes within the soil. Based on the loamy sandy soils and rapid permeability anticipated for the majority of the surface soils on the site, the potential for effluent to remain near the surface is low; therefore, there is a potential leaching from sewage effluent or other surface contaminants may affect groundwater. 2.0 GROUNDWATER ANALYSIS 2.1 Regional Groundwater Based on a review of the San Joaquin County Flood Control and Water Conservation District Groundwater Report, from 2015 to 2016, Spring & Fall depth to groundwater near the site was between approximately 50 and 60 feet bgs. Based on a review of groundwater data available on the California Department of Water Resources (DWR) Water Data Librarv, between the years 2015 and 2018, depth to groundwater measured between approximately 45 to 58 feet bgs at groundwater wells located approximately one mile north and east of the site. Based on a review of the DWR Well Completion records (Section 1.2), in 2014 depth to static water level was reported at 58 feet bgs at the adjoining southeastern groundwater well and at 68 feet bgs at the adjoining eastern groundwater well. Responsive ■ Resourceful ■ Reliable 4