SSNL - Laserfiche WebLink

Home Browse Search

Nitrate Loading Study Irerracon Cho Property ■ Ripon, Califomia September 6. 2018 ■ Terracon Proiect No. NA187038 1.2 Mass Transport Soil Properties The below additional information pertaining to mass transport for each soil type was obtained from the USDA sources listed in Section 1.1. Delhi loamy sandy soils are located across approximately 82% of the northwestern portion of the site and consist of somewhat excessively drained soils. Delhi loamy sandy soils have 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. Timor loamy sandy soils comprise approximately 12% of soils near the southwestern corner of the site and consist of moderately well drained soils. Timor loamy sandy soils have 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 depth to hardpan, approximately 4 feet below grade surface (bgs), and rapid permeability. Hardpan can be broken up by chiseling or ripping which may improve leach field absorption. Chuloak coarse sandy loam soils comprise approximately 6% of soils near the southwestern comer 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. 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. 20 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 Library, 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. The groundwater flow direction and the depth to shallow, unconfined groundwater, if present, would likely vary depending upon seasonal variations in rainfall and other hydrogeological features. Without the benefit of on-site groundwater monitoring wells surveyed to a datum, groundwater depth and flow direction beneath the site cannot be directly ascertained. Responsive ■ Resourceful ■ Reliable 4