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Fdies were conducted to test the proposed effluent receiving soils,calculate nitrate loading late the findings with the design parameters. nd chemical testing of the receiving soils was conducted. Physical testing included n testing and particle size analysis to determine soil characteristics. Chemical testing included analyses for the constituents that influence nitrate loading. • The capacities of the on-site soils were analyzed for: 1.)The ability to accept potential future sanitary wastewater effluent flows, 2.)To assess the characteristics of the on-site soil to mitigate nitrate impact, and 3.)To quantify nitrate impact potential to the underlying groundwater from percolating effluent. This was accomplished by the referenced testing and loading calculations. • Well water analyses for Nitrate and Dibromochloropropane(DBCP)has been completed by Woodbridge Winery for the on-site wells. EHD Unit Il Supervisors have determined this chemistry to be acceptable for inclusion in these Studies. • Analytical chemistry was conducted on two separate septic tank influents to accurately characterize the nitrogen concentrations and other constituents originating from the on-site sanitary wastewater. In addition, future sanitary wastewater flow volumes from the winery have been formulated to be 2,232,450 gallons per year. ✓ In summary,the soils testing and investigation has found the indigenous soils under the proposed sanitary wastewater disposal location,which is near the south end of the property,to contain a tight and compact fine sandy silt from the surface to 10 feet. Below 10 feet exists a sandy clay silt down to 25 feet where sandy fine sand is found again, and extends to 30 feet. At 35 feet, a sandy clay silt is found. The tight compactness of the soils extends down to exploratory boring termination of 35 feet. The predominately fine-grained material at typical leachline depths (42 inches)exhibited marginally acceptable percolation rates on the east side of the proposed disposal area and unacceptable percolation capabilities on the west side of this area. At the deeper depths representative of seepage pits, medium percolative capacity was observed. Although the test results show acceptable permeability in the deeper soils, long-term acceptance rates of sanitary wastewater effluent by the indigenous soils will unquestionably decrease over time. H . SOIL SUITABILITY STUDY FINDINGS BJECT PROPERTY AND SURROUNDING STUDY AREA INFORMATION .1. Surrounding land use to the north, south,east and west are vineyards,other types of agricultural tion land, and very low density housing. To the south is the Mokelumne River,which influences the ing groundwater. The land use referenced is illustrated on the San Joaquin County Parcel Viewer .1,3.2,3.3,3.4,3.5,3.6,3.7,6.8. Applications on microfiche files with the EHD reveal there have pproximately 10 permits issued for repairs/replacements/additions to existing systems on and around ery,within a one-half mile radius study area on Woodbridge Road. This can be considered a ratively high number of permits for the study area and indicates marginal soil permeability,especially top surface soils. 2 Chesney Consulting