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I - Surrounding Iand use within the Delta has been for farming and recreation for many decades. Land f use is noted on the San Joaquin County Parcel Viewer Maps. The property is currently zoned AG-80. SSS§ 3.1, 3.2,3.3, 3.4, 3.5,3.6. Applications on microfiche file with the EHD reveals one permit for the referenced schoolhouse, which subsequently became a labor cam p hat the septic system leachfield was completely re-designed p The permit indicates that Y g d by Mike Huggins, R.E.H.S., of EHD. ff "The project site has level terrain; consequently, there will be no need to incorporate f desi considerations for slopes within the mounds gn ystem area. Mound systems are sensitive to sloping, and changes in design must be taken into consideration when natural ground sloping is present. It is imperative that during the preparation of the indigenous'Peat soil surface where the mound system is to be installed, be absolutely level and properly scarified beiween eight inches and one foot in depth to accept effluent percolating through the mound system as it encounters the native soil-effluent interface. B. SOIL PHYSICAL CHARACTERISTICS AND ANALYTICAL TEST RESULTS SSS§ 5.2. The surface and subsurface soil investigation and testing began with the use of a small backhoe from Dino & Son Ditching Service. This procedure is illustrated in photographs found in Appendix H. Two backhoe test pits were excavated and soil samples retrieved from three-foot depths. The first pit was directly under the easternmost existing leachline to test for soil chemistry under this leachline (Soil Sample ID: 3FTLL). The second pit was excavated under virgin soil where there was no impact from septic system effluent for comparison purposes (Soil Sample ID: 3FT). NLS§ 1.1, 1.2. As the noted on the A&L Laboratory Soil Analysis Reports, chemical analyses of the two soil samples quantify several constituents that influence future nitrate loading from this project. The important parameters for nitrate loading assessment are the organic matter, pH, cation exchange capacity (CEC), along with nitrate-nitrogen content of the soil. �) As noted, the organic matter in the surface soils is extremely high, which is to be expected in a peat soil. Interestingly, the nitrate-nitrogen concentration is 17 ppm under the existing leachline and 4 ppm under virgin soil. These differences in concentrations indicate that nitrogen liberated from the effluent several years ago apparently remains within the soil profile. Although the nitrogen r � concentration is 4x higher under the leachlines vs. virgin soil, due to the denitrification capabilities f.v of the peat soil (since organic matter is needed for promotion of denitrification) this nitrogen concentration may have been significantly higher in another soil type such as asandy silt. The pH of the soil is very acid which has an effect on ammonium formation and stability. A Iow pH would tend to keep the nitrogen in ammonium form and not in ammonia form, as would be observed in an alkaline soil. Since ammonium is the precursor to nitrate formation, this may be a reason higher nitrate concentrations were observed under the leachline. The CEC measures the ability of the soil to theoretically trap and hold ammonium molecules. Cation ' Exchange Capacities of the soil samples are comparatively high due to the high peat content. 3 Chesney Consulting