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Fbe urce of this nitrate is indeterminable, but most likely from agricultural fertilizer applications ient to the property, and possibly from the density of surrounding septic systems. This will ussed in Section 4of this report. icted on the attached USGS Map, and the Tentative Map, the topography of the site is 105 ft MSL in the southwest comer of the property and declines to 99 ft MSL in the northeast corner of the property. Therefore, future septic system design criteria for slopes will not have to be considered if a house is built in the future. (§ 3.1, 3.2,3.3, and 3.4) Theree o " epn"air/Additiof cords on file for the septic systems that serve the on-site residential ! c es, and they have"apparently been functioning properly without any problems since the house was built moved onto the property in 1975. This may be attributable to low effluent flows from these on-site structures. (§ 3.5 .6) A review of Application Permits on microfiche file at EHD reveals there have bee three pplications for Repairs/Additions/Replacements to septic systems on Hansen Road with' one-half mile radius study area. (§ 5.4) This can be considered a high number of Repairs/Additions/Replace considering the medium density housing and may attributed to the indigeno s clay soil types at can be found in some of the surrounding shallow soils. (§ 5.1 and 6.0) SOIL PROFILE AND PERCOLATION TESTING (§ 5.4) The USDA Soil Map shows the on-site soil to consist offaCapay clay(#118 . Typically, the Capay soil is moderately well-drained,with moderately slow permeability m the shallower soils. Sufficient soil "fines" exist in the surface of the Capay soil type to impede exceedingly rapid percolation. Therefore, treatment of septic effluent under unsaturated flow conditions can occur before reaching the water table. As discussed below, the shallow and deep perc tests had excellent percolation, which was not necessarily to be expected given the Capay soil type. The perc tests indicate that the existing and any future leachlines will manage most of the septic system effluent. (§ 5.2,5.3, and 5.4) A Log of Boring using the Unified Soil Classification System(USCS), as observed in the two deep percolation test borings completed on Parcel 1 and Parcel 2, are don the E £RCOLATION TEST DADA SHEET. Generally, the underlying soils sho a clayey t with fuae_s`an�€o' ive with silt t the 10-15 foot depth (with encountered hardpan ; poorly-graded fine silty sand from 15 to 23 feet. (§ 6.1) Percolation testing was conducted in the locations as illustrated on the Tentative Map found in Appendix C. As referenced on the Tentative Map, the perc test location for Parcel I is west of the existing house and barn. The test location for Parcel 2 was west of the existing mobile home. These test locations maintained sufficient distance requirements between wells, property lines, etc. The following information describes the preparation of the percolation test borings and the actual percolation testing: Page -2- Chesney Consulting