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n. In the Chart above, it is noted that the entire soil profile has a uniform nitrate-nitrogen content throughout the property, down to 24.5 feet. These nitrate-nitrogen concentrations are low indicating the soils have not been under agricultural production for a period of time. This will -` contribute a lower concentration of nitrate in percolating vadose zone water than if the property were under agricultural production. t F Nitrification is an aerobic reaction accomplished predominately by autotrophic bacteria which convert ammonium (NH,'-) to nitrite (NO2) and subsequently to nitrate (NO3). As referenced above, both the shallow and deeper surface and subsurface soils possess sufficient clay content to bind the ammonium ions, and to create microsites within the clay lattices that are anaerobic, thus F,. forcing denitrification. As discussed below, although the shallower east side soils did not I demonstrate acceptable percolative capacity during the four-hour percolation tests, nevertheless, a ismall volume of septic effluent will infiltrate and percolate within future leachline trenches and F nitrification should be impeded. C. PERCOLATION TEST RESULTS Shallow, intermediate and deep percolation tests were conducted on all three of the potential parcel areas. Test locations are denoted on the APN map. In accordance with EHD requirements, only F,, the shallow and deep pert tests are recognized as official. The intermediate depth tests done on the Middle and East Parcels were done to illustrate the potential for sump installation. The test results indicate sumps would not be viable at the east end of the proposed project. F The perc test borings were drilled on April 30. The shallow and intermediate borings were scarified to open smeared soil surfaces caused by the drilling process and the loose material removed. It was not possible to scarify the deep borings. Three inch O.D. perforated pipe was a placed in each boring after two inches of pea gravel was added. On the morning of May 5, the West and Middle test borings were presaturated with 12 inches of clear water. Pere testing f ' commenced the following day. There was no standing water in any of the test borings after the 24 hour pre-saturation period. Each boring was perc tested for four hours in conformance with S.J.C. Policy EHD 02-02. During the perc testing of the West and Middle Parcel areas, the East Parcel test borings were presaturated for testing that started the morning of May 7. There was no standing water in the East borings at the start of testing. 'The East Parcel tests were also conducted for four hours. Fj As indicated on the FIELD PERCOLATION TESTING REPORTS found in Appendix 4, the shallow soils at the west end and middle of the property exhibited acceptable, although comparatively slow perc rates, while the shallow soils at the east end of the property revealed Fnonexistent percolation. As noted, the deep perc test for the West Parcel began with acceptable fperc rates,but then percolation inexplicably ceased. This appeared to have been due to a cave-in. Fj The perc test results are summarized below for each of the three proposed Parcels: 5 �! 4 Chesney Consulting