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� u (§ 7.0) CONCLUSIONS The perc test results for proposed Parcels 1, 2, 3 and 4 show acceptable percolation for the in of septic system effluent flows at the typical leachline depth of 42 inches. As noted from the perc test on proposed Parcel 2, the fine sandy clay soil encountered will be beneficial for the retention of ammonium molecules and increase denitrification potential for ammonium which does convert to nitrate. The percolation test for this Parcel indicate that near optimum percolation rates (not too fast or too slow) will exist within the soil environment under the new leachfield to be installed. EHD requires that there be sufficient distance for"treatment' of septic effluent before it encounters the groundwater table. This distance is normally regarded to be five feet in leachlines and 10 feet with sumps. Therefore, sufficient distance exists between the bottom of a leachline and/or sump and the current groundwater depth of 55 feet. (§ 6.8) The number of leachlines, and septic tank sizes are unknown for proposed Parcel l because at this point in time, the exact number of bedrooms is unknown. (§ 6.7)No problems are anticipated for any future septic system on the property, other than typical lifespan concerns. Engineered septic systems will not have to be installed for this proposed subdivision,unless there are continued failures on any of the Parcels. It will be at the discretion of EHD to approve the installation of sumps at the ends of the leachlines for the new residential structure on Parcel 2. The almond trees that are currently in the leachfield area may remain, again under the discretion of EHD. The trees are microsp =er irrigated; consequently, there are no inundated conditions such as would be found wr oo irrigation. I ree roots may absorb nitrogen from the leachfield, however, one significant problem with placing the leachlines down the tree middles (in-between tree rows) is root intrusion. Each new system must have at least a 50% standby replacement area incorporated into the design of the septic system, which should not be a problem on Parcel 2. Ample area exists since the leachfield and surrounding area are in almond orchard production. All related septic system structures and the new domestic well must comply with the published "distance" requirements from property borders, roads, structures, etc. As referenced, no seepage pits are allowed to be installed in this area. It is important to recognize that all septic systems have a lifespan, which is dependant on several factors and is difficult to determine. Septic system leachline failure would primarily result from the advanced formation of a"biomat" or'clogging mat' on the wetted soil/effluent interface. This mat is composed mostly of aerobic and anaerobic bacteria and bacterial products consisting of a slime of polyuronides and polysaccharides. If the soil/effluent interface is well aerated, a variety of soil microfauna such as nematodes and protozoa may digest the clogging mat bacteria. Page:-5- Chesney Consulting