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-- [5] CONCLUSIONS <br /> The shallow percolation rate for the subject parcel suggests there would be effluent percolation at <br /> the leachline depths of approximately 42 inches below grade. However, based upon the number <br /> of repairs and additions to septic systems in the project locale, leachlines in this area have a <br /> limited lifespan. Percolative capacity does exist at deeper depths because it is well known that <br /> this area possesses significant gravel strata. The final sewage disposal area for any proposed <br /> structure on Parcel 1 should be dependant upon the number of bedrooms. We are recommending <br /> a 10,000 to 12,000 square feet leachfield area to provide treatment of the septic effluent. <br /> Seepage pits must be installed for any future residential or commercial structure. If there will be <br /> several people inhabiting the structure, particularly children, a septic system should be oversized <br /> (increase the number of seepage pits) to accommodate additional wastewater flows. A 50% <br /> standby replacement area (100% for commercial) must also be incorporated into the design of the <br /> septic system. All related septic system structures and the domestic well must comply with <br /> published "distance" requirements from property borders, roads, easements, irrigation fields, etc. <br /> It must be recognized that all septic systems have lifespans. If the leachfield area should fail, the <br /> seepage pits will manage the effluent. Seepage pits can also fail, although over a longer time <br /> period. As referenced earlier, a failure would primarily result from the advanced formation of a <br /> "biomat" or "clogging mat" on the wetted soil/effluent interface. This mat is composed mostly of <br /> aerobic and anaerobic bacteria and bacterial products consisting of a slime of polyuronides and <br /> polysaccharides. If the soil/effluent interface is well aerated, a variety of soil microfauna such as <br /> nematodes and protozoa may digest the clogging mat bacteria. Since the subsurface soils consist <br /> of a tight, silty material, anaerobic conditions will probably prevail. This may hasten leachfield <br /> and seepage pit failure. <br /> If development should take place in the future on Parcel 1, we are recommending a deep perc test <br /> of 25 feet in the proposed location of the seepage pits. <br /> 3 <br />