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N%.00 ..i [5] CONCLUSIONS The perc test results indicate acceptable effluent percolation at the maximum leachline depth of 42 inches will occur. This test depth represents percolation that will take place in the proposed leachlines. The perc test also reveals that percolative capacity decreases somewhat with soil saturation. It is recommended that no sumps be installed on parcel 1 since the bottom of the sumps may encroach within five feet of the highest groundwater level. There must be a minimum five-foot distance between the highest anticipated depth to groundwater and the bottom of any septic system structure, such as a leachline, sump or seepage pit. Seepage pits are not allowed in this area. If any structure is built on Parcel 2, a percolation test must performed in the area of the proposed leachfield. A perc test was not done on this Parcel in accordance with an EHD directive from Staff. If a perc test is done on Parcel 2, it is our recommendation to only conduct a shallow perc test at 42 inches, unless there is a failing perc rate at this depth, which is highly unlikely. A deeper test would be representative of sumps and should only be done under the authorization of the EHD. As illustrated on the Site Plan, the proposed leachfield will consist of an area 56 by 100 for a total disposal area of 5,600 feet. This approximately correlates with Section 10.3.4 of the Sewage Standards whereby a perc rate less than 10 minutes/inch must have a Minimum Usable Disposal Area of 6,000 square feet. The Mohler's new home will have three bedrooms. Therefore, a 1,200 gallon septic tank and 240 Lineal Feet of Leachline (LFLL) is required. Three - eighty foot leachlines will suffice. The total leachfield disposal area width needed is: 2 ft+ 10 ft+ 2 ft+ 10 ft+2 ft = 26 feet. This allows the 'outer" 30 feet from the northernmost leachline within the disposal area to provide an area of 3,000 square feet to be the 50% replacement area. In addition, there is additional area west of the leachfield, that can also be dedicated for replacement area. All related septic system structures and the new domestic well must comply with the published "distance" requirements from property borders, roads, irrigation fields, etc. As illustrated, the new domestic well is 100 feet from the southwest corner of the leachfield. It is important to note that all septic systems have a lifespan. This lifespan is dependant on several factors and is therefore difficult to determine. From the lack of repairs and/or additions in the study area, it is evident that septic systems have longevity within this locale. Septic system 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 LLnematodes acteria and bacterial products consisting of a slime of polyuronides and ides. If the soil/effluent interface is well aerated, a variety of soil microfauna such as nd protozoa may digest the clogging mat bacteria. Since the surface soils are f silty sandy soil, this allows the downward migration of oxygen. Consequently, 3 Chesney Consulting