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(§ 7.0) CONCLUSIONS The perc test results for proposed Parcel 1 show acceptable percolation for the management of septic system effluent flows at typical leachline depths. As noted from the perc test results,as the soil becomes increasingly saturated,the percolation rate potential decreases. 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 for leachlines and 10 feet for sumps and seepage pits. Therefore, sufficient distance exists between the bottom of a maximum depth leachline trench at 42 inches,or a sump at 10 feet in depth, and the current groundwater depth of--35 feet. (§6.8) Although there°Van e4posal to build on proposed Parcel 1 or the Designated Remainder Parcel, a septic system design foruture development will be dependent upon the number of bedrooms within a new structure, or the nuof toilets. Leachime length in this locale is stipulated by EHD to be 100 feet for each bedroom. Determination of a bedroom is made by closets; if a room has a closet, it is designated as a bedroom. From the total lateral length of leachline, a filter bed area can also be calculated, if so desired. (§ 6.7)r N problems are anticipated for any future septic system on the Parcels, other than typical lifespan conceil& An engineered septic system will not have to be installed in the future for this project unless there are future system failures. Any new system must have at least a 50% standby replacement area incorporated into the design, which will be easily achieved due to the surrounding open areas. Any new septic system structures for the property must comply with the "distance" requirements from property borders, roads, irrigation ditches, etc. The on-site cropland is irrigated by subsurface irrigation tape, so there should be no inundation concerns from.irrigation water. It is important to recognize that all septic systems have a lifespan, which is dependant upon several factors and is therefore difficult to determine. Septic system leachline failure would primarily result from the advanced formation of a "biomat" or "clogging inat" on the wetted soil/effluent interface. This mat is composed mostly of aerobic and anaerobic bacteria and bacteria] 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. Since the shallow subsurface soils on the property consist of fine sands, silts and clays, aerobic conditions may prevail over time which may slightly increase the expectant life of a septic system. Lifespan will also be dependant upon the efficiency of the septic system to manage typical, or atypical effluent flows. In addition, soil moisture content of.the subsurface soils will play an important role in septic system operational capacity. For example, if heavy rains are experienced in any given winter, subsurface soil moisture content will increase, thus decreasing permeability. (§ 4.2) Water test results from the domestic well reveal that there h not been marked attenuation of the downward migration of nitrate by intervening clay strata. N' rate im acf to the derlying, shallow drinking water aquifers has most likely occurred from agricultural fertilizer inputs. " In unsewered areas anal/�o�as that ha e�eeor currently are under agricultural production, it is highly recommended that 15o tled water be used for drinking and cooking purposes. However,the Ruiz's use a reverse osmosis system to filter nitrate Prom theWdrinking and cooking water. t Fage -5- Chesney Consulting