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(§ 7.0) CONCLUSIONS r5`�The perc test results for proposed Parcel 1 and Parcel 2 show acceptable percolation for the management of any future typical septic system effluent flows at leachline depths. As noted from the perc test results, as the soil becomes increasingly saturated, the percolation rate potential does not decrease substantially. 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. Therefore, sufficient distance exists between the bottom of a maximum depth leachline trench at 42 inches, or a sump at 12 feet in depth, and the current groundwater depth of 25 feet. Q 6.8) Although there is no proposal to build on the Parcels, a septic system for any future development will be dependent upon the number of bedrooms within a new house. Leachline length in this locale is stipulated by EHD to be 80 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 be calculated, if so desired. Q,6. No problmDare nticipated for any future septic system on the Parcels, other than typical li€espan concerns.__ ineered septic system will not have to be installed for this project unless there are continual failures. The 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, and irrigation ditches, etc. As referenced, the surrounding almond,-,' orchard is irrigated by micro-sprinklers, so there should be no inundation concerns. It is important to recognize that all septic systems have a lifespan, which is dependant on several factors and is therefore difficult to determine. Septic system leachline failure would primarily resu} , 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. 01- Since Since the shallow subsurface soils on the property consist of fine sands and silts, aerobic conditions may prevail over time which may increase the expectant life of any new septic system. Lifespan will be dependant upon the efficiency of the septic system to manage typical effluent flows. Consideration should be given to installing a filter bed if there ever is a proposal to build. By nature of the construction details of a filter bed, it will be installed high in elevation, consequently, there will be a greater opportunity for oxygen intrusion from the atmosphere. This will theoretically assist in biomat degradation, along with promoting evapotranspiration. 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. Page -5- Chesney Consulting