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(§ 7.0) CONCLUSIONS The pe test results for proposed Parcel 1 and Parcel 2 show acceptable percolation for the i management of any future typical septic system effluent flows at shallow leachline depths of 36 inches. As noted from the perc test results, as the soil becomes increasingly saturated, the percolation rate potential decreases substantially. This may explain past problems with high wastewater flows into this soil type. 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 may not exist between the bottom of a minimum depth leachline trench at 36 inches and the current groundwater depth of seven feet. If there is a proposal to construct a septic system in the future, EHD will require a water table depth analysis be performed. (§ 6.8) Any septic system for a 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 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 be calculated, if so desired. (§ 6.7) No problems are anticipated for any future septic system on the Parcels, other than typical lifespan concerns. An engineered septic system will not have to be installed for this project unless there are continual failures, or as referenced above, there is water table depth encroachment and sufficient separation distance cannot be maintained. 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. Inundation from irrigation water may be a concern. 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 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. Since the shallow subsurface soils on the property consist of peatland soils, anaerobic conditions may prevail over time which may decrease 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 or mound system if there ever is a proposal to build. By nature of the construction details of a filter bed or mound, 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. Page -5- Chesney Consulting