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FrAsnoted on theperc test form, the perc test results reveal a percolation rate of 30 minutes per mpi). Perc test results from our tests conducted in March of 2000 indicate a rate of 50 mpi. ate variability is often seen in this locale due to various factors. First,the clay soil in this recent test location was highly fractured. Although pre-saturation causes the clay to swell and partially seal off these fractures,there is still sufficient porosity to allow acceptable percolation. Secondly,the soil at the perc test depth had a fair degree of moisture in it which also contributes to increased hydraulic conductivity of the clay soil. The water molecules "wick" through the micropores by capillary action. CONCLUSIONS The San Joaquin County Sewage Standards state that the required leachlines for the facility are as follows, using an average daily wastewater flow of 270 gpd: 1200 Base Tank Capacity (BTC) +270 Average Daily Flow(ADF) x 0.25 Soil Factor(SF)=370 lineal feet of leachline (LFLL). As referenced,the facility currently only has 200 lineal feet. two e�Vl •I�e (/L_ry f Y ;t, 0- -zy- = W z . s f Taking into consideration the perc test results, we find that the scientific literature and other publications (e.g., California SWRCB Guidelines for the Design, Installation and Operation of Mound Sewage Disposal Systems)have correlated the perc rate in minutes per inch with an application or acceptance rate of wastewater effluent of gallons per square foot per day (gals/ft'/day). A perc rate of 30 m tr1560alsg`/ft�/day. Taking the infiltration area of a leachline trench to be one square foot on either side of the trench and the bottom of the trench to be two square feet, we have four square feet of effluent application area per one lineal foot. There are 200 lineal feet, so total application area is 800 square feet. 800 ft'x 0.560 gals/ft'/day=448 gals/day of effluent the leachline trenches will accept. However, also as referenced in the scientific literature (Wastewater Engineering, Metcalf& Eddy 3`d Ed.), the long-term acceptance rate slows considerably, with the loading rate reaching an equilibrium of-0.25 gals/ft'/day. This is primarily due to biomat formation and is applicable for a wide range of soil types. Consequently,the acceptance rate over the long-term can be estimated at: 800 ft'x 0.250 gals/ft'/day=200 gals/day. Since the averaee dai1 ow is projected tJo.be 2 "pd, careful monitoring of bathrQolge must be done to stay this 200 gals/day volume. This includes periodic checking for leaking fixtures. 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. Eventually,the 100%replacement area will have to be utilized primarily due to the fine grained indigenous soils. This time frame may be two to three years, or it could be many years. Septic system leachline failure would primarily result from the advanced formation of the biomat on the 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 Page 3 of 4 Chesney ConsultiV