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Wastewater Management System Components: f 4-65 ft sections of leachline=260 ft 4-48 inch diameter seepage pits=4 x 90 ft of leachline equivalent=360 ft 260 ft+360 ft =620 equivalent Lineal Feet of Leachline proposed,615 LFLL required. Total Leachfield Disposal Area=65 ft.+5 ft+4 ft(length) x 46 ft (width)=3,404 Sq.Ft. 100% Reserve Replacement Area: All decentralized wastewater management systems (septic systems)will eventually fail. Consequently,the required 100%replacement must be denoted on the Site Plans and is anticipated to consist of the same structures as the primary system, for a total of 6,808 sq ft for both primary and replacement disposal areas. D. DISCUSSION ON THE USE OF THE EXISTING SEPTIC SYSTEM As noted, the existing residential structure to be converted to an office building will not be used during the week and only on the weekends during Services. Found in Appendix E, is the Permit for a �32, Repair/Addition in May 1991 for the septic system that serves this structure. A 40 ft leachline and one - 25 ft deep, 3 ft dia. seepage pit is in service. Although a shallow(40 in.)percolation test conducted in this leachfield area shows a nonexistent pert rate due to an influence of fat clays, obviously there is percolation of rainfall water, particularly evident during this past winter with one of the highest rainfall totals on record. if we assume the minimum application rate of 0.200 gallons/sq ft/day, and using the receiving area of the leachline exclusively'(excluding the seepage pit), we find this leachline tr sorb: 4 ft receiving area/ft of trench k 40 ft of trench= 160 sq ft x 0.200 gals/sq ft/day 32 gals/ acceptance volume. Given one toilet and one sink in the structure, for a total of two gal ons per use, the restroom can be used: 32gaWd4y 2 gals = 16 times per day without theoretically overloading the leachline trench, excluding the seepage pit. The seepage pit installed in 1991 gives an enormous safety factor. Additionally, this leachfield area must be maintained as a landscaped area and not paved over to be used for parking. i IV. CONCLUSIONS AND RECOMMENDATIONS ` SSS§ 5.4, 6.8. The shallow soils underlying the subject property show very slow-to-nonexistent permeability at the shallow depths representative of leachlines. Excellent permeability exists at depths representative of sumps and a very high degree of permeability within the deeper soils found at seepage pit depths. The soil analytical test results show low concentrations of subsurface soil nitrate-nitrogen, even though the subject property was under agricultural production for most of the past several decades. Also from the soil chemistry test results, it appears there is significant denitrification potential within the property soils. The amount of nitrogen applications in the past are unknown, although decomposing organic matter from residual crop decomposition'may supply subsurface nitrate- nitrogen, as was noted in the soil analytical test results. 11 Chesney Consulting