Agenda - 03-10-1987 - Laserfiche WebLink

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71 one to assume that problems will occur in the future. The -third issue, ancillary to the second, is stream quality. Because of the small drainage areas of the streams in the Rural Buffer, groundwater discharge polluted with sewage effluent may comprise the total stream flow during drought and other low flow conditions. A 1976 Duke University study recommended sewer line extension as the best means to counter wastewater pollution in Orange County . The study, however, was conducted before Orange County required the use of two-chambered septic tanks, believed to reduce the chance of failure, and before extensive field testing of alternative systems had been conducted in Region J soil types. Field tests conducted by Triangle J COG have shown promise for some alternative systems and modifications to conventional systems. These systems can address some of the problems presented by severe soils and the failure of conventinal systems. Two types of alternative systems, mound systems and low pressure pipe systems, are currently used in small numbers throughout the county . They represent less than one percent ( 1 %) and five percent ( 5%) of all systems in use, respectively . Seepage problems have been reported, though, with some mound systems . Of three alternatives; sewer line extension, alternative systems, or modified conventional systems; sewer line extension is the most expensive, with its cost increasing as density decreases. The base component charge and acreage surcharge for a two acre lot to tie in to an OWASA line is over $1700. Front footage charges, if required, raise the total to over $3600, minimum. This is exclusive of sewer pipe installation which runs about $16.50 per linear foot. By comparison, a conventional system with 400' of pipe runs about $1600. A low pressure pipe system starts at $2100 and increases as the amount of pipe and size of the home increase. A modified conventional system using dual alternating fields would probably require the most land . The additional field itself would require about 10,000 square feet. Given the poor percolation of soils in the Rural Buffer lot sizes could conceivably increase in order to accommodate a second field. IV. REFERENCES 1 . Orange County Health Department comments, January 1987 . 2. TJCOG, "Overview of Septic Tank Usage and Problems in Region J , " June 1978 . 3 . Duke University School of Engineering, "Rural Wastewater Impact on Water Quality in Orange County, " 1976 . 4. TJCOG, "208 Areawide Water Quality Management Plan ' s Final Report, " February 1980 .