Orange County NC Website
Browse       Search
7 <br /> Ground-water Availability <br /> The number of people that can be supported by ground-water supplies in the County is <br /> limited by the availability of ground water. Ground water is available in Orange County from <br /> wells tapping the iegolith bedrock aquifer system that is present throughout the Piedmont. <br /> Although previous investigations have addressed well yields and general hydrogeologic <br /> characteristics,there has been no assessment that can be easily used by planners and water <br /> managers to evaluate water-supply availability or to identify favorable areas for ground-water <br /> supply development. <br /> A recently completed study by the U.S.Geological Survey determined rates of recharge to the <br /> ground-water system in 12 drainage basins and subbasins in the county. The recharge rates <br /> represent the upper limit of long-term ground-water availability and can be used for planning on <br /> a regional scale;however,these recharge rates are the average for an entire basin or subbasin,and <br /> little is known about the distribution and range of recharge rates within a basin or subbasin. For <br /> water-supply development,especially for large supplies such as community systems or <br /> commerciailmdustrial systems,more detailed information is needed about the distribution of well <br /> yields,saturated thickness of regolith,variability of recharge rates,current ground-water use,and <br /> possible sauces of contamination within these basins and subbasins. Few well records,or other <br /> information related to ground-water availability and current use,are available in computerized <br /> files. <br /> Ground-water Quality <br /> There is a need to characterize ground-water quality,identify general areas of ground-water <br /> contannnati�,including areas vulnerable to contamination,and to design a data base that the <br /> County can use to manage ground-water resources and ground-water quality in Orange County. <br /> Most available water-quality data consist of information derived from tap samples which were <br /> not collected in a uniform manner and cannot be used to characterize ambient ground-water <br /> quality. Many of the well records have been stored in files by address and street or road name. <br /> As a result,ground-water quality cannot easily be related to hydrogeologic units or geographic <br /> areas. Data on many constituents and properties have not been entered into a computerized data <br /> base. Most chemical data are available only from paper file copies. <br /> Preliminary results from an ongoing study in nearby Guilford County indicate radon levels in <br /> ground water from some hydrogeologic units are as much as 20 times higher than the EPA <br /> proposed level of 300 pCi/L(picocuries per liter). Similar hydrogeologic units occur in Orange <br /> County and tests for radon appear warrented. <br /> 3 <br />