Orange County NC Website
Browse       Search
6 <br /> Attachment D. DRAFT information sheet about groundwater yield <br /> Maximizing Groundwater Yield from Water Supply Wells <br /> Orange County <br /> Each year, many new wells are installed in Orange County. A well may be installed <br /> after a site is cleared, graded and a new house is built on the site. Planning the well <br /> location may not be as much of a priority as it could be. Achieving a suitable supply of <br /> water from a new supply well can be difficult, possibly becoming an ongoing source of <br /> frustration for those residents dependent on the well. <br /> Research into groundwater yields from fractured rock aquifers in the Piedmont area of <br /> North Carolina, including Orange County, has determined several factors that should be <br /> considered when attempting to increase the yield of water from a new supply well. <br /> 1 . The groundwater system in the Piedmont area of North Carolina is known as a regolith- <br /> fractured bedrock aquifer system. Regolith is the unconsolidated material present <br /> above the underlying bedrock. Nearly all groundwater storage is within the regolith. As <br /> a result, wells should be located in areas that maximize the thickness of saturated <br /> regolith. Saturated regolith tends to be thickest beneath valleys and draws (-34 feet), <br /> versus that beneath hills and ridges (-20 feet) (Daniel and Dahlen, 2002). <br /> l —Stream <br /> T unsaturated �--� �Tapsoil <br /> :one r <br /> Re olith <br /> saturate �Top of water table <br /> zone a; <br /> Fractured Bedrock <br /> with groundwater <br /> Now in fractures <br /> Arrows represent �r <br /> direction of <br /> groundwater Now <br /> (Modified tram Hrrr dwd Usnid,3993) <br /> 2. Yield (the amount of water that can be extracted from the well) from a bedrock well <br /> depends upon the well intersecting fractures in the rock. As a result, steps to locate <br /> wells in areas with more fractures should increase the yield of the well. <br /> 3. The geology of the bedrock at a site affects the porosity and weathering characteristics <br /> of the fractured bedrock aquifer. More massive rock types are likely to include fewer <br /> fractures than rocks that have undergone deformation such as folding and faulting. <br />