Orange County NC Website
Browse       Search
000~82 <br />shall be, controlled through infiltrations, retention or <br />detention structures, and diversion devices. <br />ly_gry.C. infiltratiW M=Aards <br />For all new subdivisions, the preliminary and/or final plat may not <br />be approved unless provision has been made for controlling the <br />first one -half (312) inch of stormwater runoff from impervious <br />surfaces. bperviaus surfaces are those areas which prevent <br />infiltration of water into the soil and include parking areas, <br />roads, sidewalks, and other similar facilities constructed of <br />aspbalt and/or concrete. <br />Control of stormwater runoff shall be accceplisbed insofar as <br />possible through on -site infiltration of the first ane-half (1/2) <br />inch of runoff and through the use of methods which rely on natural <br />soil properties for absorption and treatment-. Infiltration <br />teCbn=p" not only remove both suspended and dissolved pollutants, <br />but they require less maintenance, reduce flooding' prcmate <br />grcundwater recharge and help maintain stream flow during dry <br />periods. <br />Where, due to soil type, steep slopes, presence of flood plains, <br />highly erodible soils, vegetative cover and/or previous land <br />disturbances, infiltration is impractical, the following <br />alternative measures may be permitted: <br />1) Flow attenuation methods, such as grass swales, to reduce <br />runoff velocity and filter out pollutants. <br />2) Retention ponds which capture stoL7lwater runoff allow <br />suspended pollutants to settle out and release the runoff at <br />reduced -rates. <br />3) Retention ponds with no outlet structures which retain all <br />runoff until it infiltrates or evaporates. <br />Where or -site infiltration methods are utilized, areas for such <br />purposes shall be designated on the plat and shall remain <br />undisturbed both during and after construction. Undisturbed areas <br />for infiltration of runoff shall also be located downslope from <br />impervious surfaces and shall not include areas characterized by <br />floodplains, highly erodible or impervious soils, steep slopes or <br />previously disturbed areas. Areas designated as suitable for <br />septic tank nitrification fields may not be used for storttaater <br />infiltration purposes. Runoff from roads, parking lots arrVor <br />sidewalks shall be directed to undisturbed areas through the use of <br />beams, grassed diversion ditches or swales, or other acceptable <br />MUM. <br />12 <br />