Agenda - 12-15-1987 - Laserfiche WebLink

Browse Search

sources. Thorough investigations have already been completed on two Piedmont reservoirs documenting both point and nonpoint sources of toxicants with recommendations for future DEM action. Other WS-III watersheds will also be investigated in the future to document potential water quality problems. Within a Water Supply (W5) watershed much greater scrutiny will be placed on any point source discharger . Close attention will be paid to compliance records, ambient data, bioassay analysis benthi-c macroinvertebrate evaluation, facility age and possible violations. In some cases, communities are actively . trying to .remove- point. source dischargers from .their water supply . watershed. Methods have included connecting the facility to a sewer line; converting the discharger over to a nondischarging land application system; or constructing a large nondischarging subsurface system. These strategies should also greatly reduce the risk of contamination from point source dischargers. NONPOINT SOURCE STRATEGY _ The main strategy of the program is to control point and nonpoint sources of pollution today and into the future. .- Controlling these sources of pollution should reduce the risk of contamination to a surface water -supply. - •- Local governments within a water supply watershed need to develop their own nonpoint source control program. All programs should . address methods of controlling surface water runoff from new development . The statewide program guidelines only deals with surface water pollution sources; however , the Division of Health Services in the Department of Human Resources and DEM's groundwater section already have regulations addressing subsurface water pollution sources. DEM guidelines address two portions 'of a watershed including the critical area and remainder of the watershed (Figure 1 ) . The critical area, defined as the area adjacent to the reservoir or water intake location, needs the greatest amount of protection. With increased impervious surfaces comes greater runoff and typically land uses having the greatest impervious surfaces (commercial and industrial sites) have a much higher potential of toxic pollutants leaving the site with stormwater runoff. This area should extend from 1/2 to 1 mile from the reservoir 's high - water-mark or intake point and- depends on the watershed, size.- A - water .supply watershed equal to or greater than 100 square miles would require a 1 mile critical area while watersheds less than 100 square miles would generally only require a 1/2 mile critical area. Control measures within the critical area should include: 1 ) density limits on new development of b% impervious surface or 1 dwelling/2 -acres with septic tanks only; 2)- natural vegetative buffers adjacent (both sides) to all perennial tributaries flowing to the reservoir or direct intake ranging in width from 50 to 150 feet depending on slope, soil , and land-use characteristics and 3) no commercial or industrial areas within