Erosion, Flood, Stormwater & Watershed Standards 12.3 Erosion And Sedimentation Control Regulations
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is required to have silt fence on the low side of the lot and a construction entrance with approved woven fabric that meets ASTM D 4632 standards. D. Sediment Basins: Sediment basins shall have settling efficiency as outlined in the North Carolina Erosion and Sediment Control Planning and Design Manual. E. Stabilization Required: Stabilization shall be provided whenever land-disturbing activities have ceased, or have temporarily ceased, on any portion of the site. Stabilization timeframes should match most recently published NCDEQ guidelines. In no instance shall the time of exposure be greater than the stabilization timeframes established by the following tables: Type of Stabilization Stabilization Timeframe Temporary Stabilization Must be completed within 14 days of any completed phase of grading Permanent Stabilization Must be completed within 10 days of competed project grading
F.
Protection from Storm Required: 1.
Falls Lake Watershed: Such erosion and sedimentation control measures, structures, and devices must be so planned, designed, and constructed as to provide protection from the calculated maximum peak rate of runoff from the 25-year storm. Runoff rates must be calculated using acceptable calculation procedures. 2. All Other Watersheds: Such erosion and sedimentation control measures, structures, and devices must be so planned, designed, and constructed as to provide protection from the calculated maximum peak rate of runoff from 10- year storm. Runoff rates must be calculated using the procedures in the USDA Natural Resources Conservation Services “National Engineering Field Manual for Conservation Practices”, or other acceptable c alculation procedures. 3. HQW Zones: In High Quality Water (HQW) zones the following design standards shall apply: a. Limit on Uncovered Areas: Uncovered areas in HQW zones shall be limited at any time to a maximum of twenty acres within the boundaries of the tract. Only the portion of the land disturbing activity within the HQW zone shall be governed by this section. Larger areas may be uncovered within the boundaries of the tract with the written approval of the Administrator. b. Maximum Peak Rate of Runoff Protection: Erosion and sedimentation control measures, structures, and devices within HQW zones shall be planned designed and constructed to provide protection from the runoff of the twenty-five year storm which produces the maximum peak rate of runoff as calculated according to the procedures in the United States Department of Agriculture Soil Conservation Service’s “National Engineering Field Manual for Conservation Practices” or according to procedures adopted by any other agency of the state or the United States or any generally recognized organization or association. c. Settling Efficiency: Sediment Basins within HQW zones shall be designed and constructed such that the basin shall be planned, designed, and constructed so that the basin will have a settling efficiency of at least 70 percent for the 40 micron size soil particle transported into the basin by the runoff of the two-year storm that produces an maximum peak runoff as calculated according the procedures in the United State Department of Agriculture an d Soil Conservation Services “National Engineering Field
Town of Wake Forest Unified Development Ordinance – July 19, 2022
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