Orange County NC Website
Browse       Search
Article 6: Development Standards40 <br /> Section 6.14: Stormwater Management <br /> multi-family residential, commercial and industrial development <br /> disturbing 12,000 square feet but less than one acre; <br /> (iv) 50% or more reduction in both nitrogen and phosphorus loading <br /> from the untreated condition for other development, including <br /> multi-family residential, commercial and industrial development <br /> disturbing more than one acre; <br /> (v) 30% or more reduction in both nitrogen and phosphorus loading <br /> from the untreated condition for proposed redevelopment <br /> activities in a designated downtown area that would replace or <br /> expand structures or improvements that existed as of December <br /> 2006. <br /> (2) Offset fees may be paid to the North Carolina Division of Mitigation Services <br /> (DMS), approved private mitigation bank, or other mitigation option as approved <br /> by the NCDEQ and Orange County. It is the policy of the NCDEQ and Orange <br /> County, as well as a requirement in certain watersheds, that offset payment <br /> funds be utilized where they are generated to the maximum extent possible. <br /> (3) Offset payment fees and calculation methods are determined by the NCDEQ as <br /> approved by the North Carolina Environmental Management Commission (EMC). <br /> The total amount of offset payment will be determined based on current NCDEQ <br /> policy and regulation on a case by case basis. <br /> (E) Permanent Nutrient Export Reduction <br /> (1) Allowable on-site SCMs for nutrient reduction shall include those listed in the <br /> most current version of the North Carolina Administrative Code Title 15A, <br /> Subchapter 02H, Sections .1000 through .1062, and the most current version of <br /> the NCDEQ Stormwater Design Manual. <br /> (2) Design, maintenance and operation of SCMs shall follow standards provided in <br /> the most current version of the North Carolina Administrative Code Title 15A, <br /> Subchapter 02H, Sections .1000 through .1062, and the most current version of <br /> the NCDEQ Stormwater Design Manual. <br /> (3) Deviations from these standards may be allowed as approved on a case by case <br /> basis. <br /> (F) Total Nutrient Removal Rates <br /> Total nutrient removal rates of SCMs, as well as SCMs in a series, will be calculated <br /> pursuant to the approved accounting tool. <br /> 6.14.8 Peak Runoff Volume <br /> (A) Standards for Falls Lake Watershed <br /> (1) For all new development, there shall be no net increase in peak flow leaving the <br /> site from the predevelopment conditions for the 1 year, 24 hour storm. <br /> (B) Standards for Jordan Lake Watershed <br /> (1) For all new development there shall be no net increase greater than 10% in peak <br /> flow leaving the site from the predevelopment conditions consistent with 15 A <br /> NCAC 02H.1002 (44). <br /> (C) Calculating Peak Runoff Volume <br /> (1) The following are acceptable methodologies for computing the pre- and post- <br /> development conditions for the 1 year, 24 hour storm: <br /> (a) Rational Method, <br /> Orange County, North Carolina—Unified Development Ordinance Page 6-100 <br />