5-1-24 PB Agenda Packet - Laserfiche WebLink

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multi-family residential, commercial and industrial development disturbing 12,000 square feet but less than one acre; (iv) 50% or more reduction in both nitrogen and phosphorus loading from the untreated condition for other development, including multi-family residential, commercial and industrial development disturbing more than one acre; (v) 30% or more reduction in both nitrogen and phosphorus loading from the untreated condition for proposed redevelopment activities in a designated downtown area that would replace or expand structures or improvements that existed as of December 2006. (2) Offset fees may be paid to the North Carolina Division of Mitigation Services (DMS), approved private mitigation bank, or other mitigation option as approved by the NCDEQ and Orange County. It is the policy of the NCDEQ and Orange County, as well as a requirement in certain watersheds, that offset payment funds be utilized where they are generated to the maximum extent possible. (3) Offset payment fees and calculation methods are determined by the NCDEQ as approved by the North Carolina Environmental Management Commission (EMC). The total amount of offset payment will be determined based on current NCDEQ policy and regulation on a case by case basis. (E) Permanent Nutrient Export Reduction (1) Allowable on-site SCMs for nutrient reduction shall include those listed in the most current version of the North Carolina Administrative Code Title 15A, Subchapter 02H, Sections .1000 through .1062, and the most current version of the NCDEQ Stormwater Design Manual. (2) Design, maintenance and operation of SCMs shall follow standards provided in the most current version of the North Carolina Administrative Code Title 15A, Subchapter 02H, Sections .1000 through .1062, and the most current version of the NCDEQ Stormwater Design Manual. (3) Deviations from these standards may be allowed as approved on a case by case basis. (F) Total Nutrient Removal Rates Total nutrient removal rates of SCMs, as well as SCMs in a series, will be calculated pursuant to the approved accounting tool. 6.14.8 Peak Runoff Volume (A) Standards for Falls Lake Watershed (1) For all new development, there shall be no net increase in peak flow leaving the site from the predevelopment conditions for the 1 year, 24 hour storm. (B) Standards for Jordan Lake Watershed (1) For all new development there shall be no net increase greater than 10% in peak flow leaving the site from the predevelopment conditions consistent with 15 A NCAC 02H.1002 (44). (C) Calculating Peak Runoff Volume (1) The following are acceptable methodologies for computing the pre- and post- development conditions for the 1 year, 24 hour storm: (a) Rational Method, 127