5-1-24 PB Agenda Packet - Laserfiche WebLink

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(4) New development that would exceed the nutrient loading rates set out herein, shall include engineered stormwater controls designed to have a Primary and/or Secondary SCM per NCDEQ requirements. (5) Proposed new development may satisfy the review criteria standards of this section using a Runoff Volume Match design approach (also referred to as a Low Impact Development (LID) design approach) in conformance with 15A NCAC 02H.1002 (44). If pursued, a Runoff Volume Match design approach must include the use of the accounting methodologies approved by the North Carolina Division of Energy, Mineral, and Land Resources (NCDEMLR). (B) Additional Standards – Falls Lake Watershed (1) In addition to the standards contained in Section 6.14.6 (A) of this Ordinance, development shall observe a no net increase in peak flow leaving the site from predevelopment conditions for the 1 year, 24 hour, storm. (2) Proposed new development using a Runoff Volume Match design approach for satisfying stormwater management requirements must also include the estimation of pre-development and post-development nutrient export rates (e.g. Nitrogen and Phosphorous) for the proposed development, using the nutrient accounting methodologies approved by the North Carolina Division of Water Resources (NCDWR). Nutrient export estimates are required for Runoff Volume Match record-keeping purposes. 6.14.7 Nutrient Load (A) Nitrogen and phosphorus loads contributed by proposed new development shall not exceed the following unit-area mass loading rates: (1) Falls Lake Watershed (a) Nitrogen, 2.2 pounds per acre per year (b) Phosphorus, 0.33 pounds per acre per year (B) The nutrient export from each new development shall be calculated in pounds per acre per year (using the approved accounting tool) in accordance with the methodologies approved by the North Carolina Division of Water Resources (NCDWR). (C) If a proposed development subject to nutrient load requirements contributes nutrients greater than the standards listed above, the developer may install SCMs to meet the required nutrient load standards or do a combination of SCMs and offset payments to achieve the standard. (D) Offset Payments (1) Offset fees may be permitted to meet the nutrient export levels set for new development. In order to utilize offset fees, the proposed new development subject to the nutrient load standards must attain nitrogen and phosphorus loading rate reductions on-site that meet the following criteria prior to using an offsite offset measure: (a) Falls Lake Watershed (i) 30% or more reduction in both nitrogen and phosphorus loading from the untreated conditions for any single-family, detached and duplex residential development disturbing one half acre but less than one acre; (ii) 50% or more reduction in both nitrogen and phosphorus loading from the untreated conditions for any single-family, detached and duplex residential development disturbing more than one acre; (iii) 30% or more reduction in both nitrogen and phosphorus loading from the untreated condition for other development, including 126