Secondary and Cumulative Impacts Master Management Plan - 2014

Article 9. Stormwater Management

Part 1

General Provisions

9-10 Purpose The stormwater management regulations of this article establish minimum requirements to address adverse effects of stormwater runoff associated with new development. Proper management of stormwater runoff will protect property, control stream channel erosion, reduce flooding, protect floodplains, wetlands, water resources, riparian and aquatic ecosystems, and otherwise provide for environmentally sound use of the county’s natural resources. 9-11 Scope Except as otherwise expressly stated, the stormwater management regulations of this article apply to all development within unincorporated Wake County outside the extraterritorial jurisdiction and incorporated boundaries of any municipality. 9-12 Exemptions The stormwater management regulations of this article do not apply to any of the following development activities: 9-12-1 Agriculture, forestry, or mining. 9-12-2 Office, institutional, commercial, or industrial development that disturbs a land area of one- half acre or less. 9-12-3 Any development in which the owner has accrued a vested right. Wake County recognizes a vested right if either of the following occurred: (A) A subdivision plan, site plan, or development permit was officially approved by Wake County or the State before August 13, 2006 and that plan or permit remains unexpired. (B) The landowner otherwise demonstrates a vested right has accrued under North Carolina Law. Part 2 Standards for Managing Stormwater Runoff 9-20 Maximum Curve Number after Development Developers must manage residential runoff so that after development the site will not exceed the following curve numbers, in accordance with procedures specified in the United States Department of Agriculture, Natural Resource Conservation Service, Technical Release 55, Urban Hydrology for Small Watersheds.

Maximum Composite Curve Number, By Soil Group A B C D

Zoning District R-80W and R-80 R-40W and R-40

37 41 43

60 62 63

73 75 76

79 80 81

R-30, R-20, R-15, R-10, R-5, Residential Highway, Highway District, General Business and Office and Institutional

[Amended on 1/22/2008 by OA 04-07.]

Wake County Unified Development Code 9-1