Sec. 9.2.1. General Provisions

Applicability
Prior to any land disturbing activity or subdivision of land, stormwater control measures, watercourse buffers or both must be provided in conformity with the requirements of this Article.
Stormwater Design Manual Incorporated
1. The Raleigh Stormwater Design Manual and amendments, on file in the City Clerk’s Office, is adopted by reference as part of this UDO.
2. If the specifications of the above referenced adopted documents are more restrictive or apply a higher standard than other laws or regulations, that fact shall not prevent application of the specifications in these documents.
Conflict of Laws
1. This Article is not intended to modify or repeal any other ordinance, rule, regulation, or other provision of law. The requirements of this Article are in addition to the requirements of any other ordinance, rule, regulation, or other provision of law. Where any provision of this Article imposes restrictions different from those imposed by any other ordinance, rule, regulation, or other provision of law, whichever provision is more restrictive or imposes higher protective standards for human or environmental health, safety, and welfare shall control.
2. Proposed development projects shall demonstrate compliance with the riparian buffer protection requirements set forth in 15A NCAC 02B .0610, .0611, .0612, and .0714.
Authority for Interpretation
1. The Engineering Services Director and/or his or her designee has authority to determine the interpretation of this Article, as set forth in Sec. 10.2.14. This shall include the authority to recognize alternative methods for hydrology and hydraulics calculations that are necessitated by this Article. Any person may request an interpretation of this Article by submitting a written request to the Engineering Services Director and/or his or her designee.
2. Any appeal of the Engineering Services Director’s and/or his or her designee’s interpretation shall follow the procedures for appeals of administrative decisions, as set forth in Sec. 10.2.11.
Severability
1. If the provisions of any section, subsection, paragraph, subdivision, or clause of this Article shall be adjudged invalid by a court of competent jurisdiction, such judgment shall not affect or invalidate the remainder of any section, subsection, paragraph, subdivision, or clause of this Article.
Definitions
1. ‘Built-upon area’ means impervious surface and partially impervious surface to the extent that the partially impervious surface does not allow water to infiltrate through the surface and into the subsoil. ‘Existing Built-Upon Area’ means built-upon area or impervious surface area that existed on a site prior to May 1, 2001. The effective built-upon area for certain surfaces listed below are as follows:
  1. Asphalt, concrete, crusher-run, masonry, roofing materials, and other impervious surfaces are considered 100% built-upon area unless otherwise specified below.
  2. Number 57 stone, as designated by the American Society for Testing and Materials, laid at least four inches thick over a geotextile fabric shall be 0% built- upon area.
  3. Gravel. placed on areas that will not be compacted by the weight of a vehicle,shall be 0% built-upon area. These areas must be physically separated fromgravel areas that will be compacted by the weight of a motor vehicle. Gravel shall be defined using either the American Society for Testing and Materials (ASTM) standard ASTM D 2487 for the Unified Soil Classification System, or American Association of State Highway and Transportation Officials (AASHTO) standard AASHOT M 145 “Classification of Soils and Soil-Aggregate Mixtures for Highway Construction Purposes” or AASHTO M 147 “Materials for Aggregate and Soil-Aggregate Subbase, Base and Surface Courses.”
  4. Slatted decks that allow the drainage of water through the slats to a pervious surface below are 0% built-upon area.
  5. Areas that receive pedestrian or bicycle traffic that will not be compacted by the weight of a motor vehicle and whose surfaces are composed of bare soil or landscaping material, including mulch, sand, and vegetation, shall be 0% built-upon area.
  6. A trail as defined in G.S. 143B-135.94 that is either unpaved or paved as long as the pavement is porous with a hydraulic conductivity greater than 0.001 centimeters per second (1.41 inches per hour) shall be 0% built-upon area.
  7. The water surfaces of swimming pools and other natural water bodies shall be 0% built-upon area
  8. Artificial turf that is manufactured to allow water to drain through the backing of the turf, is installed per manufacturer’s specifications, and is installed over a pervious surface shall be 0% built-upon area.
  9. The surface of stormwater control measures, including permeable pavement, shall receive built-upon area credit as allowed by the NCDEQ.
  10. All other built-upon area determinations will be based on
    1. Infiltration tests of existing subgrade soils,
    2. Proposed slope,
    3. Proposed compaction of subgrade soils,
    4. Extent of porous openings in the surface material,
    5. Protection from siltation and clogging,
    6. Volume of stormwater stored, and
    7. Meeting the requirements for a stormwater control measure per Secs. 9.2.2.D, 9.2.2.G, and 9.2.2.H
  11. An applicant may choose to have a specific surface counted as a greater percentage of built-upon area when submitting a development application. The percentage of built-upon area for that specific surface may not be subsequently changed.
2. ‘Common Plan of Development’ means a site where multiple separate and distinct development activities may be taking place at different times on different schedules but governed by a single development plan regardless of ownership of the parcels. Information that may be used to determine a ‘common plan of development’ include plats, blueprints, marketing plans, contracts, building permits, public notices or hearings, zoning requests, and infrastructure development plans.
3. ‘Development’ means any land-disturbing activity that increases the amount of built-upon area or that otherwise decreases the infiltration of precipitation into the subsoil. When additional development occurs at a site that has existing development, the built-upon area of the existing development shall not be included in the density calculations for additional stormwater control requirements, and stormwater control requirements cannot be applied retroactively to existing development, unless otherwise required by federal law.
4. ‘Existing Development’ means those projects that are built or those projects that have established a vested right under North Carolina law as of May 1, 2001.
5. ‘Owner’ means any legal or beneficial owner of land, including but not limited to a mortgagee or vendee in possession, receiver, executor, trustee, or long-term or commercial lessee, or any other person or entity holding proprietary rights in the property or having legal power of management and control of the property. ‘Owner’ shall include long-term commercial tenants; management entities, such as those charged with or engaged in the management of properties for profit; and every person or entity having joint ownership of the property. A secured lender not in possession of the property does not constitute an owner, unless the secured lender is included within the meaning of ‘owner’ under another description in this definition, such as a management entity.
6. ‘Primary Stormwater Control Measure’ means a wet pond, stormwater wetland, infiltration system, sand filter, bioretention cell, permeable pavement, green roof, rainwater harvesting, or an approved new stormwater technology that is designed, constructed and maintained in accordance with the North Carolina Department of Environmental Quality Stormwater Minimum Design Criteria.
7. ‘Redevelopment’ means any land-disturbing activity that does not result in a net increase in built-upon area and that provides greater or equal stormwater control to that of the previous development.

TC Number

TC-2-25

Ordinance Number

786 TC 492

Unified Development Ordinance