For the purpose of this chapter, the following definitions shall apply unless the context clearly indicates or requires a different meaning.
1-YEAR, 24-HOUR STORM. The surface runoff resulting from a 24-hour rainfall intensity expected to be equaled or exceeded, on average, once in 12 months and with duration of 24 hours.
10-YEAR, 24-HOUR STORM. The surface runoff resulting from a 24-hour rainfall intensity expected to be equaled or exceeded, on average, one in ten chances in 12 months and with duration of 24 hours.
BUILT-UPON AREA (BUA). That portion of a development project that is covered by impervious or partially impervious surface to the extent that the partially impervious surface does not allow water to infiltrate through the surface to the subsoil. BUILT- UPON AREA includes but is not limited to, buildings, pavement and gravel areas such as roads, parking lots and paths and recreation facilities such as tennis courts. BUILT-UPON AREA does not include a slatted deck, the water area of a swimming pool, a surface of number 57 stone, as designated by the American Society of Testing and Materials, laid at least four inches thick over a geotextile fabric, or a trail as defined in G.S. 113A-85 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).
CREDITS. Represent on-going reductions in the storm water management service charge applicable to a given zoning lot or tract in recognition of on-site or off-site systems, facilities, measures and/or actions undertaken to reduce or mitigate the storm water quantity and/or quality impact(s) of the zoning lot or tract that would otherwise impact the public storm water management system. Credits shall be
conditioned on the continuing performance of the mitigation systems, facilities, measures or actions in reference to standards adopted by the Storm Water Management Utility, and may be revised or rescinded for cause. In no case shall credits exceed the amount of the storm water management service charge. The means and measures for identifying, issuing and obtaining credits will be provided in a credit manual approved by the Town Council.
CURB OUTLET SYSTEM. Constructed curb and gutter with breaks or other outlets used to convey storm water runoff to vegetated conveyances or other vegetated areas.
DEPARTMENT. The North Carolina Department of Environmental Quality.
DESIGN MANUAL. A single document or manual or collection of documents and manuals referenced by the town containing policy, criteria and information, including technical specifications and standards, for designing and operating SCMs and any conveyances, appurtenances or other structures to or from the BMP. All references herein to the Design Manual are to the latest published edition or revision.
DEVELOPED LAND. A zoning lot or tract altered from its natural state to include impervious surface area equal to or greater than 200 square feet.
DEVELOPMENT. 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 storm water control requirements and storm water control requirements cannot be applied retroactively to existing development, unless otherwise required by federal law.
DIVISION. The Division of Energy, Mineral and Land Resources in the department.
DRAINAGE SYSTEM. Natural and structural channels, swales, ditches, swamps, rivers, streams, creeks, wetlands, branches, reservoirs, ponds, drainage ways, inlets, catch basins, gutters, pipes, culverts, bridges, head walls, storm sewers, lakes and other physical works, properties and improvements that transfer, control, convey or otherwise influence the movement of storm water runoff.
EQUIVALENT RATE UNIT (ERU). An ERU represents 2,000 square feet of impervious surface or fraction thereof.
FUTURE SERVICE AREA. The land area located in Cabarrus County that the Town of Harrisburg could potentially provide municipal services and governance to in the future. This chapter will be administered throughout. This area should not be confused with the municipal limits or the extra-territorial jurisdiction area of the town.
IMPERVIOUS SURFACE AREA. Developed areas of land that prevent or significantly impede the infiltration of storm water into the soil. Typical impervious surface areas include, but are not limited to roofs, sidewalks, walkways, patios, swimming pools, private driveways, parking lots, access extensions, alleys and other paved, engineered, compacted or gravel surfaces containing materials that prevent or significantly impede the natural infiltration of storm water into the soil.
LARGER COMMON PLAN OF DEVELOPMENT OR SALE. Any area where multiple separate and distinct construction or land-disturbing activities will occur under one plan. A plan is any announcement or piece of documentation (including, but not limited to, a sign, public notice or hearing, sales pitch, advertisement, loan application, drawing, permit application, zoning request or computer design) or physical demarcation (including, but not limited to, boundary signs, lot stakes or surveyor markings) indicating that construction activities may occur on a specific plot.
NATURAL STATE. Existing undeveloped land where the soil and vegetation characteristics that have not been substantially modified or disturbed by human activities and the hydrologic function is in an unaltered or natural condition.
OWNER. The 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.
PROJECT. The proposed development activity for which an applicant is seeking a storm water permit from the state or other entity in accordance with this chapter. PROJECT shall exclude any land adjacent to the area disturbed by the project that has been counted as pervious by any other development regulated under a federal, state or local storm water regulation. Owners and developers of large developments consisting of many linked projects may consider developing a master plan that illustrates how each project fits into the design of the large development.
PROJECT AREA. Disturbed area of the development. Area that encompasses active open space, buildings or dwelling units, and street right-of-way.
REDEVELOPMENT. Any land disturbing activity that does not result in a net increase in built-upon area and that provides greater or equal storm water control to that of the previous development.
RIPARIAN. Of or pertaining to the landscape interface between an upland area and a flowing surface water body. Riparian areas exhibit their own significance in geography, particularly ecology and hydrology, which are significantly influenced by its relationship with the surface water body.
RUNOFF TREATMENT. By which the volume of storm water runoff generated from all of the built- upon area of a project at build- out during a storm of the required storm depth is treated in one or more primary SCMs or a combination of primary and secondary SCMs that provides equal or better treatment.
RUNOFF VOLUME MATCH. The annual runoff volume after development shall not be more than 10% higher than the annual runoff volume before development.
SERVICE AREA. The land within the corporate limits of the town, including all land areas legally annexed thereto.
SERVICE CHARGE. A storm water management service charge, applicable to a zoning lot or tract, that generally reflects the impact on or demand for storm water management services provided by the town to properly control and manage storm water runoff quantity and/or quality associated with the zoning lot or tract. The service charge will vary from one zoning lot or tract to another, based on the impervious surface area.
SHEET FLOW. Conveyance of surface water or runoff at a depth significantly less than the width of the flow path on which it flows. SHEET FLOW is maintained until the flow begins to concentrate into rills or micro-channels. The purpose for sheet flow in regards to this chapter is that sheet flow maintains a lower energy and higher surface area of contact with the flow path than concentrated flow.
STORM WATER. The runoff from precipitation that travels over natural state or developed land surfaces and enters a drainage system.
STORM WATER CONTROL MEASURES. A permanent structural device that is designed, constructed and maintained to remove pollutants from storm water runoff by promoting settling or filtration; or to mimic the natural hydrologic cycle by promoting infiltration, evapo-transpiration, post- filtration discharge, reuse of storm water, or a combination thereof. Also known as SCM, Best Management Practice or BMP.
STORM WATER MANAGEMENT PROGRAM. An identified set of measures and activities designed to protect, restore and/or manage storm water quality by controlling and/or reducing pollutants and to reduce and/or manage storm water quantity by controlling velocity, volume and rate.
STORM WATER SERVICES UTILITY. An organizational structure that is responsible for funding, administering and operating the town’s storm water management program, and that is supported thorough a rate structure based on the impervious surface area found on zoning lots or tracts located within the service area.
STRUCTURAL BMP. A physical device designed to trap, settle out or filter pollutants from storm water runoff, to alter or reduce storm water runoff velocity, amount, timing or other characteristics, to approximate the pre-development hydrology on a developed site or to achieve any combination of these goals. STRUCTURAL BMP includes physical practices such as constructed wetlands, vegetative practices, filter strips, grassed swales and other methods installed or created on real property. STRUCTURAL BMP is synonymous with STRUCTURAL PRACTICE, STORM WATER CONTROL FACILITY, STORM WATER CONTROL PRACTICE, STORM WATER TREATMENT PRACTICE, STORM WATER MANAGEMENT PRACTICE, STORM WATER CONTROL MEASURES, STRUCTURAL STORM WATER TREATMENT SYSTEMS and similar terms used in this chapter.
SUBSTANTIAL PROGRESS. For the purposes of determining whether sufficient progress has been made on an approved plan, one or more of the following construction activities toward the completion of a site or subdivision plan shall occur: obtaining a grading permit and conducting grading activity on a continuous basis and not discontinued for more than 30 days or installation and approval of on-site infrastructure; or obtaining a building permit for the construction and approval of a building foundation. SUBSTANTIAL PROGRESS for purposes of determining whether an approved plan is null and void is not necessarily the same as SUBSTANTIAL EXPENDITURES used for determining vested rights pursuant to applicable law.
TRACT. A parcel of land not previously recorded as a zoning lot.
UNDEVELOPED LAND. All land that is not altered from its natural state to an extent that results in 200 or more square feet of impervious surface area.
ZONING LOT. A legally subdivided lot (not a tract) shown on a legally recorded plat or deed, or a combination of such legally subdivided and recorded adjacent lots.
(Ord., passed 5-11-09; Am. Ord., passed 1-13-20; Am. Ord., passed 9-13-21)