Definitions. As used in this chapter, the following terms shall have the meanings indicated:
ACTThe Pennsylvania Municipalities Planning Code (Act of July 31, 1968, Act No. 247, as amended).
APPLICANTA landowner or developer, as defined by this chapter, who has filed an application for development, including his or her heirs, successors and assigns.
CHANNELA natural stream that conveys water; a ditch or open channel excavated for the flow of water.
DESIGN STORMThe magnitude of precipitation from a storm event measured in probability of occurrence (e.g., twenty-five-year storm) and duration (e.g., twenty-four-hour) and used in computing stormwater management control systems and erosion and sedimentation control facilities.
DEVELOPMENTAny activity, construction, alteration, change in land use or similar action that affects stormwater runoff characteristics.
DEVELOPMENT SITEA lot, parcel or tract of land on which development is taking place or is proposed.
DISCHARGEThe rate of flow, specifically fluid flow; a volume of fluid flowing from a conduit or channel or being released from detention storage, per unit of time; commonly expressed as cubic feet per second (cfs), million gallons per day (mgd), gallons per minute (gpm) or cubic meters per second (csm). See also "rate of runoff."
DRAINAGEThe interception and removal of excess surface water or groundwater from land by artificial or natural means.
DRAINAGE AREAThe contributing land area to a single drainage basin, expressed in acres, square miles or other units of area; also called a "catchment area," "watershed" or "river basin"; the land area served by a drainage system or by a watercourse receiving stormwater and surface water, also called "subarea."
DRAINAGE BASINThe land area from which water is carried off by a drainage system; also called a "watershed" or "catchment."
DRAINAGE EASEMENTA right granted by a landowner to a grantee allowing the use of private land for stormwater management purposes.
EROSIONThe natural process by which the surface of the land is worn away by the action of water, wind or chemical action.
FLOODPLAINA normally dry land area adjacent to stream channels that is susceptible to being inundated by overbank stream flows. For regulatory purposes, the Pennsylvania Flood Plain Management Act (Act of October 4, 1978, P.L. 851, No. 166) and regulations pursuant to the Act define the "floodplain" as the area inundated by a one-hundred-year flood and delineated on a map by FEMA (Federal Emergency Management Agency) or by the applicant in accordance with Borough ordinance requirements.
GRADINGAny stripping, excavating, cutting, filling or stockpiling of earth or land, including the land in its cut or filled condition.
HYDRAULICSThe branch of science concerned with the mechanics of fluids, especially liquids; as applied in erosion and sedimentation control, the study of the characteristics of water flow in and conveyance capacity of a watercourse, considering such factors as depth, velocity and turbulence.
HYDROLOGYThe science dealing with the waters of the earth and their distribution and circulation through the atmosphere. "Engineering hydrology" deals with the application of hydrologic concepts to the design of projects for use and control of water.
LAND DISTURBANCEAny activity involving grading, tilling, digging or filling or stripping of vegetation or another activity which causes land to be exposed to the danger of erosion or changed water flow characteristics.
NRCSThe Natural Resources Conservation Service, United States Department of Agriculture.
OUTFALLPoints or areas at which stormwater runoff leaves streams, storm sewers, swales or other well-defined natural or artificial drainage features, as well as areas of dispersed overland flows within the site and/or leaving the site.
PADEPThe Pennsylvania Department of Environmental Protection.
PERFORMANCE STANDARDA standard which establishes an end result or outcome which is to be achieved but does not prescribe specific means for achieving it. A "specification standard," in contrast, is one which prescribes the exact characteristic to be used, leaving little choice to the applicant.
POINT OF INTERESTA point of hydraulic concern, such as a bridge, culvert or channel section, for which the rate of runoff is computed or measured.
RATE OF RUNOFFInstantaneous measurement of water flow expressed in a unit of volume per unit of time, also referred to as "discharge"; usually stated in cubic feet per second (cfs) or gallons per minute (gpm).
RUNOFF CHARACTERISTICSThe surface components of any watershed which affect the rate, amount and direction of stormwater runoff. These may include but are not being limited to vegetation, soils, slopes and man-made landscape alterations.
SEDIMENTSolid material, both mineral and organic, that is in suspension, is being transported or has been removed from its site or origin by air, water, gravity or ice and has come to rest on the earth's surface.
SEDIMENTATIONThe process by which sediment is deposited on stream bottoms.
STORM SEWERA sewer that carries intercepted surface runoff, street water and other wash waters or drainage, but excludes domestic sewage and industrial wastes.
STORMWATER COLLECTION/CONVEYANCE SYSTEMNatural or engineered structures which collect and transport stormwater through or from a drainage area to the point of final outlet, including but not limited to any of the following: conduits and appurtenant features, canals, channels, ditches, streams, culverts, streets and pumping stations.
STORMWATER RUNOFFWaters resulting from snowmelt or precipitation within a drainage basin, flowing over the surface of the ground, collected in channels and conduits and carried by receiving streams.
SUBAREAA portion of the watershed that has similar hydrological characteristics and drains to a common point; also called a "drainage area."
SWALEA low-lying stretch of land which gathers or carries surface water runoff.
WATERCOURSE (WATERWAY)Any channel of conveyance of surface water having a defined bed and banks, whether natural or artificial, with perennial or intermittent flow.
WATERSHEDThe entire region or area drained by a river or other body of water, whether natural or artificial.
WATERS OF THIS COMMONWEALTHRivers, streams, creeks, rivulets, impoundments, ditches, watercourses, storm sewers, lakes, dammed water, wetlands, ponds, springs and other bodies or channels of conveyance of surface water or parts thereof, whether natural or artificial, within or on the boundaries of this commonwealth.