Definitions. As used in this chapter, the following terms shall have
the meanings indicated:
ACT
The Pennsylvania Municipalities Planning Code (Act of July
31, 1968, Act No. 247, as amended).
APPLICANT
A landowner or developer, as defined by this chapter, who
has filed an application for development, including his or her heirs,
successors and assigns.
CHANNEL
A natural stream that conveys water; a ditch or open channel
excavated for the flow of water.
DESIGN STORM
The 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.
DEVELOPMENT
Any activity, construction, alteration, change in land use
or similar action that affects stormwater runoff characteristics.
DEVELOPMENT SITE
A lot, parcel or tract of land on which development is taking
place or is proposed.
DISCHARGE
The 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."
DRAINAGE
The interception and removal of excess surface water or groundwater
from land by artificial or natural means.
DRAINAGE AREA
The 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 BASIN
The land area from which water is carried off by a drainage
system; also called a "watershed" or "catchment."
DRAINAGE EASEMENT
A right granted by a landowner to a grantee allowing the
use of private land for stormwater management purposes.
EROSION
The natural process by which the surface of the land is worn
away by the action of water, wind or chemical action.
FLOODPLAIN
A 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.
GRADING
Any stripping, excavating, cutting, filling or stockpiling
of earth or land, including the land in its cut or filled condition.
HYDRAULICS
The 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.
HYDROLOGY
The 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 DISTURBANCE
Any 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.
NRCS
The Natural Resources Conservation Service, United States
Department of Agriculture.
OUTFALL
Points 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.
PADEP
The Pennsylvania Department of Environmental Protection.
PERFORMANCE STANDARD
A 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 INTEREST
A point of hydraulic concern, such as a bridge, culvert or
channel section, for which the rate of runoff is computed or measured.
RATE OF RUNOFF
Instantaneous 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 CHARACTERISTICS
The 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.
SEDIMENT
Solid 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.
SEDIMENTATION
The process by which sediment is deposited on stream bottoms.
STORM SEWER
A sewer that carries intercepted surface runoff, street water
and other wash waters or drainage, but excludes domestic sewage and
industrial wastes.
STORMWATER COLLECTION/CONVEYANCE SYSTEM
Natural 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 RUNOFF
Waters 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.
SUBAREA
A portion of the watershed that has similar hydrological
characteristics and drains to a common point; also called a "drainage
area."
SWALE
A 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.
WATERSHED
The entire region or area drained by a river or other body
of water, whether natural or artificial.
WATERS OF THIS COMMONWEALTH
Rivers, 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.