Definitions.
ACCELERATED EROSION
The removal of the surface of the land through the combined
action of human activity and natural processes at a rate greater than
would occur because of the natural process alone.
AGRICULTURAL ACTIVITIES
Activities associated with agriculture such as agricultural
cultivation, agricultural operation, and animal heavy use areas. This
includes the work of producing crops, tillage, land clearing, plowing,
disking, harrowing, planting, harvesting crops, or pasturing and raising
of livestock and installation of conservation measures. Construction
of new buildings or impervious area is not considered an agricultural
activity.
ALTERATION
As applied to land, a change in topography as a result of
the moving of soil and rock from one location or position to another;
changing of surface conditions by causing the surface to be more or
less impervious; land disturbance.
APPLICANT
A landowner, developer, or other person who has filed an
application for approval to engage in any regulated activities at
a project site within the Township.
BEST MANAGEMENT PRACTICES (BMPs)
Activities, facilities, designs, measures or procedures used
to manage stormwater impacts from regulated activities, to meet state
water quality requirements, to promote groundwater recharge and to
otherwise meet the purposes of this chapter. Stormwater BMPs are commonly
grouped into one of two broad categories or measures: "non-structural"
or "structural." "Non-structural" BMPs are measures referred to as
operational and/or behavior-related practices that attempt to minimize
the contact of pollutants with stormwater runoff whereas "structural"
BMPs are measures that consist of a physical device or practice that
is installed to capture and treat stormwater runoff. "Structural"
BMPs include, but are not limited to, a wide variety of practices
and devices, from large-scale retention ponds and constructed wetlands,
to small-scale underground treatment systems, infiltration facilities,
filter strips, low-impact design, bioretention, wet ponds, permeable
paving, grassed swales, riparian or forested buffers, sand filters,
detention basins, and manufactured devices. "Structural" stormwater
BMPs are permanent appurtenances to the project site.
CHANNEL EROSION
The widening, deepening, and headward cutting of small channels
and waterways, due to erosion caused by moderate to large floods.
CISTERN
An underground reservoir or tank used for storing rainwater.
CONSERVATION DISTRICT
The Washington County Conservation District. The Washington
County Conservation District has the authority under a delegation
agreement executed with the Department of Environmental Protection
to administer and enforce all or a portion of the regulations promulgated
under 25 Pa. Code Chapter 102.
CULVERT
A structure with appurtenant works that carries a stream
and/or stormwater runoff under or through an embankment or fill.
DAM
An artificial barrier, together with its appurtenant works,
constructed for the purpose of impounding or storing water or another
fluid or semifluid, or a refuse bank, fill or structure for highway,
railroad or other purposes which does or may impound water or another
fluid or semifluid.
DESIGN STORM
The magnitude and temporal distribution of precipitation
from a storm event measured in probability of occurrence (e.g., a
twenty-five-year storm) and duration (e.g., 24 hours), used in the
design and evaluation of stormwater management systems. Also see "return
period."
DESIGNEE
The agent of this Township and/or agent of the governing
body involved with the administration, review or enforcement of any
provisions of this chapter by contract or memorandum of understanding.
DETENTION BASIN
An impoundment structure designed to manage stormwater runoff
by temporarily storing the runoff and releasing it at a predetermined
rate.
DETENTION VOLUME
The volume of runoff that is captured and released into waters
of the commonwealth at a controlled rate.
DEVELOPER
A landowner, agent of such landowner or tenant with permission
of such landowner, or any responsible person, who undertakes a subdivision,
land development in accordance with Chapter 252 of the Cecil Township
Codified Ordinances, or that undertakes any regulated activity of
this chapter.
DISTURBED AREA
An unstabilized land area where an earth disturbance activity
is occurring or has occurred.
DOWNSLOPE PROPERTY LINE
That portion of the property line of the lot, tract, or parcels
of land being developed located such that all overland or pipe flow
from the site would be directed toward it.
DRAINAGE CONVEYANCE FACILITY
A stormwater management facility designed to convey stormwater
runoff and shall include streams, channels, swales, pipes, conduits,
culverts, storm sewers, etc.
DRAINAGE EASEMENT
A right granted by a landowner to a grantee, allowing the
use of private land for stormwater management, drainage, or conveyance
purposes.
DRAINAGEWAY
Any natural or artificial watercourse, trench, ditch, pipe,
swale, channel, or similar depression into which surface water flows.
EARTH DISTURBANCE ACTIVITY
A construction or other human activity which disturbs the
surface of the land, including, but not limited to, clearing and grubbing,
grading, excavations, embankments, land development, agricultural
plowing or tilling, timber harvesting activities, road maintenance
activities, mineral extraction, and the moving, depositing, stockpiling,
or storing of soil, rock or earth materials.
EROSION
The process of breaking down and carrying away of exposed
ground surfaces by action of wind, water and temperature change.
EXCEPTIONAL VALUE WATERS
Surface waters of high quality, which satisfies Pa. Code
Title 25 Environmental Protection, Chapter 93, Water Quality Standards
93.4b(b) (relating to anti-degradation).
EXISTING CONDITIONS
The initial condition of a project site prior to the proposed
construction. If the initial condition of the site is undeveloped
land and not forested, the land use shall be considered as "meadow"
unless the natural land cover is documented to generate lower Curve
Numbers or Rational "C" Coefficient.
FEMA
The Federal Emergency Management Agency.
FLOOD
A general but temporary condition of partial or complete
inundation of normally dry land areas from the overflow of streams,
rivers, and other waters of the commonwealth.
FLOOD FRINGE
The remaining portions of the 100-year floodplain outside
of the floodway boundary.
FLOODPLAIN
Any land area susceptible to inundation by water from any
natural source or delineated by applicable Department of Housing and
Urban Development, Federal Insurance Administration Flood Hazard Boundary
- mapped as being a special flood hazard area. Included are lands
adjoining a river or stream that have been or may be inundated by
a 100-year flood. Also included are areas that comprise Group 13 Soils,
as listed in Appendix A of the Pennsylvania Department of Environmental
Protection (PADEP) Technical Manual for Sewage Enforcement Officers
(as amended or replaced from time to time by PADEP).
FLOODWAY
The channel of the watercourse and those portions of the
adjoining floodplains that are reasonably required to carry and discharge
the 100-year frequency flood. Unless otherwise specified, the boundary
of the floodway is as indicated on maps and flood insurance studies
provided by FEMA. in an area where no fema maps or studies have defined
the boundary of the 100-year frequency floodway, it is assumed - absent
evidence to the contrary - that the floodway extends from the stream
to 50 feet landward from the top of the bank of the stream.
FOREST MANAGEMENT/TIMBER OPERATIONS
Planning and activities necessary for the management of forestland.
These include timber inventory and preparation of forest management
plans, silvicultural treatment, cutting budgets, logging road design
and construction, timber harvesting, site preparation and reforestation.
FREEBOARD
A vertical distance between the elevation of the design high
water and the top of a dam, levee, tank, basin, or diversion ridge.
The space is required as a safety margin in a tank, pond or basin.
GRADE
A slope, usually of a road, channel or natural ground specified
in percent and shown on plans as specified herein.
(TO) GRADE
To finish the surface of a roadbed, top of embankment or
bottom of excavation.
HIGH QUALITY WATERS
Surface water having quality which exceeds levels necessary
to support propagation of fish, shellfish, and wildlife and recreation
in and on the water by satisfying Pa. Code Title 25 Environmental
Protection, Chapter 93 Water Quality Standards 93.4b(a).
HYDROLOGIC SOIL GROUP (HSG)
Infiltration rates of soils vary widely and are affected
by subsurface permeability as well as surface intake rates. Soils
are classified into one of four HSG (A, B, C, and D) according to
their minimum infiltration rate, which is obtained for bare soil after
prolonged wetting. The Natural Resource Conservation Service (NRCS)
of the US Department of Agriculture defines the four groups and provides
a list of most of the soils in the United States and their group classification.
The soils in the area of interest may be identified from a soil survey
report from the local NRCS office or the County Conservation District.
IMPERVIOUS SURFACE (IMPERVIOUS AREA)
A surface that prevents the infiltration of water into the
ground. Impervious surfaces (or areas) include, but are not limited
to: roofs, additional indoor living spaces, patios, garages, storage
sheds and similar structures, parking or driveway areas, and any new
streets and sidewalks. Any surface areas proposed to initially be
gravel or crushed stone shall be assumed to be impervious surfaces.
IMPOUNDMENT
A retention or detention basin designed to retain stormwater
runoff and release it at a controlled rate.
INFILTRATION STRUCTURES
A structure designed to direct runoff into the ground (e.g.,
french drains, seepage pits, seepage trench, etc.).
INLET
A surface connection to a closed drain. A structure at the
diversion end of a conduit. The upstream end of any structure through
which water may flow.
LAND DEVELOPMENT (DEVELOPMENT)
Any of the following activities:
(1)
The improvement of one lot or two or more contiguous lots, tracts,
or parcels of land for any purpose involving:
(a)
A group of two or more residential or nonresidential buildings,
whether proposed initially or cumulatively, or a single nonresidential
building on a lot or lots, regardless of the number of occupants or
tenure; or
(b)
The division or allocation of land or space, whether initially
or cumulatively, between or among two or more existing or prospective
occupants by means of, or for the purpose of, streets, common areas,
leaseholds, condominiums, building groups or other features.
(3)
Developments authorized to be excluded from the regulations
of land development under the Cecil Township Unified Development Ordinance.
LOW-IMPACT DEVELOPMENT (LID)
An approach to land development that uses various land planning
and design practices and technologies to simultaneously conserve and
protect natural resource systems and reduce infrastructure costs.
Low-impact development still allows land to be developed, but in a
cost-effective manner that helps mitigate potential environmental
impacts.
MAIN STEM (MAIN CHANNEL)
Any stream segment or other runoff conveyance facility used
as a reach in the Washington County Act 167 watershed hydrologic model(s).
MANNING EQUATION (MANNING FORMULA)
A method for calculation of velocity of flow (e.g., feet
per second) and flow rate (e.g., cubic feet per second) in open channels
based upon channel shape, roughness, depth of flow and slope. "Open
channels" may include closed conduits so long as the flow is not under
pressure.
NOAA ATLAS 14
Precipitation-Frequency Atlas of the United States, Atlas
14, Volume 2, US Department of Commerce, National Oceanic and Atmospheric
Administration, National Weather Service, Hydrometeorological Design
Studies Center, Silver Spring, Maryland (2004). NOAA's Atlas
14 can be accessed at Internet address http://hdsc.nws.noaa.gov/hdsc/pfds/.
NON-POINT SOURCE POLLUTION
Pollution that enters a water body from diffuse origins in
the watershed and does not result from discernible, confined, or discrete
conveyances.
NRCS
Natural Resource Conservation Service [previously Soil Conservation
Service (SCS)].
OPEN CHANNEL
A drainage element in which stormwater flows with an open
surface. Open channels include, but shall not be limited to, natural
and man-made drainageways, swales, streams, ditches, canals, and pipes
not under pressure.
OUTFALL
(1)
Point where water flows from a conduit, stream, or drain;
(2)
"Point Source" as described in 40 CFR 122.2 at the point where
the Township's storm sewer system discharges to surface waters
of the commonwealth.
OUTLET
Points of water disposal from a stream, river, lake, tidewater,
or artificial drain.
PADEP
The Pennsylvania Department of Environmental Protection.
PARKING LOT STORAGE
Involves the use of impervious parking areas as temporary
impoundments with controlled release rates during rainstorms.
PEAK DISCHARGE
The maximum rate of stormwater runoff from a specific storm
event.
PERSON
An individual, partnership, public or private association
or corporation, or a governmental unit, public utility or any other
legal entity whatsoever which is recognized by law as the subject
of rights and duties.
PIPE
A culvert, closed conduit, or similar structure (including
appurtenances) that conveys stormwater.
POINT SOURCE
Any discernible, confined, or discrete conveyance, including,
but not limited to: any pipe, ditch, channel, tunnel, or conduit from
which stormwater is or may be discharged, as defined in State regulations
at 25 Pa. § 92.1.
PROBABLE MAXIMUM FLOOD (PMF)
The flood that may be expected from the most severe combination
of critical meteorological and hydrologic conditions that are reasonably
possible in any area. The PMF is derived from the probable maximum
precipitation (PMP) as determined on the basis of data obtained from
the National Oceanographic and Atmospheric Administration (NOAA).
PROJECT SITE
The specific area of land where any regulated activities
in the Township are planned, conducted, or maintained.
QUALIFIED PROFESSIONAL
Any person licensed by the Pennsylvania Department of State
or otherwise qualified by law to perform the work required by this
chapter.
REDEVELOPMENT
Earth disturbance activities on land which has previously
been developed.
REGULATED ACTIVITIES
Any earth disturbance activities or any activities that involve
the alteration or development of land in a manner that may affect
stormwater runoff.
RELEASE RATE
The percentage of pre-development peak rate of runoff from
a site or subwatershed area to which the post-development peak rate
of runoff must be reduced to protect downstream areas.
RELEASE RATE DISTRICT
Those subwatershed areas in which post-development flows
must be reduced to a certain percentage of pre-development flows as
required to meet the plan requirements and the goals of Act 167.
RETENTION BASIN
An impoundment in which stormwater is stored and not released
during the storm event. Stored water may be released from the basin
at some time after the end of the storm.
RETENTION VOLUME/REMOVED RUNOFF
The volume of runoff that is captured and not released directly
into the surface waters of this commonwealth during or after a storm
event.
RETURN PERIOD
The average interval, in years, within which a storm event
of a given magnitude can be expected to recur. For example, the twenty-five-year
return period rainfall would be expected to recur on the average once
every 25 years; or stated in another way, the probability of a twenty-five-year
storm occurring in any one given year is 0.04 (i.e., a 4% chance).
RIPARIAN BUFFER
A vegetated area bordering perennial and intermittent streams
and wetlands, that serves as a protective filter to help protect streams/wetlands
from the impacts of adjacent land uses.
RISER
A vertical pipe extending from the bottom of a pond that
is used to control the discharge rate from the pond for a specified
design storm.
ROAD MAINTENANCE
Earth disturbance activities within the existing road right-of-way,
such as grading and repairing existing unpaved road surfaces, cutting
road banks, cleaning or clearing drainage ditches, and other similar
activities. Road maintenance activities that do not disturb the subbase
of a paved road (such as milling and overlays) are not considered
earth disturbance activities.
ROOFTOP DETENTION
Temporary ponding and gradual release of stormwater falling
directly onto flat roof surfaces by incorporating controlled-flow
roof drains into building designs.
RUNOFF
Any part of precipitation that flows over the land surface.
RUNOFF CAPTURE VOLUME
The volume of runoff that is captured (retained) and not
released into surface waters of the commonwealth during or after a
storm event.
SEDIMENT
Soils or other materials transported by surface water as
a product of erosion.
SEDIMENT BASIN
A barrier, dam, retention or detention basin located and
designed to retain rock, sand, gravel, silt, or other material transported
by stormwater runoff.
SEDIMENT POLLUTION
The placement, discharge, or any other introduction of sediment
into waters of the commonwealth occurring from the failure to properly
design, construct, implement or maintain control measures and control
facilities in accordance with the requirements of this chapter.
SEDIMENTATION
The process by which mineral or organic matter is accumulated
or deposited by the movement of water.
SEEPAGE PIT/SEEPAGE TRENCH
An area of excavated earth filled with loose stone or similar
coarse material, into which surface water is directed for infiltration
into the ground.
SEPARATE STORM SEWER SYSTEM
A conveyance or system of conveyances (including roads with
drainage systems, municipal streets, catch basins, curbs, gutters,
ditches, man-made channels, or storm drains) primarily used for collecting
and conveying stormwater runoff.
SHEET FLOW
Runoff that flows over the ground surface as a thin, even
layer, not concentrated in a channel.
SOIL COVER COMPLEX METHOD
A method of runoff computation developed by the NRCS that
is based on relating soil type and land use/cover to a runoff parameter
called curve number (CN).
SPILLWAY (EMERGENCY)
A depression in the embankment of a pond or basin, or other
overflow structure, that is used to pass peak discharges greater than
the maximum design storm controlled by the pond or basin.
STATE WATER QUALITY REQUIREMENTS
The regulatory requirements to protect, maintain, reclaim,
and restore water quality under Title 25 of the Pennsylvania Code
and the Clean Streams Law.
STORAGE INDICATION METHOD
A reservoir routing procedure based on solution of the continuity
equation (inflow minus outflow equals the change in storage) with
outflow defined as a function of storage volume and depth.
STORM FREQUENCY
The number of times that a given storm event occurs or is
exceeded on the average in a stated period of years. See also "return
period."
STORM SEWER
A system of pipes and/or open channels that convey intercepted
runoff and stormwater from other sources, but excludes domestic sewage
and industrial wastes.
STORMWATER
Runoff from the surface of the land resulting from precipitation,
snow, or ice melt.
STORMWATER HOTSPOT
A land use or activity that generates higher concentrations
of hydrocarbons, trace metals, or toxicants than are found in typical
stormwater runoff.
STORMWATER MANAGEMENT FACILITIES
Any structure, natural or man-made, that, due to its condition,
design, or construction, conveys, stores, or otherwise affects stormwater
runoff. Typical stormwater management facilities include, but are
not limited to: detention and retention basins, open channels, storm
sewers, pipes and infiltration facilities.
STORMWATER MANAGEMENT PLAN
The Washington County stormwater management plan for managing
stormwater runoff in Washington County as required by the Act of October
4, 1978, P.L. 864, (Act 167) and known as the "Storm Water Management
Act."
STREAM ENCLOSURE
A bridge, culvert, or other structure in excess of 100 feet
in length upstream to downstream which encloses a regulated waters
of the commonwealth.
SUBDIVISION
The division or re-division of a lot, tract, or parcel of
land by any means, into two or more lots, tracts, parcels or other
divisions of land including changes in existing lot lines for the
purpose, whether immediate or future, of lease, partition by the court
for distribution to heirs or devisees, transfer of ownership, or building
or lot development; provided, however, that the subdivision by lease
of land for agricultural purposes into parcels of more than 10 acres,
not involving any new street or easement of access or any residential
dwellings, shall be exempt.
SUBWATERSHED AREA
The smallest drainage unit of a watershed for which stormwater
management criteria has been established in the stormwater management
plan.
SWALE
A low-lying stretch of land that gathers or carries surface
water runoff.
TIME OF CONCENTRATION (Tc)
The time for surface runoff to travel from the hydraulically
most distant point of the watershed to a point of interest within
the watershed. This time is the combined total of overland flow time
and flow time in pipes or channels, if any.
TOWNSHIP
Cecil Township, Washington County, Pennsylvania.
USDA
The United States Department of Agriculture.
WATERCOURSE
A natural or man-made drainageway, which has a definite channel
and flows in a definite direction, whether continuously or intermittently,
including streams, rivers, creeks, channels, conduits, canals, drains,
gullies, ravines and the like and which is certified by a registered
surveyor or engineer as being a natural watercourse.
WATERS OF THE 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 and
underground water, or parts thereof, whether natural or artificial,
within or on the boundaries of the Commonwealth of Pennsylvania.
WATERSHED
Area drained by a river, watercourse, or other surface water,
whether natural or artificial.
WETLAND
Those areas that are inundated or saturated by surface or
groundwater at a frequency and duration sufficient to support, and
that under normal circumstances do support, a prevalence of vegetation
typically adapted for life in saturated soil conditions, including
swamps, marshes, bogs and similar areas. (The term includes but is
not limited to wetland areas listed in the State Water Plan, the United
States Forest Service Wetlands Inventory of Pennsylvania and a wetland
area designated by a river basin commission. This definition is used
by the United States Environmental Protection Agency and the United
States Army Corps of Engineers.)