As used in this chapter, the following terms shall have the
meanings indicated:
ACCELERATED EROSION
The removal of the surface of the land through the combined
action of man's activity and the natural processes at a rate
greater than would occur because of the natural process alone.
ACCESS EASEMENT
A right granted by a landowner to a grantee, allowing entry
for the purpose of inspecting, maintaining and repairing SWM facilities.
ACT 167 PLAN
A plan prepared under the authority of the Stormwater Management
Act.
AGRICULTURAL ACTIVITY
Activities associated with agriculture such as agricultural
cultivation, agricultural operation, and animal heavy use areas. This
includes the work of producing crops and raising livestock including
tillage, land clearing, plowing, disking, harrowing, planting, harvesting
crops, or pasturing and raising of livestock and installation of conservation
practices. Construction of new buildings or impervious areas is not
considered an agricultural activity.
AGRICULTURE
The cultivation of the soil and the raising and harvesting
of the products of the soil, including but not limited to nursery,
horticulture, forestry and animal husbandry activities.
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;
also the changing of surface conditions by causing the surface to
be more or less impervious; earth disturbance activity.
ANIMAL HEAVY USE AREAS
A barnyard, feedlot, loafing area, exercise lot, or other
similar area on an agricultural operation where due to the concentration
of animals, it is not possible to establish and maintain vegetative
cover of a density capable of minimizing accelerated erosion and sedimentation
by usual planting methods. The term does not include entrances, pathways
and walkways between areas where animals are housed or kept in concentration.
APPLICANT
A landowner and/or developer, including his heirs, successors
and assigns, who has filed an application to the Township for approval
to engage in any regulated activity at a development site located
within the Township.
BMP (BEST MANAGEMENT PRACTICE)
Activities, facilities, control measures, planning or procedures
used to minimize accelerated erosion and sedimentation and manage
stormwater to protect, maintain, reclaim, and restore the quality
of waters and the existing and designated uses of waters within this
Commonwealth before, during and after earth disturbance activities. See also "nonstructural BMP" and "structural BMP."
BMP MANUAL
The Pennsylvania Stormwater Best Management Practices Manual
of December 2006, or most recent version thereof.
BUILDING
Any structure, either temporary or permanent, having walls
and a roof or other covering, and designed or used for the shelter
or enclosure of any person, animal or property of any kind including
tents, awnings or vehicles situated on private property and used for
purposes stated above. For the purposes of this section, the word
"building" shall include gas or liquid storage tanks.
CARBONATE GEOLOGY
Limestone or dolomite bedrock. Carbonate geology is often
associated with karst topography.
CERTIFICATE OF COMPLETION
Documentation verifying that all permanent SWM facilities
have been constructed according to the plans and specifications and
approved revisions thereto.
CHANNEL
A natural or artificial watercourse with a definite bed and
banks that confine and conduct continuously or periodically flowing
water.
CHAPTER 102
25 Pa. Code Chapter 102, Erosion and Sediment Control.
CHAPTER 105
25 Pa. Code Chapter 105, Dam Safety and Waterway Management.
CHAPTER 106
25 Pa. Code Chapter 106, Floodplain Management.
CISTERN
A reservoir or tank for storing rainwater.
CLEAN WATER ACT
The 1972 Amendments to the Federal Water Pollution Control
Act, P.L. 92-500 of 1972, 33 U.S.C. § 1251 et seq.
CONSERVATION PLAN
A plan written by an NRCS-certified planner that identifies
conservation practices and includes site specific BMPs for agricultural
plowing or tilling activities and animal heavy use areas.
CONSERVATION PRACTICES
Practices installed on agricultural lands to improve farmland,
soil and/or water quality which have been identified in a current
conservation plan.
CONVEYANCE
A.
Any structure that carries a flow.
B.
The ability of a pipe, culvert, swale or similar facility to
carry the peak flow from the design storm.
CULVERT
A structure with appurtenant works which can convey a stream
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. The dam falls under the requirements of Chapter
105, Dam Safety and Waterway Management, if the following is true:
A.
The contributory drainage area exceeds 100 acres.
B.
The greatest depth of water measured by upstream toe of the
dam at maximum storage elevation exceeds 15 feet.
C.
The impounding capacity at maximum storage elevation exceeds
50 acre-feet.
DCNR
The Pennsylvania Department of Conservation and Natural Resources
or any agency successor thereto.
DEP or PA DEP or PADEP
The Pennsylvania Department of Environmental Protection or
any agency successor to the Pennsylvania Department of Environmental
Protection.
DESIGNEE
The agent of the Township involved with the administration,
review or enforcement of any provisions of this chapter by appointment
by the Board of Supervisors.
DESIGN STORM
The magnitude and temporal distribution of precipitation
from a storm event measured in probability of occurrence (e.g., a
five-year storm) and duration (e.g., 24 hours), used in the design
and evaluation of SWM systems.
DETENTION BASIN
An impoundment structure designed to manage stormwater runoff
by temporarily storing the runoff and releasing it at a controlled
rate.
DEVELOPER
Any landowner, agent of such landowner or tenant with the
permission of such landowner, who makes or causes to be made a subdivision
of land or a land development, or other activities covered by this
chapter.
DEVELOPMENT
Any man-made change to improved or unimproved real estate,
including but not limited to buildings or other structures, mining,
dredging, filling, grading, paving, excavation, or drilling operations.
DEVELOPMENT SITE (SITE)
The specific area of land where regulated activities in the
municipality are planned, conducted or maintained.
DISAPPEARING STREAM
A stream in an area underlain by limestone or dolomite that
flows underground for a portion of its length.
DISTURBED AREA
A land area where an earth disturbance activity is occurring
or has occurred.
DOWNSLOPE PROPERTY LINE
That portion of a property line of a parent tract located
at the topographically lowest point of the parent tract such that
some or all overland, swale, or pipe flow from a development site
would be directed toward it.
DRAINAGE CONVEYANCE FACILITY
A SWM facility designed to transmit stormwater runoff and
shall include streams, channels, swales, pipes, conduits, storm sewers,
etc.
DRAINAGE EASEMENT
Rights to occupy and use another person's real property
for the installation and operation of stormwater management facilities,
or for the maintenance of natural drainageways to preserve and maintain
a channel for the flow of stormwater therein, or to safeguard health,
safety, property, and facilities.
E&S
Erosion and sediment.
E & S MANUAL
The Erosion and Sediment Pollution Control Program Manual,
Number 363-2134-008, prepared by DEP.
E&S PLAN (EROSION AND SEDIMENT CONTROL PLAN)
A site-specific plan consisting of both drawings and a narrative
that identifies BMPs to minimize accelerated erosion and sedimentation
before, during and after earth disturbance activities in excess of
5,000 square feet.
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; operation of animal heavy use areas; timber harvesting
activities; road maintenance activities; oil and gas activities; well
drilling; mineral extraction; building construction; and the moving,
depositing, stockpiling, or storing of soil, rock, or earth materials.
ENGINEER
A professional engineer licensed by the Commonwealth of Pennsylvania.
ENVIRONMENTALLY SENSITIVE AREA
Slopes greater than 15%, shallow bedrock (located within
six feet of ground surface), wetlands, natural heritage areas and other areas designated
as conservation or preservation in Greenscapes, the Green Infrastructure
Element of the County Comprehensive Plan, where encroachment by land
development or land disturbance results in degradation of the natural
resource.
EPHEMERAL STREAM
A water conveyance which lacks substrates associated with
flowing waters and flows only in direct response to precipitation
in the immediate watershed or in response to melting snowpack and
which is always above the local water table.
EROSION
The natural process by which the surface of the land is worn
away by water, wind, or chemical action. See also "accelerated erosion"
as defined above.
EXISTING CONDITIONS
The dominant land cover during the five-year period immediately
preceding a proposed regulated activity.
FEMA
The Federal Emergency Management Agency or any agency successor
thereto.
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 this commonwealth.
FLOODPLAIN
See definition of "floodplain" under Chapter
340, Zoning.
FLOOR ELEVATION
The elevation of the lowest level of a particular building,
including the basement.
FOREST MANAGEMENT/TIMBER OPERATIONS
Planning and activities necessary for the management of forest
land. These include conducting a 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 maximum design high water
elevation and the top of a dam, levee, tank, basin, or diversion ridge.
FREQUENCY
The probability or chance that a given storm event/flood
will be equaled or exceeded in a given year.
GRADE
A.
(n) A slope, usually of a road, channel or natural ground specified
in percent and shown on plans as specified herein.
B.
(v) To finish the surface of a roadbed, top of embankment or
bottom of excavation.
GRASSED WATERWAY
A natural or constructed waterway, usually broad and shallow,
covered with erosion-resistant grasses, used to conduct surface water
from cropland.
GROUNDWATER RECHARGE
The process by which water from above the ground surface
is added to the saturated zone of an aquifer, either directly or indirectly.
HYDROLOGIC SOIL GROUP (HSG)
Refers to soils grouped according to their runoff-producing
characteristics by NRCS. There are four runoff potential groups ranging
from A to D.
A.
(Low runoff potential) Soils having high infiltration rates
even when thoroughly wetted and consisting chiefly of deep, well to
excessively drained sands or gravels. These soils have a high rate
of water transmission (greater than 0.30 inches/hour).
B.
Soils having moderate infiltration rates when thoroughly wetted
and consisting chiefly of moderately deep to deep, moderately well
to well drained soils with moderately fine to moderately coarse textures.
These soils have a moderate rate of water transmission (from 0.15
to 0.30 inches/hour).
C.
Soils having slow infiltration rates when thoroughly wetted
and consisting chiefly of soils with a layer that impedes downward
movement of water, or soils with moderately fine to fine texture.
These soils have a slow rate of water transmission (from 0.05 to 0.15
inches/hour).
D.
(High runoff potential) Soils having very slow infiltration
rates when thoroughly wetted and consisting chiefly of clay soils
with a high swelling potential, soils with a permanent high water
table, soils with a clay pan or clay layer at or near the surface,
and shallow soils over nearly impervious material. These soils have
a very slow rate of water transmission (from zero to 0.05 inches/hour).
IMPERVIOUS SURFACE (IMPERVIOUS AREA)
Surfaces which prevent the infiltration of water into the
ground. All structures, buildings, parking areas, driveways, roads,
streets, sidewalks, decks, and any areas of concrete, asphalt, packed
stone, and compacted soil shall be considered impervious surface if
they prevent infiltration.
IMPOUNDMENT
A retention or detention facility designed to retain stormwater
runoff and infiltrate it into the ground (in the case of a retention
basin) or release it at a controlled rate (in the case of a detention
basin).
INFILTRATION STRUCTURES
A structure designed to direct runoff into the ground (e.g.,
french drains, seepage pits, seepage trench, rain gardens, vegetated
swales, pervious paving, infiltration basins, etc.).
INLET
A surface connection to a closed drain. The upstream end
of any structure through which water may flow.
INTERMITTENT STREAM
A natural, transient body or conveyance of water that exists
for a relatively long time, but for weeks or months of the year is
below the local water table and obtains its flow from both surface
runoff and groundwater discharges.
INVASIVE VEGETATION (INVASIVES)
Plants which grow quickly and aggressively, spreading, and
displacing other plants. Invasives typically are introduced into a
region far from their native habitat. See Invasive Plants in Pennsylvania
by the DCNR.
KARST
A type of topography or landscape characterized by features
including but not limited to surface depressions, sinkholes, rock
pinnacles/uneven bedrock surface, underground drainage, and caves.
Karst is formed on carbonate rocks, such as limestone or dolomite.
LAND DEVELOPMENT
Any development of property considered to be a land development under Chapter
285, Subdivision and Land Development, or the MPC.
LAND DISTURBANCE
Any activity involving grading, tilling, digging, or filling
of ground or stripping of vegetation or any other activity that causes
an alteration to the natural condition of the land.
LANDOWNER
The legal or beneficial owner or owners of land including
the holder of an option or contract to purchase (whether or not such
option or contract is subject to any condition), a lessee if he is
authorized under the lease to exercise the rights of the landowner,
or other person having a proprietary interest in land.
LIMITING ZONE
A rock formation, other stratum, or soil condition which
is so slowly permeable that it effectively limits downward passage
of effluent. Season high water tables, whether perched or regional,
also constitute a limiting zone.
LINEAMENT
A linear feature in a landscape which is an expression of
an underlying geological structure such as a fault.
MAIN STEM (MAIN CHANNEL)
Any stream segment or other runoff conveyance facility used
as a reach in the Conestoga River hydrologic model.
MANNING'S EQUATION
An equation 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. Manning's
Equation assumes steady, gradually varied flow.
MAXIMUM EXTENT PRACTICABLE (MEP)
Applies when the applicant demonstrates to the Township's
satisfaction that the performance standard is not achievable. The
applicant shall take into account the best available technology, cost
effectiveness, geographic features, and other competing interests
such as protection of human safety and welfare, protection of endangered
and threatened resources, and preservation of historic properties
in making the assertion that the performance standard cannot be met
and that a different means of control is appropriate.
MPC
The Pennsylvania Municipalities Planning Code, Act of July
31, 1968, P.L. 805, No. 247, as reenacted and amended, 53 P.S. § 10101
et seq.
MUNICIPAL SEPARATE STORM SEWER
A conveyance or system of conveyances (including roads with
drainage systems, municipal streets, catch basins, curbs, gutters,
ditches, man-made channels, or storm drains), which is all of the
following:
A.
Owned or operated by a state, city, town, borough, township,
county, district, association or other public body (created under
state law) having jurisdiction over disposal of sewage, industrial
wastes, stormwater or other wastes;
B.
Designed or used for collecting or conveying stormwater;
C.
Not a combined sewer; and
D.
Not part of a publicly owned treatment works as defined at 40
CFR 122.2.
MUNICIPAL SEPARATE STORM SEWER SYSTEM (MS4)
All separate storm sewers that are defined as "large" or
"medium" or "small" municipal separate storm sewer systems pursuant
to 40 CFR 122.26(b)(18), or designated as regulated under 40 CFR 122.26(a)(1)(v).
NATIONAL POLLUTION DISCHARGE ELIMINATION SYSTEM (NPDES)
A permit issued under 25 Pa. Code Chapter 92a (relating to
National Pollutant Discharge Elimination System permitting, monitoring
and compliance) for the discharge or potential discharge of pollutants
from a point source to surface waters.
NATIVE VEGETATION
Plant species that have evolved or are indigenous to a specific
geographical area. These plants are adapted to local soil and weather
conditions as well as pests and diseases.
NATURAL GROUND COVER
Ground cover which mimics the infiltration characteristics
of predominant hydrologic soil group found at the site.
NONPOINT SOURCE POLLUTION
Any source of water pollution that does not meet the legal
definition of "point source" in Section 502(14) of the Clean Water
Act.
NONSTRUCTURAL BMPs
Planning and design approaches, operational and/or behavior-related
practices which minimize stormwater runoff generation resulting from
an alteration of the land surface or limit contact of pollutants with
stormwater runoff.
NPDES
The U.S. EPA's "National Pollution Discharge Elimination
System", which regulates point discharges (discrete conveyances such
as pipes or man-made ditches).
NRCS
Natural Resources Conservation Service (previously Soil Conservation
Service, or 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 drainage ways, swales, streams, ditches, canals, and
pipes flowing partly full. Open channels may include closed conduits
so long as the flow is not under pressure.
OUTFALL
Point where water flows from a conduit, stream, pipe, or
drain.
OUTLET
Points of water disposal from a stream, river, lake, tidewater
or artificial drain.
PaDEP
The Pennsylvania Department of Environmental Protection,
former entity the Pennsylvania Department of Environmental Resources,
or any agency successor to the Pennsylvania Department of Environmental
Protection [Note: The Department of Environmental Resources was abolished
by Act 18 of 1995].
PARENT TRACT
All contiguous land held in single and separate ownership,
regardless of whether:
A.
Such land is divided into one or more lots, parcels, purparts
or tracts;
B.
Such land was acquired by the landowner at different times or
by different deeds, devise, partition or otherwise; or
C.
Such land is bisected by public or private streets or rights-of-way,
which was held by the landowner or his predecessor in title on June
21, 2006.
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.
PennDOT
The Pennsylvania Department of Transportation or any agency
successor thereto.
PERVIOUS AREA
Any material/surface that allows water to pass through at
a rate equal to or greater than natural ground cover.
PIPE
A culvert, closed conduit, or similar structure (including
appurtenances) that conveys stormwater.
PLANS
The SWM and erosion and sediment control plans and narratives.
PLANNING COMMISSION
The Planning Commission of Warwick Township, Lancaster County,
Pennsylvania.
PMF or PROBABLE MAXIMUM FLOOD
The flood that may be expected from the most severe combination
of critical meteorologic 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).
POSITIVE DRAINAGE
To draw off or empty surface waters in a manner which eliminates
ponding, standing water or any other undesirable condition. For surface
grades, a threshold of 1% shall determine positive drainage unless
other means or facilities are provided to adequately drain surface
waters.
PROCESS WASTEWATER
Water that comes in contact with any raw material, product,
byproduct, or waste during any production or industrial process.
QUALIFIED PERSON
Any person licensed by the Pennsylvania Department of State
or otherwise qualified by law to perform the work required by this
chapter.
RATE CONTROL
SWM controls used to manage the peak flows for the purposes
of channel protection and flood mitigation.
RECORD PLAN
Where a regulated activity constitutes a subdivision or land
development, the final subdivision or land development plan which
contains the information the ordinance requires. Where a regulated
activity does not constitute a subdivision or land development, a
SWM site plan containing all required information and prepared in
a form acceptable to the Office of the Recorder of Deeds for recording.
REDEVELOPMENT
Any physical improvement to a previously developed lot that
involves earthmoving, removal, or addition of impervious surfaces.
REGIONAL STORMWATER MANAGEMENT PLAN
A plan to manage stormwater runoff from an area larger than
a single development site. A regional stormwater management plan could
include two adjacent parcels, an entire watershed, or some defined
area in between. Regional stormwater management plans can be prepared
for new development, or as a retrofit to manage runoff from already
developed areas.
REGULATED ACTIVITIES
Activities, including earth disturbance activities, that
involve the alteration or development of land in a manner that may
affect stormwater runoff. Regulated activities shall include, but
not be limited to:
A.
Land development subject to the requirements of Chapter
285, Subdivision and Land Development;
B.
Removal of ground cover, grading, filling or excavation;
C.
Construction of new or additional impervious or semi-impervious
surfaces (driveways, parking lots, etc.), and associated improvements;
D.
Construction of new buildings or additions to existing buildings;
E.
Installation or alteration of stormwater management facilities
and appurtenances thereto;
F.
Diversion or piping of any watercourse; and,
G.
Any other regulated activities where the Township determines
that said activities may affect any existing watercourse's stormwater
management facilities, or stormwater drainage patterns.
RELEASE RATE
For a specific design storm or list of design storms, the
percentage of peak flow rate for existing conditions which may not
be exceeded for the proposed conditions.
RELEASE RATE MAP
A graphical representation of the release rates for a specific
area.
RETENTION BASIN
A SWM facility that includes a permanent pool for water quality
treatment and additional capacity above the permanent pool for temporary
runoff storage.
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.
RIPARIAN
Pertaining to a stream, river or other watercourse. Also,
plant communities occurring in association with any spring, lake,
river, stream or creek through which waters flow at least periodically.
RIPARIAN BUFFER
A BMP that is an area of permanent vegetation along a watercourse.
RIPARIAN CORRIDOR
A narrow strip of land, centered on a stream or river that
includes the floodplain as well as related riparian habitats adjacent
to the floodplain.
RIPARIAN FOREST BUFFER
A type of riparian buffer that consists of permanent vegetation
that is predominantly native trees, shrubs and forbs along a watercourse
that is maintained in a natural state or sustainably managed to protect
and enhance water quality, stabilize stream channels and banks, and
separate land use activities from surface waters.
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.
ROOFTOP DETENTION
Temporary ponding and gradual release of stormwater falling
directly onto roof surfaces by incorporating controlled-flow roof
drains into building designs.
RUNOFF
Any part of precipitation that flows over the land surface.
SCS
U.S. Department of Agriculture, Soil Conservation Service
(now known as NRCS).
SEDIMENT
Soils or other materials transported by stormwater as a product
of erosion.
SEDIMENTATION
The action or process of forming or depositing sediment in
waters of this commonwealth.
SEDIMENT BASIN
A barrier, dam, retention or detention basin located and
designed to retain rock, sand, gravel, silt, or other material transported
by water.
SEDIMENT POLLUTION
The placement, discharge or any other introduction of sediment
into the waters of this commonwealth occurring from the failure to
design, construct, implement or maintain control measures and control
facilities in accordance with the requirements of this chapter.
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.
SHEET FLOW
Runoff which flows over the ground surface as a thin, even
layer, not concentrated in a channel.
SMALL PROJECT
Regulated activities that, measured on a cumulative basis
from June 21, 2006, create additional impervious areas of more than
1,000 square feet and less than 2,500 square feet or involve earth
disturbance activity of an area less than 2,500 square feet and do
not involve the alteration of stormwater facilities or watercourses.
SMALL STORM EVENT
A storm having a frequency of recurrence of once every two
years or smaller.
SOIL-COVER COMPLEX METHOD
A method of runoff computation developed by the SCS (now
NRCS) that is based on relating soil type and land use/cover to a
runoff parameter called Curve Number (CN). For more information, see
"Urban Hydrology for Small Watersheds", second edition, Technical
Release No. 55, SCS, June 1986 (or most current edition).
SPILLWAY
A depression in the embankment of a pond or basin which is
used to pass a post-development one-hundred-year storm peak flow rate.
STATE WATER QUALITY REQUIREMENTS
The regulatory requirements to protect, maintain, reclaim,
and restore water quality under Title 25 of the Pennsylvania Code,
the Clean Streams Law and the Clean Water Act.
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.
STORAGE SPACE
A volume above or below ground that is available to hold
stormwater.
STORM EVENT
A storm of a specific duration, intensity, and frequency.
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 "return period."
STORM SEWER
A system of pipes, conduits, swales or other similar structures
including appurtenant works which carries intercepted runoff, and
other drainage, but excludes domestic sewage and industrial wastes.
STORMWATER
Drainage runoff from the surface of the land resulting from
precipitation or snow or ice melt.
STORMWATER MANAGEMENT
A program of controls and measures designed to regulate the
quantity and quality of stormwater runoff from a development while
promoting the protection and conservation of groundwaters and groundwater
recharge.
STORMWATER MANAGEMENT FACILITY (SWM FACILITY)
Any structure, natural or man-made, that, due to its condition,
design, or construction, conveys, stores, infiltrates/evaporates/transpires,
cleans or otherwise affects stormwater runoff. Typical SWM facilities
include, but are not limited to, detention and retention basins, open
channels, watercourses, road gutters, swales, storm sewers, pipes,
BMPs, and infiltration structures.
STREAM ENCLOSURE
A bridge, culvert or other structure in excess of 100 feet
in length upstream to downstream which encloses a regulated water
of this commonwealth.
STRUCTURAL BMPs
Physical devices and practices that capture and treat stormwater
runoff. Structural stormwater BMPs are permanent appurtenances to
the development site.
STRUCTURE
Any man-made object having an ascertainable stationary location
on or in land or water, whether or not affixed to the land.
SUBDIVISION
Any division or development of property considered to be a subdivision under Chapter
285, Subdivision and Land Development, or the MPC.
SUBSTRATES
Inorganic sediments which are 0.05 millimeter in diameter
or larger and include sands, gravel, pebbles, cobbles and boulders,
based upon Wentworth's Classification.
SUBWATERSHED
The smallest drainage unit of a watershed for which stormwater
management criteria have been established.
SUBWATERSHED AREA
The smallest drainage unit of a watershed for which stormwater
management criteria have been established in an Act 167 Plan.
SWALE
A low-lying stretch of land which gathers or carries surface
water runoff.
SWM
Stormwater management.
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.
TOP OF STREAMBANK
First substantial break in slope between the edge of the
bed of the stream and the surrounding terrain. The top of streambank
can either be a natural or constructed (that is, road or railroad
grade) feature, lying generally parallel to the watercourse.
TOWNSHIP
Warwick Township, Lancaster County, Pennsylvania.
TR-20 (CALIBRATED)
The computer-based hydrologic modeling technique adapted
to the applicable watershed for an approved Act 167 Plan. The model
has been "calibrated" to reflect published and observed flow values
by adjusting key model input parameters.
TREATMENT TRAIN
The sequencing of structural best management practices to
achieve optimal flow management and pollutant removal from urban stormwater.
USDA
United States Department of Agriculture or any agency successor
thereto.
VOLUME CONTROL
SWM controls, or BMPs, used to remove a predetermined amount
of runoff or the increase in volume between the pre- and post-development
design storm.
WATERCOURSE
A channel or conveyance of surface water having defined bed
and banks, whether natural or artificial, with perennial or intermittent
flow, whether natural or man-made.
WATERSHED
The entire region or area drained by a watercourse.
WATERS OF THIS COMMONWEALTH
Any and all rivers, streams, creeks, rivulets, impoundments,
ditches, watercourses, storm sewers, lakes, dammed water, wetlands,
ponds, springs, and all other bodies or channels of conveyance of
surface and underground water, or parts thereof, whether natural or
artificial, within or on the boundaries of Pennsylvania.
WETLAND
Those areas that are inundated or saturated by surface or
ground water 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, ferns, and similar areas.
WET POND
A pond containing a permanent pool of water designed to store
stormwater runoff for a given storm event and release it at a predetermined
rate.
WOODLAND
Land predominantly covered with trees and shrubs. Without
limiting the foregoing, woodlands include all land areas of 10,000
square feet or greater, supporting at least 100 trees per acre, so
that either:
A.
At least 50 trees are two inches or greater in diameter at breast
height (DBH); or
B.
Fifty trees are at least 12 feet in height.