For the purposes of this chapter, certain terms and words used
herein shall be interpreted as follows:
A.
Words used in the present tense include the future tense; the singular
number includes the plural, and the plural number includes the singular;
words of masculine gender include feminine gender; and words of feminine
gender include masculine gender.
B.
The word "includes" or "including" shall not limit the term to the
specific example, but is intended to extend its meaning to all other
instances of like kind and character.
C.
The word "person" includes an individual, partnership, public or
private association or corporation, firm, trust, estate, municipality,
governmental unit, public utility or any other legal entity whatsoever
which is recognized by law as the subject of rights and duties. Whenever
used in any section prescribing or imposing a penalty, the term "person"
shall include the members of a partnership, the officers, members,
servants and agents of an association, officers, agents and servants
of a corporation, and the officers of a municipality.
D.
The words "shall" and "must" are mandatory; the words "may" and "should"
are permissive.
E.
The words "used" or "occupied" include the words "intended, designed,
maintained, or arranged to be used, occupied, or maintained."
F.
The definitions in this chapter are for the purposes of enforcing
the provisions of this chapter and have no bearing on other municipal
regulations or ordinances.
As used in this chapter, the following terms shall have the
meanings indicated:
Activities associated with agriculture such as agricultural
cultivation, agricultural operation, and animal heavy use areas. This
includes the work of producing crops, including tillage, plowing,
disking, harrowing, planting or 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.
A landowner, developer, or other person who has filed an
application to the municipality for approval to engage in any regulated
activity as defined in this chapter.
Engineering or site plans or drawings that document the actual locations, dimensions and elevations of the improvements, and building components, and changes made to the original design plans. The final version of these documents, or a copy of same, are signed and sealed by a qualified licensed professional and submitted to the municipality at the completion of the project, as per the requirements of § 144-502 of this chapter as final as-built plans.
The channel at the top-of-bank or point from where water
begins to overflow onto a floodplain.
Portion of stream discharge derived from groundwater; the
sustained discharge that does not result from direct runoff or from
water diversions, reservoir releases, piped discharges, or other human
activities.
Activities, facilities, designs, measures, or procedures
used to manage stormwater impacts from regulated activities, to provide
water quality treatment, infiltration, volume reduction, and/or peak
rate control, 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: structural or nonstructural.
In this chapter, nonstructural BMPs or measures include certain low-impact
development and conservation design practices used to minimize the
contact of pollutants with stormwater runoff. These practices aim
to limit the total volume of stormwater runoff and manage stormwater
at its source by techniques such as protecting natural systems and
incorporating existing landscape features. Nonstructural BMPs include,
but are not limited to, the protection of sensitive and special value
features such as wetlands and riparian areas, the preservation of
open space while clustering and concentrating development, the reduction
of impervious cover, and the disconnection of rooftops from storm
sewers. Structural BMPs are those that consist of a physical system
that is designed and engineered 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, bioretention, wet ponds, permeable paving,
grassed swales, riparian or forested buffers, sand filters, detention
basins, and manufactured devices. Structural and nonstructural stormwater
BMPs are permanent appurtenances to the site. [See also "stormwater
management facility" and "stormwater control measure (SCM)"].
See "riparian buffer."
See "karst."
Cubic feet per second.
A natural or artificial open drainage feature that conveys,
continuously or periodically, flowing water and through which stormwater
flows. Channels include, but shall not be limited to, natural and
man-made drainageways, swales, streams, ditches, canals, and pipes
flowing partly full.
Curve number.
Commonwealth of Pennsylvania.
A series of holistic land development design goals that maximize
protection of key land and environmental resources, preserve significant
concentrations of open space and greenways, evaluate, and maintain
site hydrology, and ensure flexibility in development design to meet
community needs for complimentary and aesthetically pleasing development.
Conservation design encompasses the following objectives: conservation/enhancement
of natural resources, wildlife habitat, biodiversity corridors, and
greenways (interconnected open space); minimization of environmental
impact resulting from a change in land use (minimum disturbance, minimum
maintenance); maintenance of a balanced water budget by making use
of site characteristics and infiltration; incorporation of unique
natural, scenic and historic site features into the configuration
of the development; preservation of the integral characteristics of
the site as viewed from adjoining roads; and reduction in maintenance
required for stormwater management practices. Such objectives can
be met on a site through an integrated development process that respects
natural site conditions and attempts, to the maximum extent possible,
to replicate or improve the natural hydrology of a site.
The Chester County Conservation District (CCCD).
A plan written by a planner certified by NRCS that identifies
conservation practices and includes site specific BMPs for agricultural
plowing or tilling activities and animal heavy use areas.
Practices installed on agricultural lands to improve farmland,
soil and/or water quality which have been identified in a current
conservation plan.
A natural or man-made, existing or proposed stormwater management
facility, feature or channel used for the transportation or transmission
of stormwater from one place to another. For the purposes of this
chapter, "conveyance" shall include pipes, drainage ditches, channels
and swales (vegetated and other), gutters, stream channels, and like
facilities or features.
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 stormwater management systems. Also see "return
period."
An impoundment designed to collect and retard stormwater
runoff by temporarily storing the runoff and releasing it at a predetermined
rate. Detention basins are designed to drain completely shortly after
any given rainfall event.
Capture and temporary storage of runoff in a stormwater management
facility for release at a controlled rate.
The volume of runoff that is captured and released into the
waters of the commonwealth at a controlled rate.
A person, company, or organization who seeks to undertake
any regulated activities at a site in the municipality.
The outside bark diameter of a tree at breast height which
is defined as 4.5 feet (1.37 meter) above the forest floor on the
uphill side of the tree.
Land area disturbed by or where an earth-disturbance activity
is occurring or has occurred.
That land area contributing runoff to a single point (including,
but not limited to, the point/line of interest used for hydrologic
and hydraulic calculations) and that is enclosed by a natural or man-made
ridgeline.
A construction or other human activity which disturbs the
surface of the land, including, but not limited to, clearing and grubbing;
grading; excavations; embankments; road maintenance; land development;
building construction; and the moving, depositing, stockpiling, or
storing of soil, rock, or earth materials.
A right of use granted by a landowner to allow a grantee
the use of the designated portion of land for a specified purpose,
such as for stormwater management or other drainage purposes.
The process by which the surface of the land, including water/stream
channels, is worn away by water, wind, or chemical action.
A plan required by the conservation district or the municipality
to minimize accelerated erosion and sedimentation, and that must be
prepared and approved per the applicable requirements.
The combined processes of evaporation from the water or soil
surface and transpiration of water by plants.
Federal Emergency Management Agency.
A temporary condition of partial or complete inundation of
land areas from the overflow of streams, rivers, and other waters
of this commonwealth.
Any land area susceptible to inundation by water from any
natural source or delineated by applicable FEMA maps and studies as
being a special flood hazard area.
The channel of the watercourse and those portions of the
adjoining floodplains that are reasonably required to carry and discharge
the 100-year flood (also called the "base flood" or "1% annual chance
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 floodway, it is assumed, absent evidence to the contrary, that
the floodway extends from the center line of the stream and to 50
feet beyond the top of the bank of the stream on both sides.
Planning and activities necessary for the management of forest
lands. These include timber inventory, preparation of forest management
plans, silvicultural treatment, cutting budgets, logging road design
and construction, timber harvesting, site preparation, and reforestation.
A vertical distance between the design high-water elevation
and the elevation of the top of a dam, levee, tank, basin, swale,
or diversion berm. The space is required as a safety margin in a pond
or basin.
A fabric manufactured from synthetic fiber that is used to
achieve specific objectives, including infiltration, separation between
different types of media (i.e., between soil and stone), or filtration.
The Board of Supervisors of Westtown Township.
Systems and practices that use or mimic natural processes
to infiltrate, evapotranspire, or reuse stormwater on the site where
it is generated.
Water that occurs in the subsurface and fills or saturates
the porous openings, fractures and fissures of underground soils and
rock units.
The replenishment of existing natural groundwater supplies
from infiltration of rain or overland flow.
The U.S. Army Corps of Engineers, Hydrologic Engineering
Center (HEC) hydrologic runoff model.
The U.S. Army Corps of Engineers, Hydrologic Engineering
Center (HEC) - Hydrologic Modeling System (HMS).
A structure which meets the following:
Is used for the production, processing, keeping, storing, sale
or shelter of an agricultural commodity as defined in Section 2 of
the Act of December 19, 1974 (P.L. 973, No. 319), known as the "Pennsylvania
Farmland and Forest Land Assessment Act of 1974," or for the storage
of agricultural equipment or supplies; and
Areas where prior or existing land use or activities can
potentially generate highly contaminated runoff with concentrations
of pollutants in excess of those typically found in stormwater.
The hydrologic system, cycle or balance that sustains the
quality and quantity of stormwater, stream base flow, storage, and
groundwater supplies under natural conditions.
A classification of soils by the Natural Resources Conservation
Service (NRCS), into four runoff potential groups. The groups range
from A soils, which are very permeable and produce little runoff,
to D soils, which are not very permeable and produce much more runoff.
A surface that has been compacted or covered with a layer
of material so that it prevents or is resistant to infiltration of
water, including, but not limited to, structures such as roofs, buildings,
storage sheds; other solid, paved or concrete areas such as streets,
driveways, sidewalks, parking lots, patios, decks, swimming pools,
tennis or other paved courts; or athletic playfields comprised of
synthetic turf materials. For the purposes of determining compliance
with this chapter, compacted soils or stone surfaces used for vehicle
parking and movement shall be considered impervious. Uncompacted gravel
areas with no vehicular traffic, such as gardens, walkways, or patios
areas, shall be considered pervious per review by the Municipal Engineer.
Surfaces that were designed to allow infiltration (i.e., areas of
porous pavement) are not to be considered impervious surface if designed
to function as a BMP per review by the Municipal Engineer. Additionally,
for the purposes of determining compliance with this chapter, the
total horizontal projection area of all ground-mounted and freestanding
solar collectors, including solar photovoltaic cells, panels, and
arrays, shall be considered pervious so long as the designs note that
natural vegetative cover will be preserved and/or restored underneath
the solar photovoltaic cells, panels, and arrays, and the area disturbed
is planned as a vegetated pervious surface.
Movement of surface water into the soil, where it is absorbed
by plant roots, evaporated into the atmosphere, or percolated downward
to recharge groundwater.
A stormwater BMP designed to collect and discharge runoff
into the subsurface in a manner that allows infiltration into underlying
soils and groundwater (e.g., french drains, seepage pits, or seepage
trenches, etc.).
A defined channel in which surface water is absent during
a portion of the year, in response to seasonal variations in precipitation
or groundwater discharge.
The lowest surface, the floor or bottom of a culvert, pipe,
drain, sewer, channel, basin, BMP, or orifice.
A type of topography that is formed over limestone or other
carbonate rock formations by dissolving or solution of the rock by
water, and that is characterized by closed depressions, sinkholes,
caves, a subsurface network of solution conduits and fissures through
which groundwater moves, and no perennial surface drainage features.
Any of the following activities:
The improvement of one lot or two or more contiguous lots, tracts,
or parcels of land for any purpose involving:
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
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;
A subdivision of land;
Development in accordance with Section 503(1.1) of the Pennsylvania
Municipalities Planning Code (as amended).
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 or
she is authorized under the lease to exercise the rights of the landowner,
or other person having a proprietary interest in the land.
A Pennsylvania registered professional engineer, registered
landscape architect, registered professional land surveyor, or registered
professional geologist, or any person licensed by the Pennsylvania
Department of State and qualified by law to perform the work required
by the chapter within the Commonwealth of Pennsylvania.
A soil horizon or condition in the soil profile or underlying
strata that includes one of the following:
A seasonal high-water table, whether perched or regional, determined
by direct observation of the water table or indicated by other subsurface
or soil conditions.
A rock with open joints, fracture or solution channels, or masses
of loose rock fragments, including gravel, with insufficient fine
soil to fill the voids between the fragments.
A rock formation, other stratum, or soil condition that is so
slowly permeable that it effectively limits downward passage of water.
Site design approaches and small-scale stormwater management
practices that promote the use of natural systems for infiltration,
evapotranspiration, and reuse of rainwater. LID can be applied to
new development, urban retrofits, and revitalization projects. LID
utilizes design techniques that infiltrate, filter, provide evapotranspiration
and store runoff close to its source. Rather than rely on costly large-scale
conveyance and treatment systems, LID addresses stormwater through
a variety of small, cost-effective landscape features located on-site.
The action taken to restore or preserve the as-built functional
design of any stormwater management facility or system.
A post-construction stormwater management (PCSM) strategy
that comprises the collection, management, and filtration of captured
runoff from the contributing drainage area through a best management
practice (BMP) that is preferably vegetated and includes release of
a portion of the captured runoff through an underdrain within the
BMP. If the MRC BMP is not vegetated, then pretreatment is required
to meet water quality requirements. MRC is intended to be used for
project areas or subareas where infiltration is considered infeasible
to meet regulatory requirements. Refer to the "Managed Release Concept"
Version 1.2 (August 25, 2020) guidance document or latest guidance
from PADEP.
Mushroom farm environmental management plan.
Act of July 31, 1968, P.L. 805, No. 247, 53 P.S. § 10101
et seq., as amended, the Pennsylvania Municipalities Planning Code,
Act 247.
Municipal separate storm sewer system.
A professional engineer licensed as such in the Commonwealth
of Pennsylvania, duly appointed as the engineer for a municipality,
planning agency, or joint planning commission.
Westtown Township, Chester County, Pennsylvania.
Any regulated activity involving placement or construction
of new impervious surface or grading over existing pervious land areas
not classified as redevelopment as defined in this chapter.
National Oceanic and Atmospheric Administration.
Pollution that enters a water body from diffuse origins in
the watershed and does not result from discernible, confined, or discrete
conveyances.
Water flowing in stormwater collection facilities, such as
pipes or swales, which is not the result of a rainfall event or snowmelt.
See "best management practice (BMP)."
National Pollutant Discharge Elimination System, the federal
government's system for issuance of permits under the Clean Water
Act,[1] which is delegated to PADEP in Pennsylvania.
Natural Resource Conservation Service (previously Soil Conservation
Service, SCS), an agency of the U.S. Department of Agriculture.
Pennsylvania Department of Environmental Protection.
The parcel of land from which a land development or subdivision
originates, determined from the date of municipal adoption of this
chapter.
The maximum rate of stormwater runoff from a specific storm
event.
Pennsylvania Department of Transportation.
Document Number 363-0300-002 (December 2006, and as subsequently
amended).
Any area not defined as impervious surface.
The Planning Commission of Westtown Township.
Any discernible, confined, and 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 Pennsylvania Code § 92.1.
Period after construction during which disturbed areas are
stabilized, stormwater controls are in place and functioning, and
all proposed improvements approved by the municipality are completed.
Ground cover conditions assumed to exist within the proposed
disturbed area prior to commencement of the regulated activity for
the purpose of calculating the predevelopment water quality volume,
infiltration volume, and peak flow rates as required in this chapter.
Techniques employed in stormwater BMPs to provide storage
or filtering, or other methods to trap or remove coarse materials
and other pollutants before they enter the stormwater system, but
may not necessarily be designed to meet the entire water quality volume
requirements of this chapter.
All new, additional and replacement impervious surfaces.
The depth of accumulated rainfall per unit of time.
The replenishment of groundwater through the infiltration
of rainfall, other surface waters, or land application of water or
treated wastewater.
Any regulated activity that involves demolition, removal,
reconstruction, or replacement of existing impervious surface(s).
Any earth-disturbance activity(ies) or any activity that
involves the alteration or development of land in a manner that may
affect stormwater runoff.
Any activity involving earth disturbance subject to regulation
under 25 Pennsylvania Code Chapter 92 or Chapter 102, or the Clean
Streams Law.[2]
Proposed impervious surface as part of a current proposed
activity and all existing impervious surfaces installed after December
16, 2013, as part of previous activity.
An impoundment that is designed to temporarily detain a certain
amount of stormwater from a catchment area and which may be designed
to permanently retain stormwater runoff from the catchment area; retention
basins always contain water.
The prevention of direct discharge of stormwater runoff into
surface waters or water bodies during or after a storm event by permanent
containment in a pond or depression; examples include systems which
discharge by percolation to groundwater, exfiltration, and/or evaporation
processes and which generally have residence times of less than three
days.
The volume of runoff that is captured and not released directly
into the surface waters of the commonwealth during or after a storm
event.
The average interval, in years, within which a storm event
of a given magnitude can be expected to occur one time. For example,
the twenty-five-year return period rainfall would be expected to occur
on average once every 25 years; or stated in another way, the probability
of a twenty-five-year storm occurring in any one year is 0.04 (i.e.,
a 4% chance).
Pertaining to anything connected with or immediately adjacent
to the banks of a stream or other body of water.
An area of land adjacent to a body of water and managed to
maintain vegetation to protect the integrity of stream channels and
shorelines, to reduce the impact of upland sources of pollution by
trapping, filtering, and converting sediments, nutrients, and other
chemicals, and to supply food, cover and thermal protection to fish
and other aquatic species and wildlife.
Any part of precipitation that flows over the land surface.
See "Subdivision and Land Development Ordinance."[3]
Soil Conservation Service, now known as the "Natural Resources
Conservation Service."
Soil or other materials transported by, suspended in or deposited
by surface water as a product of erosion.
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.
A flow process associated with broad, shallow water movement
on sloping ground surfaces that is not channelized or concentrated.
Total area of land in the municipality where any proposed
regulated activity, as defined in this chapter, is planned, conducted,
or maintained or that is otherwise impacted by the regulated activity.
A method of runoff computation developed by NRCS that is
based on relating soil type and land use/cover to a runoff parameter
called curve number (CN).
The regulatory requirements to protect, maintain, reclaim,
and restore water quality under Pennsylvania Code Title 25 and the
Clean Streams Law.[4]
See "return period."
Drainage runoff from the surface of the land resulting from
precipitation or snow or ice melt.
Physical features used to effectively control, minimize,
and treat stormwater runoff. [See "best management practice (BMP)."]
The plan prepared by the applicant or its representative, in accordance with the requirements of Article IV of this chapter, indicating how stormwater runoff will be managed at a particular site in accordance with this chapter, and including all necessary design drawings, calculations, supporting text, and documentation to demonstrate that chapter requirements have been met, herein referred to as "SWM site plan." All references in this chapter to "final" or "approved" SWM site plans shall incorporate the approved SWM site plan and all subsequent approved revisions thereto.
Any feature, natural or man-made, that, due to its condition,
design, or construction, conveys, stores, or otherwise affects stormwater
runoff quality, rate, or quantity, including best management practices
and stormwater control measures. Typical stormwater management facilities
include, but are not limited to, detention and retention basins, open
channels, storm sewers, pipes, and infiltration facilities.
A natural watercourse.
See "BMP (best management practices)."
The division or redivision of a lot, tract, or parcel of
land as defined in the Pennsylvania Municipalities Planning Code,
Act of July 31, 1968, P.L. 805, No. 247 (as amended).
Subdivision and Land Development Ordinance[5] of Westtown Township, Chester County, Pennsylvania, as
amended.
An artificial or natural waterway or low-lying stretch of
land that gathers and conveys stormwater or runoff, and is generally
vegetated for soil stabilization, stormwater pollutant removal, and
infiltration.
See "stormwater management site plan."
See "forest management."
Highest point of elevation of the bank of a stream or channel
cross section at which a rising water level just begins to flow out
of the channel and into the floodplain.
United States Department of Agriculture.
The uppermost level of saturation of pore space or fractures
by groundwater. "Seasonal high-water table" refers to a water table
that rises and falls with the seasons due either to natural or man-made
causes.
A channel or conveyance of surface water having a defined
bed and banks, whether natural or artificial, with perennial or intermittent
flow.
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 the commonwealth.
Region or area drained by a river, watercourse, or other
body of water, whether natural or artificial.
Those areas that are inundated or saturated by surface water
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. Wetlands
generally include swamps, marshes, bogs, fens, and similar areas.
Any land area of at least 0.25 acre with a natural or naturalized
ground cover (excluding manicured turf grass) and that has an average
density of two or more viable trees per 1,500 square feet with a DBH
of six inches or greater and where such trees existed at any time
within three years of the time of land development application submission
of the proposed project. The land area to be considered woods shall
be measured from the outer driplines of the outer trees.
