[Ord. 2011-O-2, 5/25/2011, § 211]
For purposes of this Part, the following terms shall be defined
as follows:
ACCELERATED EROSION
The removal of the surface of the land through the combined
action of man's activity and the natural processes of 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 including tillage, land clearing,
plowing, disking, harrowing, planting, harvesting crops or pasturing
and raising 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;
also the changing of surface conditions by causing the surface to
be more or less impervious as a result of changing the land cover
including the water, vegetation and bare soil.
APPLICANT
A person who has filed an application for approval to engage
in any regulated activity defined in § 205 of this Part.
AS-BUILT DRAWINGS
Engineering or site drawings maintained by the contractor
as he constructs the project and upon which he documents the actual
locations of the building components and changes to the original contract
documents. These documents, or a copy of same, are turned over to
the Township Engineer at the completion of the project.
BANK FULL
The channel at the top-of-bank, or point from where water
begins to overflow onto a floodplain.
BASE FLOW
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.
BEST MANAGEMENT PRACTICE (BMP)
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 Part. Stormwater BMPs are commonly
grouped into one of two broad categories or measures: "Structural"
or "nonstructural." In this Part, nonstructural BMPs or measures refer
to operational and/or behavior-related practices that attempt to minimize
the contact of pollutants with stormwater runoff whereas structural
BMPs or measures are those 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 largescale 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.
BIORETENTION
A stormwater retention area that utilizes woody and herbaceous
plants and soils to remove pollutants before infiltration occurs.
BUFFER
The area of land immediately adjacent to any stream, measured
perpendicular to and horizontally from the top-of-bank on both sides
of a stream (see "top-of-bank").
CHANNEL
An open drainage feature through which stormwater flows.
Channels include, but shall not be limited to, natural and man-made
watercourses, swales, streams, ditches, canals, and pipes that convey
continuously or periodically flowing water.
CHANNEL EROSION
The widening, deepening, or headward cutting of channels
and waterways, caused by stormwater runoff or bankfull flows.
CISTERN
An underground reservoir or tank for storing rainwater.
CULVERT
A structure with its appurtenant works, which carries water
under or through an embankment or fill.
CURVE NUMBER
Value used in the soil cover complex method. It is a measure
of the percentage of precipitation which is expected to runoff from
the watershed and is a function of the soil, vegetative cover, and
tillage method.
DAM
A man-made barrier, together with its appurtenant works,
constructed for the purpose of impounding or storing water or another
fluid or semifluid. A dam may include a refuse bank, fill or structure
for highway, railroad or other purposes which impounds or may impound
water or another fluid or semifluid.
DESIGNEE
The agent of the Bucks County Planning Commission, Bucks
County Conservation District and/or agent of the Board of Supervisors
of Newtown Township involved with the administration, review or enforcement
of any provisions of this Part by contract or memorandum of understanding.
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 stormwater management systems.
DETENTION BASIN
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 soon after
a rainfall event and become dry until the next rainfall event.
DETENTION DISTRICT
Those subareas of a watershed in which some type of detention
is required to meet the Plan requirements and the goals of Act 167.
DEVELOPER
A person that seeks to undertake any regulated earth disturbance
activities at a project site in Newtown Township.
DEVELOPMENT
Any human-induced change to improved or unimproved real estate,
whether public or private, including but not limited to land development,
construction, installation, or expansion of a building or other structure,
land division, street construction, drilling, and site alteration
such as embankments, dredging, grubbing, grading, paving, parking
or storage facilities, excavation, filling, stockpiling, or clearing.
As used in this Part, development encompasses both new development
and redevelopment.
DEVELOPMENT SITE
The specific tract or parcel of land where any regulated
activity set forth in § 205 is planned, conducted or maintained.
DIFFUSED DRAINAGE DISCHARGE
Drainage discharge that is not confined to a single point
location or channel, including sheet flow or shallow concentrated
flow.
DISCHARGE
(1) (verb) To release water from a project, site, aquifer,
drainage basin or other point of interest; (2) (noun) The rate and
volume of flow of water such as in a stream, generally expressed in
cubic feet per second. See also "peak discharge."
DISCONNECTED IMPERVIOUS AREA (DIA)
An impervious or impermeable surface that is disconnected
from any stormwater drainage or conveyance system and is redirected
or directed to a pervious area, which allows for infiltration, filtration,
and increased time of concentration.
DISTURBED AREAS
Unstabilized land area where an earth disturbance activity
is occurring or has occurred.
DITCH
A man-made waterway constructed for irrigation or stormwater
conveyance purposes.
DOWNSLOPE PROPERTY LINE
That portion of the property line of the lot, tract, or parcels
of land being developed, located such that overland or pipe flow from
the project site would be directed towards it by gravity.
DRAINAGE CONVEYANCE FACILITY
A stormwater management facility designed to transport stormwater
runoff that includes channels, swales, pipes, conduits, culverts,
and stone sewers.
DRAINAGE EASEMENT
A right granted by a landowner to a grantee, allowing the
use of private land for stormwater management purposes.
DRAINAGE PERMIT
A permit issued by Newtown Township after the stormwater
management plan has been approved.
EARTH DISTURBANCE ACTIVITY
A construction or other human activity which disturbs the
surface of 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.
EMERGENCY SPILLWAY
A conveyance that is used to pass the peak discharge of the
maximum design storm that is controlled by the stormwater facility.
ENCROACHMENT
A structure or activity that changes, expands or diminishes
the course, current or cross section of a watercourse, floodway or
body of water.
EROSION
The process by which the surface of the land, including water/stream
channels, is worn away by water, wind, or chemical action.
EROSION AND SEDIMENT CONTROL PLAN
A site-specific plan identifying BMPs to minimize accelerated
erosion and sedimentation. For agricultural plowing or tilling activities,
the erosion and sediment control plan is that portion of a conservation
plan identifying BMPs to minimize accelerated erosion and sedimentation.
Said plan may be required to be submitted to and approved by the Bucks
County Conservation District before construction can begin.
EXCEPTIONAL VALUE WATERS
Surface waters of high quality which satisfy Pennsylvania
Code Title 25, "Environmental Protection," Chapter 93, "Water Quality
Standards," § 93.4b(b) (relating to anti-degradation).
EXISTING RECHARGE AREA
Undisturbed surface area or depression where stormwater collects
and a portion of which infiltrates and replenishes the groundwater.
FLOOD
A general but temporary condition of partial or complete
inundation of land areas from the overflow of streams, rivers, and
other waters of the Commonwealth.
FLOODPLAIN
Any land area susceptible to partial or complete inundation
from an adjoining or nearby stream, river or watercourse and/or any
area subject to the unusual and rapid accumulation of surface waters
from any source.
FLOODWAY
The designated area of a floodplain required to carry and
discharge flood waters of the one-hundred-year storm. In areas of
the Township where no detailed flood profiles or elevations have been
provided by the Flood Insurance Study, the floodplain district shall
include the approximate one-hundred-year flood boundary as shown on
the Flood Insurance Rate Map for the Township and land areas which
contain soil characteristics indicative of flooding conditions, hereinafter
referred to as "floodplain soils."
FLUVIAL GEOMORPHOLOGY
The study of landforms associated with river channels and
the processes that form them.
FOREST MANAGEMENT/TIMBER OPERATIONS
Planning and associated 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 and reforestation.
FREEBOARD
A vertical distance between the elevation of the design high-water
and 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.
GRADE
(1) (noun) A slope, usually of a road, channel or natural
ground specified in percent and shown on plans as specified herein.
(2) (verb) To finish the surface of a roadbed, the top of an embankment,
or the bottom of excavation.
GRASSED WATERWAY
A natural or man-made waterway, usually broad and shallow,
covered with erosion-resistant grasses, used to convey surface water.
GROUNDWATER
Water beneath the earth's surface that supplies wells and
springs, and is often between saturated soil and rock.
GROUNDWATER RECHARGE
The replenishment of existing natural underground water supplies
from rain or overland flow.
HEC-HMS
The U.S. Army Corps of Engineers, Hydrologic Engineering
Center (HEC) - Hydrologic Modeling System (HMS). This model was used
to model the Neshaminy Creek watershed during the Act 167 Plan development
and was the basis for the standards and criteria of this Part.
HIGH QUALITY WATERS
Surface waters having quality which exceeds levels necessary
to support propagation of fish, shellfish, and wildlife and recreation
in and on the water by satisfying Pennsylvania Code, Title 25, "Environmental
Protection," Chapter 93, "Water Quality Standards," § 93.4b(a).
HOTSPOTS
Areas where land use or activities generate highly contaminated
runoff, with concentrations of pollutants in excess of those typically
found in stormwater.
HYDROGRAPH
A graph representing the discharge of water versus time for
a selected point in the drainage system.
HYDROLOGIC REGIME
The hydrologic cycle or balance that sustains quality and
quantity of stormwater, baseflow, storage, and groundwater supplies
under natural conditions.
HYDROLOGIC SOIL GROUP
A classification of soils by the Natural Resources Conservation
Service, formerly the Soil Conservation Service, 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.
IMPERVIOUS SURFACE
A surface that prevents the infiltration of water into the
ground. Impervious surfaces include, but are not limited to, streets,
sidewalks, pavement, roofs, parking areas or driveway areas. Any of
these surface areas designed to be gravel or crushed stone shall be
regarded as impervious surfaces. In addition, other areas determined
by the Township Engineer to be impervious within the meaning of this
definition will also be classified as impervious.
IMPOUNDMENT
A retention or detention basin designed to retain stormwater
runoff and release it at a controlled rate.
INFILL
Development that occurs on smaller parcels that remain undeveloped
but are within or very close proximity to urban or densely developed
areas. Infill development usually relies on existing infrastructure
and does not require an extension of water, sewer or other public
utilities.
INFILTRATION
Movement of surface water into the soil, where it is absorbed
by plant roots, evaporated into the atmosphere, or percolated downward
to recharge groundwater.
INFILTRATION STRUCTURES
A structure designed to direct runoff into the underground
water (e.g., French drains, seepage pits, or seepage trenches).
INLET
The upstream end of any structure through which water may
flow or a structure designed to drain runoff to a storm sewer system.
INTERMITTENT STREAM
A stream that flows only part of the time. Flow generally
occurs for several weeks or months in response to seasonal precipitation
or groundwater discharge.
LAND 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.
(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)
Development in accordance with § 503(1.1) of the Pennsylvania
Municipalities Planning Code, 53 P.S. § 10503(1.1).
LIMITING ZONE
A soil horizon or condition in the soil profile or underlying
strata that includes one of the following:
(1)
A seasonal high water table, whether perched or regional, determined
by direct observation of the water table or indicated by soil mottling.
(2)
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.
(3)
A rock formation, other stratum or soil condition that is so
slowly permeable that it effectively limits downward passage of effluent
or runoff.
LOT
A designated parcel, tract or area of land established by
a plat or otherwise as permitted by law and to be used, developed
or built upon as a unit.
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.
MUNICIPAL ENGINEER
A professional engineer licensed as such in the Commonwealth
of Pennsylvania, duly appointed as the engineer for Newtown Township.
NATURAL RECHARGE AREA
Undisturbed surface area or depression where stormwater collects,
and a portion of which infiltrates and replenishes the underground
and groundwater.
NONPOINT SOURCE POLLUTION
Pollution that enters a water body from diffuse origins in
the watershed and does not result from discernible, confined, or discrete
conveyances.
NON-STORMWATER DISCHARGES
Water flowing in stormwater collection facilities, such as
pipes or swales, which is not the result of a rainfall event or snowmelt.
NONSTRUCTURAL BEST MANAGEMENT PRACTICE (BMPS)
Methods of controlling stormwater runoff quantity and quality,
such as innovative site planning, impervious area and grading reduction,
protection of natural depression areas, temporary ponding on site
and other techniques.
NPDES
National Pollutant Discharge Elimination System, the Federal
government's system for issuance of permits under the Clean Water
Act, which is delegated to DEP in Pennsylvania.
NRCS
Natural Resource Conservation Service (previously Soil Conservation
Service).
OUTFALL
"Point source" as described in 40 CFR § 122.2 at
the point where Newtown Township's storm sewer system discharges to
surface waters of the Commonwealth.
OUTLET
Points of water disposal to a stream, river, lake, tidewater
or artificial drain.
PARENT TRACT
The parcel of land from which a land development or subdivision
originates, determined from the effective date of this Part.
PEAK DISCHARGE
The maximum rate of stormwater runoff from a specific storm
event.
PERENNIAL STREAM
A stream which contains water at all times except during
drought conditions.
PERVIOUS SURFACE
A surface that allows the infiltration of water into the
ground.
PIPE
A culvert, closed conduit, or similar structure (including
appurtenances) that conveys stormwater.
POINT SOURCE
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 Pa. Code, Chapter 92.1.
POST CONSTRUCTION
Period after construction during which disturbed areas are
stabilized, stormwater controls are in place and functioning and all
proposed improvements in the approved land development plan are completed.
PROJECT SITE
The specific area of land where any regulated activities
in Newtown Township are planned, conducted or maintained.
QUALIFIED DESIGN PROFESSIONAL
Any person licensed by the State of Pennsylvania or otherwise
qualified by law to perform the work required by this Part.
RECHARGE
The replenishment of groundwater through the infiltration
of rainfall, other surface waters, or land application of water or
treated wastewater.
REDEVELOPMENT
Any development that requires demolition or removal of existing
structures or impervious surfaces at a site and replacement with new
impervious surfaces. Maintenance activities such as top-layer grinding
and re-paving are not considered to be redevelopment. Interior remodeling
projects and tenant improvements are also not considered to be redevelopment.
Utility trenches in streets are not considered redevelopment.
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 existing conditions peak rate of runoff
from a site or subarea to which the proposed conditions peak rate
of runoff must be reduced to protect downstream areas.
RETENTION BASIN
A structure in which stormwater is stored and designed to
infiltrate into the ground. Retention basins are designed for infiltration
purposes. The retention basin must infiltrate stored water in four
days or less.
RETENTION VOLUME/REMOVED RUNOFF
The volume of runoff that is captured and not released directly
into the surface waters of the Commonwealth during or after a storm
event.
RETURN PERIOD
The probability an event will occur in any given year. Typically
displayed as a whole number, e.g., twenty-five year event, and represents
the inverse of the frequency of that event. For example, the twenty-five-year
return period rainfall gives the probability, 1/25 or 4%, which that
size storm will occur in any given year.
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 cross-section,
such as grading and repairing existing unpaved road surfaces, cutting
road banks, cleaning or clearing drainage ditches and other similar
activities.
ROOF DRAINS
A drainage conduit or pipe that collects water runoff from
a roof and leads it away from the structure.
ROOFTOP DETENTION
The temporary ponding and gradual release of stormwater falling
directly onto flat roof surfaces using controlled-flow roof drains
into building designs.
RUNOFF
Any part of precipitation that flows over the land surface.
SALDO
The Newtown Township Subdivision and Land Development Ordinance [Chapter
22].
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 in such a way as to retain rock, sand, gravel, silt, or other
material transported by water during construction.
SEDIMENT POLLUTION
The placement, discharge or any other introduction of sediment
into the waters of the Commonwealth.
SEDIMENTATION
The process by which mineral or organic matter is accumulated
or deposited by the movement of water or air.
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 underground water.
SEPARATE STORM SEWER SYSTEM
A conveyance or system of conveyances (including roads with
drainage systems, Township streets, catch basins, curbs, gutters,
ditches, man-made channels or storm drains) primarily used for collecting
and conveying stormwater runoff.
SHALLOW CONCENTRATED FLOW
Stormwater runoff flowing in a shallow, defined swale prior
to entering a defined channel or waterway.
SHEET FLOW
A flow process associated with broad, shallow water movement
on sloping ground surfaces that is not channelized or concentrated.
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).
SPECIAL PROTECTION SUBWATERSHEDS
Watersheds that have been designated in Pennsylvania Code,
Title 25, "Environmental Protection," Chapter 93, "Water Quality Standards,"
as exceptional value (EV) or high quality (HQ) waters.
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 "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
The surface runoff generated by precipitation reaching the
ground surface.
STORMWATER MANAGEMENT FACILITY
Any structure, natural or man-made, that, due to its condition,
design, or construction, conveys, stores, or otherwise affects stormwater
runoff quality, rate or quantity. Typical stormwater management facilities
include, but are not limited to, detention basins, retention basins,
wet basins, open channels, storm sewers, pipes, and infiltration structures.
STORMWATER MANAGEMENT PLAN
The watershed plan, known as either the "Neshaminy Creek
Watershed Stormwater Management Plan," for managing those land use
activities that will influence stormwater runoff quality and quantity
and that would impact the Neshaminy Creek Watershed or the "Delaware
River South Watershed Act 167 Stormwater Management Plan" for managing
those land use activities that will influence stormwater runoff quality
and quantity and that would impact the Delaware River South Watershed
(whichever is applicable) adopted by Bucks and Montgomery County as
required by the Act of October 4, 1978, P.L. 864 (Act 167).
STORMWATER MANAGEMENT SITE PLAN
The plan prepared by the applicant or his representative
indicating how stormwater runoff will be managed at the particular
site of interest.
STREAM
A flow of water in a natural channel or bed, as a brook,
rivulet or a small river.
STREAM BANK EROSION
The widening, deepening or headward cutting of channels and
waterways, caused by stormwater runoff or bankfull flows.
STREAM BUFFER
The land area adjacent to each side of a stream, essential
to maintaining water quality. (See "buffer.")
STREAM ENCLOSURE
A bridge, culvert or other structure which encloses a regulated
water of the Commonwealth.
SUBAREA (SUBWATERSHED)
The smallest drainage unit of a watershed for which stormwater
management criteria have been established in the Stormwater Management
Plan.
SUBDIVISION
The division or redivision 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
dwelling, shall be exempted.
SWALE
A low lying stretch of land that gathers or carries surface
water runoff.
TIME-OF-CONCENTRATION (TC)
The time required 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,
concentrated flow time and flow time in pipes or channels, if any.
TOP-OF-BANK
Highest point of elevation in a stream channel cross-section
at which a rising water level just begins to flow out of the channel.
TOWNSHIP ENGINEER
A professional engineer licensed as such in the Commonwealth
of Pennsylvania, duly appointed as the engineer for Newtown Township.
VEGETATED SWALE
A natural or man-made waterway, usually broad and shallow,
covered with erosion-resistant grasses, used to convey surface water.
VERNAL POND/VERNAL POOL
Seasonal depressional wetlands that are covered by shallow
water for variable periods from winter to spring, but may be completely
dry for most of the summer and fall.
WATERCOURSE
A channel or conveyance of surface water having a defined
bed and banks, whether natural or artificial, with perennial or intermittent
flow.
WATERS OF THE COMMONWEALTH
Any and all rivers, streams, creeks, rivulets, 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.
WATERSHED
Region or area drained by a river, watercourse or other body
of water, whether natural or artificial.
WET BASIN
Pond for urban runoff management that is designed to detain
urban runoff and always contains water.
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. Wetlands
generally include swamps, marshes, bogs, ferns, and similar areas.