These definitions do not necessarily reflect the definitions contained
in pertinent regulations or statutes and are intended for this Part
only.
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.
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 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;
also the 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 to the municipality for approval to engage in any regulated activities at a project site in the municipality as defined in §
26-104 of this Part.
AS-BUILT DRAWINGS
Those 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, or a copy of
the same, are turned over to the Engineer at the completion of the
project.
BANKFULL
The channel at the top of bank or point where water beings
to overflow onto a floodplain.
BASE FLOW
The portion of stream flow that is sustained by groundwater
discharge.
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 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.
BIORETENTION
A stormwater management facility which utilizes woody and
herbaceous plants and soils to remove pollutants before infiltration
occurs.
CHANNEL EROSION
The widening, deepening, and headward cutting of small channels
and waterways caused by moderate to large floods.
CISTERN
An underground reservoir or tank for storing rainwater.
CONSERVATION DISTRICT
A conservation district, as defined in Section 3(c) of the
Conservation District Law [3 P.S. § 851(c)] that has the
authority under a delegation agreement executed with DEP to administer
and enforce all or a portion of the regulations promulgated under
25 Pa. Code 102.
CULVERT
A structure with appurtenant works which carries 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 that does or may impound water or another
fluid or semifluid.
DEP
The Pennsylvania Department of Environmental Protection.
DEPARTMENT
Pennsylvania Department of Environmental Protection.
DESIGN PROFESSIONAL (QUALIFIED)
A Pennsylvania registered professional engineer, registered
landscape architect, or a registered professional land surveyor trained
to develop stormwater management plans.
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. Also see "return
period."
DESIGNEE
The agent of the Bristol Borough Planning Commission and/or
agent of the governing body involved with the administration, review,
or enforcement of any provisions of this Part 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 DISTRICT
Those subareas in which some type of detention is required
to meet the plan requirements and the goals of Act 167.
DETENTION VOLUME
The volume of runoff that is captured and released into the
waters of the commonwealth at a controlled rate.
DIFFUSED DRAINAGE DISCHARGE
Drainage discharge not confined to a single point location
or channel, such as sheet flow or shallow concentrated flow.
DISTURBED AREAS
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 towards it.
DRAINAGE CONVEYANCE FACILITY
A stormwater management facility designed to transmit 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 purposes.
DRAINAGE PERMIT
A permit issued by the Municipal governing body after the
drainage plan has been approved. Said permit is issued prior to or
with the final Municipal approval.
DRAINAGE PLAN
The documentation of the stormwater management system, to be used for a given development site, the contents of which are established in §
26-143.
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; road maintenance; building construction;
and the moving, depositing, stockpiling, or storing of soil, rock,
or earth materials.
EMERGENCY SPILLWAY
A conveyance area that is used to pass peak discharge greater
than the maximum design storm 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 natural process by which the surface of the land is worn
away by water, wind, or chemical action.
ERSAM
Existing Resource and Site Analysis Map.
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 antidegradation).
EXISTING CONDITION
The dominant land cover during the five-year period immediately
preceding a proposed regulated activity.
FEMA
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 this commonwealth.
FLOODPLAIN
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. Also includes areas that comprise
Group 13 Soils, as listed in Appendix A of the Pennsylvania Department
of Environmental Protection (DEP) Technical Manual for Sewage Enforcement
Officers (as amended or replaced from time to time by DEP).
FLOODWAY
The channel of the watercourse and those portions of the
adjoining floodplains that are reasonably required to carry and discharge
the 100-year 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 floodway, it is assumed — absent evidence
to the contrary — that the floodway extends from the stream
to 50 feet from the top of the bank of the stream.
FOREST MANAGEMENT/TIMBER OPERATIONS
Planning and activities necessary for the management of forestland.
These include conducting a timber inventory, 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 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.
GRASSED WATERWAY
A natural or constructed waterway, usually broad and shallow,
covered with erosion-resistant grasses, used to conduct surface water.
GREEN INFRASTRUCTURE
Systems and practices that use or mimic natural processes
to infiltrate, evapotranspire, or reuse stormwater on the site where
it is generated.
HEC-HMS
The U.S. Army Corps of Engineers, Hydrologic Engineering
Center (HEC) - Hydrologic Modeling System (HMS) adapted to the Delaware
River South watershed.
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).
HYDROLOGIC REGIME (NATURAL)
The hydrologic cycle or balance that sustains quality and
quantity of stormwater, baseflow, storage, and groundwater supplies
under natural conditions.
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 four HSGs (A, B, C, and D) according to their
minimum infiltration rate, which is obtained for bare soil after prolonged
wetting. The NRCS 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 the development site may be identified from
a soil survey report that can be obtained from local NRCS offices
or conservation district offices. Soils become less pervious as the
HSG varies from A to D (NRCS).
HYETOGRAPH
A graphical representation of average rainfall, rainfall
excess rates, or volumes over specified areas during successive units
of time during a storm.
IMPERVIOUS SURFACE (IMPERVIOUS AREA)
A surface that prevents the infiltration of water into the
ground. Impervious surfaces (or areas) shall include, but not be limited
to roofs; additional indoor living spaces, patios, garages, storage
sheds and similar structures; and any new streets or sidewalks. Decks,
parking areas, and driveway areas are not counted as impervious areas
if they do not prevent infiltration.
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 in very close proximity to urban areas. The development
relies on existing infrastructure and does not require an extension
of water, sewer, or other public utilities.
INFILTRATION
The passing of stormwater through the soil from the surface.
INFILTRATION STRUCTURES
A structure designed to direct runoff into the ground (e.g.,
french drains, seepage pits, seepage trench).
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.
KARST
A type of topography or landscape characterized by 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 (DEVELOPMENT)
Inclusive of any or all of the following meanings:
A.
The improvement of one lot or two or more contiguous lots, tracts,
or parcels of land for any purpose involving:
(1)
A group of two or more buildings; or
(2)
The division or allocation of land or space 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;
C.
Development in accordance with § 503(1.1) of the Pennsylvania
Municipalities Planning Code.
LAND EARTH 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.
LIMITING ZONE
A soil horizon or condition in the soil profile or underlying
strata which includes one of the following:
A.
A seasonal high water table, whether perched or regional, determined
by direct observation of the water table or indicated by soil mottling.
B.
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.
C.
A rock formation, other stratum or soil condition which is so
slowly permeable that it effectively limits downward passage of effluent.
LOW-IMPACT DEVELOPMENT (LID)
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, evaporate, 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.
MAIN STEM (MAIN CHANNEL)
Any stream segment or other runoff conveyance facility used
as a reach in the Delaware River South Creek hydrologic model.
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.
MUNICIPALITY
Borough of Bristol, Bucks County, Pennsylvania.
NONPOINT SOURCE POLLUTION
Pollution that enters a body of water from diffuse origins
in the watershed and does not result from confined or discrete conveyances.
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
USDA Natural Resources Conservation Service (previously 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 manmade drainageways, swales, streams, ditches, canals, and pipes
flowing partly full.
OUTFALL
Point where water flows from a conduit, stream, or drain.
OUTLET
Points of water disposal from a stream, river, lake, tidewater
or artificial drain.
PARENT TRACT
The parcel of land from which a land development or subdivision
originates as of the date of the original Delaware River South Creek
stormwater ordinance adoption.
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.
PENN STATE RUNOFF MODEL (CALIBRATED)
The computer-based hydrologic modeling technique adapted
to the Delaware River South Watershed for the Act 167 plan. The model
has been "calibrated" to reflect actual recorded flow values by adjoining
key model input parameters.
PIPE
A culvert, closed conduit, or similar structure (including
appurtenances) that conveys stormwater.
PMF - PROBABLE MAXIMUM FLOOD
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 based on data obtained from the
National Oceanographic and Atmospheric Administration (NOAA).
POINT SOURCE
Any discernible, confined and discreet 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 § 92.1.
PRETREATMENT
Techniques employed in stormwater BMPs to provide storage
or filtering to help trap coarse materials and other pollutants before
they enter the system.
PROJECT SITE
The specific area of land where any regulated activities
in the municipality 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
Part.
RECHARGE AREA
Undisturbed surface area or depression where stormwater collects,
and a portion of which infiltrates and replenishes the underground
and groundwater.
RECONSTRUCTION
The process by which existing developed area is adaptively
reused, rehabilitated, restored, renovated, and/or expanded. The development
relies on existing infrastructure and does not require an extension
of water, sewer, or other public utilities.
RECORD DRAWINGS
Original documents revised to suit the as-built conditional
and subsequently provided by the Engineer to the client. The Engineer
takes the contractor's as-builts, reviews them in detail with
his/her own records for completeness, then either turns these over
to the client or transfers the information to a set of reproducibles,
in both cases for the client's permanent records.
REDEVELOPMENT
The construction, alteration, or improvement exceeding 5,000
square feet of land disturbance performed on sites where existing
land use is commercial, industrial, institutional, or multifamily
residential.
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
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 occur one time. For example,
the twenty-five-year return period rainfall would be expected to occur
on average of 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).
RIPARIAN BUFFER
A permanent area of trees and shrubs located adjacent to
streams, lakes, ponds and wetlands.
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 cleaning drainage ditches and other similar
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.
SALDO
Subdivision and Land Development Ordinance.
SEDIMENT
Soils or other materials transported by surface water as
a product of erosion.
SEDIMENT BASIN
A barrier, dam, or 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 the commonwealth occurring from the failure to
design, construct, implement or maintain control measures and control
facilities in accordance with the requirements of the DEP Erosion
and Sediment Pollution Control Program Manual.
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, manmade 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
A conveyance that is used to pass the peak discharge of the
maximum design storm controlled by the stormwater facility.
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 "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
Drainage runoff from the surface of the land resulting from
precipitation or snow or ice melt.
STORMWATER MANAGEMENT FACILITY
Any structure, natural or manmade, 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 plan for managing stormwater runoff in the Delaware River
South Watershed adopted by Bucks County as required by the Act of
October 4, 1978, P.L. 864, (Act 167), and known as the Delaware River
South Watershed Act 167 Stormwater Management Plan.
STORMWATER MANAGEMENT SITE PLAN
The plan prepared by the developer or his representative
indicating how stormwater runoff will be managed at the development
site in accordance with this Part. Stormwater management site plan
will be designated as SWM site plan throughout this Part.
STREAM BUFFER
The land area adjacent to each side of a stream, essential
to maintaining water quality measured 150 feet from the top of the
bank.
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.
SUBAREA
The smallest drainage unit of a watershed for which stormwater
management criteria have been established in the stormwater management
plan.
SUBDIVISION
As defined in The Pennsylvania Municipalities Planning Code,
Act of July 31, 1968, P.L. 805, No. 247.
SWALE
A low-lying stretch of land which 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.
USDA
United States Department of Agriculture.
WATERCOURSE
River, brook, creek, or a channel or ditch for water, whether
natural or man-made with perennial or intermittent flow.
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 this commonwealth.
WATERSHED
Region or area drained by a river, watercourse, or other
surface water of this commonwealth.
WELLHEAD
A.
A structure built over a well.
B.
The source of water for a well.
WELLHEAD PROTECTION AREA
The surface and subsurface area surrounding a water supply
well, well field, spring, or infiltration gallery supplying a public
water system, through which contaminants are reasonably likely to
move towards and reach the water source.
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, ferns, and similar areas.