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 human activities and natural processes, at a rate greater
than would occur because of the natural process alone.
AGRICULTURAL ACTIVITY
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.
APPLICANT
A landowner, developer, or other person who has filed an
application to the municipality for approval to engage in any regulated
activity at a project site in the municipality.
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 chapter. Stormwater BMPs
are commonly grouped into one of two broad categories or measures:
"structural" or "nonstructural." In this chapter, 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
Densely vegetated, depressed features that store stormwater
and filter it through vegetation, mulch, planting soil, etc. Ultimately,
stormwater is evapotranspirated, infiltrated, or discharged. Optimal
bioretention areas mimic natural forest ecosystems in terms of species
diversity, density, distribution, use of native plants, etc.
CAPTURE/REUSE
Stormwater management techniques such as cisterns and rain
barrels which direct runoff into storage devices, surface or subsurface,
for later reuse, such as for irrigation of gardens and other planted
areas. Because this stormwater is utilized and no pollutant discharge
results, water quality performance is superior to other noninfiltration
BMPs.
CATCH BASIN SUMPS
A chamber which provides storage below the outlet in a storm
structure to collect sediment, debris and associated pollutants, typically
requiring periodic cleanout.
CISTERN
An underground reservoir or tank for storing rainwater.
CLOSED DEPRESSION
A distinctive bowl-shaped depression in the land surface.
It is characterized by internal drainage, varying magnitude, and an
unbroken ground surface.
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 Chapter 102.
CONSTRUCTED WETLANDS
Constructed wetlands are similar to wet ponds (see below)
and consist of a basin which provides for necessary stormwater storage
as well as a permanent pool or water level, planted with wetland vegetation.
To be successful, constructed wetlands must have adequate natural
hydrology (runoff inputs as well as soils and water table which allow
for maintenance of a permanent pool of water). In these cases, the
permanent pool must be designed carefully, usually with shallow edge
benches, so that water levels are appropriate to support carefully
selected wetland vegetation.
CULVERT
A pipe, conduit or similar structure, including appurtenant
works, which carries surface water.
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.
DEP
The Pennsylvania Department of Environmental Protection (formerly
the Pennsylvania Department of Environmental Resources).
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."
DETENTION BASIN
A basin designed to retard stormwater runoff by temporarily
storing the runoff and releasing it at a predetermined rate.
DETENTION VOLUME
The volume of runoff that is captured and released into the
waters of the commonwealth at a controlled rate.
DEVELOPER
A person, partnership, association, corporation or other
entity, or any responsible person therein or agent thereof, that undertakes
any regulated activity of this chapter.
DRAINAGE EASEMENT
A right granted by a landowner to a grantee, allowing the
use of private land for stormwater management purposes.
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, building construction and the moving,
depositing, stockpiling or storing of soil, rock or earth materials.
EROSION
The natural process by which the surface of the land is worn
away by water, wind, or chemical action.
EXISTING CONDITION
The dominant land cover during the five-year period immediately
preceding a proposed regulated activity.
EXISTING USES
Those uses actually attained in the water body on or after
November 28, 1975, whether or not they are included in the water quality
standards. (See 25 Pa. Code § 93.1.)
FEMA
Federal Emergency Management Agency.
FILL
Man-made deposits of natural soils or rock products and waste
materials.
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 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
The incremental depth in a stormwater management structure,
provided as a safety factor of design, above that required to convey
the design runoff event.
GREEN INFRASTRUCTURE
Systems and practices that use or mimic natural processes
to infiltrate, evapotranspire, or reuse stormwater on the site where
it is generated.
HARDSHIP WAIVER REQUEST
A written request for a waiver alleging that the provisions
of this chapter inflict unnecessary hardship upon the applicant. Waivers
from the water quality provisions of this chapter shall not be granted.
HOT SPOT LAND USES
A land use or activity that generates higher concentrations of hydrocarbons, trace metals or other toxic substances than typically found in stormwater runoff. These land uses are listed in §
23-304, Subsection
12.
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 rates, which is obtained for bare soil after prolonged
wetting. The Natural Resources Conservation Service (NRCS) of the
U.S. Department of Agriculture defines the four groups and provides
a list of most of the soils in the United States and their group classification.
The soils in the area of 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 permeable as the
HSG varies from A to D (NRCS1,2).
IMPERVIOUS SURFACE (IMPERVIOUS COVER)
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.
INFILTRATION PRACTICE
A practice designed to direct runoff into the ground, e.g.,
french drain, seepage pit, seepage trench or bioretention area.
KARST
A type of topography or landscape characterized by surface
depressions, sinkholes, underground drainage and caves. Karst is usually
formed on carbonate rocks, such as limestones or dolomites.
LAND DEVELOPMENT
Any of the following activities:
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 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
(2)
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;
C.
Development in accordance with § 503 (1.1) of the
Pennsylvania Municipalities Planning Code.
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.
MAINSTEM (MAIN CHANNEL)
Any stream segment or other conveyance used as a reach in
the Bushkill Creek, Martins/Jacoby Creek and Delaware River Sub-Basin
1 hydrologic models.
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.
MARYLAND STORMWATER DESIGN MANUAL
A stormwater design manual written by the Maryland Department
of the Environment and the Center for Watershed Protection. As of
January 2004, the manual can be obtained through the following website:
www.mde.state.md.us.
MINIMUM DISTURBANCE/MINIMUM MAINTENANCE PRACTICES (MD/MM)
A site design practice in which careful limits are placed
on site clearance prior to development allowing for maximum retention
of existing vegetation (woodlands and other), minimum disturbance
and compaction of existing soil mantle and minimum site application
of chemicals post-development. Typically, MD/MM includes disturbance
setback criteria from buildings as well as related site improvements
such as walkways, driveways, roadways, and any other improvements.
These criteria may vary by community context as well as by type of
development being proposed. Additionally, MD/MM also shall include
provisions (e.g., deed restrictions, conservation easements) to protect
these areas from future disturbance and from application of fertilizers,
pesticides, and herbicides.
MUNICIPALITY
Plainfield Township, Northampton County, Pennsylvania.
NO-HARM OPTION
The option of using a less restrictive runoff quantity control
if it can be shown that adequate and safe runoff conveyance exists
and that the less restrictive control would not adversely affect health,
safety and property.
NPDES
National Pollutant Discharge Elimination System.
NRCS
Natural Resource Conservation Service, U.S. Department of
Agriculture. (Formerly the Soil Conservation Service.)
OIL/WATER SEPARATOR
A structural mechanism designed to remove free oil and grease
(and possibly solids) from stormwater runoff.
OUTFALL
"Point source" as described in 40 CFR 122.2 at the point
where the municipality's storm sewer system discharges to surface
waters of the commonwealth.
PEAK DISCHARGE
The maximum rate of flow of stormwater runoff at a given
location and time resulting from a specified storm event.
PENN STATE RUNOFF MODEL (PSRM)
The computer-based hydrologic modeling technique used in
previous Act 167 plans. PSRM was also updated to include water quality
modeling capabilities and renamed "PSRM-QUAL."
PERSON
An individual, partnership, public or private association
or corporation, or a governmental unit, public utility or other for-profit
or not-for-profit statutory entity or other legal entity whatsoever
which is recognized by law as the subject of rights and duties.
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 § 92.1.
PRELIMINARY SITE INVESTIGATION
The determination of the depth to bedrock, the depth to the
seasonal high-water table and the soil permeability for a possible
infiltration location on a site through the use of published data
and on-site surveys.
PROJECT SITE
The specific area of land where any regulated activities
in the municipality are planned, conducted, or maintained.
PUBLIC WATER SYSTEM
A system which provides water to the public for human consumption
which has at least 15 service connections or regularly serves an average
of at least 25 individuals daily at least 60 days out of the year.
(See 25 Pa. Code Chapter 109.)
QUALIFIED PROFESSIONAL
Any person licensed by the Pennsylvania Department of State
or otherwise qualified by law to perform the work required by this
chapter.
RATIONAL METHOD
A method of peak runoff calculation using a standardized
runoff coefficient (rational "c"), acreage of tract and rainfall intensity
determined by return period and by the time necessary for the entire
tract to contribute runoff. The Rational Method formula is stated
as follows: Q = ciA, where "Q" is the calculated peak flow rate in
cubic feet per second, "c" is the dimensionless runoff coefficient
(see Appendix 23-C), "i" is the rainfall intensity in inches per hour, and
"A" is the area of the tract in acres.
REACH
Any of the natural or man-made runoff conveyance channels
used for watershed runoff modeling purposes to connect the subareas
and transport flows downstream.
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 the predevelopment peak rate of runoff
for a development site to which the post-development peak rate of
runoff must be controlled to avoid peak flow increases throughout
the watershed.
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 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 four-percent chance).
RIPARIAN BUFFER
A permanent area of trees and shrubs located adjacent to
streams, lakes, pond and wetlands.
RUNOFF
That part of precipitation which flows over the land.
SEDIMENT
Soils or other materials transported by surface water as
a product of erosion.
SEEPAGE PIT/SEEPAGE TRENCH
An area of excavated earth filled with loose stone or similar
material and into which surface water is directed for infiltration
into the ground.
SEPARATE STORM SEWER SYSTEM
A conveyance or system of conveyances (including roads with
drainage systems, municipal streets, catch basins, curbs, gutters,
ditches, man-made channels or storm drains) primarily used for collecting
and conveying stormwater runoff.
SHEET FLOW
Stormwater runoff flowing in a thin layer over the ground
surface.
SOIL-COVER-COMPLEX METHOD
A method of runoff computation developed by NRCS which is
based upon relating soil type and land use/cover to a runoff parameter
called a "curve number."
SPILL PREVENTION AND RESPONSE PROGRAM
A program that identifies procedures for preventing and,
as needed, cleaning up potential spills and makes such procedures
known and the necessary equipment available to appropriate personnel.
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 method of routing or moving an inflow hydrograph through
a reservoir or detention structure. The method solves the mass conservation
equation to determine an outflow hydrograph as it leaves the storage
facility.
STORM DRAINAGE PROBLEM AREAS
Areas which lack adequate stormwater collection and/or conveyance
facilities and which present a hazard to persons or property. These
areas are either documented in Appendix 23-B or identified by the municipality or municipal engineer.
STORM SEWER
A system of pipes or other conduits which carries intercepted
surface runoff, street water and other wash waters, or 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 FILTERS
Structural mechanisms such as multichamber catch basins,
sand/peat filters, sand filters, etc., which are installed to intercept
stormwater flow and remove pollutants prior to discharge. Typically,
these systems require periodic maintenance and cleanout.
STORMWATER MANAGEMENT FACILITY
Any structure, natural or man-made, that, due to its condition,
design, or construction, conveys, stores, or otherwise affects stormwater
runoff. Typical stormwater management facilities include, but are
not limited to: detention and retention basins; open channels; storm
sewers; pipes; and infiltration facilities.
STORMWATER MANAGEMENT PLAN
The plan for managing stormwater runoff adopted by Northampton
County for the Bushkill Creek Watershed and Martins/Jacoby Creek Watershed
and Delaware River Sub-Basin 1 as required by the Act of October 4,
1978, P.L. 864 (Act 167), as amended, and known as the "Storm Water
Management Act."
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 chapter. Stormwater management site plan
designated as SWM site plan throughout this chapter.
STREAMSIDE BUFFER
A zone of variable width located along a stream that is vegetated
and is designed to filter pollutants from runoff.
SUBAREA
The smallest unit of watershed breakdown for hydrologic modeling
purposes for which the runoff control 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. See also "vegetated swales."
TRASH/DEBRIS COLLECTORS
Racks, screens or other similar devices installed in a storm
drainage system to capture coarse pollutants such as trash, leaves,
etc.
USDA
United States Department of Agriculture.
VEGETATED BUFFERS
Gently sloping areas that convey stormwater as sheet flow
over a broad, densely vegetated earthen area, possibly coupled with
the use of level spreading devices. Vegetated buffers should be situated
on minimally disturbed soils, have low-flow velocities and extended
residence times.
VEGETATED ROOFS
Vegetated systems installed on roofs that generally consist
of a waterproof layer, a root-barrier, drainage layer (optional),
growth media, and suitable vegetation. Vegetated roofs store and eventually
evapotranspirate the collected rooftop rainfall; overflows may be
provided for larger storms.
VEGETATED SWALES
Broad, shallow, densely vegetated, earthen channels designed
to treat stormwater while slowly infiltrating, evapotranspirating,
and conveying it. Swales should be gently sloping with low flow velocities
to prevent erosion. Check dams may be added to enhance performance.
WATER QUALITY INSERTS
Any number of commercially available devices that are inserted
into storm inlets to capture sediment, oil, grease, metals, trash,
debris, etc.
WATERCOURSE
Any channel of conveyance of surface water having defined
bed and banks, whether natural or artificial, 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.
WET DETENTION PONDS
A basin that provides for necessary stormwater storage as
well as a permanent pool of water. To be successful, wet ponds must
have adequate natural hydrology (runoff inputs as well as soils and
water table which allow for maintenance of a permanent pool of water)
and must be able to support a healthy aquatic community so as to avoid
creation of mosquito and other health and nuisance problems.
WETLAND
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, including
swamps, marshes, bogs, and similar areas.