[Ord. 2014-03, 9/8/2014]
For the purposes of this chapter, the following words, terms,
and phrases have the meaning indicated herein:
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 processes 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 livestock, and installation of conservation measures.
Construction of new buildings or impervious area is not considered
agricultural activity.
ALLUVIAL SOIL
Areas subject to periodic flooding as defined in latest officially
issued soil survey information by the U.S. Conservation and Natural
Resources Service.
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; or earth disturbance.
APPLICANT
A landowner or developer who has filed an application for approval to engage in any regulated activities as defined in §
23-105 of this chapter.
AS-BUILT PLAN
Plans that are maintained during construction of the project
and which document the actual locations of the site improvements.
As-built plan must be prepared by a professional land surveyor or
professional engineer licensed in and in good standing with the Commonwealth
of Pennsylvania.
BANKFULL
The channel at the top of bank or point where water begins
to overflow onto a floodplain.
BASE FLOW
The portion of stream flow that is sustained by groundwater
discharge.
BEST MANAGEMENT PRACTICE (BMP)
Activities, facilities, measures or procedures used to manage stormwater quantity and quality impacts from the regulated activities listed in §
23-105, 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 or two broad categories or measures: "structural" or "nonstructural." In this chapter, nonstructural BMPs or measures refer to operation 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.
BMP MANUAL
Pennsylvania Best Management Practices Manual, December 2006,
as amended.
BUFFER
A.
STREAMSIDE BUFFERA zone of variable width located along a stream that is vegetated and is designed to filter pollutants from runoff.
B.
SPECIAL GEOLOGIC FEATURE BUFFERA required isolation distance from a special geologic feature to a proposed BMP needed to reduce the risk of sinkhole formation due to stormwater management activities.
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.
CARBONATE BEDROCK
Rock consisting chiefly of carbonate minerals, such as limestone
and dolomite; specifically a sedimentary rock composed of more than
50% by weight of carbonate minerals that underlies soil or other unconsolidated,
superficial material.
CATCH BASIN SUMPS
Chambers which provide storage below the outlet in a storm
inlet to collect sediment, debris and associated pollutants, typically
requiring periodic cleanout.
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, and headward cutting of channels
and waterways, due to erosion caused by stormwater runoff.
CISTERN
An underground reservoir or tank for storing rainwater.
CLOSED DEPRESSION
A distinctive bowl-shaped depression in the land's surface.
It is characterized by internal drainage, varying magnitude, and an
unbroken ground surface.
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 (both 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.
DESIGN STORM
The depth and time distribution of precipitation from a storm
event measured in probability of occurrence (e.g., one-hundred-year
storm) and duration (e.g., twenty-four-hour) and used in computing
stormwater management control systems.
DESIGNEE
The agent of Northampton County, Northampton County Conservation
District and/or governing body involved with the administration, review,
or enforcement of any provisions of this chapter.
DETENTION BASIN
A basin designed to retard stormwater runoff by temporarily
storing the runoff and releasing it at the appropriate release rate.
DETENTION DISTRICT
Those subareas in which some type of detention is required
to meet the plan requirements and 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.
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.
DIRECT RECHARGE (D-RE) BMP
A BMP which directs runoff to an underground infiltration
surface. Examples include infiltration trenches, seepage beds, and
dry wells such that nearly all runoff becomes recharge to groundwater.
DISCHARGE
A.
(verb) To release water from a project, site, aquifer, drainage
basin or other point of interest;
B.
(noun) The rate and volume of flow of water such as in a stream,
generally expressed in cubic feet per second (cfs).
DISCONNECTED IMPERVIOUS AREA (DIA)
An impervious 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.
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 toward it.
DRAINAGE CONVEYANCE FACILITY
A stormwater management facility designed to transmit stormwater
runoff which 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 Township after the SWM plan has been
approved.
DRAINAGE PLAN
The documentation of the proposed stormwater quantity and quality management controls to be used for a given development site, including a BMP operations and maintenance plan, the contents of which are established in §
23-403.
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, 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.
ENGINEER
A person licensed as a professional who is by state regulation
allowed to prepare subdivision and land development plans registered
and in good standing with the Commonwealth of Pennsylvania.
EROSION
The removal of soil particles by the action of water, wind,
ice, or other geological agents.
EVAPOTRANSPIRATION (ET) BMP
A BMP which provides opportunity for runoff evaporation and
transpiration by vegetation. Examples include bioretention and surface
infiltration basins.
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 CONDITIONS
The initial condition of a project site prior to the proposed
construction and development. Farm field, disturbed earth, or undeveloped
cover conditions of a site or portions of a site used for modeling
purposes, shall be considered "meadow" unless the natural ground cover
generates lower curve numbers or Rational "C" value, such as forested
land. Existing man-made impervious surfaces shall be considered as
"meadow" when developing "cover complex" calculations.
EXISTING RESOURCES AND SITE ANALYSIS PLAN (ERSAP)
A base map which identifies fundamental environmental site information including floodplains, wetlands, topography, vegetative site features, natural areas, prime agricultural land (as defined in Chapter
27, Zoning) and areas supportive of endangered species.
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. (25 Pa. Code Chapter 93.1)
FILL
Man-made deposits of natural soils or rock products and waste
materials.
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
Those areas of Lower Mount Bethel Township which are subject
to the one-hundred-year flood, as identified in the Flood Insurance
Study (FIS) dated April 06, 2001, as amended, and the accompanying
maps prepared for the Township by the Federal Emergency Management
Agency (FEMA), or most recent revision thereof; and also those areas
along streams, ponds, or lakes not identified within the Flood Insurance
Study which are inundated by the one-hundred-year reoccurrence interval
flood.
FLOODWAY
The channel of the watercourse and those portions of the
adjoining floodplains that are reasonably required to carry and discharge
the one-hundred-year frequency 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 one-hundred-year frequency 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 associated activities necessary for the management
of forest. These include timber inventory and preparation of forest
management plans, silvicultural treatment, cutting budgets, logging
road design and construction, timber harvesting, and reforestation.
FREEBOARD
Vertical distance between the elevation of the design high
water and the top of a dam, levee, tank, basin, or diversion ridge,
provided as a safety factor of design, above that required to convey
the design runoff event.
GRADE
A.
(noun) A slope usually of a street, other public way, land area,
drainage facility or pipe specified in percent;
B.
(verb) To finish the surface of a road bed, 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.
GROUNDWATER
Water beneath the earth's surface that supplies wells
and springs, and is often between saturated soil and rock.
HARDSHIP WAIVER REQUEST
A written request for a waiver alleging that the provisions
of this chapter inflict unnecessary hardship upon the applicant. A
hardship waiver does not apply to and is not available from the water
quality provisions of this chapter and shall not be granted.
HEC-HMS
The U.S. Army Corps of Engineers, Hydrologic Engineering
Center (HEC) — Hydrologic Modeling System (HMS).
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).
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
16. Typical pollutant loadings in stormwater may be found in Chapter
8, Section 6, of the Pennsylvania Stormwater Best Management Practices Manual, Pennsylvania Department of Environmental Protection (PADEP), No. 363-0300-002 (2006). More information concerning hot spots may be found in Appendix K of this chapter.
HYDRIC SOIL
A soil that is saturated, flooded, or ponded long enough
during the growing season to develop an anaerobic condition in the
upper part.
HYDROLOGIC REGIME (NATURAL)
The hydrologic cycle or balance that sustains quality and
quantity of stormwater, baseflow, storage, and groundwater supplies
under the 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 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 pervious as the
HSG varies from A to D.
HYDROGRAPH
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 COVER)
A surface which prevents the percolation of water into the
ground. All buildings, parking areas, driveways, roads, sidewalks,
swimming pools, and any areas containing concrete, asphalt, packed
stone, compacted soils, or other equivalent surfaces shall be considered
impervious within this definition. In addition, other areas determined
by the Township Engineer to be impervious within the meaning of this
definition shall be classified as impervious surfaces.
IMPOUNDMENT
A retention or detention basin designed to retain stormwater
runoff and release it at a controlled rate.
INFILTRATION PRACTICE
A practice designed to direct runoff into the ground, e.g.,
french drain, seepage pit, seepage trench or bioretention area.
INFILTRATION STRUCTURES
A structure designed to direct runoff into the ground (e.g.,
french drains, seepage pits, seepage trench, biofiltration swale,
infiltration basins).
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.
INVERT
The inside bottom of a culvert or other conduit.
KARST
A type of topography or landscape characterized by depressions,
sinkholes, limestone towers and steep-sided hills, underground drainage
and caves. Karst is usually formed on carbonate rocks, such as limestones
or dolomites and sometimes gypsum.
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: 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.
C.
Development in accordance with Section 503(1.1) of the Pennsylvania
Municipalities Planning Code.
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 is effectively limits downward passage of effluent.
LOADING RATE
The ratio of the land area draining to the system, as modified by the weighting factors in §
23-308, Subsection
16, compared to the base area of the infiltration system.
LOW-IMPACT DEVELOPMENT (LID)
A development approach that promotes practices that will
minimize post-development runoff rates and volumes thereby minimizing
needs for artificial conveyance and storage facilities. Site design
practices include preserving natural drainage features, minimizing
impervious surface area, reducing the hydraulic connectivity of impervious
surfaces and protecting natural depression storage.
MAINSTEM (MAIN CHANNEL)
Any stream segment or other conveyance used as a reach in
the Martins/Jacoby Creeks Watershed and Delaware River Sub-Basin 1
Watershed 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.
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 web
site: www.mde.state.md.us.
MINIMUM DISTURBANCE/MINIMUM MAINTENANCE PRACTICES (MD/MM)
Site design practices 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.
MUNICIPAL ENGINEER
A professional engineer licensed in the Commonwealth of Pennsylvania
and appointed by the Township pursuant to Article V of the Second
Class Township Code.
MUNICIPALITY
Lower Mount Bethel Township, Northampton County, Pennsylvania.
NO-HARM OPTION
The option of using a less restrictive runoff quantity control
if it can be shown to the satisfaction of the municipality's
engineer and any other applicable reviewing agencies, such as the
Conservation District or DEP, that adequate and safe runoff conveyance
exists and that the less restrictive control would not adversely affect
health, safety and property.
NONPOINT SOURCE POLLUTION
Pollution that enters a watery body from diffuse origins
in the watershed and does not result from discernible, confined, or
discrete conveyances.
NONSTORMWATER DISCHARGES
Water flowing in stormwater collection facilities, such as
pipes or swales, which is not the result of a rainfall event or snowmelt.
NPDES
National Pollutant Discharge Elimination System.
NRCS
Natural Resources 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.
OUTLET
Points of water disposal to a stream, river, lake, tidewater
or artificial basin.
OWNER
One with an interest in and often dominion over a property.
PARENT TRACT
Tracts of land in existence as of the date of the municipal
ordinance adoption of the original Lower Mount Bethel Township Act
167 Stormwater Management Ordinance (February 1996) shall be the starting
point from which to consider tracts as "parent tracts" in which future
subdivisions and respective impervious area computations shall be
cumulatively considered.
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 adapted
to each watershed for the Act 167 Plans. The model was "calibrated"
to reflect actual flow values by adjusting key model input parameters.
PERMANENTLY PRESERVED LAND
A parcel or tract of land that is subject to a recorded conservation
easement, in perpetuity, in a manner acceptable to the Township.
PERMANENTLY REMOVED VOLUME (PRV)
The volume of runoff that is permanently removed from the
runoff and not released into surface waters of the commonwealth during
or after a storm event.
PERSON
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.
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 meteorologic and hydrologic conditions that are reasonably
possible in any area. The PMF is derived from the probable maximum
precipitation (PMP) as determined on the basis of data obtained from
the National Oceanographic and Atmospheric Administration (NOAA).
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.
POST-CONSTRUCTION
Period after construction during which disturbed areas are
stabilized, stormwater controls are in place and functioning, and
all improvements in the approved SWM plan are completed.
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. In carbonate bedrock areas, the location of special
geologic features must also be determined along with the associated
buffer distance to the possible infiltration area. See Appendix H.
PRETREATMENT
Techniques employed in stormwater BMPs to provide storage
or filtering to trap coarse materials and other pollutants before
they enter the system.
PROJECT SITE
The specific tract of land where any regulated activity in
the Township is 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.)
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 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
Actions or proposed actions which impact upon proper management of stormwater runoff and which are governed by this chapter as specified in §
23-105.
REGULATED EARTH DISTURBANCE ACTIVITIES
Other than agricultural plowing or tilling activities, animal
heavy use areas, timber harvesting activities or road maintenance
activities, a person proposing an earth disturbance activity that
involves equal to or greater than one acre (0.4 hectare) of earth
disturbance, or an earth disturbance on any portion, part, or during
any stage of, a larger common plan of development or sale that involves
equal to or greater than one acre (0.4 hectare) of earth disturbance,
shall obtain an individual NPDES permit or coverage under a general
NPDES permit for stormwater discharges associated with construction
activities prior to commencing the earth disturbance activity.
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 BASIN
A pocket of storage similar to a detention basin but with
the purpose of providing a permanent obstruction and withholding of
water that would otherwise flow downstream.
RETURN PERIOD
The average interval in years over which an event of a given
magnitude can be expected to recur. For example, the twenty-five-year
return period rainfall or runoff event would be expected to recur
on the average once every 25 years.
RIPARIAN CORRIDOR
A vegetated ecosystem along a water body that serves to buffer
the water body from the effects of runoff by providing water quality
filtering, bank stability, recharge, rate attenuation and volume reduction,
and shading of the water body by vegetation. Riparian corridors also
provide habitat and may include stream banks, wetlands, floodplains,
and transitional areas.
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 a structure.
RUNOFF
That part of precipitation which flows over the land.
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.
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
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.
SHALLOW CONCENTRATED FLOW
Stormwater runoff flowing in shallow, defined ruts prior
to entering a defined channel or waterway.
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 (CN).
SPECIAL GEOLOGIC FEATURES
Carbonate bedrock features, including but not limited to
closed depressions, existing sinkholes, fracture traces, lineaments,
joints, faults, caves, pinnacles and geologic contacts between carbonate
and non-carbonate bedrock which may exist and must be identified on
a site when stormwater management BMPs are being considered.
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.
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
As defined under state regulations, protection of designated
and existing uses (see 25 Pa. Code Chapters 93 and 96), including:
A.
Each stream segment in Pennsylvania has a "designated use,"
such as "cold water fishes" or "potable water supply," which is listed
in Chapter 93. These uses must be protected and maintained, under
state regulations.
B.
"Existing uses" are those attained as of November 1975, regardless
of whether they have been designated in Chapter 93. Regulated earth
disturbance activities must be designed to protect and maintain existing
uses and maintain the level of water quality necessary to protect
those uses in all streams, and to protect and maintain water quality
in special protection streams.
C.
Water quality involves the chemical, biological and physical
characteristics of surface water bodies. After regulated earth disturbance
activities are complete, these characteristics can be impacted by
addition of pollutants such as sediment, and changes in habitat through
increased flow volumes and/or rates as a result of changes in land
surface area from those activities. Therefore, permanent discharges
to surface waters must be managed to protect the stream bank, streambed
and structural integrity of the waterway, to prevent these impacts.
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 B of this chapter or identified by the municipality or municipal engineer.
STORM FREQUENCY
The number of times that a given storm event occurs or is
exceeded on the average in a stated period of years. Refer to "return
period."
STORM SEWER
A system of pipes or other conduits which carries intercepted
surface runoff, street water, or drainage, but excludes domestic sewage,
industrial wastes or any other discharges considered illicit by PADEP.
STORMWATER
Rain or snowmelt runoff that accumulates in natural and/or
constructed storage facilities and stormwater systems during and immediately
following a storm event.
STORMWATER FILTERS
Any number of structural mechanisms such as multi-chamber
catch basins, sand/peat filters, sand filters, and so forth 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, infiltration structures, and other BMPs.
STORMWATER MANAGEMENT PERMIT
A permit issued by the Township after the drainage plan has
been approved. Said permit is issued prior to or with the final Township
approval of the proposed development activity.
STORMWATER MANAGEMENT PLAN
The plan for managing stormwater runoff adopted by Northampton
County for the Martins/Jacoby Creeks Watershed and Delaware River
Sub-Basin 1 Watershed as required by the Act of October 4, 1978, P.L.
864, (Act 167), as amended, and known as the "Storm Water Management
Act."
STREAM
Rivers, creeks, springs, and other perennial or intermittent
watercourses containing water at least on a seasonal basis during
an average water year. The term "stream" shall include all "intermittent
streams" and all "perennial streams."
B.
STREAM, EPHEMERALA reach of stream that flows only during and for short periods following precipitation, and flows in low areas that may or may not be a well defined channel. Ephemeral stream beds are located above the water table year-round. Groundwater is not a source of water for the stream. Some commonly used names for ephemeral streams include: stormwater channel, drain, swale, gully, dry stream channel, hollow, or saddle.
C.
STREAM, HEADWATERThe beginning reach of a stream, which collects water from springs and seeps and provides a hydrologic connection to a perennial stream. These channels may be ill defined and may move from year to year depending upon groundwater input, snowmelt, and runoff, but are typified by hydric soils and hydric vegetation.
D.
STREAM, INTERMITTENTA reach of stream that flows only during wet periods of the year and flows in a continuous well-defined channel. During dry periods, when the water table is depressed by seasonal aridity or drought, intermittent streams may go down to a trickle of water and appear dry, when in fact there is water flowing within the stream bottom or "substrate."
E.
STREAM, PERENNIAL or WATERCOURSE, PERENNIALA body of water in a channel that flows throughout a majority of the year in a defined channel and is capable, in the absence of pollution, drought, or man-made stream disturbances, of supporting a benthic macroinvertebrate community that is composed of two or more recognizable taxonomic groups of organisms, large enough to be seen by the unaided eye and can be retained by a U.S. Standard No. 30 sieve (28 meshes per inch, 0.595 mm openings) and live at least part of their life cycles within or upon available substrates in a body of water or water transport system. A perennial stream can have Q7-10 flow of zero. For the purposes of this document, a perennial stream includes lakes and ponds.
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.
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 (SUBWATERSHED)
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
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 which gathers or carries surface
water runoff. See also "vegetated swale."
TIME OF CONCENTRATION (Tc)
The time for surface runoff to travel from the hydraulically
most distant point of the watershed to a point of interest within
the watershed. This time is the combined total of overland flow time
and flow time in pipes or channels, if any.
TOP OF 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
and over the floodplain.
TRASH/DEBRIS COLLECTORS
Racks, screens or other similar devices installed in a storm
drainage system to capture coarse pollutants (trash, leaves, etc.).
TRIBUTARY AREA
The portion of a watershed that contributes runoff to a particular
point in that watershed.
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
A.
Vegetated earthen channels designed to convey stormwater. These
swales are not considered to be water quality BMPs.
B.
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.
VERNAL POOL
Seasonal depressional wetlands that are covered by shallow
water for variable period from winter to spring, but may be completely
dry for most of the summer and fall.
WATER QUALITY INSERTS
Any number of commercially available devices that are inserted
into storm inlets to capture sediment, oil, grease, metals, trash,
debris, etc.
WATER QUALITY REQUIREMENTS
As defined under state regulations, protection of designated
and existing uses (refer to 25 Pa. Code Chapters 93 and 96). These
impact:
A.
Each stream segment in Pennsylvania has a "designated use,"
such as "cold water fishery" or "potable water supply," which are
listed in Chapter 93. These uses must be protected and maintained,
under state regulations.
B.
"Existing uses" are those attained as of November 1975, regardless
of whether they have been designated in Chapter 93. Land development
must be designed to protect and maintain existing uses and maintain
the level of water quality necessary to protect those uses in all
streams, and to protect and maintain water quality in special protection
streams.
C.
Water quality involves the chemical, biological, and physical
characteristics of surface water bodies. After land development, these
characteristics can be impacted by addition of pollutants such as
sediment, and changes in habitat through increased flow volumes and/or
rates. Therefore, discharge to surface waters must be designed and
managed to protect the stream bank, streambed, and structural integrity
of the waterway, to prevent these impacts.
WATERCOURSE
Any channel of conveyance of surface water having defined
bed and banks, whether natural or artificial, with perennial or intermittent
flow.
WATERS OF THE 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.
WATERS OF THE UNITED STATES (or WATERS OF THE U.S.)
A.
All waters which are currently used, were used in the past,
or may be susceptible to use in interstate or foreign commerce, including
all waters which are subject to the ebb and flow of the tide;
B.
All interstate waters, including interstate wetlands;
C.
All other waters such as intrastate lakes, rivers, streams (including
intermittent streams), mudflats, sandflats, wetlands, sloughs, prairie
potholes, wet meadows, playa lakes, or natural ponds the use, degradation,
or destruction of which would affect or could affect interstate or
foreign commerce including any such waters: (1) which are or could
be used by interstate or foreign travelers for recreational or other
purposes; (2) from which fish or shellfish are or could be taken and
sold in interstate or foreign commerce; or (3) which are used or could
be used for industrial purposes by industries in interstate commerce;
D.
All impoundments of waters otherwise defined as waters of the
United States under this definition;
E.
Tributaries of waters identified in Subsections
A through
D of this definition;
G.
"Wetlands" adjacent to waters (other than waters that are themselves wetlands) identified in Subsections
A through
F of this definition.
WATERSHED
The entire region or area drained by a river or other body
of water, whether natural or artificial.
WET DETENTION PONDS
Basins that provide for necessary stormwater storage as well
as a permanent pool of water. To be successful, wet ponds must have
adequate natural hydrology (both 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
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, fens, and similar areas.
WETLAND DELINEATION
The process by which wetland limits are determined. Wetlands
must be delineated by a qualified specialist according to the 1989
Federal Manual (as amended) for the Delineation of Jurisdictional
Wetlands (whichever is greater) or according to any subsequent federal
or state regulation. "Qualified specialist" shall include those persons
being Certified Professional Soil Scientists as registered with Registry
of Certified Professionals in Agronomy Crops and Soils (ARCPACS);
or as contained on consultant's list of Pennsylvania Association
of Professional Soil Scientists (PAPSS); or as registered with National
Society of Consulting Soil Scientists (NSCSS), or as certified by
state and/or federal certification programs; or by a qualified biologist/ecologist.