For the purposes of this chapter, certain terms and words used
herein shall be interpreted as follows:
A.
Words used in the present tense include the future tense; the singular
number includes the plural, and the plural number includes the singular;
words of masculine gender include feminine gender; and words of feminine
gender include masculine gender;
B.
The word "includes" or "including" shall not limit the term to the
specific example but is intended to extend its meaning to all other
instances of like kind and character; and
C.
The words "shall" and "must" are mandatory; the words "may" and "should"
are permissive.
As used in this chapter, the following terms shall have the
meanings indicated:
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.
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.
Activities, facilities, measures or procedures used to manage stormwater quantity and quality impacts from the regulated activities listed in Section § 219-5, to meet state water quality requirements, to promote groundwater recharge and to otherwise meet the purposes of this chapter.
Documentation, included as part of a drainage plan, detailing
the proposed BMPs, how they will be operated and maintained and who
will be responsible.
Densely vegetated, depressed features that store stormwater
and filter it through vegetation, mulch, planting soil, etc. Ultimately
stormwater is evapotransplrated, infiltrated or discharged. Optimal
bioretention areas mimic natural forest ecosystems in terms of species
diversity, density, distribution, use of native plants, etc.
STREAMSIDE BUFFERA zone of variable width located along a stream that is vegetated and is designed to filter pollutants from runoff.
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.
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.
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.
An underground reservoir or tank for storing rainwater.
A distinctive bowl-shaped depression in the land surface.
It is characterized by internal drainage, varying magnitude and an
unbroken ground surface.
Stormwater runoff leaving a property via a point source.
The Northampton County Conservation District.
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.
A pipe, conduit or similar structure including appurtenant
works which carries surface water.
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.
The Pennsylvania Department of Environmental Protection.
The depth and time distribution of precipitation from a storm
event measured in probability of occurrence (e.g., 100-year storm)
and duration (e.g., 24 hours) and used in computing stormwater management
control systems.
A basin designed to retard stormwater runoff by temporarily
storing the runoff and releasing it at a predetermined rate.
A person, partnership, association, corporation or other
entity, or any responsible person therein or agent thereof, that undertakes
any regulated activity of this chapter.
The specific tract of land for which a regulated activity
is proposed.
See "sheet flow."
A BMP designed to direct runoff to groundwater recharge without
providing for vegetative uptake. Examples include infiltration trenches,
seepage beds, drywells and stormwater drainage wells such that nearly
all runoff becomes recharge to groundwater.
A right granted by a landowner to a grantee, allowing the
use of private land for stormwater management purposes.
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 § 219-23.
A construction or other human activity which disturbs the
surface of the land, including, but not limited to, clearing and grubbing,
grading, excavations, embankments, land development, agricultural
activity, timber harvesting activities, road maintenance activities,
mineral extraction, building construction and the moving, depositing,
stockpiling or storing of soil, rock or earth materials.
The removal of soil particles by the action of water, wind,
ice or other geological agents.
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)
Man-made deposits of natural soils or rock products and waste
materials.
See "vegetated buffers."
The incremental depth in a stormwater management structure,
provided as a safety factor of design, above that required to convey
the design runoff event.
Replenishment of existing natural underground water supplies.
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 should not be granted.
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 Appendix
H.[1]
The computer-based hydrologic modeling technique developed
by the U.S. Army Corps of Engineers and adapted to the Monocacy Creek
Watershed for the Act 167 Plan Update. The model was "calibrated"
to reflect actual flow values by adjusting key model input parameters.
Soils are classified into four HSGs (A, B, C and D) to indicate
the minimum infiltration rates, which are 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. Soils become less permeable as the HSG varies
from A to D. The soils in the area of the development site may be
identified from a web soil survey report that can be accessed at www.websoilsurvey.sc.egov.usda.gov/App/HomePage.htm.
A surface which prevents the percolation of water into the
ground.
A practice designed to allow runoff an opportunity to infiltrate
into the ground (e.g., french drain, seepage pit, seepage trench or
bioretention area).
A type of topography or landscape characterized by surface
depressions, sinkholes, rock pinnacles and an uneven bedrock structure,
underground drainage and caves. Karst is formed on carbonate rocks,
such as limestone or dolomite.
Any of the following activities:
The improvement of one lot or two or more contiguous lots, tracts
or parcels of land for any purpose involving: i) 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 of tenure; or ii) 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.
A subdivision of land.
Development in accordance with Section 503(1.1) of the Pennsylvania
Municipalities Planning Code.[2]
The ratio of the land area draining to the system, as modified by the weighting factors in § 219-20B compared to the base area of the infiltration system.
Any natural channel or man-made conveyance system which has
the purpose of transporting runoff from the site to the mainstem.
A development approach that promotes practices that will
minimize postdevelopment 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.
Any stream segment or other conveyance used as a reach in
the Monocacy Creek hydrologic model.
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.
A stormwater design manual written by the Maryland Department
of the Environment and the Center for Watershed Protection. The Manual
can be obtained through the following web site: www.mde.state.md.us.
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 postdevelopment. 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 shall include provisions
(e.g., deed restrictions, conservation easements) to protect these
areas from future disturbance and from application of fertilizers,
pesticides and herbicides.
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.
National Pollutant Discharge Elimination System.
Natural Resources Conservation Service U.S. Department of
Agriculture (formerly the Soil Conservation Service).
A structural mechanism designed to remove free oil and grease
(and possibly solids) from stormwater runoff.
"Point source" as described in 40 CFR 122.2 at the point
where the municipality's storm sewer system discharges to waters
of the commonwealth.
One with an interest in and often dominion over a property.
The maximum rate of flow of stormwater runoff at a given
location and time resulting from a specified storm event.
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.
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.
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 G.[3]
Measures implemented for hot spot land uses designed to reduce
the concentration of hydrocarbons, trace metals and other toxic substances
to levels typically found in stormwater runoff.
A person who owns or operates a 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.)
A licensed professional geologist or a licensed professional
engineer who has a background or expertise in geology or hydrogeology.
A method of 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
for peak rate calculation 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[4]), "i" is the rainfall intensity in inches per hour, and
"A" is the area of the tract in acres. The Rational Method formula
for runoff volume calculation is as follows: V = cPA/12, where "c"
and "A" are as noted above, "P" is the total depth of precipitation
for the design event in inches, and "V" is the total runoff volume
in acre-feet.
Any of the natural or man-made runoff conveyance channels
used for watershed runoff modeling purposes to connect the subareas
and transport flows downstream.
All activities that may affect stormwater runoff, including
land development and earth disturbance activity, which are subject
to regulation by this chapter.
The percentage of the predevelopment peak rate of runoff
for a development site to which the postdevelopment peak rate of runoff
must be controlled to avoid peak flow increases throughout the watershed.
An expression of the intensity of an event based on its statistical
chance of being equaled or exceeded in any given year. An event with
a 1% chance in any given year is stated to have a 100-year return
period. An event with a 50% chance is stated to have a two-year return
period. Over a very long period of record, events might be expected
to recur on average in accordance with their return period.
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.
That part of precipitation which flows over the land.
A BMP designed for essentially the full volume of runoff
entering the BMP to be discharged off site.
Chambers which provide storage below the outlet in a storm
inlet to collect sediment, debris and associated pollutants, typically
requiring periodic clean out.
An area of excavated earth filled with loose stone or similar
material and into which surface water is directed for infiltration
into the ground.
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.
Stormwater runoff flowing in a thin layer over the ground
surface.
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."
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 noncarbonate bedrock which may exist and must be identified on
a site when stormwater management BMPs are being considered.
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.
As defined under state regulations protection of designated
and existing uses (See 25 Pa. Code Chapters 93 and 96) including:
Each stream segment in Pennsylvania has a "designated use,"
such as "cold water fishes" or "potable water supply," which is listed
in 25 Pa. Code Chapter 93. These uses must be protected and maintained,
under state regulations.
"Existing uses" are those attained as of November 1975, regardless
whether they have been designated in 25 Pa Code 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.
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.
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.
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[7] of this chapter or identified by the municipality or municipal
engineer.
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.
The surface runoff generated by precipitation reaching the
ground surface.
Wells for injection of stormwater to the subsurface that
are regulated by the U.S. Environmental Protection Agency to protect
underground sources of drinking water.
Any number of structural mechanisms such as multichamber
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 clean out.
The plan for managing stormwater runoff adopted by Lehigh
and/or Northampton County for the Monocacy Creek Watershed as required
by the Act of October 4, 1978, P.L. 864, (Act 167), as amended, and
known as the Stormwater Management Act.[8]
A watercourse.
The smallest unit of watershed breakdown for hydrologic modeling
purposes for which the runoff control criteria have been established
in the stormwater management plan.
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.
Perennial and intermittent streams, rivers, lakes, reservoirs,
ponds, wetlands, springs, natural seeps and estuaries, excluding water
at facilities approved for wastewater treatment such as wastewater
treatment impoundments, cooling water ponds and constructed wetlands
used as part of a wastewater treatment process.
A low-lying stretch of land which gathers or carries surface
water runoff. See also "vegetated swale."
The report written by Cahill Associates that addresses the
feasibility of infiltration in carbonate bedrock areas in the Little
Lehigh Creek Watershed. The report is available at the Lehigh Valley
Planning Commission offices.
Earth disturbance activities, including the construction
of skid trails, logging roads, landing areas and other similar logging
or silvicultural practices.
Racks, screens or other similar devices installed in a storm
drainage system to capture coarse pollutants (trash, leaves, etc.).
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. As water quality BMPs, vegetated
buffers serve to filter pollutants from runoff and promote infiltration.
Vegetated buffers should be situated on minimally disturbed soils,
have low-flow velocities and extended residence times. Vegetated buffers
may be, but are not restricted to, use in riparian (streamside) conditions.
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 earthen channels designed to convey and possibly
treat stormwater. As water quality BMPs, these are broad, shallow,
densely vegetated, earthen channels designed to treat stormwater through
infiltration, evapotranspiration, and sedimentation. Swales should
be gently sloping with low-flow velocities to prevent erosion. Check
dams may be added to enhance performance.
A BMP designed to provide vegetative uptake and soil renovation
or surface infiltration of runoff. Capture/reuse BMPs are included
if the captured runoff is applied to vegetated areas. Examples include
bioretention and surface infiltration basins.
Any number of commercially available devices that are inserted
into storm inlets to capture sediment, oil, grease, metals, trash,
debris, etc.
The increase in runoff volume on a development site associated
with a two-year, twenty-four-hour storm event.
Any channel of conveyance of surface water having defined
bed and banks, whether natural or artificial, with perennial or intermittent
flow.
Any and all rivers, streams, creeks, rivulets, impoundments,
ditches, watercourses, storm sewers, lakes, dammed water, wetlands,
ponds, springs and all other bodies or channels of conveyance of surface
water, or parts thereof, whether natural or artificial, within or
on the boundaries of this commonwealth.
The entire region or area drained by a river or other body
of water, whether natural or artificial.
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.
[1]
Editor's Note: Appendix H is on file in the Township
offices.
[2]
Editor's Note: See 53 P.S. § 10503(1.1).
[3]
Editor's Note: Appendix G is on file in the Township
offices.
[4]
Editor's Note: Appendix C is on file in the Township
offices.
[5]
Editor's Note: Chapter 92 of Title 25 of the Pennsylvania
Code was reserved 10-8-2010, effective 10-9-2010. It was replaced
by Chapter 92a, National Pollutant Discharge Elimination System (NPDES)
Permitting, Monitoring and Compliance.
[6]
Editor's Note: See 35 P.S. § 691.1 et seq.
[7]
Editor's Note: Appendix B is on file in the Township
offices.
[8]
Editor's Note: See 32 P.S. § 680.1 et seq.
