These regulations are adopted and implemented to achieve the
following general purposes and objectives:
A. To manage stormwater runoff resulting from land alteration and disturbance
activities in accordance with Houston Borough Stormwater Management
Plan as adopted by the Houston Borough Municipality Supervisors.
B. To utilize and preserve the desirable existing natural drainage systems,
preserve the flood-carrying capacity of existing streams, and preserve
existing storm event water surface elevations in existing streams.
C. To encourage natural infiltration of rainfall to preserve groundwater
supplies and stream flows.
D. To provide for adequate maintenance of all permanent stormwater management
facilities in the municipality.
The municipality is empowered to regulate land use activities
that affect runoff and surface and groundwater quality and quantity
by the authority of:
A. Act of October 4, 1978, 32 P.S., P.L. 864 (Act 167) Section 680.1
et seq., as amended, the "Stormwater Management Act" (hereinafter
referred to as "the Act");
B. Water Resources Management Act of 2002, as amended;
C. Second Class Municipality Code, 53 P.S. Sections 66501 et seq., 66601
et seq., and the Borough Code, 53 P.S. Section 46201 et seq.;
D. Pennsylvania Municipalities Planning Code, Act 247, as amended.
The provisions of this chapter shall apply to all subdivision
and land developments unless specifically exempted on otherwise modified
herein.
The following activities are defined as "regulated activities"
and shall be regulated by this chapter unless exempted by § 253-5:
B. Subdivisions, where impermeable or less permeable surfaces, earth
disturbances, or other disturbance or manipulation of the stormwater
is performed;
C. Alteration of the natural hydrologic regime;
D. Construction of or addition of new impervious or semipervious surfaces
(i.e., driveways, parking lots, roads, etc.);
E. Construction of new buildings or additions to existing buildings;
G. Diversion piping or encroachments in any natural or man-made channel;
H. Nonstructural and structural stormwater management BMPs or appurtenances
thereto;
I. Earth disturbance activities of greater than 5,000 square feet.
NOTE 1: This chapter applies to any earth disturbance activity
greater than or equal to 5,000 square feet that is associated with
a development or redevelopment project. Earth disturbance activities
and associated stormwater management controls are also regulated under
existing state law and implementing regulations. This chapter shall
operate in coordination with those parallel requirements; the requirements
of this chapter shall be no less restrictive in meeting the purposes
of this chapter than state law. Table 102.1 summarizes the applicability
requirements of the chapter. "Proposed Impervious Surface" in Table
102.1 includes new, additional, or replacement impervious surface/cover.
Repaving existing surfaces without reconstruction does not constitute
replacement.
Table 102.1
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Chapter Applicability
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Chapter Article or Section
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Type of Project
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Proposed Impervious Surface
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Earth Disturbance
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0-5,000 square feet
|
5,000-10,000 square feet
(Small)
|
10,000 square feet to 1 Acre
(Large)
|
> 1 Acre
(Large)
|
0-5,000 square feet
|
5,000 to 10,000 square feet
(Small)
|
> 10,000 square feet
(Large)
|
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Stormwater management plan
|
Development
|
N/A
|
Modified to a drainage plan
|
Yes
|
Yes
|
N/A
|
Modified to a drainage plan
|
Yes
|
Nonstructural BMP practices in design
|
Development
|
N/A
|
Yes
|
Yes
|
Yes
|
Yes
|
Yes
|
Yes
|
Groundwater recharge
|
Development
|
N/A
|
Yes
|
Yes
|
Yes
|
Yes
|
N/A
|
Yes
|
Water quality requirements
|
Development
|
N/A
|
Yes
|
Yes
|
Yes
|
Yes
|
N/A
|
Yes
|
Stormwater peak rate control
|
All development and earth disturbance
|
N/A
|
Exempt
|
Yes
|
Yes
|
Yes
|
Yes
|
Yes
|
Erosion and sediment control plan submission to WCD
|
Development
|
N/A
|
Yes
|
Yes
|
Yes
|
Yes
|
Yes
|
Yes
|
|
Redevelopment
|
N/A
|
Yes
|
Yes
|
Yes
|
Yes
|
Yes
|
Yes
|
Legend:
|
Yes: stormwater management plan required.
|
N/A: not applicable; exempt from drainage plan submission.
|
Exempt: exempt from required section provision; drainage plan
submission may still be required if other section provisions are applicable
(yes in box).
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Modified: modified drainage plan required; sites with between
5,000 square feet and 10,000 square feet of proposed impervious surface
or earth disturbance must submit a drainage plan to the municipality.
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For the purposes of this chapter, these terms shall be defined
as follows:
APPLICANT
A landowner or developer, as defined by this chapter, who
has filed an application for development, including his/her heirs,
successors and assigns.
BMP (BEST MANAGEMENT PRACTICE)
Methods, measures, or practices used to prevent on reduce
surface runoff and/or water pollution, including, but not limited
to, structural and nonstructural stormwater management practices and
operation and maintenance procedures. See also "nonstructural best
management practice (BMP).
CHANNEL
A natural stream that conveys water; a ditch or open channel
excavated for the flow of water.
DBH (DIAMETER AT BREAST HEIGHT)
The location of standard measurement of a tree diameter in
accordance with the USDA Forest Service's Forest Inventory and
Analysis (FIA) program manual, available from that department, presently
measured at 4 1/2 feet from the ground surface.
DESIGN STORM
The magnitude of precipitation from a storm event measured
in probability of occurrence (e.g., twenty-five-year storm) and duration
(e.g., twenty-four-hour), and used in computing stormwater management
control systems.
DETENTION
The slowing, dampening, or attenuation of runoff entering
the natural drainage pattern or storm drainage system by temporarily
holding water in a detention basin, retention basin, reservoir on
rooftops, in streets, parking lots, or within the drainage system
itself, and releasing the water at a desired rate of discharge.
DETENTION BASIN
A facility designed to attenuate peak stormwater runoff by
storing and releasing the runoff at a predetermined rate. A detention
facility is designed to drain completely after a rainfall event. The
facility shall not hold any water for longer than 24 hours after the
peak discharge from the facility occurs.
DEVELOPER
Any landowner, agent of such landowner, or tenant with permission
of such landowner, who makes or causes to be made a subdivision of
land or land development.
DEVELOPMENT
Any activity, construction, alteration, or change in land
use, or similar action, that affects stormwater runoff characteristics.
DEVELOPMENT SITE
A lot, parcel, or tract of land on which development is taking
place or is proposed.
DISCHARGE
Rate of flow, specifically fluid flow. A volume of fluid
flowing from a conduit or channel, or being released from detention
storage, per unit of time, commonly expressed as cubic feet per second
(cfs), million gallons per day (mgd), gallons per minute (gpm), or
cubic meters per second (cms).
DRAINAGE
Interception and removal of excess surface water or groundwater
from land by artificial or natural means.
DRAINAGE AREA
The contributing area to a single drainage basin, expressed
in acres, square miles, or other units of area; also called a "catchment
area," "watershed," "or river basin"; the area served by a drainage
system or by a watercourse receiving stormwater and surface water.
DRAINAGE BASIN
The area from which water is carried off by the drainage
system; a watershed or catchment area.
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 land, including, but not limited to, clearing and grubbing,
grading, excavations, embankments, land development, agricultural
plowing or tilling, timber harvesting activities, road maintenance
activities, mineral extraction, and the moving, depositing, stockpiling,
or storing of soil, rock, or earth materials.
EMERGENCY SPILLWAY
A conveyance 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 process by which the surface of the land, including water/stream
channels, is worn away by water, wind, on chemical action.
EROSION AND SEDIMENT CONTROL PLAN
A plan that is designed to minimize accelerated erosion and
sedimentation. Said plan must be submitted to and approved by the
appropriate conservation district before construction can begin.
EXCEPTIONAL VALUE WATERS
Surface waters of high quality which satisfy Pennsylvania Code Title 25, Environmental Protection, Chapter
93, Water Quality Standards, § 93.4b(b) (relating to antidegradation).
FLOODPLAIN
A normally dry land area adjacent to stream channels that
is susceptible to being inundated by over bank stream flows. For regulatory
purposes, the Pennsylvania Flood Plain Management Act (Act of October
4, 1978, P.L. 851, No. 166) and regulations pursuant to the Act define the "floodplain"
as the area inundated by a 100-year flood and delineated on a map
by FEMA (Federal Emergency Management Agency) or by the applicant
in accordance with municipal ordinance requirements.
FLOODWAY
The channel of a watercourse, and those portions of the adjoining
floodplains, which are reasonably required to carry and discharge
the 100-year frequency flood. Unless otherwise specified, the boundary
of the floodway is as indicated on maps and flood insurance studies
provided by the Federal Emergency Management Agency (FEMA). In an
area where no FEMA maps or studies have defined the boundary of the
100-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-bank.
FREEBOARD
Measurement from a water surface elevation to the top of
a hydraulic structure, (e.g., detention/retention basin, inlets, manholes,
etc.).
HEC-RAS (HYDROLOGIC ENGINEERING CENTER)
Computer model developed by the Army Corps of Engineers to
perform one-dimensional hydraulic calculations for a full network
of natural and constructed channels.
HIGH-QUALITY WATERS
Surface waters having a level of 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).
HYDRAULICS
The branch of science concerned with the mechanics of fluids,
especially liquids. As applied in stormwater management, the study
of the characteristics of water flow in, and conveyance capacity of,
a channel, conduit or watercourse, considering such factors as depth,
velocity and turbulence.
HYDROLOGY
The science dealing with waters of the earth and their distribution
and circulation through the atmosphere. Engineering hydrology deals
with the application of hydrologic concepts to determine volume and
rate of runoff.
IMPERVIOUS SURFACE
A surface that prevents the infiltration of water into the
ground. Impervious surfaces include, but are not limited to, streets,
sidewalks, pavements, driveway areas, or roofs. Any surface areas
designed to be gravel or crushed stone shall be regarded as impervious
surfaces.
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 on 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 Section 503(1.1) of the PA Municipalities
Planning Code.
LAND DISTURBANCE
Any activity involving grading, tilling, digging or filling
or stripping of vegetation; or any other activity which causes land
to be exposed to the danger of erosion or changed water flow characteristics.
LANDOWNER
The legal or beneficial owner or owners of land, including
the holder of an option or contract to purchase (whether or not such
option or contract is subject to any condition), a lessee if he/she
is authorized under a lease agreement to exercise the rights of the
landowner, or other persons having a proprietary interest in land.
LARGE LAND DEVELOPMENT
A land development as defined in the regulated activities,
being larger than a small development.
NONPOINT SOURCE POLLUTION
Pollution that enters a water body from diffuse origins in
the watershed and does not result from discernible, confined, or discrete
conveyances.
NONSTORMWATER DISCHARGES
Water flowing in stormwater collection facilities, such as
pipes or swales, which is not the result of a rainfall event or snowmelt.
NONSTRUCTURAL BEST MANAGEMENT PRACTICE (BMP)
Methods of controlling stormwater runoff quantity and quality,
such as innovative site planning, impervious area and grading reduction,
protection of natural depression areas, temporary ponding or site,
and other techniques.
OUTFALL
Points or areas at which stormwater runoff leaves a structure
or site, which may include streams, storm sewers, swales or other
well-defined natural or artificial drainage features, as well as areas
of dispersed overland flows.
NRCS
Natural Resources Conservation Service, U.S. Department of
Agriculture.
OUTLET STRUCTURE
A structure designed to control the volume of stormwater
runoff that passes through it during a specific length of time.
PADEP
Pennsylvania Department of Environmental Protection.
PERFORMANCE STANDARD
A standard which establishes an end result or outcome which
is to be achieved but does not prescribe specific means for achieving
it. A "specification standard," in contrast, is one which prescribes
the exact characteristics to be used, leaving little choice to the
applicant. The release rate percentage is an example of a performance
standard; the design standards for storm sewers are specification
standards.
POINT OF INTEREST (CONTROL POINT)
A point of hydraulic concern, such as a bridge, culvert,
or channel section, for which the rate of runoff is computed or measured,
and usually located at the downstream limits of a subarea.
RATE OF RUNOFF
Instantaneous measurement of water flow expressed in a unit
of volume per unit of time, also referred to as "discharge," usually
stated in cubic feet per second (cfs) or gallons per minute (gpm).
RATIONAL METHOD
Defined method of using a process of calculation to determine
rainfall contributions from drainage basin stormwater runoff.
REGULATED EARTH DISTURBANCE ACTIVITY
Defined under NPDES Phase II regulations as earth disturbance
activity of one acre or more with a point source discharge to surface
waters or the municipality's storm sewer system on five acres
or more regardless of the planned runoff. This includes earth disturbance
on any portion of, part, or during any stage of a larger common plan
of development.
RELEASE RATE PERCENTAGE
The percentage of predevelopment peak rate of runoff from
a watershed subarea (as delineated in a watershed plan), which defines
the allowable post development peak discharge from any development
site in that subarea. The release rate percentage is determined by
computing the following ratio:
Subarea post development peak rate of runoff × 100 = Release
Rate Percentage Subarea predevelopment peak rate of runoff
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RETENTION-FACILITY
A facility designed to attenuate peak stormwater runoff while
maintaining a permanent pool of water, and releasing the remaining
runoff at a predetermined rate.
RUNOFF CHARACTERISTICS
The surface components of any watershed which affect the
rate, amount, and direction of stormwater runoff. These may include
but are not limited to: vegetation, soils, slopes, and man-made landscape
alterations.
SEASONAL HIGH-WATER TABLE (SHWT)
Soil zone where repeat water saturation has occurred as evident
from water level monitoring record, or by mottled (discolored due
to lack of oxygen) zones of soils exist.
SEDIMENT
Solid material, both mineral and organic, that is in suspension,
is being transported, or has been moved from its site or origin by
air, water, gravity, or ice and has come to rest on the earth's
surface.
SLOPE (or PERCENT SLOPE)
To diverge from the vertical on horizontal; incline. The
amount on degree of such deviation. An inclined line, surface, plane,
position, or direction.
SMALL DEVELOPMENT
Any subdivision, land development, or development which results,
or will result when fully constructed, in the creation of an aggregate
total of 10,000 square feet, or less, of additional impervious surface
area from the date of this chapter.
SOIL COVER COMPLEX METHOD
A method or runoff computation developed by the U.S. Natural
Resources Conservation Service and found in its publication "Urban
Hydrology for Small Watersheds," Technical Release No. 55, NRCS, January
1975 (or most current edition).
STATE WATER QUALITY REQUIREMENTS
As defined under state regulations: protection of designated and existing uses (see 25 Pennsylvania Code Chapters
93 and 96), including:
A.
Each stream segment in Pennsylvania has a designated use, such as cold water fishery 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
the 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, stream
bed, and structural integrity of the waterway to prevent these impacts.
STORM SEWER
An underground conduit that carries intercepted surface runoff,
street water, and other drainage, but excludes domestic sewage and
industrial wastes.
STORMWATER COLLECTION/CONVEYANCE SYSTEM
Natural or engineered structures which collect and transport
stormwater through or from a drainage area to the point of final outlet,
including, but not limited to, any of the following: conduits and
appurtenant features, basins, canals, channels, ditches, streams,
culverts, streets and pumping stations.
STORMWATER MANAGEMENT PLAN
The plan for managing stormwater runoff from a specific development
site, prepared by a professional engineer registered to practice in
Pennsylvania.
STORMWATER RUNOFF
Waters resulting from snow melt on precipitation within a
drainage basin, flowing over the surface of the ground, collected
in channels and conduits, and carried by receiving streams.
SUBAREA
A portion of the watershed that has similar hydrological
characteristics and drains to a common point of interest.
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.
SURFACE WATERS OF THE COMMONWEALTH
Any and all rivers, streams, creeks, rivulets, ditches, watercourses,
storm sewers, lakes, dammed water, wetlands, ponds, springs, and all
other bodies or channels of conveyance of surface waters, or parts
thereof, whether natural or artificial, within or on the boundaries
of the commonwealth.
SWALE
A low-lying stretch of land which gathers or carries surface
water runoff.
TYPE II RAINFALL
Rainfall pattern and distribution of magnitude and duration,
defined by the US Natural Resources Conservation Service, defined
for a given geographical area of the United States, in the local geographical
area defined as a "Type II" pattern.
VOLUME OF STORMWATER RUNOFF
Quantity of water normally measured in inches, cubic feet,
or acre-feet, measured or determined analytically from:
B.
Rainfall/runoff ratios; and
C.
Areas underneath hydrographs.
WATERCOURSE (WATERWAY)
Any channel of conveyance of surface water having a defined
bed and banks, whether natural or artificial, with perennial or intermittent
flow.
WATERSHED
The entire region or area drained by a river or other body
of water whether natural or artificial. A "designated watershed" is
an area delineated by PADEP, and approved by the Environmental Quality
Board as one for which the county is required to prepare a watershed
stormwater management plan in accordance with the Pennsylvania Storm
Water Management Act.
WETLAND
Those areas that are inundated on 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. Wetlands
generally include swamps, marshes, bogs, fens, and similar areas.
WOODS
A natural ground cover with more than one viable tree of
a DBH of six inches or greater per 1,500 square feet which existed
within three years of application; a cover condition for which NRCS
curve numbers have been assigned, or to which equivalent Rational
Method runoff coefficients have been assigned.
The following permit requirements may apply to certain regulated
earth disturbance activities and must be met prior to commencement
of regulated earth disturbance activities, as applicable:
A. A Permit to construct the stormwater facilities as approved by the
municipality Council.
B. All regulated earth disturbance activities subject to permit requirements
by DEP under regulations at 25 Pennsylvania Code Chapter 102.
C. Work within natural drainageways subject to permit by DEP under 25
Pennsylvania Code Chapter 105.
D. Any stormwater management facility that would be located in or adjacent
to surface waters of the commonwealth, including wetlands, subject
to permit by DEP under 25 Pennsylvania Code Chapter 105.
E. Any stormwater management facility that would be located on a state
highway right-of-way or require access from a state highway shall
be subject to approval by PennDOT. In the case where a driveway entrance
is required from a state road to access stormwater facilities, a highway
occupancy permit and any further approval required by the PennDOT
will be applied and obtained by the applicant for the development.
F. Culverts, bridges, storm sewers, or any other facilities which must
pass or convey flows from the tributary area and any facility which
may constitute a dam subject to permit by DEP under 25 Pennsylvania
Code Chapter 105.
Upon providing adequate financial guarantees, as outlined in Chapter
248, Subdivision and Land Development, and after the municipality has issued a permit and the notice to proceed, the applicant may commence to install or implement the approved stormwater management controls, subject to the provisions of §
235-14B(6) as above. If site development or building construction does not begin within two years of the date of the final approval of the subdivision or land development plan, then before doing so, the applicant shall resubmit the stormwater management plans to verify that no condition has changed within the watershed that would affect the feasibility or effectiveness of the previously approved stormwater management controls. Further, if for any reason development activities are suspended for two years or more, then the same requirement for resubmission of the stormwater management plan shall apply.
It shall be unlawful to alter or remove any permanent stormwater
control and BMP required by an approved stormwater control and BMP
operations and maintenance plan or to allow the property to remain
in a condition which does not conform to an approved stormwater control
and BMP operations and maintenance plan.
The provisions of this chapter are severable, and if any of
its provisions or any part of any provision shall be held unconstitutional,
the decision of the court shall not affect or impair any of the remaining
provisions. It is hereby declared to be the intent of the municipality
Supervisors that this chapter would have been enacted had such unconstitutional
provisions or parts thereof not been included herein.