[Ord. No. 1177, 11/1/2022]
1.
For all regulated activities, unless preparation of an SWM site plan is specifically exempted in § 26-113:
A.
Preparation and implementation of an approved SWM site plan is required
meeting the following:
(1)
Minor Land Disturbance. An application for a stormwater management
permit for a minor land disturbance, as defined in this Part, shall
include:
(b)
Three paper copies and one electronic PDF of the stormwater management plan (see § 26-118 for plan contents).
(c)
Filing fee in the amount specified in the fee schedule as established
by resolution or ordinance of the Borough Council.
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In the event the review of the minor land disturbance permit
application reveals the potential for impacts to downstream properties,
the Borough may require the applicant to submit additional information
to demonstrate compliance with the requirements of this Part. Such
information may include portions or all of the requirements for a
major land disturbance.
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(2)
Major Land Disturbance. An application for a stormwater management
permit for a major land disturbance activity, as defined in this Part,
shall include the following items:
B.
No regulated activities shall commence until the municipality issues
written approval of an SWM site plan, which demonstrates compliance
with the requirements of this Part.
2.
SWM site plans approved by the municipality, in accordance with § 26-123, shall be on site throughout the duration of the regulated activity.
3.
The municipality may, after consultation with DEP, approve measures
for meeting the state water quality requirements other than those
in this Part, provided that they meet the minimum requirements of,
and do not conflict with, state law, including, but not limited to,
the Clean Streams Law.[3]
[3]
Editor's Note: See 35 P.S. § 691.1 et seq.
4.
For all regulated earth disturbance activities, erosion and sediment
control BMPs shall be designed, implemented, operated, and maintained
during the regulated earth disturbance activities (e.g., during construction)
to meet the purposes and requirements of this Part and to meet all
requirements under Title 25 of the Pennsylvania Code and the Clean
Streams Law.[4] Various BMPs and their design standards are listed in
the Erosion and Sediment Pollution Control Program Manual (E&S
Manual[5]), No. 363-2134-008, as amended and updated.
5.
Impervious Areas.
A.
The measurement of impervious areas shall include all of the impervious
areas in the total proposed development even if development is to
take place in stages.
B.
For development taking place in stages, the entire development plan
must be used in determining conformance with this Part.
C.
For projects that add impervious area to a parcel, the total impervious area on the parcel is subject to the requirements of this Part; except that the volume controls in § 26-114 and the peak rate controls of § 26-115 do not need to be retrofitted to existing impervious areas that are not being altered by the proposed regulated activity.
6.
Stormwater flows onto adjacent property shall not be created, increased,
decreased, relocated, or otherwise altered without written notification
to the adjacent property owner(s). Such stormwater flows shall be
subject to the requirements of this Part.
7.
All regulated activities shall include such measures as necessary
to:
A.
Protect health, safety, and property.
B.
Meet the water quality goals of this Part by implementing measures
to:
(1)
Minimize disturbance to floodplains, wetlands, and wooded areas.
(2)
Maintain or extend riparian buffers.
(3)
Avoid erosive flow conditions in natural flow pathways.
(4)
Minimize thermal impacts to waters of this commonwealth.
(5)
Disconnect impervious surfaces by directing runoff to pervious
areas, wherever possible.
C.
Incorporate methods described in the Pennsylvania Stormwater Best
Management Practices Manual (BMP Manual[6]). If methods other than green infrastructure and LID methods
are proposed to achieve the volume and rate controls required under
this Part, the SWM site plan must include a detailed justification
demonstrating that the use of LID and green infrastructure is not
practicable.
8.
The design of all facilities over karst shall include an evaluation
of measures to minimize adverse effects, prepared by a qualified professional.
9.
Infiltration BMPs should be spread out, made as shallow as practicable,
and located to maximize use of natural on-site infiltration features
while still meeting the other requirements of this Part.
10.
Normally dry, open top, storage facilities should completely drain
both the volume control and rate control capacities over a period
of time not less than 24 and not more than 72 hours from the end of
the design storm.
11.
The design storm volumes to be used in the analysis of peak rates
of discharge should be obtained from the latest version of the Precipitation-Frequency
Atlas of the United States, National Oceanic and Atmospheric Administration
(NOAA), National Weather Service, Hydrometeorological Design Studies
Center, Silver Spring, Maryland.
NOAA's Atlas 14[7] can be accessed at: http://hdsc.nws.noaa.gov/hdsc/pfds/.
[Ord. No. 1177, 11/1/2022]
1.
Regulated activities that result in cumulative earth disturbances or new impervious areas listed below are exempt from the requirements in § 26-114, § 26-115, and Subpart D of this Part, subject to the following:
A.
New impervious areas or land disturbance areas shall not exceed the
following based on total lot area:
|
Parcel Size
(Acre)
|
Land Disturbance Area
|
New Impervious Area
|
|---|---|---|
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< 0.5
|
< 10,000 S.F.
|
< 1,000 S.F.
|
|
0.5 - 1.0
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< 10,000 S.F.
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< 1,500 S.F.
|
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1.0 or greater
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< 43,560 S.F.
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< 2,000 S.F.
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B.
All concentrated discharges from downspouts, pipes or channels shall
be set back a minimum of 10 feet from the property line and/or public
right-of-way and provide for diffused flow at the property line.
2.
Agricultural activity is exempt from the SWM site plan preparation
requirements of this Part provided the activities are performed according
to the requirements of 25 Pa. Code Chapter 102.
3.
Forest management and timber operations are exempt from the SWM site
plan preparation requirements of this Part provided the activities
are performed according to the requirements of 25 Pa. Code Chapter
102.
5.
The municipality may deny or revoke any exemption pursuant to this
section at any time for any project that the municipality believes
may pose a threat to public health and safety or the environment.
[Ord. No. 1177, 11/1/2022]
The green infrastructure and low-impact development practices
provided in the BMP Manual[1] shall be utilized for all regulated activities wherever
possible. Water volume controls shall be implemented using the Design
Storm Method in Subsection 1 or the Simplified Method in Subsection
2, below. For regulated activity areas equal or less than one acre
that do not require hydrologic routing to design the stormwater facilities,
this Part establishes no preference for either methodology; therefore,
the applicant may select either methodology on the basis of economic
considerations, the intrinsic limitations on applicability of the
analytical procedures associated with each methodology and other factors.
1.
The Design Storm Method (CG-1 in the BMP Manual[2]) is applicable to any size of regulated activity. This
method requires detailed modeling based on site conditions.
A.
Do not increase the postdevelopment total runoff volume for all storms
equal to or less than the two-year twenty-four-hour-duration precipitation.
2.
The Simplified Method (CG-2 in the BMP Manual[3]) provided below is independent of site conditions and
should be used if the Design Storm Method is not followed. This method
is not applicable to regulated activities greater than one acre or
for projects that require design of stormwater storage facilities.
For new impervious surfaces:
A.
Stormwater facilities shall capture at least the first two inches
of runoff from all new impervious surfaces.
B.
At least the first one inch of runoff from new impervious surfaces
shall be permanently removed from the runoff flow, i.e., it shall
not be released into the surface waters of this commonwealth. Removal
options include reuse, evaporation, transpiration, and infiltration.
C.
Wherever possible, infiltration facilities should be designed to
accommodate infiltration of the entire permanently removed runoff;
however, in all cases at least the first 0.5 inch of the permanently
removed runoff should be infiltrated.
[Ord. No. 1177, 11/1/2022]
1.
For areas not covered by a release rate map from an approved Act
167 Stormwater Management Plan:
A.
Postdevelopment discharge rates shall not exceed the predevelopment
discharge rates for the one-, two-, five-, ten-, twenty-five-, fifty-,
and 100-year, twenty-four-hour storm events. If it is shown that the
peak rates of discharge indicated by the postdevelopment analysis
are less than or equal to the peak rates of discharge indicated by
the predevelopment analysis for one-, two-, five-, ten-, twenty-five-,
fifty-, and 100-year, twenty-four-hour storms, then the requirements
of this section have been met. Otherwise, the applicant shall provide
additional controls as necessary to satisfy the peak rate of discharge
requirement.
2.
For areas covered by a release rate map from an approved Act 167
Stormwater Management Plan:
A.
For the one-, two-, five-, ten-, twenty-five-, fifty-, and 100-year,
twenty-four-hour storm events, the postdevelopment peak discharge
rates will follow the applicable approved release rate maps. For any
areas not shown on the release rate maps, the postdevelopment discharge
rates shall not exceed the predevelopment discharge rates.
[Ord. No. 1177, 11/1/2022]
1.
In order to protect and improve water quality, a riparian buffer
easement shall be created and recorded as part of any subdivision
or land development that encompasses a riparian buffer.
3.
Minimum Management Requirements for Riparian Buffers.
A.
Existing native vegetation shall be protected and maintained within
the riparian buffer easement.
B.
Whenever practicable invasive vegetation shall be actively removed,
and the riparian buffer easement shall be planted with native trees,
shrubs and other vegetation to create a diverse native plant community
appropriate to the intended ecological context of the site.
4.
The riparian buffer easement shall be enforceable by the municipality
and shall be recorded in the appropriate County Recorder of Deeds
Office, so that it shall run with the land and shall limit the use
of the property located therein. The easement shall allow for the
continued private ownership and shall count toward the minimum lot
area as required by zoning, unless otherwise specified in the municipal
Zoning Ordinance.[2]
5.
Any permitted use within the riparian buffer easement shall be conducted
in a manner that will maintain the extent of the existing 100-year
floodplain, improve or maintain the stream stability, and preserve
and protect the ecological function of the floodplain.
7.
Septic drainfields and sewage disposal systems shall not be permitted
within the riparian buffer easement and shall comply with setback
requirements established under 25 Pa. Code Chapter 73.
[Ord. No. 1177, 11/1/2022]
1.
Collection and Conveyance Facilities.
A.
The design of stormwater management collection and conveyance facilities
that service drainage areas within the site shall be based upon the
peak flow from a twenty-five-year storm frequency event.
B.
All developments shall include design provisions that allow for the
overland conveyance of the postdevelopment 100-year peak flows through
the site without damage to any private or public property.
C.
Method of Calculations. Runoff calculations for on-site stormwater
conveyance facilities shall be based upon the Rational Method or an
acceptable engineering design method, subject to Borough approval.
D.
Criteria, Methodology and Assumptions. Appropriate values for runoff
coefficients, time of concentration, and rainfall intensity shall
be from the latest edition of the Commonwealth of Pennsylvania, Department
of Transportation Design Manual, Part 2, Highway Design, Chapter 10.
Use of other criteria, methodology, assumptions, references, calculation
methods and/or computer modeling may be accepted, provided detailed
design information and programming with references are submitted and
approved by the Borough.
2.
Stormwater Basins.
A.
The peak discharges and volumes of runoff may be determined by using
the latest version of Technical Release No. 55, Urban Hydrology for
Small Watersheds, or an acceptable engineering method, subject to
Borough approval.
B.
Retention basins and detention basins shall be designed with a minimum
one foot freeboard above the design elevation of the 100-year water
surface at the emergency spillway. Additionally, basins shall be designed
to safely discharge the full 100-year peak discharge of a postdevelopment
storm event through an emergency spillway in a manner which will not
damage the integrity of the basin. Basins shall not be located over
any existing or proposed utility line. Infiltration facilities with
a depth of 18 inches or less shall not be subject to this requirement.
C.
Stormwater basins located in known sinkhole-prone areas are required
to be lined to prevent infiltration into the ground, unless intended
to be infiltration facilities.
D.
Basins shall be constructed and maintained to ensure the design capacity
after sedimentation has taken place.
E.
Basin discharge outlets shall be designed to release runoff in a
condition which reflects predevelopment characteristics.
F.
Basins which are not designed to release all stormwater shall be
specifically identified as retention basins or permanent pond basins.
All surface basins shall have provisions for de-watering, particularly
the bottom, and shall not create swampy and/or unmaintainable conditions.
G.
Discharge structures shall be designed to eliminate the possibility
of blockage during operation.
H.
Basins which are located in or adjacent to a residential zone and
viewed by the Borough as a potential hazard to the public safety shall
be completely surrounded by a fence or wall of not less than four
feet in height.
I.
Earth Fill Dams. Basins which are designed with earth fill dams shall
be designed by a registered professional engineer with experience
in earth-filled dams and shall incorporate the following minimum standards:
(1)
The maximum water depth (measured from the base to the crest
of the emergency spillway) shall not exceed six feet, unless approved
by waiver of the Borough.
(2)
The minimum top width of all dams shall be five feet, unless
approved by waiver of the Borough.
(3)
The side slopes of earth fill dams shall not be steeper than
three horizontal to one vertical on both sides of the embankment.
(4)
Basins without restricted access shall have impoundment areas
with side slopes no greater than five horizontal to one vertical.
(5)
A cutoff trench of impervious material shall be provided under
all dams.
(6)
All pipes and culverts through dams shall be reinforced concrete
or HDPE and have properly spaced concrete cutoff collars.
(7)
All outlet structures shall be reinforced concrete.
(8)
Minimum floor elevations for all structures that would be affected
by a basin, other temporary impoundments, or open conveyance systems
where ponding may occur shall be two feet above the 100-year water
surface elevation and/or one foot above the 500-year water surface
elevation. If basement or underground facilities are proposed, detailed
calculations addressing the effects of stormwater ponding on the structure
and waterproofing and/or floodproofing design information shall be
submitted for approval.
J.
The Borough may, upon recommendation of the Borough Engineer, impose
additional requirements on earth fill dams for the safety and welfare
of the Borough.
3.
Pipe and Swale Design.
A.
The capacity of gutters, inlets, culverts, outlet structures and
swales shall consider all possible hydraulic conditions. The following
are minimum design standards.
(1)
Grass swales and roadside gutters shall consider both the channel
velocity and stability.
(2)
The "n" factors to be used for paved or rip-rap swales or gutters
shall be based on the latest edition of the Pennsylvania Department
of Transportation Design Manual, Part 2, Highway Design, Chapter 10.
(3)
The "n" factors for corrugated metal pipe shall be based upon
the manufacturer's standard.
(4)
The velocity to be used in the design of any piped stormwater
conveyance system shall be a minimum of 2 1/2 feet per second.
(5)
Inlets, culverts, and basin discharge systems shall be designed
for the worst case condition. Inlet capacity shall be based on design
standards provided by the latest edition of the Pennsylvania Department
of Transportation's Design Manual, Part 2, Highway Design, Chapter
10. If acceptable information is not available, inlets in non-ponding
areas shall be designed for a maximum capacity of five cubic feet
per second. Where ponding occurs, inlet capacity shall be based on
accepted engineering design practices. Culvert design shall consider
either inlet/outlet control or a combination of hydraulic losses through
the system, whichever is greater. Basin discharge systems shall be
designed to the same standards as culverts. If it cannot be readily
determined which hydraulic condition controls, the basin discharge
rate shall be based on the highest possible discharge rating curve,
with the basin capacity sized to store the excessive storm runoff,
based on the lowest possible discharge rating curve.
B.
Stormwater Flow Along Streets and Access Drives. Inlets shall be
along the curbline and are not permitted along the curb radius at
an intersection. When possible, inlets shall be located away from
the side lot property line to avoid conflicts with driveways. For
the purpose of inlet placement, curb, gutter, or roadside swale, flow
depths for a ten-year storm frequency with a five-minute duration
shall not exceed three inches in a swale condition, two inches in
a gutter condition, and one-half inch across intersections and travel
lanes. In no case shall inlets be spaced more than 600 feet apart
and function at less than 65% efficiency based on the criteria in
the PennDOT Design Manual.
C.
Manhole Locations. Manholes shall not be spaced more than 500 feet
apart. Additionally, manholes shall be placed at points of changes
in the horizontal or vertical direction of storm sewers. Inlets may
be substituted for manholes where they will serve a useful purpose.
D.
Alignment Requirement. If less than a forty-eight-inch diameter,
curves in pipes or box culverts without an inlet or manhole are prohibited.
T-joints, elbows, and wyes are always prohibited on piping 12 inches
or greater.
E.
Minimum Pipe Size. Stormwater management pipe collection and conveyance
systems shall have a minimum diameter of 15 inches.
F.
Material Specifications. All materials and installations must be
approved for use by the Borough Engineer and comply with the Borough
Specification Manual.
G.
Surface Flow Characteristics. The maximum swale, gutter, or curb
velocity of stormwater runoff shall be maintained at levels which
result in a stable condition both during and after construction. The
following are considered characteristics of a stable condition:
(1)
It neither aggrades nor degrades beyond tolerable limits.
(2)
The channel banks do not erode to the extent that the channel
cross section is changed appreciably.
(3)
Sediment bars do not develop.
(4)
Erosion does not occur around culverts and bridges or elsewhere.
(5)
Gullies do not form or enlarge due to the entry of uncontrolled
stormwater runoff.
(6)
Grass-lined channels shall be considered stable if the calculated
velocity does not exceed the allowable velocities shown below:
(a)
Three feet per second where only sparse vegetation can be established
and maintained because of shade or soil condition.
(b)
Four feet per second where normal growing conditions exist and
vegetation is to be established by seeding.
(c)
Five feet per second where a dense, vigorous sod can be quickly
established or where water can be temporarily diverted during establishment
of vegetation. Netting and mulch or other equivalent methods for establishing
vegetation shall be used.
(d)
Six feet per second where there exists a well-established sod
of good quality.
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Where swale bends occur, the allowable velocities listed above
shall be divided by the following factors:
|
|
Degree of Bend
|
Velocity
|
|---|---|
|
0 to 30
|
1.50
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30 to 60
|
1.75
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60 to 90
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2.00
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90 and over
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2.50
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The above grass-lined channel flows may be exceeded if the designer
can provide acceptable supportive design criteria as proof of erosion
prevention.
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H.
Where the velocity of stormwater runoff exceeds the allowable velocity,
erosion protection must be provided. The method of erosion protection
proposed must be supported by the appropriate design information and/or
references.
I.
Sump pump discharges and roof drains will be directed to lawn areas
away from residences, into areas that will surface drain to conveyance
structures (e.g., swales and storm sewer collection systems).
4.
Erosion and Sedimentation.
A.
All land disturbance facilities shall conform to the requirements
of the Cumberland County Conservation District and the Pennsylvania
Department of Environmental Protection, and with the following provisions:
B.
A Pennsylvania Department of Environmental Protection "NPDES Construction
Activities" permit in compliance with 25 Pa. Code Chapter 92 is required
for any earth disturbance of one acre regardless of the planned runoff
(hereinafter collectively referred to as "regulated earth disturbance
activities"). This includes earth disturbance on any portion of, part
of, or during any stage of, a larger common plan of development.
C.
Evidence of any necessary permit(s) for regulated earth disturbance activities from the appropriate DEP regional office or County Conservation District must be provided to the Borough. The issuance of an NPDES construction permit [or permit coverage under the statewide General Permit (PAG-2)] satisfies the requirements of Subsection 4A.
D.
A copy of the erosion and sediment control plan and any required
permit, as required by DEP regulations, shall be always available
at the project site.
E.
The following principles shall be applied to the design plan and
construction schedule to minimize soil erosion and sedimentation.
(1)
Stripping of vegetation, grading, or other soil disturbance
shall be done in a manner which will minimize soil erosion.
(2)
Whenever feasible, natural vegetation shall be retained and
protected.
(3)
The extent of the disturbed area and the duration of its exposure
shall be kept to a minimum, within practical limits.
(4)
Either temporary seeding, mulching, or other suitable stabilization
measures shall be used to protect exposed critical areas during construction.
(5)
Drainage provisions shall accommodate the stormwater runoff
both during and after construction.
(6)
Soil erosion and sedimentation facilities shall be installed
prior to any on-site grading.
(7)
The design plan and construction schedule shall incorporate
measures to minimize soil erosion and sedimentation.
(8)
Retention and/or detention basins and water-carrying facilities
shall be stabilized in accordance with current engineering and Soil
Conservation Service practices.
F.
Floodplain. All stormwater management plans shall conform with the
floodplain standards specified in latest ordinance as amended.
G.
Easements. When considered appropriate, easements shall be provided
where stormwater or surface water drainage facilities are existing
or proposed, whether located within or beyond the boundaries of the
property. Easements for maintenance of pipes and culverts shall run
from outlet to inlet. Normal lot grading will not require easements.
Swales which receive runoff from more than one other lot must be provided
with an easement. Easements shall have a minimum width of 20 feet
and shall be adequately designed to provide area for: a) the collection
and discharge of water; b) the maintenance, repair, and reconstruction
of the drainage facilities; and c) the passage of machinery for such
work. When considered appropriate, easements shall include a description
of an ownership and maintenance program, in a recordable form, that
clearly sets forth responsibility for all temporary and permanent
stormwater management facilities.
5.
Ownership and Maintenance of Stormwater Management Facilities.
A.
The intent of these regulations is to provide private ownership and
maintenance of stormwater management facilities, erosion and sedimentation
control facilities and floodplain control facilities. Under no circumstances
does the Borough intend to accept dedication of erosion control and
sedimentation basins. The Borough does not encourage the dedication
of stormwater management facilities that are located outside public
street rights-of-way. Where the Stormwater Management Plan proposes
that the Borough own or maintain a stormwater management facility,
a description of the methods, procedures, and the extent of maintenance
shall be described in such an offer.
B.
Maintenance of all stormwater management facilities during development
shall be the sole responsibility of the developer and shall include,
but not be limited to:
(1)
Removal of silt from all basins, traps or other structures or
measures when 30% of capacity is filled with silt;
(2)
Periodic maintenance of temporary control facilities as described
in the soil erosion and sedimentation control plan such as replacement
of silt fencing, straw filters or similar measures;
(3)
Establishment or re-establishment of vegetation by seeding and
mulching or sodding of scoured areas or areas where vegetation has
not successfully been established;
(4)
Installation of necessary controls to correct unforeseen problems
caused by storm events within designed frequencies;
(5)
Removal of all temporary measures and installation of permanent
measures upon completion of the project; and
(6)
Requirements of the Pennsylvania Department of Environmental
Protection, Chapter 102 regulations.
C.
Ownership of all stormwater management facilities after construction
shall be the sole responsibility of the developer or the private landowner
as set forth in the plan. The only stormwater management facilities
which are to be controlled by the Borough shall be those facilities
which have been offered for dedication and accepted for dedication
by the Borough. Future offers for dedication can only be made for
facilities which meet current Borough specifications.
