[Ord. 954, 12/19/2013]
1.
Preparation of an SWM site plan is required for all regulated activities,
unless preparation and submission of the SWM site plan is specifically
exempted according to § 401 or the activity qualifies as
a small project.
2.
No regulated activities shall commence until the Borough of Elizabethtown
issues unconditional written approval of a land disturbance plan in
the form of a stormwater permit.
3.
SWM site plans approved by the Borough of Elizabethtown, in accordance
with § 406, shall be on site throughout the duration of
the regulated activity.
4.
The Borough may, after consultation with the DEP, approve measures
for meeting the state water quality requirements other than those
in this chapter, provided that they meet the minimum requirements
of, and do not conflict with, state law, including, but not limited
to, the Clean Streams Law. The Borough shall maintain a record of
consultations with the DEP pursuant to this subsection. Where an NPDES
permit for stormwater discharges associated with construction activities
is required, issuance of an NPDES permit shall constitute satisfaction
of consultation with the DEP. The applicant shall initiate and facilitate
all consultations between the DEP and the Borough.
5.
For all regulated activities, erosion and sediment control and stormwater
management BMPs shall be designed, implemented, operated and maintained
to meet the purposes and requirements of this chapter and to meet
all requirements under Title 25 of the Pennsylvania Code and the Clean
Streams Law. Various BMPs and their design standards are listed in
the E&S Manual, BMP Manual and § 307 of this chapter.
6.
Developers have the option to propose a regional stormwater management plan or participate in a regional stormwater management plan developed by others. A regional stormwater management plan may include off-site volume and rate control, as appropriate, and supported by a detailed design approved by the Borough in accordance with § 301, Subsection 4. A regional stormwater management plan must meet all of the volume and rate control standards required by this chapter for the area defined by the regional stormwater management plan, but not necessarily for each individual development site. Appropriate agreements must be established to ensure the requirements of this chapter and the requirements of the regional stormwater management plan are met.
7.
Unless prohibited by Chapter 27, Zoning, or Chapter 8, Floodplains, which regulates construction and development within the areas of the Borough subject to flooding, and any other applicable requirements of the Flood Plain Management Act,[1] stormwater management facilities located in the floodplain
are permitted when designed and constructed in accordance with the
provisions of the BMP Manual, regulatory requirements and the requirements
of this chapter.
[1]
Editor's Note: See 32 P.S. § 679.101 et seq.
8.
Impervious Areas.
A.
The measurement of impervious area shall include all of the impervious
areas in the total proposed development even if development is to
take place in stages or phases.
B.
For development taking place in stages or phases, the entire development
plan must be used in determining conformance with this chapter.
C.
Any areas designed to initially be gravel or crushed stone shall
be assumed to be impervious if subject to vehicular/pedestrian traffic.
9.
All regulated activities shall include such measures as necessary
to:
A.
Protect health, safety and property;
B.
Meet the water quality goals of this chapter by implementing measures
to:
(1)
Protect and/or improve the function of floodplains, wetlands
and wooded areas.
(2)
Protect and/or improve native plant communities, including those
within the riparian corridor.
(3)
Protect and/or improve natural drainageways from erosion.
(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 4). If methods other than green infrastructure
and LID methods are proposed to achieve the volume and rate controls
required under this chapter, the SWM site plan must include a detailed
justification demonstrating that the use of LID and green infrastructure
is not practicable.
[Added by Ord. No. 1004, 8/18/2022]
10.
The design of all stormwater management facilities over karst shall
include an evaluation of measures to minimize adverse effects and
to certify the following:
A.
No stormwater facilities shall be placed in, over or immediately
adjacent to the following features:
B.
Stormwater management facilities shall not be located closer than
100 feet from the rim of sinkholes or closed depressions, nor within
100 feet from disappearing streams; nor shall these facilities be
located closer than 50 feet from lineaments or fracture traces; nor
shall these facilities be located closer than 25 feet from surface
or identified subsurface pinnacles unless lined with an impermeable
liner or equivalent design as signed and sealed by a professional
geologist.
C.
Stormwater resulting from regulated activities shall not be discharged
into sinkholes.
D.
It shall be the developer's responsibility to verify if the
development is underlain by carbonate geology. The following certificate
shall be included on all stormwater site plans and shall be signed
and sealed by the developer's qualified professional consultant:
[Amended by Ord. No. 1004, 8/18/2022]
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"I, __________, certify that the proposed stormwater/BMP facility
(circle one) is/is not underlain by carbonate geology."
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E.
Whenever an SWM facility will be located in an area underlain by carbonate geology, a geological evaluation of the proposed location by a registered professional geologist shall be conducted to determine susceptibility to sinkhole formation. The evaluation may include the use of impermeable liners to reduce or eliminate the separation distances listed in Subsection 10A and B.
11.
Infiltration BMPs shall 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 chapter. Infiltration
BMPs shall include pretreatment BMPs unless shown to be unnecessary.
12.
Infiltration BMPs intended to receive runoff from developed areas
shall be selected based on suitability of soils and development site
conditions and shall be constructed on soils that have the following
characteristics:
A.
A minimum depth of 24 inches between the bottom of the facility and
the limiting zone. Modifications will be considered if it is demonstrated
to the satisfaction of the Borough that the selected BMP has design
criteria which allow for a smaller separation.
B.
A stabilized infiltration rate sufficient to accept the additional
stormwater load and drain completely as determined by field tests
conducted by the applicant's professional designer.
13.
The calculation methodology to be used in the analysis of volume
and peak rates of discharge shall be as required in § 305.
14.
A planting plan is required for all vegetated stormwater BMPs.
A.
Native or naturalized/noninvasive vegetation suitable to the soil
and hydrologic conditions of the development site shall be used unless
otherwise specified in the BMP Manual.
B.
Invasive vegetation may not be included in any planting schedule.
The List of Invasive Vegetation in Pennsylvania can be found on the
DCNR website at the following address: www.dcnr.state.pa.us/forestry/plants/invasiveplants/index.htm.
C.
The limit of existing, native vegetation to remain shall be delineated
on the plan along with proposed construction protection measures.
D.
Prior to construction, a tree protection zone shall be delineated
at the dripline of the tree canopy. All trees scheduled to remain
during construction shall be marked; however, where groups of trees
exist, only the tress on the outside edge need to be effectively marked
to promote protection of the trees during construction. No construction,
storage of material, temporary parking, pollution of soil, or regrading
shall occur within the tree protection zone.
E.
All planting shall be performed in conformance with good nursery
and landscape practice. Plant materials shall conform to the standards
recommended by the American Association of Nurseryman, Inc., in the
American Standard of Nursery Stock.
15.
To the maximum extent practicable, areas proposed for infiltration
BMPs shall be protected from sedimentation and compaction during the
construction phase to maintain maximum infiltration capacity, including
but not limited to fencing to limit construction traffic over the
infiltration area. Staging of earthmoving activities and selection
of construction equipment should consider this protection.
[Amended by Ord. No. 1004, 8/18/2022]
16.
To the maximum extent practicable, infiltration BMPs shall not be
constructed nor receive runoff from disturbed areas until the entire
contributory drainage area to the infiltration BMP has achieved final
stabilization.
[Amended by Ord. No. 1004, 8/18/2022]
17.
A minimum twenty-foot-wide access easement shall be provided for
all SWM facilities with tributary areas equal to or greater than 1,000
square feet and not located within a public right-of-way. Easements
shall provide for ingress and egress to a public right-of-way. This
shall be noted on the plan.
18.
Drainage easements shall be provided where the conveyance, treatment
or storage of stormwater, either existing or proposed, is identified
on the SWM site plan. Drainage easements shall be provided to contain
and convey the one-hundred-year frequency flood.
19.
The Borough may require additional stormwater control measures for
stormwater discharges to special management areas, including, but
not limited to:
A.
Water bodies listed as "impaired" on Pennsylvania's Clean Water Act
303(d)/305(b) Integrated List.
B.
Any water body or watershed with an approved total maximum daily
load (TMDL).
C.
Critical areas with sensitive resources (e.g., state-designated special
protection waters, cold-water fisheries, carbonate or other groundwater
recharge areas highly vulnerable to contamination, drainage areas
to water supply reservoirs, source water protection zones, etc.).
20.
Roof drains and sump pumps shall be tributary to surface infiltration
or vegetative BMPs. Use of catchment facilities for the purpose of
reuse is also permitted. When it is more advantageous to connect directly
to streets or storm sewers, roof drain connections to streets or roadside
ditches may be permitted on a case-by-case basis by the Borough. It
shall be the burden of the person seeking to make the connection to
demonstrate to the Borough that such connection is more advantageous
and such connection shall not violate any state or federal statute,
rule or regulation. Proposed storm sewer piping may connect to an
existing storm sewer piping system, provided the existing storm sewer
is adequate.
21.
Nonstructural BMPs shall be utilized for all regulated activities
unless proven to be impractical.
22.
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,
[Added by Ord. No. 1004, 8/18/2022]
[Ord. 954, 12/19/2013]
Volume control BMPs are intended to maintain existing hydrologic
conditions for small storm events by promoting groundwater recharge
and/or evapotranspiration as described in this section. Runoff volume
controls shall be implemented using the Design Storm Method described
in Subsection A below, or through continuous modeling approaches or
other means as described in the BMP Manual. Small projects may use
the method described in Subsection B to design volume control BMPs.
A.
The Design Storm Method is applicable to any size of regulated activity.
This method requires detailed modeling based on site conditions.
(1)
Do
not increase the post-development total runoff volume for all storms
equal to or less than the two-year, twenty-four-hour storm event.
(2)
For modeling purposes:
(a)
Existing (predevelopment), nonforested, pervious areas must
be considered meadow in good condition.
(b)
When the existing project site contains impervious area, 20%
of existing impervious area to be disturbed shall be considered meadow
in good condition in the model for existing conditions.
(c)
The maximum loading ratio for volume control facilities in karst
areas shall be 3:1 impervious drainage area to infiltration area and
5:1 total drainage area to infiltration area. The maximum loading
ratio for volume control facilities in nonkarst areas shall be 5:1
impervious drainage area to infiltration area and 8:1 total drainage
area to infiltration area. A higher ratio may be approved by the Borough
if justification is provided. Hydraulic depth may be used as an alternative
to an area-based loading ratio if the design hydraulic depth is shown
to be less than the depth that could result from the maximum area
loading ratio.
B.
Volume Control for Small Projects. At least the first one inch of
runoff from new impervious surfaces or an equivalent volume 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.
A detailed geologic evaluation of the development site shall be performed
in areas of carbonate geology to determine the design parameters of
recharge facilities. A report shall be prepared in accordance with
Section 504 of this chapter.
D.
Storage facilities, including normally dry, open-top facilities,
shall completely drain the volume control storage over a period of
time not less than 24 hours and not more than 72 hours from the end
of the design storm. Any designed infiltration at such facilities
is exempt from the minimum twenty-four-hour standard, i.e., may infiltrate
in a shorter period of time based on a field-tested infiltration rate,
provided that none of this water will be discharged into waters of
this commonwealth.
E.
Any portion of the volume control storage that meets all of the following
criteria may also be used as rate control storage:
(1)
Volume control storage that depends on infiltration is designed
according to the infiltration standards in § 301.
(2)
The volume control storage which will be used for rate control
is that storage which is available within 24 hours from the end of
the design storm based on the stabilized infiltration rate and/or
the evapotranspiration rate.
F.
Volume control storage facilities designed to infiltrate shall avoid
the least-permeable hydrologic soil group(s) at the development site.
[Ord. 954, 12/19/2013]
Rate control for large storms, up to the one-hundred-year event,
is essential to protect against immediate downstream erosion and flooding.
A.
Match Predevelopment Hydrograph. Applicants shall provide infiltration
facilities or utilize other techniques which will allow the post-development
one-hundred-year hydrograph to match the predevelopment one-hundred-year
hydrograph for the development site. To match the predevelopment hydrograph,
the post-development peak rate must be less than or equal to the predevelopment
peak rate, and the post-development runoff volume must be less than
or equal to the predevelopment volume for the same storm event.
B.
Where the predevelopment hydrograph cannot be matched, the post-development
discharge rates shall not exceed the predevelopment discharge rates
for the two-, ten-, twenty-five-, fifty- and one-hundred-year, twenty-four-hour
storm events.* If it is shown that the peak rates of discharge indicated
by the post-development analysis are less than or equal to the peak
rates of discharge indicated by the predevelopment analysis for two-,
ten-, twenty-five, fifty- and one-hundred-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.
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* A twenty-four-hour SCS Type II storm or an IDF Curve Rational
Method storm. (See Table 3-1 in § 305.)
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C.
Normally dry, open-top, storage facilities shall completely drain
the rate control storage over a period of time less than or equal
to 24 hours from the peak one-hundred-year water surface design elevation.
D.
A variety of BMPs should be employed and tailored to suit the development
site. The following is a partial listing of BMPs which can be utilized
in SWM systems for rate control where appropriate:
(1)
Decreased impervious surface coverage.
(2)
Routed flow over grass.
(3)
Grassed channels and vegetated strips.
(4)
Bioretention areas (rain gardens).
(5)
Concrete lattice block or permeable surfaces.
(6)
Seepage pits, seepage trenches or other infiltration structures.
(7)
Rooftop detention.
(8)
Parking lot detention.
(9)
Cisterns and underground reservoirs.
(10)
Amended soils.
(11)
Retention basins.
(12)
Detention basins.
(13)
Other methods as may be found in the BMP Manual.
E.
Small projects are not required to provide for rate control.
[Ord. 954, 12/19/2013]
1.
Runoff from impervious areas shall be drained to pervious areas within
the development site, unless the site has 85% or more impervious cover
and is a redevelopment,10 in which case
the portion of the site that discharges to pervious areas shall be
maximized.
2.
Stormwater runoff from a development site to an adjacent property
shall flow directly into a natural drainageway, watercourse or into
an existing storm sewer system or onto adjacent properties in a manner
similar to the runoff characteristics of the predevelopment flow.
3.
Stormwater flows onto adjacent property shall not be created, increased,
decreased, relocated or otherwise altered without evidence of a written
certified letter of notification to the adjacent property owner(s)
by the developer. Such stormwater flows shall be subject to the requirements
of this chapter, including the establishment of a drainage easement.
Copies of all such notifications shall be included in land disturbance
plan submission.
4.
Existing on-site natural and man-made SWM facilities shall be used
to the maximum extent practicable.
5.
Stormwater runoff shall not be transferred from one subwatershed
to another unless they are subwatersheds of a common watershed that
join together within the perimeter of the development site and the
effect of the transfer does not alter the peak discharge onto adjacent
lands.
6.
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 one-hundred-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.
7.
All stormwater-conveyance facilities (excluding detention, retention,
and wetland basin outfall structures) shall be designed to convey
a twenty-five-year storm event.* All stormwater-conveyance facilities
(excluding detention, retention, and wetland basin outfall structures)
conveying water originating from off site shall be designed to convey
a fifty-year storm event.* The SWM report shall also provide calculations
verifying the safe conveyance of the one-hundred-year runoff event*
to appropriate peak rate control BMPs must be demonstrated in the
design.
* A twenty-four-hour SCS Type II storm or an IDF Curve Rational
Method storm.
8.
Erosion protection shall be provided along all open channels and
at all points of discharge. Flow velocities from any storm sewer may
not result in erosion of the receiving channel.
[Ord. 954, 12/19/2013]
1.
Any stormwater runoff calculations involving drainage areas greater
than 200 acres and time of concentration (Tc) greater than 60 minutes,
including on- and off-site areas, shall use generally accepted calculation
techniques based on the NRCS Soil-Cover-Complex Method.
2.
Stormwater runoff from all development sites shall be calculated
using either the Modified Rational Method, a Soil-Cover-Complex Methodology,
or other method acceptable to the Borough. Table 3-1 summarizes acceptable
computation methods. It is assumed that all methods will be selected
by the design professional based on the individual limitations and
suitability of each method for a particular development site.
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Table 3-1
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Acceptable Computation Methodologies for Stormwater Management
Plans
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|
Method
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Method Developed by
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Applicability
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TR-20 (or commercial computer package based on TR-20)
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USDA NRCS
|
Applicable where use of full hydrology computer model is desirable
or necessary
|
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Win TR-55 (or commercial computer package based on TR-55)
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USDA NRCS
|
Applicable for land development plans within limitations described
in TR-55
|
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HEC-1/HEC-HMS
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U.S. Army Corps of Engineers
|
Applicable where use of full hydrologic computer model is desirable
or necessary
|
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Rational Method (or commercial computer package based on Rational
Method)
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Emil Kuichling (1889)
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For development sites less than 200 acres, Tc<60 min. or
as approved by the Borough
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EFH2
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USDA NRCS
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Applicable in rural and undeveloped areas subject to the program
limits
|
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Other methods
|
Varies
|
Other methodologies approved by the Borough
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3.
If the SCS Method is used, Antecedent Moisture Condition 1 is to
be used in areas of carbonate geology, and Antecedent Moisture Condition
2 is to be used in all other areas. A Type II distribution shall be
used in all areas.
4.
If the Rational Method is used, the National Oceanic and Atmospheric Administration (NOAA) Atlas 14 data (see Subsection 2 above) or PennDOT Publication 584, "PennDOT Drainage Manual," shall be used to determine the rainfall intensity in inches per hour based on the information for the five- through sixty-minute duration storm events. (Refer to Appendix B-3).[1]
[1]
Editor's Note: Appendix B is included as an attachment to this chapter.
5.
Hydrographs may be obtained from NRCS methods such as TR-55, TR20
or from use of the "modified" or "unit hydrograph" rational methods.
If "modified" or "unit hydrograph" rational methods are used, the
ascending leg of the hydrograph shall have a length equal to three
times the time of concentration (3 x Tc), and the descending leg shall
have a length equal to seven times the time of concentration (7 x
Tc) to approximate an SCS Type II hydrograph.11
6.
Runoff calculations shall include a hydrologic and hydraulic analysis
indicating volume and velocities of flow and the grades, sizes and
capacities of water-carrying structures, sediment basins, retention
and detention structures and sufficient design information to construct
such facilities. Runoff calculations shall also indicate both predevelopment
and post-development rates for peak discharge of stormwater runoff
from all discharge points.
7.
For the purpose of calculating predevelopment peak discharges, all
runoff coefficients, both on-site and off-site, shall be based on
actual land use assuming summer or good land conditions. Post-development
runoff coefficients for off-site discharges used to design conveyance
facilities shall be based on actual land use assuming winter or poor
land conditions.
8.
Criteria and assumptions to be used in the determination of stormwater
runoff and design of management facilities are as follows:
A.
Runoff coefficients shall be based on the information contained in
Appendix B-1 and B-2 if the actual land use is listed in those appendixes.[2] If the actual land use is not listed in those appendixes,
runoff coefficients shall be chosen from other published documentation,
and a copy of said documentation shall be submitted with the SWM plan
for review and approval by the Borough.
[2]
Editor's Note: Appendix B is included as an attachment to this chapter.
B.
A sample worksheet for calculating Tc is provided in Appendix B-5.[3] Times of concentration (Tc) shall be based on the following
design parameters or as calculated by an approved hydraulic program:
(1)
Sheet Flow: The maximum length for each reach of sheet or overland
flow before shallow concentrated or open channel flow develops is
150 feet. Flow lengths greater than 100 feet shall be justified based
on the actual conditions at each development site. Sheet flow may
be determined using the nomograph in Appendix B-4 or Manning's kinematic
solution shown in the sheet flow section of Worksheet No. 1 in Appendix
B-5.[4]
[4]
Editor's Note: Appendix B is included as an attachment to this chapter.
(2)
Shallow Concentrated Flow: Travel time for shallow concentrated
flow shall be determined using Figure 3-1 from TR-55, Urban Hydrology
for small watersheds, as shown in Appendix B-6.[5]
[5]
Editor's Note: Appendix B is included as an attachment to this chapter.
(3)
Open Channel Flow: At points where sheet and shallow concentrated
flows concentrate in field depressions, swales, gutters, curbs or
pipe collection systems, the travel times to the downstream end of
the development site between these design points shall be based upon
Manning's Equation and/or acceptable engineering design standards
as determined by the Borough Engineer.
[3]
Editor's Note: Appendix B is included as an attachment to this chapter.
C.
The developer may use stormwater credits for nonstructural BMPs in
accordance with the BMP Manual. The allowable reduction will be determined
by the Borough.
D.
Peak rate control is not required for off-site runoff. Off-site runoff
may be bypassed around the site, provided all other discharge requirements
are met. If off-site runoff is routed through rate control facilities,
runoff coefficients for off-site discharges used to design those rate
control facilities shall be based on actual land use assuming winter
or poor land conditions.
9.
Times of concentration shall be calculated based on the methodology
recommended in the respective model used. Tc for channel and pipe
flow shall be computed using Manning's Equation. Supporting documentation
and calculations must be submitted for review and approval.
[Ord. 954, 12/19/2013]
1.
In order to protect and improve water quality, a riparian corridor
easement shall be created and recorded as part of any subdivision
or land development that encompasses a riparian corridor.
2.
Except as otherwise required by Chapter 102, the riparian corridor
easement shall be measured to be the greater of the limit of the one-hundred-year
floodplain or 35 feet from the top of stream bank (on each side).
3.
Minimum Management Requirements for Riparian Corridors.
A.
Existing native vegetation shall be protected and maintained within
the riparian corridor easement.
B.
Whenever practicable, invasive vegetation shall be actively removed
and the riparian corridor 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 corridor easement shall be enforceable by the Borough and shall be recorded in the Lancaster 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 continued private ownership and shall count toward the minimum lot area as required by Chapter 27, Zoning.
5.
Any permitted use (as listed below) within the riparian corridor
easement shall be conducted in a manner that will maintain the extent
of the existing one-hundred-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 corridor easement and shall comply with setback
requirements established under 25 Pa Code Chapter 73.
[Ord. 954, 12/19/2013]
1.
General.
A.
For all aboveground storage facilities, the bottom of the excavated
basin shall be a minimum of two feet or 24 inches above the seasonal
high water table or bedrock, or other limiting zone. Soil sampling,
test pits or auger testing must be completed in the proposed location
of the facilities in support of the design.
B.
Aboveground storage facilities without restricted access shall have
impoundment areas with side slopes no greater than five horizontal
to one vertical (5:1). Basins with side slopes steeper than five horizontal
to one vertical (5:1) shall be protected by fencing that will discourage
access.
C.
Aboveground storage facilities with a facility depth greater than
eight feet shall not be permitted in residential areas.
D.
Aboveground storage facilities with a facility depth greater than
15 feet require a dam permit from DEP.
E.
All pipe collars, when required, shall be designed in accordance with Chapter 7 of the E&S Manual. The material shall consist of concrete, or otherwise nondegradable material approved by the Borough Engineer, around the outfall barrel and shall be watertight.
F.
The embankment fill material shall be taken from an appropriate borrow
area, which shall be free of roots, stumps, wood, rubbish, stones
greater than six inches, or frozen or other objectionable materials.
G.
When required, embankments shall be compacted by sheepsfoot or pad
roller. The loose lift thickness shall be nine inches or less, depending
on roller size, and the maximum particle size is six inches or less
(2/3 of the lift thickness). Five passes of the compaction equipment
over the entire surface of each lift are required. Embankment compaction
to visible nonmovement is also required.
H.
The minimum bottom slope of facilities not designed for infiltration
shall be 1%. A flatter slope may be used if an equivalent dewatering
mechanism is provided.
I.
When required, dewatering shall be provided through the use of underdrain,
surface device or alternate approved by the Borough Engineer. If the
facility is to be used for infiltration, the dewatering device should
be capable of being disconnected and shall only be made operational
if the basin is not dewatering within the required time frame.
J.
When required, pretreatment elements shall consist of forebays, filter
strips or alternate approved by the Borough Engineer, to keep silt
to a smaller portion of the facility for ease of maintenance.
K.
Within basins designed for infiltration, existing native vegetation
shall be preserved, if possible. For existing unvegetated areas or
for infiltration basins that require excavation, a planting plan shall
be prepared, in accordance with § 301, Subsection 14, and
the BMP Manual, which is designed to promote infiltration.
L.
For facilities with a depth of two feet or greater, a Type D-W endwall
or riser box outlet structure shall be provided.
M.
For facilities with a depth less than two feet, no outlet structure
is required.
N.
All discharge control devices with appurtenances shall be made of
reinforced concrete and stainless steel. Bolts/fasteners shall be
stainless steel.
O.
The spillway shall be designed to provide a nonerosive, stable condition
when the project is completed.
P.
The spillway shall be designed to convey the one-hundred-year post-development
peak inflow when required.
Q.
Freeboard shall be measured from the top of the water surface elevation
in the spillway to the top of the berm for emergency use.
R.
The Borough may require a breach analysis for basins based on site-specific
conditions and concern of threat for downstream property. When required,
the breach analysis shall be conducted in accordance with the NRCS
methodology, the United States Army Corps of Engineers methodology
(HEC-1) or other methodologies as approved by the Borough.
S.
Embankment construction.
(1)
An impervious core/key trench, when required, shall consist
of a cutoff trench (below existing grade) and a core trench (above
existing grade). A key trench may not be required wherever it can
be shown that another design feature, such as the use of an impermeable
liner, accomplishes the same purpose.
(2)
Materials used for the core shall conform to the Unified Soil
Classification GC, SC, CH, or CL and must have at least 30% passing
the No. 200 sieve. The contractor shall provide the soils test results
to the Borough.
(3)
The dimensions of the core shall provide a minimum trench depth
of two feet below existing grade, a minimum width of four feet and
a side slope of 1H:1V or flatter.
(4)
The core should extend up both abutments to the ten-year water
surface elevation or six inches below the emergency spillway elevation,
whichever is lower.
(5)
The core shall extend four feet below any pipe penetrations
through the impervious core. The core shall be installed along or
parallel to the center line of the embankment.
(6)
Compaction requirements shall be the same as those for the embankment
to assure maximum density and minimum permeability.
(7)
The core shall be constructed concurrently with the outer shell
of the embankment.
(8)
The trench shall be dewatered during backfilling and compaction
operations.
2.
Aboveground Storage Facilities. Aboveground storage facilities consist
of all stormwater facilities which store, infiltrate/evaporate/transpire,
clean or otherwise affect stormwater runoff and the top of which is
exposed to the natural environment. Aboveground storage facilities
are located above the finished ground elevation. Aboveground storage
facilities do not include stormwater management facilities designed
for conveyance or cisterns.
A.
Design Criteria. Refer to Table 3-2, Aboveground Storage Facility
Design Criteria.
(1)
Facility with facility depth of less than two feet:
(a)
The minimum top of embankment width shall be two feet.
(b)
The maximum interior side slope shall be 2:1.
(c)
The maximum exterior side slope shall be 2:1.
(d)
The minimum outlet pipe diameter shall be six inches.
(e)
Outlet pipe material shall be PVC, HDPE or RCP.
(f)
An anticlogging device is required in the outlet structure.
(g)
The spillway freeboard shall be a minimum of three inches.
(h)
The spillway may be used to route the one-hundred-year storm.
(2)
Facility with depth of two to eight feet:
(a)
The embankment minimum top width shall be five feet.
(b)
The maximum interior side slope shall be 5:1.
(c)
The maximum exterior side slope shall be 3:1.
(d)
A key trench and antiseep collar shall be provided.
(e)
Compaction density testing of the embankment is required. Test
logs shall be provided to the Borough as part of the inspection requirements.
(f)
A dewatering feature is required.
(g)
Pretreatment filtering of runoff prior to entering the facility
is required.
(h)
The minimum outlet pipe diameter shall be 12 inches.
(i)
Outlet pipe material shall be HDPE or RCP.
(j)
An anticlogging device is required in the outlet structure.
(k)
The outlet structure is required to have an antivortex design.
(l)
Watertight joints shall be provided.
(m)
The spillway freeboard shall be a minimum of six inches.
(n)
The minimum spillway width is 10 feet, and the maximum spillway
width is 50 feet.
(o)
The downstream channel into which the spillway discharges shall
be checked for adequate capacity and stability.
(p)
The spillway shall not be considered to function as part of
the primary outlet structure and shall be only for emergency situations.
(3)
Facility with depth greater than eight feet:
(a)
The embankment minimum top width shall be eight feet.
(b)
The maximum interior side slope shall be 5:1.
(c)
The maximum exterior side slope shall be 3:1.
(d)
A key trench and antiseep collar shall be provided.
(e)
Compaction density testing of the embankment is required. Test
logs shall be provided to the Borough as part of the inspection requirements.
(f)
A dewatering feature for the facility is required.
(g)
Pretreatment filtering of runoff prior to entering the facility
is required.
(h)
The minimum outlet pipe diameter is 15 inches.
(i)
Outlet pipe material shall be RCP.
(j)
An anticlogging device is required in the outlet structure.
(k)
The outlet structure is required to have an antivortex design
as required.
(l)
Watertight joints shall be provided.
(m)
The spillway freeboard shall be a minimum of 12 inches.
(n)
The minimum spillway width is 20 feet; the maximum spillway
width is 50 feet.
(o)
The downstream channel into which the spillway discharges shall
be checked for adequate capacity and stability.
(p)
The spillway shall not be considered to function as part of
the primary outlet structure and shall be only for emergency situations.
(4)
General Requirements for Aboveground Storage Facilities:
(a)
Where practical, the spillway shall be constructed in undisturbed
ground.
(b)
The effect on the downstream areas if the facility embankment
fails shall be considered in the design of all facilities. Where possible
the facility shall be designed to minimize the potential damage caused
by such failure of the embankment.
(c)
For all aboveground facilities that do not rely on infiltration
to dewater the runoff, a flow path length-to-width ratio of 2:1 shall
be provided to maximize the treatment time between the inflow point
and the outlet structure.
|
Table 3-2
Aboveground Storage Facility Design Criteria
[Amended by Ord. No. 1004, 8/18/2022] | |||
|---|---|---|---|
|
Facility Depth
| |||
|
Less than 2 Feet
|
2 Feet to 8 Feet
|
Greater than 8 Feet
| |
|
Embankment Geometry
| |||
|
Top width (minimum)
|
2 feet
|
5 feet
|
8 feet
|
|
Interior side slope (maximum)
|
2:1
|
5:1
|
5:1
|
|
Exterior side slope (maximum)
|
2:1
|
3:1
|
3:1
|
|
Embankment Construction
| |||
|
Key trench
|
Not required
|
Required
|
Required
|
|
Pipe collar
|
Not required
|
Required
|
Required
|
|
Compaction density
|
Not required
|
Required
|
Required
|
|
Internal Construction
| |||
|
Dewatering feature
|
N/A
|
Required
|
Required
|
|
Pretreatment elements
|
Not required
|
Required
|
Required
|
|
Outlet Structure
| |||
|
Pipe size (minimum)
|
6 inches
|
12 inches
|
15 inches
|
|
Pipe material
|
HDPE, PVC, RCP
|
HDPE, RCP
|
RCP
|
|
Anticlogging devices
|
Required
|
Required
|
Required
|
|
Antivortex design
|
Not required
|
Required
|
Required
|
|
Watertight joints in piping
|
Yes
|
Yes
|
Yes
|
|
Spillway Requirements
| |||
|
Spillway freeboard (minimum)
|
3 inches
|
6 inches
|
12 inches
|
|
Width (minimum)
|
5 feet
|
10 feet
|
20 feet
|
|
Width (maximum)
|
50 feet
|
50 feet
|
50 feet
|
|
Spillway channel design
|
Not required
|
Required
|
Required
|
|
Routing of 100-year storm
|
Permitted
|
Not permitted
|
Not permitted
|
3.
Subsurface Storage Facilities. Subsurface storage facilities consist
of all SWM facilities which store, infiltrate/evaporate/transpire,
clean or otherwise affect stormwater runoff and the top of which is
not exposed to the natural environment. Subsurface facilities are
located below the finished ground elevation. Subsurface facilities
do not include SWM facilities designed for conveyance.
A.
General.
(1)
The stone used for infiltration beds shall be clean washed,
uniformly graded coarse aggregate (AASHTO No. 3 or equivalent approved
by the Borough). The void ratio for design shall be assumed to be
0.4.
(2)
Material consistency and placement depths for backfill shall be (at a minimum) per all applicable pipe manufacturer's recommendations, further providing it should be free of large (not exceeding six inches in any dimension), objectionable or detritus material. Select nonaggregate material should be indigenous to the surrounding soil material for nonvehicular areas. Backfill within vehicular areas shall comply with this section unless otherwise specified in Chapter 21, Streets and Sidewalks, or Chapter 22, Subdivision and Land Development. Furthermore, if the design concept includes the migration of runoff through the backfill to reach the infiltration facility, the material shall be well-drained, free of excess clay or clay-like materials and generally uniform in gradation.
(3)
Nonwoven geotextiles shall be placed on the sides and top of
subsurface infiltration facilities. No geotextiles shall be placed
on the bottom of subsurface infiltration facilities.
(4)
When located under pavement, the top of the subsurface facility,
facility piping or conveyance shall be a minimum of six inches below
the bottom of the pavement subbase. Where located under vegetative
cover, the top of the subsurface facility shall be a minimum of 12
inches below the surface elevation or as required to establish vegetation.
(5)
Subsurface facilities shall be designed to safely convey and/or
bypass flows from storms exceeding the design storm.
B.
Design Criteria. Refer to Table 3-3, Subsurface Storage Facility
Design Criteria.
(1)
Infiltration and Storage Facility:
(a)
Maximum depth from surface: two feet less than limiting zone.
(b)
Loading ratio: per December 2006 BMP Manual, as amended. The
maximum impervious loading ratio is 5:1 relating impervious drainage
area to infiltration area. The maximum total loading ratio is 8:1
relating to total drainage area to infiltration area. In areas of
karst geology, the maximum impervious drainage area to infiltration
area is 3:1.
(c)
The minimum distribution pipe size shall be four inches. Distribution
system piping may be PVC or HDPE.
(d)
Pretreatment of runoff to the facility is required to provide
a method to eliminate solids, sediment, and other debris from entering
the subsurface facility.
(e)
Observation/access ports shall be provided in the facility.
For facilities with the bottom less than 12 feet below the average
grade of the ground surface, a cleanout shall be an acceptable observation
port. For facilities with the bottom 12 feet or more below the average
grade of the ground surface, a manhole or other means acceptable to
the Borough shall be provided for access to and monitoring of the
facility. The number of access points shall be sufficient to flush
or otherwise clean out the system.
(f)
The facility shall be designed to provide a means of evenly
balancing the flow across the surface of the facility to be used for
infiltration.
(2)
Storage Without Infiltration Facility.
(a)
The minimum distribution pipe size shall be four inches. Distribution
system piping may be PVC, HDPE or RCP.
(b)
Pretreatment of runoff to the facility is required to provide
a method to eliminate solids, sediment, and other debris from entering
the subsurface facility.
(c)
Observation/access ports shall be provided in the facility.
For facilities with the bottom less than 12 feet below the average
grade of the ground surface, a cleanout shall be an acceptable observation
port. For facilities with the bottom 12 feet or more below the average
grade of the ground surface, a manhole or other means acceptable to
the Borough shall be provided for access to and monitoring of the
facility. The number of access points shall be sufficient to flush
or otherwise clean out the system.
|
Table 3-3
Subsurface Storage Facility Design Criteria
| |||
|---|---|---|---|
|
Facility Type
| |||
|
Infiltration and Storage
|
Storage without Infiltration
| ||
|
Facility Geometry
| |||
|
Depth from surface (maximum)
|
2 feet less than limiting zone
|
N/A
| |
|
Loading ratio (maximum)
|
Per BMP Manual*
|
N/A
| |
|
Distribution System Requirements
| |||
|
Pipe size (minimum)
|
4 inches
|
4 inches
| |
|
Pretreatment
|
Required
|
Required
| |
|
Loading/balancing
|
Required
|
Not required
| |
|
Observation/access ports
|
Required
|
Required
| |
|
NOTES:
| |
|---|---|
|
*Unless otherwise determined by professional geologic evaluation.
|
4.
Conveyance Facilities. Conveyance facilities consist of all SWM facilities
which carry flow, which may be located either above or below the finished
grade. Conveyance facilities do not include SWM facilities which store,
infiltrate/evaporate/transpire, or clean stormwater runoff.
A.
General.
(1)
Conveyance pipes, culverts, manholes, inlets and endwalls within
the public street right-of-way or proposed for dedication shall conform
to the requirements of PennDOT Standards for Roadway Construction,
Publication No. 72M.
(2)
Conveyance pipes, culverts, manholes, inlets and endwalls which
are otherwise subject to vehicular loading shall be designed for the
HS-25 loading condition.
(3)
Backfill Material. Material consistency and placement depths
for backfill shall be (at a minimum) per all applicable pipe manufacturer's
recommendations, further providing it should be free of large (not
exceeding six inches in any dimension), objectionable or detritus
material. Select nonaggregate material should be indigenous to the
surrounding soil material for nonvehicular areas. Backfill within
vehicular areas shall comply with this section unless otherwise specified
in governing municipal road/street or subdivision and land development
ordinances.
(4)
Inlets or manholes shall be placed at all points of changes
in the horizontal or vertical directions of conveyance pipes. Curved
pipe sections are prohibited. Roof downspout leaders that are eight
inches in diameter or less may use pipe fittings (e.g., elbows, wyes,
tees, etc.) at changes in direction.
[Amended by Ord. No. 1004, 8/18/2022]
(5)
Access/maintenance ports. An access/maintenance port is required
and may either be an inlet or manhole.
(6)
Watertight joints shall be provided where pipe sections are
joined, except for perforated pipe installed as pavement base drain.
(7)
Elliptical pipe of an equivalent cross-sectional area may be
substituted in lieu of circular pipe where cover or utility conflict
conditions exist.
(8)
The roughness coefficient (Manning's "n" values) used for conveyance pipe capacity calculations should be determined in accordance with the manufacturer's specifications or with PennDOT Publication 13M, Design Manual, Part 2, Highway Design, Chapter 10, Appendix 4, as included below in Table 3-4.
|
Table 3-4
Roughness Coefficient "n" for Manning's Equation
| |
|---|---|
|
Manning's "n"
|
Types of Pipe
|
|
0.010
|
Polyvinyl chloride (PVC) with smooth inner walls
|
|
0.012
|
Porous cement concrete pipe; corrugated high-density polyethylene
(HDPE) with smooth inner walls
|
|
0.015
|
Corrugated high-density polyethylene (HDPE) with corrugated
inner walls
|
(9)
All pipes must enter inlets completely through one of the sides.
No corner entry of pipes is permitted.
(10)
Within the public street right-of-way, the gutter spread based
on the twenty-five-year storm shall be no greater than 1/2 of the
travel lane and shall have a maximum depth of three inches at the
curbline. A parking lane shall not be considered as part of the travel
lane. In the absence of pavement markings separating a travel lane
from the parking lane, the parking lane shall be assumed to be seven
feet wide if parking is permitted on the street.
(11)
Flow Depth Within Intersections. Within intersections of streets,
the maximum depth of flow shall be 1 1/2 inches based on the
twenty-five-year storm.
(12)
Inlets in streets shall be located along the curbline and have
PennDOT Type C top units. The hood shall be aligned with the adjacent
curb height accounting for the required two-inch inlet sump.
(13)
All inlets placed in paved areas shall have heavy-duty, bicycle-safe
grating consistent with PennDOT Publication 72M. A note to this effect
shall be added to the SWM site plan or inlet details therein.
(14)
Inlets, junction boxes, or manholes greater than five feet in
depth shall be detailed on the SWM site plan.
(15)
A swale shall be considered as any man-made ditch designed to
convey stormwater directly to another SWM facility or surface waters.
(16)
Inlets within swales shall have PennDOT Type M top units or
equivalent approved by the Borough Engineer.
(17)
Swale capacities and velocities shall be computed using the
Manning Equation using the following design parameters:
(a)
Vegetated Swales.
[1]
The first condition shall consider swale stability
based upon a low degree of retardance ("n" = 0.03);
[2]
The second condition shall consider swale capacity
based upon a higher degree of retardance ("n" = 0.05); and
[3]
All vegetated swales shall have a minimum slope
of 1% unless otherwise approved by the Borough Engineer.
[4]
The "n" factors to be used for paved or riprap
swales or gutters shall be based upon accepted engineering design
practices, as approved by the Borough Engineer.
(18)
Trash racks shall be provided on all endwalls and storm sewer
discharge points for pipe diameters of 18 inches of greater. The proposed
trash rack shall be subject to review and approval by the Borough.
Such protection devices shall be designed to be removable for cleaning.
(19)
Headwalls and endwalls shall be constructed of concrete.
(20)
Flared end sections shall be of the same material as the connecting
pipe and shall be designed for the size of the connecting pipe.
(22)
Energy dissipaters shall be designed in accordance with the
requirements in the E&S Manual.
(23)
SWM facilities which qualify as a dam per DEP regulations or
facilities deemed a potential threat to the life, safety or welfare
of the general public shall be subject to the following requirements:
(a)
Facilities which qualify as a dam per DEP regulation shall obtain
the required permit through the DEP and design the facility in accordance
with DEP standards.
(b)
Additional requirements and analysis may be required by the
Borough to prove that the proposed facility has been designed to limit
the potential risk to the life, safety or welfare of the general public.
(24)
In addition to the material requirements in this section, culverts
designed to convey waters of the commonwealth may be constructed with
either a corrugated metal arch or a precast concrete culvert pending
DEP approval of the necessary permit(s).
B.
Design Criteria. Refer to Table 3-5, Conveyance Facility Design Criteria.
(1)
Within a public street right-of-way:
(a)
Conveyance system material shall consist of HDPE or RCP pipe.
(b)
The minimum pipe slope shall be 0.5%.
(c)
A minimum one foot of cover to the stone subgrade shall be provided
over the conveyance pipes in paved or vehicular areas; in grassed
areas, a minimum pipe cover of one foot shall be provided.
(d)
The minimum pipe diameter shall be 15 inches.
(e)
The minimum street-crossing angle for the conveyance system
shall be 75° to 90°. The street-crossing angle shall be measured
between the pipe center line and the street center line.
(f)
The maximum spacing between access or maintenance ports shall
be 400 feet.
(g)
Inlets and manholes shall be concrete.
(h)
Inlets shall be depressed a minimum of two inches below the
surface grade to provide positive flow.
(i)
Swales shall be provided with a minimum freeboard of six inches.
(j)
The maximum swale velocity shall be determined based on the
stability of the channel.
(k)
The minimum allowable swale slope shall be 1%.
(l)
Swale side slopes in residential and nonresidential areas shall
be a maximum of 4:1.
(m)
The bottom width to flow depth ratio in any swale shall be 12:1.
(n)
Pipe entrances/discharges in public street rights-of-way shall
be provided with a headwall/endwall treatment or equivalent as approved
by the Borough.
(o)
The conveyance system discharge locations shall be provided
with an energy dissipater designed to handle the anticipated flow
conditions. The supporting design calculations shall be provided in
the stormwater management report.
(2)
Outside public street right-of-way: vehicular loading.
(a)
Conveyance system material shall consist of PVC, HDPE or RCP
pipe.
(b)
The minimum pipe slope shall be 0.5%.
(c)
A minimum one foot of cover to the stone subgrade shall be provided
over the conveyance pipes.
(d)
The minimum pipe diameter shall be 15 inches.
(e)
The maximum spacing between access or maintenance ports shall
be 400 feet.
(f)
Inlets and manholes shall be constructed of concrete.
(g)
Inlets shall be depressed a minimum of two inches below the
surface grade to provide positive flow.
(3)
Outside public street right-of-way: nonvehicular loading.
(a)
Conveyance system material shall consist of PVC, HDPE or RCP
pipe.
(b)
The minimum pipe slope shall be 0.5%.
(c)
A minimum one foot of cover to the surface shall be provided
over the conveyance pipes.
(d)
The minimum pipe diameter shall be eight inches.
(e)
Maximum spacing between access or maintenance ports shall be
400 feet.
(f)
Manholes shall be constructed of concrete.
(g)
Inlets shall be depressed a minimum of one inch below the surface
grade to provide positive flow.
(h)
Swales shall be provided with a minimum freeboard of six inches.
(i)
The maximum swale velocity shall be determined based on the
stability of the channel.
(j)
The minimum swale slope (longitudinal) shall be 1%.
(k)
Swale side slopes in residential areas shall be a maximum of
4:1, and a maximum of 3:1 in nonresidential areas.
(l)
The bottom width to flow depth ratio in swales shall be 12:1.
(m)
Pipe entrances/discharges in public street rights-of-way shall
be provided with a headwall/endwall or flared end section treatment.
(n)
The conveyance system discharge locations shall be provided
with an energy dissipater designed to handle the anticipated flow
conditions.
|
Table 3-5
Conveyance Facility Design Criteria
[Amended by Ord. No. 1004, 8/18/2022] | ||||
|---|---|---|---|---|
|
Location
|
Within Public Street Right-of-Way
|
Outside Public Street Right-of-Way
| ||
|
Loading
|
All
|
Vehicular Loading
|
Nonvehicular Loading
| |
|
Pipe design
| ||||
|
Material
|
HDPE, RCP
|
PVC, HDPE, RCP
|
PVC, HDPE, RCP
| |
|
Slope (minimum)
|
0.5%
|
0.5%
|
0.5%
| |
|
Cover
|
1 foot to stone subgrade
|
1 foot to stone subgrade
|
1 foot to surface
| |
|
Diameter (minimum)
|
15 inches
|
15 inches
|
8 inches
| |
|
Street-crossing angle
|
75° to 90°
|
N/A
|
N/A
| |
|
Access/ maintenance port frequency (maximum)
|
400 feet
|
400 feet
|
400 feet
| |
|
Inlet design
| ||||
|
Material
|
Concrete
|
Concrete
|
N/A
| |
|
Grate depression
|
2 inches
|
2 inches
|
1-inch minimum
| |
|
Manhole design
| ||||
|
Material
|
Concrete
|
Concrete
|
Concrete
| |
|
Swale design
| ||||
|
Freeboard (minimum)
|
6 inches
|
N/A
|
6 inches
| |
|
Velocity (maximum)
|
Stability check
|
N/A
|
Stability check
| |
|
Slope (minimum)
|
1%
|
N/A
|
1%
| |
|
Side slopes (residential area)
|
4:1 max
|
N/A
|
4:1 max
| |
|
Side slopes (nonresidential area)
|
4:1 max
|
N/A
|
3:1 max
| |
|
Bottom width to flow depth ratio
|
12:1 max
|
N/A
|
12:1 max
| |
|
Outlet design
| ||||
|
End treatment
|
Headwall/ endwall
|
N/A
|
Headwall/ endwall or flared end section
| |
|
Energy dissipater
|
Required
|
N/A
|
Required
| |
5.
Capture and Reuse Facilities.
A.
Design Requirements:
(1)
Calculation of water usage to ensure adequate capacity is available
for storage of follow-up rainfall events. The property will draw from
the cistern on a daily basis; the cistern shall be dewatered in 72
hours to maintain the capacity of the storage facility. This shall
be noted on the plan and maintenance agreement.
(2)
Verification of conveyance pipe capacity in the roof leader
design shall be provided in the stormwater management report.
(3)
The stormwater runoff storage container(s) shall be protected
from direct sunlight to minimize algae growth.
(4)
An alternative supply of water shall be available for the property
use during dry periods if the reuse facility is used for supplying
the dwelling with water.
(5)
Stormwater runoff storage containers should be watertight with
smooth interior surfaces.
(6)
The cover (or lid) should have a tight fit to keep out surface
water, children, animals, dust and light. The cover or lid opening
should be a minimum 24 inches in order to access the facility for
maintenance and repair.
(7)
Cisterns shall be designed to store the runoff volume of a one-hundred-year
storm event for the area served by the stormwater runoff storage facility.
(8)
Every stormwater runoff storage facility (cistern, rain barrel,
etc.) shall be provided with an overflow or an emergency outlet. The
overflow shall be designed to discharge away from buildings and other
structures and towards existing natural or man-made channels, stormwater
facilities or vegetated slopes.
(10)
Maintenance responsibilities for water storage and reuse facilities
shall include flushing the storage units to remove any accumulated
sediment; the inside surfaces shall be brushed and thoroughly disinfected.
(11)
The stormwater runoff collected shall not be allowed to freeze
in the devices.
[Ord. 954, 12/19/2013]
1.
The applicant must comply with the erosion control rules and regulations
of Chapter 102.
2.
The design plan and construction schedule shall incorporate measures
to prevent soil erosion and sedimentation.
3.
The following principles shall be applied to the design plan and
construction schedule to minimize soil erosion and sedimentation:
A.
Erosion and sedimentation controls designed in conformance with the
E&S Manual shall be implemented during the construction and post-construction
periods to prevent soil erosion, sedimentation and other pollutants
from entering streams, lakes, etc.
B.
Natural vegetation shall be retained and protected on all undisturbed
areas.
C.
The extent of the disturbed area and the duration of its exposure
shall be kept to a minimum. Stockpiles to remain in place longer than
20 days shall be seeded.
D.
It shall be the applicant's responsibility during construction to
prevent soil pollution to neighboring property, public streets, and
streams. Soil dropped from construction equipment and sedimentation
shall be immediately removed from roads, public and private property,
and streams.
E.
Drainage provisions shall accommodate the stormwater runoff both
during and after construction.
F.
Soil erosion and sedimentation facilities shall be installed prior
to any on-site earth disturbances.
4.
The developer shall maintain a copy of the erosion and sedimentation
control plan and notes on site during construction.
[Added by Ord. No. 1004, 8/18/2022]
1.
Regulated activities that result in cumulative earth disturbances less than (Enter no more than one acre. A more restrictive area may be entered.) are exempt from the requirements in Section 303, Section 304, and Part 4 of this chapter.
2.
Agricultural activity is exempt from the SWM site plan preparation
requirements of this chapter 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 chapter provided the activities
are performed according to the requirements of 25 Pa. Code Chapter
102.
4.
Exemptions from any provisions of this chapter shall not relieve the applicant from the requirements in § 301, Subsections 4 through 22.
5.
The Borough may deny or revoke any exemption pursuant to this section
at any time for any project that the Borough believes may pose a threat
to public health and safety or the environment.
