[Ord. No. 2023-1, 1/11/2023]
1.
For all regulated activities, submission of the stormwater management
permit application provided in Appendix B[1] is required.
[1]
Editor's Note: Said appendix is included as an attachment to this chapter.
2.
For all regulated activities, unless preparation of an SWM site plan
is specifically exempted in § 302:
3.
SWM site plans approved by the Township, in accordance with Part
4, shall be on site throughout the duration of the regulated activity.
4.
The Township may, after consultation with 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.[2]
[2]
Editor's Note: See 35 P.S. § 691.1 et seq.
5.
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 chapter and to meet
all requirements under Title 25 of the Pennsylvania Code and the Clean
Streams Law.[3] Various BMPs and their design standards are listed in
the Erosion and Sediment Pollution Control Program Manual (E&S
Manual[4]), No. 363-2134-008, as amended and updated.
6.
Stormwater drainage systems shall be provided in order to permit
unimpeded flow along natural watercourses, except as modified by stormwater
management facilities or open channels consistent with this chapter.
7.
Stormwater flows onto adjacent property shall not be created, increased,
decreased, relocated, or otherwise altered without written notification
of the adjacent property owner(s). Such stormwater flows shall be
subject to the requirements of this chapter.
8.
Areas of existing diffused drainage discharge shall be subject to
any applicable discharge criteria in the general direction of existing
discharge, whether proposed to be concentrated or maintained as diffused
drainage areas, except as otherwise provided by this chapter. If diffused
flow is proposed to be concentrated and discharged onto adjacent property,
the developer must document that adequate downstream conveyance facilities
exist to safely transport the concentrated discharge, or otherwise
prove that no erosion, sedimentation, flooding or other harm will
result from the concentrated discharge.
9.
Where a development site is traversed by watercourses, drainage easements
shall be provided conforming to the line of such watercourses. The
terms of the easement shall prohibit excavation, the placing of fill
or structures, and any alterations that may adversely affect the flow
of stormwater within any portion of the easement. Also, maintenance,
including mowing of vegetation within the easement, shall be required,
except as approved by the appropriate governing authority.
10.
When it can be shown that, due to topographic conditions, natural
drainageways on the site cannot adequately provide for drainage, open
channels may be constructed conforming substantially to the line and
grade of such natural drainageways. Work within natural drainageways
shall be subject to approval by DEP through the joint permit application
process, or, where deemed appropriate by DEP, through the general
permit process.
11.
Any stormwater management facilities regulated by this chapter that
would be located in or adjacent to waters of the commonwealth or wetlands
shall be subject to approval by DEP through the joint permit application
process, or, where deemed appropriate by DEP, the general permit process.
When there is a question whether wetlands may be involved, it is the
responsibility of the developer or his agent to show that the land
in question cannot be classified as wetlands; otherwise approval to
work in the area must be obtained from DEP.
12.
Any stormwater management facilities regulated by this chapter that
would be located on state highway rights-of-way shall be subject to
approval by the Pennsylvania Department of Transportation (PennDOT).
13.
Minimization of impervious surfaces and infiltration of runoff through
seepage beds, infiltration trenches, etc., are encouraged, where soil
conditions permit, to reduce the size or eliminate the need for detention
facilities.
14.
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 chapter.
C.
For projects that add impervious area to a parcel, the total impervious
area on the parcel is subject to the requirements of this chapter;
except that the volume controls in § 308 and the peak rate
controls of § 303 do not need to be retrofitted to existing
impervious areas that are not being altered by the proposed regulated
activity.
15.
Roof drains must not be connected to streets, sanitary or storm sewers
or roadside ditches in order to promote overland flow and infiltration/percolation
of stormwater.
16.
All regulated activities shall include measures to:
A.
Protect health, safety, and property.
B.
Meet the water quality goals of this chapter by implementing measures
outlined in the Pennsylvania Stormwater Best Management Practices
Manual (BMP Manual) 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[5]). 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.
17.
The design of all facilities over karst shall include an evaluation
of measures to minimize adverse effects.
18.
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 chapter.
19.
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.
20.
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[6] can be accessed at: http://hdsc.nws.noaa.gov/hdsc/pfds/.
21.
22.
Various BMPs and their design standards are listed in the BMP Manual.
[Ord. No. 2023-1, 1/11/2023]
1.
Regulated activities that create impervious areas or earth disturbance
shall adhere to Table III-1 to meet the requirements of this chapter.
The larger of the two areas determines the applicable requirements
of this chapter (i.e., if only 500 square feet of impervious area
is proposed, but 15,000 square feet of earth disturbance is proposed,
the requirements follow Row 3 of Table III-1).
|
Table III-1
Stormwater Management Requirements and Exemptions
| |||||
|---|---|---|---|---|---|
|
SWM Level
(Refer to Appendix B[1])
|
Proposed Impervious Area
(square feet)
|
Proposed Total Earth Disturbance
(square feet)
|
Exemptions
|
Stormwater Management Requirements
|
What is required to submit to Township?*
|
|
Level 1
|
<1,000
|
<5,000
|
§§ 303 and 308, and Part 4 of this chapter
|
Ensure § 301 general requirements are met
|
N/A*
|
|
Level 2
|
1,000 to 5,000
|
5,000 to 10,000
|
§§ 303 and 308, and Part 4 of this chapter
|
Disconnected impervious area (DIA) as in Appendix C.1[2]
OR
Capture and control first 1 inch of runoff over proposed impervious
area as in Appendix E
|
Appendix C.1[3] worksheet and sketch (or equivalent)
OR
Appendix E[4] worksheet and sketch (or equivalent)
|
|
Level 3
|
5,000 to 10,000
|
10,000 to 20,000
|
§§ 303 and 304, and Part 4 of this chapter
|
Capture and permanently remove the first 2 inches of runoff
over proposed impervious areas as in § 308B of this chapter
|
Appendix D[5] worksheet and sketch (or equivalent)
|
|
Level 4
|
>10,000
|
>20,000
|
None
|
All requirements of this chapter
|
SWM site plan
|
|
NOTES:
| |
|
*
|
In addition to the stormwater management permit application
provided in Appendix B.[6]
|
[1]
Editor's Note: Said appendix is included as an attachment to this chapter.
[2]
Editor's Note: Said appendix is included as an attachment to this chapter.
[3]
Editor's Note: Said appendix is included as an attachment to this chapter.
[4]
Editor's Note: Said appendix is included as an attachment to this chapter.
[5]
Editor's Note: Said appendix is included as an attachment to this chapter.
[6]
Editor's Note: Said appendix is included as an attachment to this chapter.
2.
Agricultural activity is exempt from the rate control and SWM site
plan preparation requirements of this chapter, provided the activities
are performed according to the requirements under 25 Pa. Code, Chapter
102.
3.
Forest management and timber operations are exempt from the rate
control and SWM site plan preparation requirements of this chapter,
provided the activities are performed according to the requirements
under 25 Pa. Code, Chapter 102.
4.
Exemptions from any provisions of this chapter shall not relieve the applicant from the requirements in § 301, Subsections 1 through 22.
5.
The Township may deny or revoke any exemption pursuant to this section
at any time for any project that the Township believes may pose a
threat to public health and safety or the environment.
[Ord. No. 2023-1, 1/11/2023]
1.
Areas not covered by a Stormwater Management District Map contained
in Appendix F.1[1] of this chapter: Postdevelopment discharge rates shall
not exceed the predevelopment discharge rates for the one- through
100-year, twenty-four-hour storms. 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- through 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.
[1]
Editor's Note: Said appendix is on file in the Township
offices.
2.
Areas covered by a Stormwater Management District Map contained in
Appendix F.1[2] of this chapter: For the one- through 100-year storms,
the postdevelopment peak discharge rates will follow the applicable
approved Stormwater Management District Maps. For any areas not shown
on the Stormwater Management District Maps, the postdevelopment discharge
rates shall not exceed the predevelopment discharge rates.
[2]
Editor's Note: Said appendix is on file in the Township
offices.
[Ord. No. 2023-1, 1/11/2023]
1.
General. Postdevelopment rates of runoff from any regulated activity
shall not exceed the peak release rates of runoff prior to development
for the design storms specified on the Stormwater Management District
Map (Appendix F.1[1]) and § 303 of this chapter.
[1]
Editor's Note: Said appendix is on file in the Township
offices.
2.
District Boundaries. The boundaries of the stormwater management
districts are shown on an official map which is available for inspections
at the Township office. A copy of the official map at a reduced scale
is included in Appendix F.1.[2] The exact location of the stormwater management district
boundaries as they apply to a given development site shall be determined
by mapping the boundaries using the two-foot topographic contours
(or most accurate data required) provided as part of the SWM site
plan.
[2]
Editor's Note: Said appendix is on file in the Township
offices.
3.
Sites Located in More Than One District. For a proposed site located
within two or more stormwater management district category subareas,
the peak discharge rate from any subarea shall be the predevelopment
peak discharge for that subarea as indicated in § 303 and
on the Stormwater Management District Maps in Appendix F.1.[3]
[3]
Editor's Note: Said appendix is on file in the Township
offices.
4.
Off-Site Areas. Off-site areas which drain through a proposed development
site, although not detained, must be considered when determining allowable
peak runoff rates at the project site's discharge point(s). On-site
drainage facilities shall be designed to safely convey off-site flows
through the development site.
[Ord. No. 2023-1, 1/11/2023]
1.
Any stormwater facility located on state highway rights-of-way shall
be subject to approval by the Pennsylvania Department of Transportation
(PennDOT).
2.
Any stormwater management facility (i.e., detention basin) designed
to store runoff and requiring a berm or earthen embankment required
or regulated by this chapter shall be designed to provide an emergency
spillway to handle flow up to and including the 100-year postdevelopment
conditions. The height of embankment must be set as to provide a minimum
one-foot of freeboard above the maximum pool elevation computed when
the facility functions for the 100-year postdevelopment inflow. Should
any stormwater management facility require a dam safety permit under
25 Pa. Code, Chapter 105 (DEP Chapter 105), the facility shall be
designed in accordance with DEP Chapter 105 and meet the regulations
of DEP Chapter 105 concerning dam safety which may be required to
pass storms larger than a 100-year event.
3.
Any facilities that constitute water obstructions (e.g., culverts,
bridges, outfalls, or stream enclosures), and any work involving wetlands
as directed in DEP Chapter 105 regulations (as amended or replaced
from time to time by DEP), shall be designed in accordance with DEP
Chapter 105 and will require a permit from DEP. Any other drainage
conveyance facility that does not fall under DEP Chapter 105 regulations
must be able to convey, without damage to the drainage structure or
roadway, runoff from the twenty-five-year design storm with a minimum
one-foot of freeboard measured below the lowest point along the top
of the roadway. Roadway crossings located within designated floodplain
areas must be able to convey runoff from a 100-year design storm with
a minimum one-foot of freeboard measured below the lowest point along
the top of roadway. Any facility that constitutes a dam as defined
in DEP Chapter 105 regulations may require a permit under dam safety
regulations. Any facility located within a PennDOT right-of-way must
meet PennDOT minimum design standards and permit submission requirements.
4.
Any drainage conveyance facility and/or channel that does not fall
under DEP Chapter 105 regulations must be able to convey, without
damage to the drainage structure or roadway, runoff from the twenty-five-year
design storm. Conveyance facilities to or exiting from stormwater
management facilities (i.e., detention basins) shall be designed to
convey the design flow to or from that structure. Roadway crossings
located within designated floodplain areas must be able to convey
runoff from a 100-year design storm. Any facility located within a
PennDOT right-of-way must meet PennDOT minimum design standards and
permit submission requirements.
5.
Storm sewers must be able to convey postdevelopment runoff from a
twenty-five-year design storm without surcharging inlets, where appropriate.
6.
Adequate erosion protection shall be provided along all open channels,
and at all points of discharge.
7.
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 chapter.
8.
Storage facilities, to the greatest extent possible and at the discretion
of the Township Engineer, shall completely drain both the volume control
and rate control capacities over a period of time not less than 24
hours and not more than 72 hours from the end of the design storm.
9.
Storage facilities shall incorporate features to maximize the length
of the flow path and increase the travel time through the facility.
10.
The design of all stormwater management facilities shall incorporate
sound engineering principles and practices. The Township shall reserve
the right to disapprove any design that would result in the occupancy
or continuation of an adverse hydrologic or hydraulic condition within
the watershed.
[Ord. No. 2023-1, 1/11/2023]
1.
Any stormwater runoff calculations involving drainage areas greater
than 200 acres, including on- and off-site areas, shall use generally
accepted calculation techniques that are based on the NRCS soil cover
complex method. Table III-2 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 site. The Township may approve the use of the Rational
Method to estimate peak discharges from drainage areas that contain
less than 200 acres.
2.
The design storm volumes to be used in the analysis of peak rates
of discharge should be obtained from the Precipitation-Frequency Atlas
of the United States, Atlas 14, Volume 2, Version 3.0, U.S. Department
of Commerce, National Oceanic and Atmospheric Administration (NOAA),
National Weather Service, Hydrometeorological Design Studies Center,
Silver Spring, Maryland. NOAA's Atlas 14 can be accessed at:
http://hdsc.nws.noaa.gov/hdsc/pfds/.
3.
For the purposes of predevelopment flow rate determination, undeveloped
land, including disturbed areas, shall be considered as "meadow" in
good condition, unless the natural ground cover generates a lower
curve number or Rational C value (i.e., forest).
4.
Where uniform flow is anticipated, the Manning equation shall be
used for hydraulic computations, and to determine the capacity of
open channels, pipes, and storm sewers. Outlet structures for stormwater
management facilities shall be designed to meet the performance standards
of this chapter using any generally accepted hydraulic analysis technique
or method.
5.
The design of any stormwater detention facilities intended to meet
the performance standards of this chapter shall be verified by routing
the design storm hydrograph through these facilities using the Storage-Indication
Method. The design storm hydrograph shall be computed using a calculation
method that produces a full hydrograph. The Township may approve the
use of any generally accepted full hydrograph approximation technique
which shall use a total runoff volume that is consistent with the
volume from a method that produces a full hydrograph.
6.
The Township has the authority to require that computed existing
runoff rates be reconciled with field observations and conditions.
If the designer can substantiate through actual physical calibration
that more appropriate runoff and time-of-concentration values should
be utilized at a particular site, then appropriate variations may
be made upon review and recommendations of the Township Engineer.
Calibration shall require detailed gauge and rainfall data for the
particular site in question.
|
Table III-2
Acceptable Computation Methodologies For Stormwater Management
Plans
| ||
|---|---|---|
|
Method
|
Method Developed By
|
Applicability
|
|
TR-20 (or commercial computer package based on TR-20)
|
USDA NRCS
|
Applicable where use of full hydrology computer model is desirable
or necessary
|
|
TR-55 (or commercial computer package based on TR-55)
|
USDA NRCS
|
Applicable for land development plans within limitations described
in TR-55
|
|
Hydrologic Engineering Center-Hydraulic Modeling System (HEC-HMS)
|
U.S. Army Corps of Engineers
|
Applicable where use of full hydrologic computer model is desirable
or necessary
|
|
Rational Method (or commercial computer package based on Rational
Method)
|
Emil Kuichling (1889)
|
For sites less than 200 acres or as approved by the Township
and Township Engineer
|
|
Other methods
|
Varies
|
Other computation methodologies approved by the Township and
Township Engineer
|
[Ord. No. 2023-1, 1/11/2023]
1.
Whenever the vegetation and topography are to be disturbed, such
activity must be in conformance with 25 Pa. Code, Chapter 102, Erosion
and Sediment Control rules and regulations; Part I, Department of
Environmental Protection, Subpart C, Protection of Natural Resources,
Article II, Water Resources; and in accordance with the Luzerne Conservation
District and the standards and specifications of the Township of Kingston.
2.
Additional erosion and sedimentation control design standards and
criteria that must be or are recommended to be applied where infiltration
BMPs are proposed shall include the following:
A.
Areas proposed for infiltration BMPs shall be protected from sedimentation
and compaction during the construction phase, so as to maintain their
maximum infiltration capacity.
B.
Infiltration BMPs shall not be constructed nor receive runoff until
the entire contributory drainage area to the infiltration BMP has
received final stabilization.
[Ord. No. 2023-1, 1/11/2023]
1.
The low-impact development practices provided in the BMP Manual shall be utilized for all regulated activities to the maximum extent practicable. Water volume controls shall be implemented using the Design Storm Method in Subsection 1A or the Simplified Method in Subsection 1B below. For all regulated activities that require submission of a formal SWM site plan, both the Design Storm Method and the Simplified Method shall be calculated; the larger control volume based on the two calculations shall be controlled. Subsection 1C below provides requirements for mined, Karst, or other geologically limiting areas where infiltration shall not occur.
A.
The Design Storm Method (CG-1 in the BMP Manual) is applicable to
any size of regulated activity. This method requires detailed modeling
based on site conditions.
(1)
Do not increase the postdevelopment total runoff volume for
all storms equal to or less than the two-year, twenty-four-hour duration
precipitation.
B.
When Design Storm Method CG-1 guidelines are not used, the Simplified
Method (CG-2 in the BMP Manual) has been modified to accommodate two
inches of permanently removed runoff volume. This method (provided
below) is independent of site conditions and should be used if the
Design Storm Method is not followed. For new impervious surfaces:
(1)
The first two inches 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.
(2)
Wherever possible, infiltration facilities should be designed
to accommodate infiltration of the entire permanently removed runoff;
however, in all cases at least the 0.5 inch of the permanently removed
runoff should be infiltrated.
(3)
Facilities, to the greatest extent possible and subject to the
Township Engineer's discretion, shall be designed to drain the
permanently removed runoff volume in a period no less than 24 hours
and no greater than 72 hours.
(4)
Runoff volume in excess of two inches shall be safely conveyed
to existing stormwater collection systems or streams, in the direction
of the existing drainage course.
(5)
This method is exempt from the requirements of § 303,
Stormwater Management Peak Rate Controls.
C.
Before infiltration is proposed on a site, site conditions shall
be evaluated by a qualified design professional through subsurface
investigation and testing to determine if site conditions are suitable
to support proposed infiltration facilities to manage runoff. If it
is determined that infiltration is not feasible due to physical constraints
of the site, or will adversely impact the environment as demonstrated
by the presence of acid mine drainage, sinkhole formation, or other
serious environmental issues, then the above volume controls must
be achieved through surface BMP mitigation. Reference the BMP Manual
for alternative mitigation measures that do not require infiltration.
[Ord. No. 2023-1, 1/11/2023]
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.
2.
Except as required by Chapter 102, the riparian buffer easement shall
be measured to be the greater of the limit of the 100-year floodplain
or a minimum of 35 feet from the top of the stream bank (on each side).
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 a required by zoning, unless otherwise specified in the municipal
Zoning Ordinance.[1]
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.
