[Ord. No. 2-2022, 9/19/2022]
1. For all regulated activities, unless preparation of an SWM site plan is specifically exempted in §
23-302:
A. Preparation and implementation of an approved SWM site plan is required.
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 chapter.
2. SWM site plans approved by the municipality, in accordance with §
23-406, 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 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.
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 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 Erosion and Sediment Pollution Control Program Manual (E&S
Manual4), 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 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 §
23-303 and the peak rate controls of §
23-304, 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 and written permission from the adjacent property owner(s). Such
stormwater flows shall be subject to the requirements of this chapter.
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 chapter 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 Manual4). 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.
8. The design of all facilities over karst shall include an evaluation
of measures to minimize adverse effects.
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 chapter.
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.
12. For all regulated activities, SWM 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, the Clean Streams Law, and the Storm Water Management Act.
13. Various BMPs and their design standards are listed in the BMP Manual3.
[Ord. No. 2-2022, 9/19/2022]
1. Select low-impact regulated activities may be exempt from §§
23-303,
23-304 and Part
4 of this chapter based upon the size of the proposed regulated activities. Both earth disturbance and new impervious surface shall be quantified to identify the applicable sections of the ordinance, and the larger of the two areas shall be used to identify exempted portions of the ordinance.
A. Earth disturbances between 0 to 10,000 square feet are exempt from §
23-303, Stormwater Volume, and §
23-304, Rate Requirements.
B. Earth disturbances between 10,000 and 20,000 square feet are exempt from §
23-304, Rate Control, only.
C. Proposed impervious area 0 to 5,000 square feet are exempt §
23-303, Stormwater Volume, and §
23-304, Rate Requirements.
D. Proposed impervious area 5,000 to 10,000 square feet are exempt from §
23-304, Rate Controls, only.
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. Domestic gardening and landscaping are exempt from all sections of
this chapter as long as such activities are performed according to
the requirements of 25 Pa. Code Chapter 102 and not used for commercial
purposes.
5. Exemptions from any provisions of this chapter shall not relieve the applicant from the requirements in §
23-301, Subsection
4 through
11.
6. 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. 2-2022, 9/19/2022]
The green infrastructure and low-impact development practices
provided in the BMP Manual
4 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 not greater than 5,000 square feet of impervious surface or otherwise exempted by §
23-302 and that do not require hydrologic routing to design the stormwater facilities, this chapter 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 Manual4) is applicable to any size of regulated activity. This method requires
detailed modeling based on site conditions.
A. Do not increase the post-development total runoff volume for all
storms equal to or less than the two-year twenty-four-hour duration
precipitation.
B. For modeling purposes:
(1)
Existing (predevelopment) nonforested pervious areas must be
considered meadow in good condition.
(2)
Twenty percent of existing impervious area, when present, shall
be considered meadow in good condition in the model for existing conditions.
2. The Simplified Method (CG-2 in the BMP Manual4) 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.
D. This method is exempt from the requirements of §
23-304, Rate Controls.
[Ord. No. 2-2022, 9/19/2022]
1. For areas not covered by a release rate map from an approved Act
167 Stormwater Management Plan: Post-development 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 post-development 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: For the one-, two-, five-, ten-, twenty-five-,
fifty-, and 100-year, twenty-four-hour storm events, the post-development
peak discharge rates will follow the applicable approved release rate
maps. For any areas not shown on the release rate maps, the post-development
discharge rates shall not exceed the predevelopment discharge rates.
[Ord. No. 2-2022, 9/19/2022]
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.
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 streambank (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.
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.
6. The following conditions shall apply when public and/or private recreation
trails are permitted within riparian buffers:
A. Trails shall be for nonmotorized use only.
B. Trails shall be designed to have the least impact on native plant
species and other sensitive environmental features.
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.