[Ord. No. 1598, 3-9-2015]
For any of the activities regulated by this ordinance, the preliminary
or final approval of subdivision and/or land development plans, the
issuance of any building or occupancy permit, the commencement of
any earth disturbance or activity, may not proceed until the property
owner or applicant or his/her agent has received written approval
of a SWM site plan from the municipality and an approval of an adequate
erosion and sediment (E & S) control plan review from the municipality
or County Conservation District.
[Ord. No. 1598, 3-9-2015]
The SWM site plan shall consist of a general description of
the project, including calculations, maps, and plans. A note on the
maps shall refer to the associated computations and E&S control
plan by title and date. The cover sheet of the computations and E&S
control plan shall refer to the associated maps by title and date.
All SWM site plan materials shall be submitted to the municipality
in a format that is clear, concise, legible, neat, and well organized;
otherwise, the SWM site plan shall not be accepted for review and
shall be returned to the applicant.
The following items shall be included in the SWM site plan:
A. General.
1. General description of the project including plan contents described
in Section 402B.
2. General description of proposed SWM techniques to be used for SWM
facilities.
3. Complete hydrologic and hydraulic computations for all SWM facilities.
4. All reviews and letters of adequacy from the Conservation District
for the erosion and sedimentation plan as required by Plymouth Township,
county or state regulations.
5. A general description of proposed nonpoint source pollution controls.
6. The SWM site plan application and associated fee for all regulated
activities not already paying a fee under the SALDO regulations.
7. Appropriate sections from the municipality's Subdivision and
Land Development Ordinance, and other applicable local ordinances, shall be followed
in preparing the SWM site plan.
B.
Plans. SWM site plan shall provide
the following information:
1. The overall stormwater management concept for the project.
2. A determination of natural site conditions and stormwater management
needs. This shall include, but not be limited to:
a. Site features:
1)
The location of the project relative to highways, municipal
boundaries or other identifiable landmarks.
2)
The locations of all existing and proposed utilities, sanitary
sewers, and waterlines on site and to within fifty (50) feet of property
lines.
3)
Proposed structures, roads, paved areas, and buildings.
4)
The total tract boundary and size with distances marked to the
nearest foot and bearings to the nearest degree.
5)
Plan and profile drawings of all SWM BMPs, including drainage
structures, pipes, open channels, and swales. At a minimum this should
include pre- and postdrainage area maps, an overall postconstruction
stormwater management plan, stormwater details sheets, and landscape
plans (if proposing bioretention facilities, low-impact development,
bioretention, or vegetative basins).
6)
The locations and minimum setback distances of existing and
proposed on-lot wastewater facilities and water supply wells.
7)
The location of all erosion and sediment control facilities.
8)
The location of proposed septic tank infiltration areas and
wells in cases where groundwater recharge measures such as seepage
pits, beds or trenches are proposed.
b. Natural site conditions:
1)
An existing resource and site analysis map (ERSAM) showing environmentally
sensitive areas including, but not limited to, steep slopes, ponds,
lakes, streams, wetlands, hydric soils, hydrologic soil Groups A and
B, vernal pools, stream buffers, open channels, existing recharge
areas, and floodplains. The area of each of these sensitive areas
shall be calculated and should be consistent with the runoff volume
calculation Section 304.
2)
A detailed site evaluation for projects proposed in areas of
frequent flooding, karst topography, and other environmentally sensitive
areas, such as brownfields and source water protection areas.
3)
Existing and proposed contour lines (2 ft).
4)
The total extent of the drainage area upstream from the site
and all downgradient receiving channels, swales and waters to which
stormwater runoff or drainage will be discharged.
c. Stormwater runoff design computations and documentation as specified
in this Ordinance, or as otherwise necessary to demonstrate that the
maximum practicable measures have been taken to meet the requirements
of this Ordinance, including the recommendations and general requirements
in Section 301.
d. The effect of the project (in terms of runoff volumes, water quality,
and peak flows) on surrounding properties and aquatic features and
on any existing stormwater conveyance system that may be affected
by the project.
3. The format of the plan shall include the following:
a. The expected project time schedule.
b. The name of the development, the name and address of the owner of
the property, and the name of the individual or firm preparing the
plan.
d. A graphic and written scale of one (1) inch equals no more than fifty
(50) feet; for tracts of twenty (20) acres or more, the scale shall
be one (1) inch equals no more than one hundred (100) feet.
f. An access easement around all stormwater management facilities is
required that would provide ingress to and egress from a public right-of-way.
The size of the easement shall commensurate with the maintenance and
access requirements determined in the design of the BMP.
g. A key map showing all existing man-made features beyond the property
boundary that would be affected by the project.
h. A note on the plan indicating the location and responsibility for
maintenance of stormwater management facilities. All facilities shall
meet the performance standards and design criteria specified in this
ordinance.
i. The following signature block for the Design Engineer: "I, (Design
Engineer), on this date (date of signature), hereby certify that the
SWM Site Plan meets all design standards and criteria of The Plymouth
Township Stormwater Management Ordinance or Plan."
j. A statement, signed by the applicant, acknowledging that any revision
to the approved SWM site plan must be approved by the municipality
and that a revised E&S plan must be submitted to the Conservation
District.
4. A soil erosion and sediment control plan, where applicable, as prepared
for and submitted to the approval authority.
5. The SWM site plan shall include an operations and maintenance (O&M)
plan for all existing and proposed physical stormwater management
facilities, as well as schedules and costs for O&M activities.
This plan shall address long-term ownership and responsibilities for
O&M.
[Added by Ord. No. 1623, § 4, 8-8-2016]
Areas of karst geology shall generally be as depicted on the
Watershed Map of Plymouth Township, included in Appendix A of the
Stormwater Management Plan. Other areas of the Township where karst
geology is present, whether or not shown on the map, shall also be
subject to these requirements.
A. All of the following specific requirements shall apply to any activity
regulated by this ordinance when that activity occurs in areas where
karst geology is present.
1. Buildings, structures or stormwater management basins shall not be
placed in or over the following features if non-remediated in accordance
with the terms of this ordinance: Sinkholes, closed depressions, ghost
lakes, historical surface mines, lineaments related to geologic features,
or faults.
2. Buildings, structures and stormwater management basins shall be located
no closer than 75 feet from the rim of non-remediated sinkholes or
historical surface mines and no closer than 50 feet from non-remediated
lineament features such as large joints and faults, or closed depressions,
or at the discretion of the Geotechnical Engineer or Geologist after
having evaluated the continued outward growth of the sinkhole.
3. Outflow from a stormwater management basin and/or post development
stormwater flows shall not be directly recharged to sinkholes, closed
depressions, ghost lakes or historical surface mines, so as not to
use those features for stormwater disposal.
4. All stormwater management basins in areas deemed to have a moderate
to high risk of sinkhole formation or those areas which pose an immediate
health and safety concern should a sinkhole form, such as pavements,
structures or other critical site features, must be lined to render
them impermeable to infiltration, as set forth in the definitions
section of these regulations.
5. Any unprotected/unlined containment of substances defined as toxic
and/or hazardous by the Pennsylvania Department of Environmental Protection
is not permitted.
6. Storage and handling areas for hazardous materials must have impermeable
surfaces designed to contain materials stored/handled from which they
shall be directed to a predetermined collection point.
7. The land application of hazardous materials is not permitted.
8. The underground storage of any hazardous materials, except the lawful
storage of gasoline and diesel fuel in regulatory compliant containers,
shall be prohibited.
9. Groundwater monitoring devices approved by the Township are required
for all facilities handling hazardous materials.
10. Where a river and/or creek and/or stream flow adjacent to the property,
and over karst limestone bedrock, measures should be implemented to
minimize below ground horizontal infiltration of river or creek water
onto the property, flowing between the soil and the bedrock, to reduce
the risk of soil scouring, and piping of soil, into the epikarst.
Such measures may include impermeable lining of the embankments of
the waterway, grout curtains or other measures as deemed appropriate
by the Geotechnical Engineer or Geologist.
11. Outflow from a stormwater basin to a nearby river and/or creek and/or
stream should be downstream or downgradient of the critical site features
of the property to prevent recharge back onto the property.
B. The Township Council shall not entertain request for waivers from
the requirements listed above until a Carbonate Assessment Report,
as required by these regulations, has been submitted to the Township
Engineer for review and comment.
C. Carbonate Assessment Report.
1. All development shall be evaluated by a Licensed Professional Geotechnical
Engineer or a Licensed Professional Geologist. Each of said experts
must be licensed in their field of expertise by the Commonwealth of
Pennsylvania. Any report issued shall be signed by the licensed Professional
Geotechnical Engineer or a licensed Professional Geologist.
2. The Carbonate Assessment Report shall include, but not be limited
to, the following:
a. Statement of purpose: This section shall indicate those specific
regulations being addressed in the report and whether the applicant
is attempting to demonstrate compliance or justify noncompliance with
these specific regulations.
b. Description of existing conditions: This section shall present a
description of existing characteristics of the property, and up to
200 feet beyond the property, with respect to geology, karst features,
topography, surface water hydrology, hydrogeology, soils, vegetation,
and existing improvements and uses of the property.
c. A map, at scale no smaller than one inch equals 100 feet and a contour
interval of two feet indicating the location of the property and all
proposed improvements.
d. Information for the affected properties indicating the presence of
any of the following carbonate features: closed depressions, sinkholes,
ghost lakes, disappearing streams, fissures, lineaments, faults, outcrops
of bedrock, seasonal high water table levels, soil mottling, springs,
surface drainage entering the ground, and caverns.
e. A recommended plan for the grouting repair or other remediation of
karst-related surface or subsurface features that may negatively impact
the proposed development as well as the adjacent improved or unimproved
properties. The repair plan will be specific for buildings, parking
lots, and other types of development.
f. The information requested above shall be based upon previously published
data and field surveys which may include reconnaissance mapping and
surveys, test borings, excavation of test pits, groundwater tracer
testing, geotechnical probes, or geophysical methods.
3. The Carbonate Assessment Report must be received by the Township
when a plan is submitted for approval. Four copies of the report shall
be submitted to the Township. The report shall be reviewed by the
Township Engineer and other consultants as designated by the Township.
D. In addition to the Carbonate Assessment Report, the developer/applicant
shall also be required to provide the following information upon submittal
of the stormwater management plan:
1. A plan indicating the existing and proposed drainage conditions,
locations of all proposed private and public sewage disposal systems,
and the location of existing private and public water supplies on
adjoining properties (within 250 feet of applicant's property).
2. Type, location and phasing of proposed site disturbance and construction,
as well as proposed future ownership, utilization and maintenance
of the property and the proposed improvements, such as a homeowners'
association, property manager or other alternative.
3. Proposed measures to control potential adverse environmental impacts
on groundwater quality and stormwater management resulting from the
development and utilization of the property.
4. Plans describing the design and construction of the proposed stormwater
management facilities proposed for the project. A description of these
minimum requirements is outlined below.
E. Stormwater management.
1. All submissions for proposed developments must include a stormwater
management plan prepared in accordance with adopted regulations and
which limits surface water runoff and minimizes the concentrated infiltration
of surface water into the subsurface. The stormwater management facilities
that are required as part of the stormwater management plan include
the collection of all runoff from commercial, office and industrial
building roofs into storm drains by water tight gasketed joint conduits
or adequately lined drainage swales and the collection of surface
water flow on pavements into drop inlets connected to a water tight
gasketed joint stormwater conduit or adequately lined drainage swales.
The stormwater conduit must discharge into approved detention basins.
2. Approved stormwater conduits are HDPE, PVC, and concrete pipe, all
with water tight rubber gaskets at each joint. The use of corrugated
metal pipe is not permitted. Construction of the piping system must
follow all other applicable ordinances. Where rock is encountered
at or above the planned conduit design grade the rock shall be undercut
and over excavated a minimum of one foot and backfilled with a compacted
fine grained soil.
3. All detention basins in areas of sinkhole-prone soil shall be lined.
The liner used in a detention basin may consist of a clay liner, a
composite synthetic and soil liner or a synthetic liner. The permeability
of the clay liner shall be less than or equal to 10-6 centimeters per second. The type of liner required shall depend
on the condition of the detention basin bottom and the probability
of sinkhole occurrence resulting from the construction of the detention
basin. The use of low flow channel may also be required depending
on the duration and frequency of stormwater discharge into the detention
basin. Subsurface detention systems must be in leak proof tanks or
piping. The determination of the type of liner required for areas
with a moderate to high risk of sinkhole activity shall be determined
by the Geotechnical Engineer or Geologist and submitted to the Township
Engineer for review and approval.
4. Additional items that must be included in the stormwater management
plan include details with regard to the sealing of all pavement curbs
and gutters, manholes and drop inlets.
F. Limitations. In carbonate bedrock, alteration and development of
land may be hazardous with respect to foundation safety of structures,
the creation of unstable land as a result of changes in drainage,
the contamination of ground and surface waters, and infringements
on ground stability by neighboring uses. Within the limitations of
the information available at the time of the review of individual
applications, the Township shall attempt to make reasonable judgments
as to the applicant's compliance with these regulations. Under
no circumstances shall the Township of Plymouth or any officer or
employee of the Township or consultant to the Township assume any
liability for any damages that may result from an applicant's
or any interested party's reliance upon the regulations or any
decisions made by the Township in the administration of such regulations
by an applicant, developer, and/or any other interested party.
[Ord. No. 1598, 3-9-2015]
The municipality requires submission of a complete SWM site
plan, as specified in this Ordinance.
A. Proof of application or documentation of required permit(s) or approvals
for the programs listed below shall be part of the plan:
1. NPDES Permit for Stormwater Discharges From Construction Activities.
2. Any other permit under applicable state or federal regulations.
B. Six (6) copies of the SWM site plan shall be submitted to the following
agencies:
1. Two (2) copies to the municipality accompanied by the requisite municipal
review fee, as specified in this Ordinance.
2. Two (2) copies to the County Conservation District.
3. One (1) copy to the municipal engineer (where applicable).
4. One (1) copy to the County Planning Commission/Department if the
regulated activity is also required to submit a subdivision and/or
land development plan to the County Planning Commission in accordance
with the Pennsylvania Municipalities Planning Code.
C. Any submissions to the agencies listed above that are found to be
incomplete shall not be accepted for review and shall be returned
to the applicant with a notification in writing of the specific manner
in which the submission is incomplete.
D. Additional copies shall be submitted as requested by the municipality
or PADEP.
[Ord. No. 1598, 3-9-2015]
A. The SWM site plan shall be reviewed by a qualified professional on
behalf of the municipality for consistency with the provisions of
this Ordinance. After review, the qualified professional shall provide
a written recommendation for the municipality to approve or disapprove
the SWM site plan. If it is recommended to disapprove the SWM site
plan, the qualified professional shall state the reasons for the disapproval
in writing. The qualified professional also may recommend approval
of the SWM site plan with conditions and, if so, shall provide the
acceptable conditions for approval in writing. The SWM site plan review
and recommendations shall be completed within the time allowed by
the Municipalities Planning Code for reviewing subdivision plans.
B. The municipality will notify the applicant in writing within 45 days
whether the SWM site plan is approved or disapproved. If the SWM site
plan involves a subdivision and land development plan, the notification
period is 90 days. If a longer notification period is provided by
other statute, regulation, or ordinance, the applicant will be so
notified by the municipality. If the municipality disapproves the
SWM site plan, the municipality shall cite the reasons for disapproval
in writing.
[Ord. No. 1598, 3-9-2015]
A modification to a submitted SWM site plan that involves a
change in SWM BMPs or techniques, or that involves the relocation
or redesign of SWM BMPs, or that is necessary because soil or other
conditions are not as stated on the SWM site plan as determined by
the municipality shall require a resubmission of the modified SWM
site plan in accordance with this article.
[Ord. No. 1598, 3-9-2015]
A disapproved SWM site plan may be resubmitted, with the revisions
addressing the municipality's concerns, to the municipality in
accordance with this article. The applicable review fee must accompany
a resubmission of a disapproved SWM site plan.
[Ord. No. 1598, 3-9-2015]
The municipality's approval of an SWM site plan authorizes
the regulated activities contained in the SWM site plan for a maximum
term of validity of 5 years following the date of approval. The municipality
may specify a term of validity shorter than 5 years in the approval
for any specific SWM site plan. Terms of validity shall commence on
the date the municipality signs the approval for an SWM site plan.
If an approved SWM site plan is not completed according to Section
407 within the term of validity, the municipality may consider the
SWM site plan disapproved and may revoke any and all permits. SWM
site plans that are considered disapproved by the municipality shall
be resubmitted in accordance with Section 406 of this Ordinance.