[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.
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.
c.
The date of submission.
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.
e.
A North arrow.
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.
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.[1]
[1]
Editor's Note: See 53 P.S. § 10101 et seq.
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[1] for reviewing subdivision plans.
[1]
Editor's Note: See 53 P.S. § 10101 et seq.
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.
