(a) All wet basins shall be designed in a manner that seeks to mitigate the proliferation of mosquito breeding habitats and the potential spread of the West Nile Virus. This can be accomplished through the following means:
(1) The design of a storm water wetland/wet basin must include the selection of hydrophytic plant species for their pollutant uptake capabilities and for not contributing to the potential for vector mosquito breeding. The establishment of hydrophytic vegetation will promote the population of the wetland/ wet basin by amphibians and other mosquito predators. In natural wetlands, predatory insects and amphibians are effective at keeping mosquito populations in check during the larval stage of development while birds and bats prey on adult mosquitoes. Refer to Appendix B of the PA SWM BMP Manual (current version) for hydrophytic native plant species lists.
(2) Aeration fountains and stocked fish can be added to keep larval mosquito populations in check.
(b) The Municipality reserves the right to disapprove any design that would result in the construction or continuation of a storm water problem area.
(c) When the elevation of any existing or proposed entrance to a structure, including windows, is lower than the elevation of the public cartway serving that site, a grading plan shall be submitted, reviewed and approved as part of the SWM approval process for the proposed structure.
(d) No storm water detention facility shall be placed within 50 feet of a special geologic feature. No subsurface storm water conveyance facility shall be constructed within 50 feet of a special geologic feature, without written permission of the Municipality.
(e) Storm water management facilities located outside of existing or proposed public rights-of-way shall be located within and accessible by easements granted to the Municipality as follows:
(1) Access easements. Where proposed storm water management facilities are not adjacent to proposed or existing public right-of-ways or are not accessible due to physical constraints, as determined by the Municipality, a 20-foot-wide access easement specifying rights of entry shall be provided commensurate to need. Access easements shall provide for vehicle ingress and egress on grades of less than 10% for carrying out inspection or maintenance activities. A permanent 15-foot wide vehicular access road within the easement(s) shall be provided around all SWM BMPs, such as ponds and infiltration structures. The access roads shall connect to a public thoroughfare. The access road (when applicable) will also provide access at a slope no greater than 20% to the bottom of all ponds and associated outlet structures. The access road shall be constructed of either gravel or pavement and maintained per the maintenance agreement. The Municipality reserves the right to alter the design of the access to any SWM BMP. Vehicle ingress and egress and access roads are not required for SWM BMPs serving one Single-Family Residential lot and located on the same lot they serve.
(2) Maintenance easements.
A. The maintenance easement must be located 20 feet outside of the footprint for the storm water facility and appurtenances.
B. Maintenance easements are not required for SWM BMPs serving one Single-Family Residential lot and located on the same lot they serve.
(3) Easements shall state that no trees, shrubs, structures, excavation, placement of fill, or re-grading are to be performed within the easement without written approval from the Municipality upon review by the Municipal Engineer. Upon approval of the Municipality, such landscaping may be placed in maintenance easements, provided it does not impede access.
(4) Whenever practicable, easements shall be parallel to width and linked to property lines of the subdivision.
(5) All easement agreements shall be recorded with a reference to the recorded easement indicated on the site plan. The format and content of the easement agreement shall be reviewed and approved by the Municipality and Solicitor.
(f) In order to promote overland flow and infiltration, roof drains shall not discharge directly to streets or storm sewers. Roof drains may discharge directly to streets or storm sewers when deemed necessary by the Municipality. Under no circumstances shall roof drains discharge directly to sanitary sewer systems.
Projects that have the potential to discharge into surface waters that have existing or designated HQ or EV uses (including EV wetlands), have impairments due to storm water, are connected to combined sewer systems, or have the potential to have an adverse effect on threatened or endangered species, or critical habitat for such species, are subject to additional BMP measures that must be considered and implemented for projects occurring in these more environmentally-sensitive areas:
Constructed wetlands/Wet ponds | Significant detention of peak flow rates is needed and the contributing drainage area is large; retrofit existing detention basins or construct new in open median or interchange areas |
Permeable pavement | Limited to park-and-ride sites and parking lots |
Manufactured products: Subsurface storage, water quality inlets, etc. | Subsurface storage products are designed to temper peak runoff events through infiltration and/or discharge rate reduction. Storm sewer inlet structures or inserts are designed to minimize the discharge of solids, floatables, and oil/grease pollutants. Regular maintenance of these products is necessary and is an important factor in assessing the feasibility of using one of these products. |
Proposed infiltration BMPs within two miles on either side of surface water supply areas or surface waters that have existing or designated HQ or EV uses (including EV wetlands) must be designed and constructed to provide maximum pollutant removal prior to the runoff being infiltrated or discharged to the receiving stream. PADEP defines the following zones around such waters:
(1) Zone A. Represents a 1/4-mile buffer on either side of the river or stream extending from the area 1/4 mile downstream of the intake upstream to the five-hour time-of-travel (TOT) (Pennsylvania Department of Environmental Protection, 2006).
(2) Zone B. Represents a two-mile buffer on either side of the water body extending from the area 1/4-mile downstream of the intake upstream to the 25-hour TOT. (Pennsylvania Department of Environmental Protection, 2006).
(3) Zone C. The remainder of the watershed area (Pennsylvania Department of Environmental Protection, 2006).
(g) Ground Water Supply Protection.
(1) Zone 1. The innermost protective zone surrounding a well, spring, or existing infiltrative gallery. Zone 1 is the area within a radius of 400 feet around a community or public water supply source unless information is presented supporting a reduction of this requirement. Proposed infiltration BMPs are not permitted within Zone 1 protection areas (Pennsylvania Department of Environmental Protection, 2006).
(2) Zone 2. The capture zone that encompasses the area of the aquifer through which it supplies water to a well, spring, or existing infiltration gallery. Zone 2 is one-half mile radius around a community or public water supply source unless more extensive hydrogeological testing is done. Extreme care should be used when implementing infiltration BMPs in Zone 2 areas. Pretreatment measures must be used to filter and diminish pollutants (Pennsylvania Department of Environmental Protection, 2006).
(3) Zone 3. The area outside Zone 2 that contributes significant recharge to the capture zone aquifer in Zone 2 (Pennsylvania Department of Environmental Protection, 2006). Use of infiltration BMPs is not restricted.
(4) Infiltration BMPs are not permitted within a radius of 50 feet from privately-owned wells and water sources serving non-community supply systems (Pennsylvania Department of Environmental Protection, 2006).
(Ord. 2458. Passed 11-15-10.)