A. All regulated activities within the Township which do not fall under the exemption criteria contained within Section 105 of this Ordinance shall submit a SWM Site Plan consistent with this Ordinance to the Township for review. These criteria shall apply to the total proposed development even if development is to take place in stages. Impervious surface shall include, but not be limited to, any roof, parking or driveway areas and any new streets and sidewalks. All gravel and crushed stone areas shall be assumed to be impervious unless designed as a BMP (e.g. pervious paver blocks, reinforced turf, gravel filled grids, etc.). (Refer definition of Impervious Surface within Article II of this Ordinance).
B. Regulated activities shall be designed, implemented, operated, and maintained to meet the purposes of this Ordinance, through these two elements:
1. Erosion and sediment control prevention during land development (i.e., earth disturbance during construction), and
2. Water quality protection measures after completion of land development (i.e., post- construction).
C. No approval of any subdivision or land development plan, or issuance of any building, Erosion and Sedimentation Control and Grading Permit, occupancy permit, or the commencement of any earth disturbance at a project site within the Township, shall proceed until the requirements of this Ordinance are met, including approval of a SWM Site Plan under Section 401 and a permit under PADEP regulations, where applicable.
D. Erosion and sediment control during land development shall be addressed as required by Section 310.
F. All Best Management Practices (BMPs) shall conform to the design criteria of this Ordinance and Pennsylvania Stormwater Management Practices Manual, December 30, 2006.
G. Stormwater drainage systems shall be provided in order to permit unimpeded flow along natural watercourses, except as modified by stormwater management facilities designed to encourage infiltration, groundwater recharge, and improved water quality.
H. Stormwater flows onto adjacent property shall not be created, increased, decreased, relocated, or otherwise altered without written notification to the adjacent property owner(s). Such stormwater flows shall be subject to the requirements of this Ordinance.
I. Existing points of concentrated drainage that discharge onto adjacent property shall not be altered without written approval of the affected property owner(s) and shall be subject to any applicable discharge criteria specified in this ordinance.
J. For all subdivision and land development applications, the tributary area discharging drainage to any location along the site property boundary shall not increase by more than twenty-five percent (25%) over the predevelopment condition without written approval from the adjacent affected property owner(s) and the Township.
K. Where a development site is traversed by watercourses, drainage easements shall be provided conforming to the line of such watercourses. The width of the easement shall be adequate to provide for the unimpeded flow of stormwater runoff from the 100-year storm event. However, in no case shall the easement be less than thirty (30) feet in width. 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. Periodic maintenance of the easement shall be required by the landowner to ensure proper runoff conveyance. The developer shall maintain the easement until such time as one of the following is accomplished:
1. For subdivisions or land developments where there is no homeowner’s association, condominium association, or other common ownership arrangement; the individual lot owner assumes responsibility for the maintenance of the portion of their property through which the easement passes. The record plan shall contain a description of such easement(s) and notation indicating the maintenance responsibilities.
2. A homeowner’s association or other legal entity approved by the Township assumes responsibility for maintenance of the development, including the watercourse easement. The record plan shall contain a description of such easement(s) and notation indicating the maintenance responsibilities.
L. 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 PADEP through the Joint Permit Application process, or, where deemed appropriate by PADEP, through the General Permit process.
M. Any stormwater management facilities regulated by this Ordinance that would be located on state highway rights-of-way, or discharge stormwater to facilities located within a state highway right-of-way, shall be subject to approval by the Pennsylvania Department of Transportation (PennDOT).
N. Site disturbance and impervious surface shall be minimized. Infiltrating stormwater runoff through seepage beds, infiltration trenches, etc. shall be required, where soil conditions permit, to reduce the size or eliminate the need for retention/detention facilities.
O. Roof drains and sump pumps shall discharge to an infiltration bed, natural watercourse, storm sewer system, or drainage swale (within a stormwater easement). Roof drains and sump pumps may be connected to storm sewer, drainage structure, or other approved stormwater conveyance facility when designed as part of a stormwater management BMP. In no case shall roof drains or sump pumps be connected to a sanitary sewer or permitted to discharge across a sidewalk, walkway, or to a street through the curb.
P. 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 Ordinance.
Q. 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.
R. 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.
S. If methods other than green infrastructure and LID methods are proposed to achieve the volume and rate controls required under this Ordinance, the SWM Site Plan must include a detailed justification demonstrating that the use of LID and green infrastructure is not practicable.
T. Special requirements for watersheds draining to high quality (HQ) and exceptional value (EV) waters: The temperature and quality of water and streams that have been determined to be exceptional value and high quality are to be maintained as defined in Chapter 93, Water Quality Standards, Title 25 Pennsylvania Department of Environmental Protection Rules and Regulations. Maintaining the multiple values of these Special Protection Waters occurs through maintaining the pre-development or natural water cycle; not decreasing infiltration and recharge; and not increasing runoff. In so doing, critical temperature considerations are provided (optimal temperature control is achieved through infiltration of precipitation to groundwater which maximizes temperature-moderated stream base flow). In those cases where Runoff Volume Control cannot be achieved as per Section 303.A.1, temperature sensitive BMPs and stormwater conveyance systems are to be used and designed with storage pool areas (drawing outflow from the bottom of the pool) and supply outflow channels shall be shaded with trees. This will require modification of berms for permanent ponds and the relaxation of restrictions on planting vegetation within the facilities, provided that capacity for volumes and rate control is maintained. At a minimum, the southern half of pond shorelines shall be planted with shade or canopy trees within ten (10) feet of the pond shoreline. In conjunction with this requirement, the maximum slope allowed on the berm area to be planted is 10 to 1. This will lessen the destabilization of berm soils due to root growth. A long-term maintenance schedule and management plan for the thermal control BMPs is to be established and recorded for all development sites.
U. All collected stormwater runoff shall be pretreated for water quality prior to discharge to surface or groundwater as required by Section 303 of this Ordinance.
V. Completed stormwater management facilities, including detention/retention basins, shall be surveyed by a professional land surveyor or engineer licensed in the Commonwealth of Pennsylvania, to verify compliance with the character of stormwater management facilities as depicted on the approved final plan (or subsequently approved revision, thereof). As-constructed plans shall be submitted to Springfield Township for review and approval, upon completion of construction of all facilities and prior to offer of dedication of any public facilities and/or submission of financial security for the required maintenance period. Public facilities will not be accepted by Springfield Township until such time the as-constructed plans have been reviewed and approved by the Township Engineer.
W. The record plan and development agreement for the approved subdivision or land development shall define the ownership and maintenance responsibilities as well as access rights for all drainage related easements. Specifically, the record plan shall contain a provision permitting access to such easement(s), at any reasonable time, for inspection and/or emergency repair/maintenance, by Springfield Township or its designee, of all facilities deemed critical to public welfare. In the event the lot owner or homeowner’s association fails to honor their maintenance responsibilities set forth herein, in any manner, Springfield Township shall have the right of entry upon and within the area of the easement to undertake any required corrective or maintenance effort. The total cost of such, including administrative, engineering, and legal costs for enforcement, may be imposed upon the responsible party as determined by Springfield Township.
(Ord. 186, passed 9-12-2017)