A. All regulated activities within the Township shall be designed, implemented, operated and maintained to meet the purposes of this chapter, through these two elements:
(1) Erosion and sediment control during earth disturbance and construction activities (e.g., during construction).
(2) Water quality protection measures after completion of earth disturbance and construction activities, including operations and maintenance. These measures are also known as "postconstruction stormwater management."
B. No regulated activities within the Township shall commence until the requirements of this chapter are met.
C. Erosion and sediment control during regulated activities shall be addressed as required by § 206-33.
D. Postconstruction water quality protection shall be addressed as required by § 206-34. Operations and maintenance of permanent stormwater BMPs shall be addressed as required by Article IV and Article V of this chapter.
E. All BMPs used to meet the requirements of this chapter shall conform to the state water quality requirements, and any more stringent requirements as determined by the Township.
F. Techniques for low-impact development practices described in Article XI of this chapter are encouraged because they reduce the impacts on development and promulgate compliance with the requirements of this chapter and the state water quality requirements.
G. The standards referred to in this article shall apply as minimum design standards; however, federal and state regulations may impose additional standards subject to their jurisdiction.
H. Chapter 240 and the following requirements apply to existing watercourses and natural drainage features:
(1) Whenever a watercourse is located within a development site, it shall remain open in a natural state to maintain pre-development conditions. This requirement may be waived on a case-by-case basis by the Board to limit enclosure and disturbance in furtherance of public health, safety and welfare.
(2) The existing points of natural drainage discharge onto adjacent property shall not be altered without the written approval of the affected landowners and the grant of a permanent drainage easement by the landowners.
(3) No stormwater runoff or natural drainage shall be so diverted as to overload existing drainage systems (including existing stormwater management facilities) or create flooding.
(4) The Township may require a developer to grant to the Township a permanent drainage easement along any watercourse located within or along the boundary of any property being subdivided or developed. The purpose of any such easement shall be for the maintenance of the channel of any watercourse. The terms of the easement shall prohibit the placing of fill or structures and any alterations which may adversely affect the watercourse. The required width of any such easement shall be determined by the Township Engineer, and in no case shall such easement be less than 50 feet in width. The developer will retain maintenance responsibility for the easement until such time as the following are accomplished:
(a) The easement is offered for dedication by the developer and accepted by the Township; and
(b) If an easement acceptable to the Township is established and officially entered upon the deeds of those properties affected by the easement by the Montgomery County Office for the Recording of Deeds, the maintenance shall then be the responsibility of the individual lot owners over whose property the easement passes. For land developments, the maintenance shall then be the responsibility of the lot owner upon which the watercourse traverses; or
(c) A homeowners' association or other approved legal entity, approved by the Township, assumes responsibility for the maintenance of the development, including the watercourse easement.
I. Developers shall construct and/or install stormwater management facilities, on and offsite, as necessary to:
(1) Prevent erosion damage and to satisfactorily carry off, detain or retain and control the rate and volume of stormwatcr discharge.
(2) Manage the anticipated peak discharge from property being developed and existing runoff being contributed from all land at a higher elevation in the same watershed.
(3) Manage volume of runoff. Postdevelopment conditions shall not exceed predevelopment conditions.
(4) Convey stormwater along or through the property to an outfall.
(a) If diffused flow is proposed to be concentrated and discharged onto an adjacent property, the developer must document that adequate downstream conveyance facilities exist to safely transport the concentrated discharge or otherwise prove that no erosion, sedimentation, flooding or other harm will result from the concentrated discharge.
(b) An outfall shall have sufficient capacity to receive stormwater without deterioration of the facility and without adversely affecting property in the Township. This outfall may be a stream or other drainage facility so designated by the township.
(c) Roof runoff.
[1] Roof runoff shall be conveyed into watercourses on the property or to a storm drainage system of the Township. However, a direct connection of roof drains to watercourses and storm drainage systems is prohibited unless approved by the Township Engineer. Discharge from roof drains over a sidewalk, into a driveway, over a parking area or into gutters will not be permitted.
[2] Compliance with groundwater recharge requirements requires that roof runoff generated by the groundwater recharge design storm be infiltrated on-site. Infiltration can be achieved locally (e.g., dry wells, french drain) or in conjunction with other on site BMP's (e.g., infiltration trench, bioretention area, porous pavement sand filter).
[3] Where conditions are not suitable for groundwater recharge, roof drains are required to discharge onto a vegetated surface (e.g., lawn, filter strip, swale, grassed waterway). The minimum length of the flow path between the drain outlet and the point of discharge to a watercourse or storm sewer inlet shall be 20 feet.
[4] Unsuitable groundwater recharge conditions must be documented to the satisfaction of the Township Engineer.
[5] Roof runoff discharge points shall be no closer than 20 feet to an adjoining property.
(d) Water originating from other than natural sources, such as air-conditioning units, sump pumps or other dry weather flow, wherever practicable, shall be discharged to infiltration areas or negative BMPs at the direction of the Township Engineer. Discharge from sump pumps shall be no closer than 20 feet to an adjoining property.
(e) Water from swimming pools or similar uses containing chlorine shall be pretreated to remove chlorine to acceptable limits prior to discharge.
J. A horizontal riparian corridor buffer area shall be established between the top of bank or high water mark of a water body and a line one foot above the one-hundred-year base flood elevation or from the top of bank or high water mark of a water body and a line 50 feet from the top of bank or high water mark of the water body, whichever distance is greater. The riparian corridor may be part of any lot to meet minimum lot area and minimum yard requirements. No building or structure of any kind or any work, such as earth disturbance or excavation, shall be permitted within the riparian corridor except as permitted within the Floodplain Conservation District under chapter 255, Article XXII, Floodplain Conservation District.
K. Where applicable, construction of stormwater management facilities shall comply with the requirements of chapter 102 (Erosion Control), chapter 105 (Dam Safety and Waterway Management) and chapter 106 (Flood Plain Management) of Title 25, Pa Code, Rules and Regulations of DEP. Inquiries regarding dam safety permit requirements or other concerns shall be addressed to DEP. Copies of any correspondence to and from DEP must be provided to the Township.
L. Stormwater management facilities which are located in, adjacent to or that will discharge to a state highway right-of-way shall be subject to the approval of the Pennsylvania Department of Transportation (PennDOT). Copies of any correspondence to and from PennDOT must be provided to the Township.
M. Stormwater management facilities located within or affecting any floodplain shall be subject to the requirements of applicable DEP codes and the Township Code which regulates construction and development within areas which are subject to flooding. See Chapter 255, Zoning, Article XXII, Floodplain Conservation District.
N. A permanent access easement to stormwater management facilities for maintenance purposes shall be granted to the Township for maintenance and operation of the facilities. Accessways shall be cleared and stabilized to a minimum of 20 feet wide, with an all-weather surface suitable for access for maintenance equipment and personnel. Proximity of facilities to public rights-of-way shall be encouraged in order to minimize the length of accessways. Multiple accessways shall be encouraged for major or regional facilities. The owner of the servient property shall be responsible for maintenance of the easement. A deed restriction to the satisfaction of the Township Solicitor shall be submitted to provide for maintenance, to authorize the Township to take corrective maintenance measures if necessary and to lien the cost of the work against the property should corrective measures not be performed by the homeowner, association or entity owning the property.
0. Additional studies and higher levels of control than the minimum provided in the requirements and criteria of this chapter may be required by the Board of Commissioners to ensure adequate protection of life and property and preservation of water quality.
P. A drainage release or easement, in a form approved by the Township Solicitor, may be required by the Township for discharges to adjoining properties and watercourses.
Q. Landowners shall comply with any future requirements promulgated by the Township in order to conform with any local, county, state or federal watershed management plans adopted in the future.