(A) All regulated activities in the borough shall be subject to the stormwater management requirements of this chapter.
(B) Storm drainage systems shall be provided to permit unobstructed flow in natural watercourses except as modified by stormwater detention facilities, recharge facilities, water quality facilities, pipe systems or open channels consistent with this chapter.
(C) The existing locations of concentrated drainage discharge onto adjacent property shall not be altered without written approval of the affected property owner(s).
(D) Areas of existing diffused drainage discharge onto adjacent property shall be managed such that, at minimum, the peak diffused flow does not increase in the general direction of discharge, except as otherwise provided in this chapter. If diffused flow is proposed to be concentrated and discharged onto adjacent property, the developer must document that there are adequate downstream conveyance facilities to safely transport the concentrated discharge to the point of predevelopment flow concentration, to the stream reach or otherwise prove that no harm will result from the concentrated discharge. Areas of existing diffused drainage discharge shall be subject to any applicable release rate criteria in the general direction of existing discharge whether they are proposed to be concentrated or maintained as diffused drainage areas.
(E) Where a site is traversed by watercourses other than those for which a 100-year floodplain is defined by the borough, there shall be provided drainage easements conforming substantially with the line of such watercourses. The width of any easement shall be adequate to provide for unobstructed flow of storm runoff based on calculations made in conformance with § 153.041 for the 100-year return period runoff and to provide a freeboard allowance of one-half foot above the design water surface level. The terms of the easement shall prohibit excavation, the placing of fill or structures, and any alterations which may adversely affect the flow of stormwater within any portion of the easement. Also, periodic maintenance of the easement to ensure proper runoff conveyance shall be required. Watercourses for which the 100-year floodplain is formally defined are subject to the applicable borough floodplain regulations.
(F) When it can be shown that, due to topographic conditions, natural drainage swales on the site cannot adequately provide for drainage, open channels may be constructed conforming substantially to the line and grade of such natural drainage swales. Capacities of open channels shall be calculated using the Manning Equation.
(G) Post construction BMPs shall be designed, installed, operated and maintained to meet the requirements of the Clean Streams Law, 35 P.S. §§ 691.1 to 691.1001 and implementing regulations, including the established practices in 25 Pa. Code Chapter 102 and the specifications of this chapter as to prevent accelerated erosion in watercourse channels and at all points of discharge.
(H) No earth disturbance activities associated with any regulated activities shall commence until approval by the borough of a plan which demonstrates compliance with the requirements of this chapter.
(I) Techniques described in Appendix F (Low Impact Development) of this chapter are encouraged because they reduce the costs of complying with the requirements of this chapter and the state water quality requirements.
(J) Infiltration for stormwater management is encouraged where soils and geology permit, consistent with the provisions of this chapter and, where appropriate, the Recommendation Chart for Infiltration Stormwater Management BMPs in Carbonate Bedrock in Appendix D.
(Ord. 226-2007, passed 5-7-2007)