Subpart C. Stormwater Management.
§221. General Requirements.
1. Applicants proposing regulated activities in the Township which do not fall under the exemption criteria in §232 shall submit a drainage plan consistent with the applicable Act 167 Plan and this Part to the Township for review and approval. These exemption criteria shall apply to the total proposed development even if development is to take place in stages.
2. The applicant is required to perform and submit an alternatives analysis to find practicable alternatives to the surface discharge of stormwater, the creation of impervious surfaces and the degradation of waters of the Commonwealth, and must maintain as much as possible the natural hydrologic regime.
3. The applicant shall design the drainage plan through an alternatives analysis consistent with the sequencing provisions of §222 to ensure maintenance of the natural hydrologic regime and to promote groundwater recharge and protect groundwater and surface water quality and quantity. The drainage plan design professional must proceed sequentially in accordance with Part 2C of this Part and present evidence demonstrating that he has followed the sequence with the drainage plan.
4. The applicant shall provide stormwater drainage systems in order to permit unimpeded flow along natural watercourses, except as modified by stormwater management facilities or open channels consistent with this Part.
No person all alter existing points of concentrated drainage that discharge onto adjacent property in any manner which could cause property damage without permission of the affected property owner. All alteration of existing points of discharge shall be subject to any applicable discharge criteria specified in this Part.
5. Areas of existing diffused drainage discharge shall be subject to any applicable discharge criteria in the general direction of existing discharge, whether proposed to be concentrated or maintained as diffused drainage areas, except as otherwise provided by this Part. If diffused drainage discharge is proposed to be concentrated and discharged onto adjacent property, the applicant shall document that adequate downstream conveyance facilities exist to safely transport the concentrated discharge, or otherwise prove that no erosion, sedimentation, flooding or other impacts will result from the concentrated discharge.
6. Where a development site is traversed by existing watercourses, drainage easements (for natural and artificial watercourse) shall be provided conforming to the line of such watercourses. The terms of the easement shall conform to the stream buffer requirements (for natural watercourses) contained in §223(I)(6) of this Part.
7. All drainage plans shall include a consumptive use tracking report as required in §229.
8. Any stormwater management facilities regulated by this Part that would be located in or adjacent to waters of the Commonwealth or wetlands shall be subject to approval by DEP through the joint permit application process, or, where deemed appropriate by DEP, the general permit process. When there is a question whether wetlands may be involved, it is the responsibility of the applicant to show that the land in question cannot be classified as wetlands, otherwise approval to work in the area must be obtained from DEP.
9. Any stormwater management facilities regulated by this Part that would be located on State highway rights-of-way shall be subject to approval by PennDOT.
10. Infiltration of runoff through seepage beds, infiltration trenches, etc., where soil conditions permit, and minimization of impervious surfaces to the extent permitted by the Zoning Ordinance [Chapter 27] are encouraged to reduce the size or eliminate the need for, detention facilities or other structural BMPs.
11. Roof drains shall not be connected to streets, sanitary or storm sewers or roadside ditches in order to promote overland flow and infiltration/ percolation of stormwater where advantageous to do so. Considering potential pollutant loading, roof drain runoff in most cases will not require pretreatment.
12. All stormwater runoff, other than roof top runoff discussed in subsection (11) above, shall be treated for water quality prior to discharge to surface or groundwater. (Ord. 181, 10/11/2006, §301)