(A) Lots shall be laid out and graded to provide positive drainage away from buildings. The Township Board of Supervisors may require a grading and drainage plan for individual lots indicating a buildable area within each lot, complying with the setback requirements, for which positive drainage is assured.
(B) No person, corporation or other entity shall block, impede the flow of, alter, construct any structure or deposit any material or thing, or commit any act which will affect normal or flood flow in any communal stream or watercourse without having obtained prior approval from the Department of Environmental Protection.
(C) Where a subdivision or land development is traversed by a natural watercourse, there shall be provided a drainage easement or right-of-way conforming substantially with the line of such watercourse and of such width as will be adequate to preserve natural drainage.
(D) The subdivider or developer, and each person, corporation or other entity which makes any surface changes, shall be required to:
(1) Collect on-site surface runoff and dispose of it to the point of discharge into the common natural watercourse of the drainage area; and
(2) Design, construct and/or install such drainage structures and facilities as are necessary to prevent erosion damage to the subdivision or land development, adjacent property and downstream property. Such structures and facilities shall satisfactorily convey such surface waters to the nearest practical street, storm drain, detention pond or natural watercourse.
(E) All storm drainage facilities shall be adequately designed for the anticipated runoff when the area is fully developed, using criteria or other methods approved by the Township Engineer. Storm drainage facilities shall comply with, but are not limited to, the following.
(1) Storm sewers shall be located in the street right-of-way or in designated drainage easements.
(2) All pipe culverts and related installations used in the construction of storm sewers shall be in accordance with standards and specifications of the township, county or state, as designated and approved by the governing body.
(3) Manholes or inlets will generally be required at changes in alignment and grade.
(4) At no time will roof drains or foundation drains be allowed to be connected to a sanitary sewer system.
(5) Any springs encountered during construction shall be piped and connected to the storm sewer system or extended to a natural watercourse as may be approved by the Township Engineer.
(6) Concrete headwall and splash aprons shall be constructed at the outfall of all storm sewers. Where watercourses are piped and filled, concrete headwalls and splash aprons shall be constructed at both ends of the pipe.
(7) Whenever construction stops or concentrates the natural flow of surface drainage in such a way as to affect adjoining properties, written approval must be obtained from the adjoining property owners. Where storm drainage is piped onto adjoining properties other than natural watercourses, written permission, a release of damages and right-of-way must be obtained from the adjoining property owners before the storm sewers are taken over by the township. Approval of plans by the township does not authorize or sanction drainage affecting adjoining properties.
(8) All bridges and culverts shall be designed to support expected loads and to carry expected flows and shall meet the current specifications and standards of the Pennsylvania Department of Transportation.
(9) A complete drainage plan of the subdivision shall be submitted, including all necessary storm sewers and appurtenances, the design of which is based on a ten-year storm frequency, except in those areas where, in the judgment of the Township Engineer or governing body, the likelihood of exceptional damage resulting from stormwater is such that additional design criteria is required. The drainage plan shall show the method of drainage of adjacent and contiguous territory and the method of disposal of all stormwater collected. The drainage plan shall be accompanied by design calculations.
(10) The storm drainage system shall be provided as necessary to:
(a) Discharge stormwater runoff into common natural watercourses;
(b) Adequately drain all low points along streets;
(c) Intercept street stormwater runoff at intervals related to the extent and grade of the area drained;
(d) Provide positive drainage away from sewage facilities;
(e) Handle existing off-site runoff through the subdivision; and
(f) Ensure safe and proper disposal of stormwater where open watercourses are planned, through adequate safety, erosion and aesthetic measures.
(11) Stormwater management shall meet all state, county and local standards.
(2003 Code, § 146-24) (Ord. 2-96, passed 7-5-1996)