See the provisions of the township stormwater management and floodplain regulations (see also Chapters 151 and 152).
(A) Landscaped screening of detention basins.
(1) A detention basin with a basin depth of greater than 20 inches shall have landscaping that screens it from view of existing dwellings, a residential zoning district or a public street, unless the basin would meet either of the following conditions:
(a) It would have an average slope of less than four to one (4:1) on the inside of the berm of the basin and both the inside and outside of the basin would be planted in grass and intended to be mowed or planted in other attractive vegetative ground cover; or
(b) It would be designed to closely resemble a natural pond and be a scenic asset.
(2) Any required screening shall meet the landscaping standards of the township zoning ordinance, unless the Board of Supervisors approve an alternate landscaping arrangement that serves the same purposes. This landscaping shall not be required along an area where natural vegetation will be maintained that will completely fulfill this purpose.
(3) Thorny and prickly shrubs (that are also attractive) are encouraged to be used around detention basins to discourage entry by children, if there may be a hazard.
(4) Areas of stormwater basins that are visible from streets and dwellings shall be attractively maintained.
(5) Recreation: when reasonable, efforts should be made to allow suitable recreational uses of portions of detention areas. This might include designing a detention basin with a low-flow channel so that only a portion would be wet after a minor storm, and the remainder would be well-drained during all except the most serious storms. These areas may be acceptable at the discretion of the township as part of any township requirement to provide recreation land.
(B) Stormwater easements.
(1) Where required: where a subdivision or development is traversed by a watercourse, drainageway, channel or stream that the Township Engineer determines is subject to significant stormwater flows, there shall be provided a drainage easement established along the following:
(a) The 100-year floodway, where that is defined; and
(b) Where a 100-year floodway is not defined, a width shall be used that includes a minimum of 25 feet on each side of the top of the primary bank of the waterway.
(2) The drainage easements required by division (B)(1) above are intended to preserve the unimpeded flow of natural drainage and to provide for future possible widening, deepening, relocating, improving or protecting of such drainage facilities. The Township Engineer may require up to a one-half foot freeboard and/or an additional ten feet building setback if deemed necessary along newly constructed watercourses.
(3) If a major human-made drainage channel would pass within close proximity to homes and possibly threaten the safety of persons, the Board of Supervisors, based upon the advice of the Township Engineer, may require such certain lengths of such channel to be placed within appropriate underground pipes.
(4) It shall be the responsibility of the applicant to obtain all stormwater easements on, over or through other properties that are needed to carry out the proposed storm management plan.
(5) Areas where stormwater easements have or will be granted shall not be obstructed during or after construction.
(6) See also the easement requirements in § 154.170, including provisions regarding maintenance and obstructions.
(C) Floodplain regulations. See the township floodplain regulations and the relevant provisions of the State Construction Codes.
(1) Fill shall not be allowed within the 100-year floodplain if it would cause any increase in flood levels.
(2) If fill is used within the 100-year floodplain, it shall meet the following additional requirements:
(a) It shall extend laterally at least 15 feet beyond any proposed building footprint;
(b) It shall consist of well-compacted materials to provide the necessary resistance to erosion, scouring or settling; and
(c) It shall not have a finished slope greater than three to one (3:1).
(3) The finished elevation of a proposed street shall be above the 100-year flood level. The applicant shall provide profiles and elevations to show that this requirement will be met.
(4) Any structure within the 100-year floodplain shall include openings as needed to allow flood flows to be discharged without increasing flood heights.
(5) Sanitary sewage systems shall be floodproofed up to the 100-year flood level.
(6) No on-lot septic system shall be located within the 100-year floodplain.
(7) All water supply facilities shall be floodproofed up to the 100-year flood level and shall be designed to minimize infiltration of floodwaters into the water supply.
(D) Fencing. The Board of Supervisors may require secure fencing to be placed around a stormwater basin.
(Ord. 127, passed 3-18-2010)