[Ord. #585, § 511A; Ord. #1103, § 25]
All development applications shall include drainage facilities capable of providing for stormwater as described below.
No development application shall be approved which causes an increase in the rate of discharge from the property as determined for a one-hundred-year storm with a twenty-four-hour duration except as provided herein.
The system shall be adequate to carry off or store the stormwater and natural drainage which originates not only within the lot or tract boundaries, but also that which originates beyond the lot or tract boundaries and traverses the site. No stormwater runoff or natural drainage shall be diverted so as to overload existing drainage systems or create flooding or the need for additional drainage structures on other private properties or public lands without adequate provision for off-tract improvements to accommodate the condition(s). Final disposition of stormwater shall be to an existing natural watercourse.
Techniques for computing stormwater runoff shall be as established by Somerset County. If alternate methods are used, they shall be submitted for review in addition to the required method.
As required, approval for drainage structures shall be obtained from the appropriate municipal, county, state and federal agencies and offices, or such approval shall be a condition of preliminary approval. When required, each applicant shall make application to the State Division of Water Policy and Supply of the Department of Environmental Protection, to the County Engineering Department and to the Township Engineer. Letters of approval from the appropriate governmental authorities shall be furnished to the Board Secretary, with copies to the Township Engineer.
All sump pumps, roof leaders and foundation drains shall be connected to the drainage system, if available.
Where a lot or a tract is traversed by a watercourse, surface or underground drainage system, channel or stream carrying water from an adjacent tract of land, there shall be provided and dedicated a drainage right-of-way easement to the Township conforming substantially with the lines of such watercourse, and such further width or construction or both as will be adequate to accommodate expected stormwater runoff in the future, based upon reasonable growth potential in the Township and, in any event, meeting the minimum widths and locations shown on an adopted Official Map or element of the Master Plan for the Township, or where not so shown, having a minimum width of 20 feet.
Detention Facilities. In lieu of on-site detention or retention, the applicant may request to provide an off-tract improvement in accordance with Article IX of this chapter. If agreed to by the Township, contributions for off-tract improvements shall be used for the study, design and/or construction of an off-tract detention or retention facility necessary to provide for the control of stormwater runoff in the drainage basin within which the proposed development is located.
As-built drawings of detention basins are to be certified by a New Jersey licensed professional engineer to confirm that the basin(s) have been constructed in accordance with Township standards and the approved subdivision or site plan.
[Ord. #585, § 511B]
Construction within a floodplain shall be in accordance with Subsection 21-14.3.
[Ord. #585, § 511C]
Storm sewers, open channels, bridges and culverts shall be designed for minimum flow capacities as follows:
[Ord. #585, § 511D]
See Section 21-42.