All storm drains shall be tangent between inlets, manholes or other structures, except that the use of fittings or factory-curved or mitered pipe may be allowed by the Township Engineer when necessary to accommodate existing geometry or utilities. Prior to laying any storm drains, the bottom of all trenches shall be inspected by the Township Engineer. Should the Township Engineer determine that the trench is unsuitable for placement of the pipe, the developer shall take all necessary action to remove or eliminate any unsuitable conditions. These may include, but are not limited to, excavation and backfilling with suitable material, placement of bedding material, construction of pipe cradles or such other action necessary to remove all unsuitable conditions. Proposed storm drainage installations which do not conform to the above must be fully detailed and approved as part of the final plat.

Materials used in the construction of storm sewers shall be constructed of reinforced concrete, ductile iron, corrugated polyethylene, or corrugated polypropylene or, when approved by the municipal engineer, corrugated metal. The most cost-effective materials shall be permitted that conform to local site conditions and reflect the relevant operations, maintenance, and system character of the municipal stormwater system. In unpaved areas, design engineers shall have the option to use inline drains and catch basins made from polyvinyl chloride (PVC). Installation shall conform to manufacturers' specifications. Specifications referred to, such as ASTM or AWWA, shall be the latest revision in effect at the time of application.

In continuous conduit runs, spacing between structures (inlets or manholes) shall not exceed 600 feet.

Structures (inlets or manholes) shall be located so as not to interfere with primary routes of pedestrian travel or any proposed handicapped ramp or similar facility.

In general, surface flow length, for flows of four or more cubic feet per second, on paved surfaces shall not exceed 750 feet, provided that:

Maximum design capacities which may be used to determine actual inlet location and spacing are:

Only Type B inlets shall be used in curbed roadways or curbed access or major circulation drives.

Generally, sufficient inlets will be placed to eliminate any flow exceeding two cubic feet per second across any intersections.

Parking areas may be designed to allow ponding in order to decrease intensity of runoff. In such case, ponding will not be allowed in any access or major circulation drive or in any area of heavy pedestrian activity and shall not exceed six inches at any point calculated for the appropriate design storm in accordance with Subsection H(1) and shall meet the criteria set forth in Subsection H(11).

Open channels shall be designed to contain the required flow and shall have a design velocity low enough, in the judgment of the Planning Board Engineer, to prevent erosion. The minimum easement for open channel sections shall be the maximum design top width of the channel section segment plus 25 feet rounded to the next highest five-foot increment. The excess easement area shall be provided offset to that side of the channel most convenient for use by maintenance crews. The minimum distance between the channel top edge and any easement line shall be five feet. Excess velocity, if any, as determined by the Planning Board Engineer, in open channels must be controlled by sod, riprap, paving, ditch checks or other suitable methods. Changes of direction in open channels must have a maximum radius of 800 feet or be adequately paved or riprapped.

Generally, unlined open channel cross sections shall have side slopes not steeper than 4:1 for channel depths of two feet or less and not steeper than 8:1 for channel depths of more than two feet. Lined open channel side slopes shall not be steeper than 2:1.

The bottoms of all unlined open channels and the channel side slopes, to at least the design flow level, will be sodded with suitable coarse grass sod.

All unlined open channel side slopes above the design minimum flow level will be topsoiled and seeded or otherwise suitably stabilized in accordance with an approved soil disturbance permit.

All unlined open channels which can be expected to have a base flow of five cubic feet per second or more for at least two out of every 12 months will be provided with a low flow channel using gabions, riprap, lining, one-third pipe sections or other arrangements approved as part of the final plat submission.

Design storm frequency.

Runoff calculations. Runoff determinations should be made using the rational formula or, in unusual cases, other methods with the prior approval of the Planning Board. Upstream areas should be considered based on their full development potential according to current zoning or the current use, whichever produces the greatest runoff. Runoff coefficients used should generally fall in the following ranges:

Velocity restriction.

Design formulas and friction factors. In general, the Manning formula will be used by the Planning Board to review the adequacy of proposed drainage facilities. Other formulas may be used in particular cases with the previous agreement of the Board. A friction factor (n) of 0.012 will be used for nonporous concrete pipe; a factor of 0.020 will be used for fully coated corrugated-metal pipe with paved invert. Commensurate factors will be used for other pipe types or shapes. A friction factor (n) of not less than 0.012 will be used for fully lined concrete channels; a factor of not less than 0.025 will be used for good earth channels; and a factor of not less than 0.100 will be used for fair to poor natural streams and watercourses. Commensurate factors will be used for other channel types.

All drainage facilities carrying runoff from tributary areas larger than 1/2 square mile must have the approval of the New Jersey Division of Water Policy and Supply.

All encroachments of natural waterways must be referred to the New Jersey Division of Water Policy and Supply for approval in accordance with statute. The state may retain jurisdiction, in which case a permit will be necessary as set forth above, or may refer the matter to the County Engineer for review.

All nonpipe culverts shall be designed for AASHO H20-44 loading. All culverts of any type shall be carried to the roadway right-of-way and shall terminate with headwalls or other approved end treatment. All conduits terminating or beginning in open channels shall be provided with headwalls or other appropriate end treatment.

Guardrails and/or railings shall be placed at all drainage structures where the interests of pedestrian or vehicular safety would dictate. The Planning Board may require that any open channel, other than naturally occurring streams, be fenced with chain link fencing 48 inches high if the banks of the channel are steeper than one foot vertically for every four feet horizontally and either the total depth of the channel exceeds four feet, or the channel would be expected to have a depth of flow greater than two feet more often than once every 10 years. For maintenance purposes, gates may be required by the Planning Board at approximately two-hundred-foot intervals.

Storm drainage systems shall be designed to include not only the proper drainage of the actual area of the specific development and the area tributary thereto but shall also include the disposal of the stormwater runoff to an adequate outlet or other means of final disposal of the stormwater, such as an ocean, river, running stream, lagoon or an existing adequate storm sewer.

The use of siltation and oil separation basins with controlled outflows will be required to prevent pollution of waterways when discharge is into a lagoon, bay or other standing body of water.

Whenever sump conditions occur, an analysis shall be made of the effect of the occurrence of a major storm having at least a one-hundred-year return frequency. The effect of such storm and the flooding limits anticipated shall be shown. Site design, grading and drainage shall anticipate such major storm and be so arranged as to prevent damage to existing or proposed structures or adjacent properties under such conditions.

The existing system of natural drainage within each development shall be preserved to the maximum extent possible. To this end, the Board may require the preservation of natural drainage swales, recharge areas, wet weather ponds and similar features and may require suitable drainage and conservation easements and possible increases in lot size to allow usable lots with the preservation of such features.

Subject to review and approval by the Board, the design of the development may be modified to take advantage of the natural drainage features of the land. In such review, the Board will use the following criteria:

All developments or portions of total schemes of development which, based upon the preliminary plat submission, total 15 or more acres will be expected, to the extent that the Board considers possible, to limit the total stormwater runoff from the site after development to not more than 115% of the runoff from the site in its undeveloped state. The utilization of the provisions of this section to limit such runoff are encouraged. However, the Board may require the use of reasonable artificial methods of detention and/or recharge if it determines that natural provisions are not feasible. The Board may waive the provisions of this section if the nature of the development, the character of adjacent previously developed areas or other factors make the utilization of natural drainage features or runoff-limiting devices inadvisable or impractical.

Single-family/two-family residential subdivisions and multifamily residential developments.

Nonresidential subdivisions, commercial and/or industrial developments. All storm drainage facilities constructed and/or located within nonresidential subdivisions or associated with commercial and/or industrial developments shall not be dedicated to the Township. The repair, construction and/or maintenance of such facilities shall remain the responsibility of the developer and all subsequent owners of the subject property. All proposed drainage facilities shall, however, meet all standards of this chapter and shall be subject to the review and approval of the Planning Board, the Board of Adjustment or the Township Engineer, as the case may be. Notwithstanding this provision, the developer shall grant to the Township an easement permitting the Township to enter upon the subject property to repair, reconstruct and/or maintain such private drainage facilities in the event of a default by the developer or any subsequent owner to so repair, reconstruct and/or maintain said drainage facilities. Said easement shall provide that the Township shall have the right but not the obligation to enter onto the subject property to perform all acts necessary to repair, reconstruct and/or maintain such facilities. Said easement shall further provide that in such an event the Township shall assess the developer or the subsequent owner a sum equal to 120% of the actual costs incurred by the Township relating to the repair, reconstruction and/or maintenance of said facilities and reasonable attorney fees and court costs. The rights of the Township shall be enforceable in a court of competent jurisdiction. The form of said easement shall be reviewed and approved by the Attorney for the Planning Board, Board of Adjustment and by the Township Engineer or his designee. Upon approval, said easement shall be recorded by the developer with the Ocean County Clerk prior to the signing of the approved site plan or issuance of a building permit, as the case may be.