Design Details. Plans for drainage improvements shall show the full area included within the proposed drainage limits, including lands outside the tract; present and future land use and approximate average slope of the drainage basin; the profile and rate of gradient; location and size of proposed storm drain; its point of discharge into stream, lake, existing storm drain, etc.; and show all existing storm sewers indicating size, grade and elevation. The minimum design requirements for storm sewers shall be based on a sewer size of sufficient capacity to carry runoff for a storm frequency period of 50 years with the land use fully developed. The rational or the Soil Conservation Service method shall be used to determine the quantity of runoff. The gradients of the storm sewers shall be set to provide velocities of 2-FPS-minimum flowing full and 15 FPS maximum. (Use Mannings Formula) Minimum size of pipe for storm sewer and cross drains shall be 15 inches in diameter. The interval between inlets shall be in accordance with good engineering design but in no event exceed 400 feet on both sides of the street. Inlets shall be at each intersection, as directed by the Borough Engineer. Any structure for enclosing, damming, or bridging a natural stream shall be in accordance with the regulation of the State of New Jersey, Department of Environmental Protection. Relocating or improving the channel of any such stream may also require a permit from said agency.
All storm drains shall be constructed of reinforced concrete storm drain pipe conforming to the requirements of the New Jersey State D.O.T. Standard Specifications, with amendments or what may be deemed appropriate by the Borough Engineer.
All manholes, inlets and catch basins shall be constructed in accordance with the New Jersey State D.O.T. Standard Specifications, with amendments. Manholes shall be constructed at all changes in grade or direction or as directed by the Borough Engineer.
Headwalls shall be constructed in accordance with the New Jersey State D.O.T. Standard Specifications, with amendments. The backfill for all storm drain pipe and around inlets, manholes and other subsurface structures shall be thoroughly compacted in strict accordance with the New Jersey State D.O.T. Standard Specifications, with amendments.
Subbase outlet drains shall be constructed in general conformity with the requirements of underdrain type F. The pipe used in this drain shall be reinforced concrete storm drain pipe conforming to the provisions of the New Jersey State D.O.T. Standard Specifications, with amendments.
Underdrains, type F, shall be constructed to intercept side hill seepage, to drain wet sections of the roadway and to drain springs and other underground water which affect the stability of the subgrade. These shall be installed where and when directed by the Borough Engineer.
Subbase outlet drains shall be constructed to drain all subbased areas as directed by the Borough Engineer.
Pipe for underdrains and subbase outlet drains shall be porous wall concrete pipe when laid outside the street pavement, and shall be perforated bituminous coated corrugated metal pipe when laid under the street pavement. The pipe shall conform to the New Jersey State D.O.T. Standard Specifications with amendments.
Underdrains, type F, and subbase outlet drains shall be constructed in accordance with the New Jersey State D.O.T. Standard Specifications, with amendments, and shall conform to Borough details.