Long Hill Township City Zoning Code
§ LU-146.3
Design Standards.
[2-24-2021 by Ord. No. 469-21]
a.
Major Developments. All major developments shall have their stormwater management designed in accordance with the Residential Site Improvement Standards (RSIS, N.J.A.C. 5:21) and the NJDEP Stormwater Rule (N.J.A.C. 7:8) to include green infrastructure as outlined in N.J.A.C. 7:8. These standards shall apply to all projects, residential and nonresidential as well as projects by the Township, Board of Education and other agencies subject to review by the Township.
b.
Minor developments shall be designed to include the following stormwater management measures where applicable:
1.
Seepage pits or other infiltration measures shall be provided with a capacity of four inches of runoff for each square foot of increased impervious area.
2.
When the approving agency finds that the existing conditions are not conducive to infiltration, the applicant may provide other stormwater management facilities as to result in a zero net runoff as calculated by the Modified Rational Method.
3.
When the ground surface is changed in character such that an increase in runoff results, but the new surface is not impervious, seepage pits or other stormwater management facilities shall be provided to result in a zero net runoff rate as calculated by the Modified Rational Method.
c.
Drywell Design: Stone used in the infiltration devices shall be 2 1/2 inches clean stone and design void ratio of 33% shall be used. The infiltration measures shall be designed with an overflow to the surface which shall be stabilized and directed to an existing stormwater conveyance system or in a manner to keep the overflow on the developed property to the greatest extent feasible. If the new impervious surface is not roof area, an equivalent area of existing roof may be directed to the infiltration system. This shall be permitted where the existing roof is not already directed to infiltration devices. The infiltration of water during the rainfall event shall not be counted as a "credit" toward the storage requirement.
d.
Soil erosion and sediment control measures shall be installed in accordance with the Standards for Soil Erosion and Sediment Control in New Jersey.
e.
For the purposes of this section, gravel areas that are subject to compaction (such as driveways, parking areas and walking paths) shall be considered impervious. Pool surface areas, patios and decks shall be considered impervious. Gravel areas not subject to compaction (such as decorative stone used in planting beds) shall be considered pervious.
f.
All roof gutters shall be protected from the accumulation of leaves and litter by the installation of a gutter cap leaf separation device within the project area. Gutter screens or louvers are not acceptable.