Rockleigh City Zoning Code

The application is for an alteration or addition to or the construction of a single one-family residence on a single lot not contiguous with another lot of the same ownership.

The application is for an alteration or addition or the construction of a building on land which is part of a major subdivision which meets the standards of § 32-7.5 of Chapter 32, Land Subdivision; that provisions for detention of the additional stormwater runoff from such improvement were provided by the subdivider; and that construction proposals provide proper connections to such detention systems and do not exceed their capacity. Where verification of the above is required by the Construction Official, he shall submit the application to the Borough Engineer, who shall provide a written report stating either that the permit may be granted because it meets the standards of this Article or that the permit shall be denied and for what reasons.

Where the Construction Official determines the improvement will increase the runoff, he shall submit the detailed drawings to the Borough Engineer, who shall provide a written report stating that the permit may be granted because it meets the standards of this Article or that the permit shall be denied and for what reasons.

For one-family dwellings for which site plan submissions are required to be made under Chapter 31, Site Plan Review, the following information shall be submitted in order to protect against adverse consequences for surface water drainage:

Fill shall be no lower than one foot above the flood hazard design elevation and shall extend as such for a distance of at least 15 feet beyond the limits of any structure erected thereon.

Structures shall be built so that the first floor and/or basements are at a minimum of one foot above the flood hazard design elevation, except that pavement and related site structures such as storm sewers, manholes, curbing, etc., shall be set at grades to be approved by the Borough Engineer.

Floodproofing measures shall be consistent with the flood protection elevation for the particular area, flood velocities, durations, rates of rise, hydrostatic and hydrodynamic forces and other similar factors. The applicant may be required to submit a plan or document certified by a licensed professional engineer that the floodproofing measures are consistent with the flood hazard design elevation and associated flood factors. Any or all of the following floodproofing measures may be required:

The rate of stormwater runoff from the area is not increased over that which occurs under existing conditions.

The drainage characteristics of adjacent areas are not adversely affected.

Soil erosion during and after development is not increased over that which occurs under existing conditions.

Soil absorption and groundwater recharge capacity of the area is not decreased below that which occurs under existing conditions.

The natural drainage pattern of the area is not significantly disturbed.

Depressions in parking areas, excavations, basins created through use of curbs, stabilized earth berms or dikes or other form of grading which serves to temporarily and safely impound and store stormwater.

Rooftops which temporarily and safely impound and store stormwater, including drain outlets which restrict the rate of runoff from the roof surface.

Dry wells or leaching basins which control stormwater runoff through ground absorption restricted outflow.

Porous asphaltic pavement which preserves the natural ground absorption rate of a site and provides a subsurface reservoir for temporary storage of stormwater.

Any system of porous media, such as gravel trenches drained by porous wall or perforated pipe, which temporarily stores and dissipates stormwater through ground absorption.

Any combination of the above systems which limits stormwater runoff from a given site to that which occurs under existing conditions.

Stormwater detention facilities shall be designed to contain a volume of water equal to the increase in volume of runoff which would result from development of any site based upon the total rainfall which produced the flood of record for the area involved. The total rainfall which produced the flood of record shall be determined from records of the United States Department of Commerce, National Weather Service.

Rainfall Excess Computation.

The runoff coefficients shall be determined for each site for both existing and proposed conditions, and the difference in the two shall be used to compute the volume of rainfall excess for design of stormwater detention facilities. The volume used for design of the detention facilities shall be equal to the depth of the rainfall excess multiplied by the area of the surface.

Detention facilities which utilize porous media for absorption, such as dry wells and porous pavement, shall be of such a size to contain the total volume of rainfall excess within the voids. Ground absorption systems shall be used only where the infiltration rate of the receiving soil is acceptable as determined by percolation tests and soil borings or as determined by the Borough Engineer. Provisions shall be made to contain overflow of such systems on site or to surface drain the overflow in such a way as not to adversely affect any adjacent property.

Detention facilities which utilize surface impoundment, such as depression in parking areas, rooftops and diked areas, shall provide sufficient volume to fully contain the total volume of rainfall excess. The outlets of such facilities shall be designed to limit the maximum discharge rate of stormwater runoff to that which occurs at the site under existing conditions and shall discharge in such a way as to not adversely affect adjacent property. If rooftop storage is proposed, the weight of the water on the roof shall be provided for in the structural design of the building, and the roof shall be designed to provide maximum protection against leakage. Earth berms or dikes used to create an impounding area shall be stabilized with the slopes protected with vegetative cover, paving or riprap to protect against failure or breaching.

If a combination of different stormwater techniques is used, the system shall be adequate to fully control the total volume of rainfall excess.

Stormwater detention facilities shall be maintained by the owner to ensure continual functioning of the systems as designed and to prevent hazards associated with debris buildup and stagnant water. Water shall not be allowed to remain long enough to constitute mosquito breeding, disease or any other type of health problem. Easements shall be provided to all detention facilities from public rights-of-way, if required, so that such facilities are available to municipal authorities for the purposes of determining if the facilities are properly maintained and, where necessary, to maintain the facilities.

Detention, sediment and erosion control facilities shall be designed in conformance with the Standards for Soil Erosion and Sediment Control in New Jersey of the New Jersey State Soil Conservation District.

Facilities to control sediment and erosion shall be built prior to any other site development and shall be in operation during all stages of development. Increased runoff resulting from modified soil and surface conditions caused by the proposed development shall be minimized and, where possible, retained on the site. Increased erosion and sediment resulting from construction at the proposed development will be prohibited.