[HISTORY: Adopted by the City Council of the City of Rahway 7-9-1984 by Ord. No. A-12-84 as Ch. 170 of the 1984 Code; amended in its entirety 3-13-2006 by Ord. No. O-13-06. Subsequent amendments noted where applicable.]
This chapter shall be known and may be cited as the "Stormwater Runoff Control Ordinance of the City of Rahway."
It is the purpose of the ordinance to establish minimum stormwater requirements and controls for projects (residential and nonresidential) that fall below the threshold of major development.
All nonresidential major development site plans and nonresidential major development subdivisions shall conform with the City of Rahway's Stormwater Control Ordinance for Nonresidential Major Development, Chapter 362.
It is hereby found that areas within the municipality of Rahway are subject to recurrent flooding, that such flooding endangers life and damages public and private property and facilities, that this condition is aggravated by developments, that all developments contribute to the condition by increasing local stormwater runoff and erosion and that the most appropriate means of alleviating such condition is through the regulation of such developments.
It is, therefore, determined that a special and paramount public interest in the control of storm drainage justifies the regulation of storm drainage for the entire municipal area as provided in this chapter, which is in the exercise of the police power of the municipality, for the protection of the persons and property of its inhabitants and for the preservation of the health, safety and general welfare.
Among the purposes of this chapter are:
To prevent loss of life.
To protect the public health and promote public safety and welfare.
To minimize losses and damages to public and private property due to stormwater runoff.
To prevent an increase in volume and rate of surface runoff on the subject property or on neighboring properties due to development or modification to natural grade.
[Amended 3-13-2017 by Ord. No. O-07-17]
To reduce public expenditures for emergency operations, evacuations and restorations.
To prevent damage to transportation and utility systems.
For the purposes of this chapter, unless the context clearly indicates otherwise, the following words shall mean as indicated:
- The division of a parcel of land into two or more parcels, the construction, reconstruction, conversion, structural alteration, relocation or enlargement of any building or structure, any mining excavation or landfill and any use or change in the use of any building or other structure, or land or extension of use of land, by any person, for which permission is required under the Municipal Land Use Law, N.J.S.A. 40:55-D-1 et seq. In the case of development of agricultural lands, "development" means: any activity that requires a state permit; any activity reviewed by the County Agricultural Board (CAB) and the State Agricultural Development Committee (SADC), and municipal review of any activity not exempted by the Right to Farm Act, N.J.S.A. 4LIC-1 et seq.
- MAJOR DEVELOPMENT
- Any development that provides for ultimately disturbing one or more acres of land. "Disturbance" for the purpose of this rule is the placement of impervious surface or exposure and/or movement of soil or bedrock or clearing, cutting, or removing of vegetation.
- PERMEABILITY TEST
- A test designed to determine the ability of the ground to absorb water. The test shall be performed by a licensed professional engineer with proven competency in the field of soils engineering and shall be in accordance with acceptable engineering standards and practices. A detailed report of the test shall be submitted to the Planning Board and City Engineer for review.
- Corporations, companies, associations, societies, firms, partnerships, and joint-stock companies, as well as individuals, the state and all political subdivisions of the state or any agencies or instrumentalities thereof.
- RAINFALL EXCESS
- The portion of rainfall which becomes direct surface runoff.
- STORMWATER DETENTION
- Any storm drainage technique which retards or detains runoff, such as a detention basin, parking lot storage, rooftop storage, porous pavement, dry wells or any combination thereof.
No construction or development shall take place on any site within the municipal boundaries unless a site plan and any other required information shall have been submitted to the Planning Board for its review and approval, except for one- and two-family dwellings, in which case the site plan shall be reviewed and approved by the City Engineer. Said site plan shall meet the requirements of § 213-4A of the Code of the City of Rahway, except that proof of stream encroachment lines shall not be required if the entire site is not in the floodplain. The fee for review and approval by the City Engineer under this section shall be $250.
[Amended 9-8-2008 by Ord. No. O-23-08]
In reviewing any proposed construction or development, the Planning Board shall be reasonably assured that any structure, when built or altered, can be occupied without peril to the health or safety of the occupants and that the proposed land use does not increase local runoff and does not increase erosion.
No land area shall be developed by any person such that:
The volume and/or rate of stormwater runoff occurring at the area is increased over what occurs there under existing conditions;
The drainage of adjacent areas is adversely affected;
Soil erosion during and after development is increased over what naturally occurs there;
Soil absorption and groundwater recharge capacity of the area is decreased below what occurs there under existing conditions; and/or
The natural drainage pattern of the area is significantly altered.
In order to duplicate as nearly as possible natural drainage conditions, regulation and control of stormwater runoff and erosion for any land area to be developed shall be through on-site stormwater detention and/or ground absorption systems, which include, but are not limited to, the following:
[Amended 3-13-2017 by Ord. No. O-07-17]
Detention areas which may be depressions in parking areas, excavated basins, basins created through use of curbs, stabilized earth berms or dikes or any other form of grading which serves to impound and store water temporarily.
Rooftop storage through temporary impoundment and storage of stormwater on flat or slightly pitched building rooftops by the use of drain outlets which restrict the stormwater runoff from the roof surface.
Dry wells or leaching basins which control stormwater runoff through ground absorption and temporary storage.
Porous asphaltic pavement, which preserves the natural ground absorption capacity 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 store and dissipate stormwater through ground absorption.
Any combination of the above-mentioned techniques which serve to limit stormwater runoff from a given site to what presently occurs there.
[Added 3-13-2017 by Ord. No. O-07-17]
A geotechnical investigation shall be performed to determine the seasonal high groundwater table, where required by the City Engineer.
Where a basement is proposed, the elevation of same shall be set a minimum of one foot above the seasonal high groundwater table or as determined by a geotechnical engineer to minimize the need to pump groundwater.
[Added 3-13-2017 by Ord. No. O-07-17]
The property owner shall be responsible for the installation and maintenance of the sump pump system and its appurtenances, and shall seek applicable permits from the City or applicable governing agency for the same.
The frequency of sump pump discharge from existing structures into a public street within the City's right-of-way shall be set such that public health and/or safety issues and impact to the public street created by same are minimized.
The property owner shall keep the point of discharge within the right-of-way free of debris, leaves, ice, etc., to allow an obstacle-free flow and prevent public health or safety concerns.
Stormwater detention facilities shall be designed to contain an amount equal to the increase in volume of runoff which would result from the development of any site. The volume of runoff shall be computed on the basis of the total rainfall which produced the flood of record for the area involved and shall be equivalent to the rainfall excess (i.e., the portion of rainfall which becomes direct surface runoff). The total rainfall which produced the flood of record shall be determined from records of the United States Department of Commerce, National Weather Services.
The rainfall excess shall be computed for each site using accepted, published runoff coefficients which reflect land use and topography. Acceptable runoff coefficients currently in practice include, but are not limited to, the following:
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 for the design is equal to the depth of the rainfall excess multiplied by the area of the site.
If, in the opinion of the City Engineer, the proposed development is too small to warrant professional engineering services or if, in the opinion of the City Engineer, the cost of securing professional engineering services would impose an undue economic hardship on the developer, the City Engineer shall determine the required type and size of stormwater detention facilities. This would not guarantee adequate performance of such systems, since it is for the convenience of the developer and is based on conditions that may vary.
In the case of detention facilities utilizing porous media for ground absorption, such as dry wells, porous pavement or the like, the volume of the porous media shall be large enough 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 City 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 affect adversely any other property.
If detention facilities utilizing surface impoundment, such as detention basins or rooftop storage, are used, sufficient volume to contain fully the total volume of rainfall excess shall be provided. The outlets of such facilities shall be designed to limit the maximum discharge rate of stormwater runoff to what occurs at the site under existing conditions and shall discharge in such a way as not to affect adversely other property. If rooftop storage is proposed, the weight of the impounded water on the roof shall be accounted for in the structural design of the building, and the roof shall be designed to provide maximum protection against leakage. If earth berms or dikes are used to create the impounding area, they shall be stabilized adequately and the slopes protected with vegetative cover, paving or riprap to protect against failure or breaching.
If a combination of different stormwater detention techniques is used, the combined volume of the systems shall be large enough to fully contain the total volume of rainfall excess.
Stormwater detention facilities shall be maintained regularly by the owner to ensure continual functioning of the systems at design capacity and to prevent the health hazards associated with debris buildup and stagnant water. In no case shall water be allowed to remain in any facility long enough to constitute a mosquito-breeding disease or any other type of health problem. If the land containing the stormwater detention facility or facilities is dedicated to the municipality, then the municipality shall be responsible for maintenance.
In accordance with the New Jersey Soil Erosion and Sediment Control Act (Chapter 251, Public Law 1975), sediment and erosion control measures shall be installed prior to any other site development, shall apply to all aspects of the proposed development and shall be in operation during all stages of development. Increased runoff and sediment, resulting from modified soil and surface conditions caused by the proposed development, shall be minimized and, where possible, retained on site. Detention and sediment and erosion control facilities shall be designed in conformance with the Standard for Soil Erosion and Sediment Control in New Jersey of the New Jersey State Soil Conservation Committee and administered by the Somerset-Union Soil Conservation District.
All development in those areas of the City of Rahway which fall within the limits of the tidal influence according to the United States Army Corps of Engineers' New Jersey Special Flood Hazard Information Report, 1971, shall be exempt from the requirements of this chapter, unless otherwise stated in the following subsections:
Development within those areas of the City of Rahway which fall within the limits of the tidal influence area shall only be exempt if the increased volume of stormwater runoff shall not increase flood damage below the point of discharge.
Areas along the westerly fringe which fall within the limits of tidal influence according to the U.S. Army Corps of Engineers Mapping are not exempt since sewer separation has taken place and is, therefore, not tidally influenced.
For the purpose of this exclusion, the area excluded shall adjoin the current Federal Emergency Management Agency (FEMA) flood hazard area, as adopted by the City of Rahway, and be downstream from the limits of tidal influence and within the downstream limits of the one-hundred-year flood as indicated on the attached map entitled "Map of Drainage Area Affected by Army Corps of Engineers' Tidal Limits and Adjoining Flood Hazard Area," dated March 1, 1983, prepared by the Division of Engineering, City of Rahway.
Editor's Note: Said map is on file in the City's offices.
Should the provisions of this chapter conflict with the provisions of any other ordinance of the City of Rahway, the provisions of this chapter shall take precedence.
[Added 3-13-2017 by Ord. No. O-07-17]
The Division of Health and Housing shall be the enforcement entity for this chapter of the Code.
Any person who violates any provisions of this chapter shall, upon conviction thereof, be liable for a fine not exceeding $2,000 or imprisonment for a term not exceeding 90 days, or both. Each day in which such violation continues shall constitute a separate violation or offense.