[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."
A.
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.
B.
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.
C.
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.
D.
Among the purposes of this chapter are:
(1)
To prevent loss of life.
(2)
To protect the public health and promote public safety
and welfare.
(3)
To minimize losses and damages to public and private
property due to stormwater runoff.
(4)
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]
(5)
To reduce public expenditures for emergency operations,
evacuations and restorations.
(6)
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.
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.
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.
The portion of rainfall which becomes direct surface runoff.
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.
A.
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]
B.
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.
C.
No land area shall be developed by any person such
that:
(1)
The volume and/or rate of stormwater runoff occurring
at the area is increased over what occurs there under existing conditions;
(2)
The drainage of adjacent areas is adversely affected;
(3)
Soil erosion during and after development is increased
over what naturally occurs there;
(4)
Soil absorption and groundwater recharge capacity
of the area is decreased below what occurs there under existing conditions;
and/or
(5)
The natural drainage pattern of the area is significantly
altered.
D.
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]
(1)
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.
(2)
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.
(3)
Dry wells or leaching basins which control stormwater
runoff through ground absorption and temporary storage.
(4)
Porous asphaltic pavement, which preserves the natural
ground absorption capacity of a site and provides a subsurface reservoir
for temporary storage of stormwater.
(5)
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.
(6)
Any combination of the above-mentioned techniques
which serve to limit stormwater runoff from a given site to what presently
occurs there.
E.
New construction.
[Added 3-13-2017 by Ord.
No. O-07-17]
(1)
A geotechnical investigation shall be performed to determine the
seasonal high groundwater table, where required by the City Engineer.
(2)
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.
F.
Existing structures.
[Added 3-13-2017 by Ord.
No. O-07-17]
(1)
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.
(2)
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.
(3)
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.
A.
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.
B.
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:
|
Land Use Type
|
Runoff Coefficients
| ||
|---|---|---|---|
|
Business:
| |||
|
Downtown areas
|
0.70 to 0.95
| ||
|
Neighborhood areas
|
0.50 to 0.70
| ||
|
Residential:
| |||
|
Single-family areas
|
0.30 to 0.50
| ||
|
Multi-units, detached
|
0.40 to 0.60
| ||
|
Multi-units, attached
|
0.60 to 0.75
| ||
|
Residential (suburban)
|
0.25 to 0.40
| ||
|
Apartment dwelling areas
|
0.50 to 0.70
| ||
|
Industrial:
| |||
|
Light areas
|
0.50 to 0.80
| ||
|
Heavy areas
|
0.60 to 0.90
| ||
|
Parks; cemeteries
|
0.10 to 0.25
| ||
|
Playgrounds
|
0.20 to 0.35
| ||
|
Railroad yard areas
|
0.20 to 0.40
| ||
|
Unimproved areas
|
0.10 to 0.30
| ||
|
Surface Type
|
Runoff Coefficients
| ||
|---|---|---|---|
|
Streets:
| |||
|
Asphaltic
|
0.70 to 0.95
| ||
|
Concrete
|
0.80 to 0.96
| ||
|
Brick
|
0.70 to 0.85
| ||
|
Drives and walks
|
0.75 to 0.85
| ||
|
Roofs
|
0.75 to 0.95
| ||
|
Lawns; sandy soil:
| |||
|
Flat, 2%
|
0.05 to 0.10
| ||
|
Average, 2% to 7%
|
0.10 to 0.15
| ||
|
Steep, 7%
|
0.15 to 0.20
| ||
|
Lawns; heavy soil:
| |||
|
Flat, 2%
|
0.13 to 0.17
| ||
|
Average, 2% to 7%
|
0.18 to 0.22
| ||
|
Steep, 7%
|
0.25 to 0.35
| ||
|
The range of coefficients for each land use
and surface type reflects differences in land slope, intensity of
development, amount of impervious surface and degree of ground saturation
due to antecedent precipitation.
| |||
C.
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.
D.
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.
E.
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.
F.
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.
G.
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.
H.
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.
I.
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.
A.
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:
(1)
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.
(2)
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.
B.
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[1] 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.
[1]
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[1]]
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.
