[MC 2002.29 § 17:12.1, December 2, 2002]
Editor's Note: For Stormwater management for major development see § 17:12-2.
A.
All development shall be provided with a stormwater management plan
consisting of, but not limited to, inlets, manholes and pipes where
necessary for proper surface drainage. The system shall be adequate
to carry off and/or store the stormwater and natural surface runoff,
which originates not only within the property in question, but also
beyond the tract boundaries.
B.
Where possible, all runoff within a site shall ultimately leave the
site in the same watershed in which it originated and shall be released
in such a manner so as to not overload existing drainage systems,
create flooding creating a need for additional drainage facilities
on other public or private lands or increase predevelopment erosion
of adjacent lands.
C.
The peak rate of runoff from a site during and after development
shall not exceed the predevelopment peak rate of runoff. Development
upstream of known areas of problem flooding shall be required to further
reduce the peak rate of runoff below the predeveloped rate. Where
the upstream tributary drainage area exceeds fifty (50) acres, the
standards established in the Technical Manual for Stream Encroachment,
N.J.A.C. 7:13-2.8, Stormwater Management, NJDEP, shall govern.
D.
The increase in volume of runoff from a site, during and after development,
from the predevelopment total of volume of runoff shall be minimized.
Runoff control measures shall be used to retard or reduce -runoff and increase recharge. Depending on the soil
characteristics natural and artificial recharge area and systems should
be employed whenever practical to minimize the volume of surface water
runoff. These include, but are not limited to, infiltration pits,
dry wells, infiltration trenches and the extensive use of sheet flow
through vegetated areas. The use of such measures will not eliminate
or reduce, even partially, the need for other requirements of this
section.
E.
The peak rate of runoff for areas of up to twenty (20) acres shall
be calculated by the rational method or derivatives. The equation
for the rational method is as follows:
Qp = CIA
Where
Qp = The peak runoff rate in cubic feet
per second (cfs).
C = The runoff coefficient.
I = The average rainfall intensity in inches per hour (in/hr),
occurring at the time of concentration Tc (min).
T = The time of concentration in minutes (min).
A = The size of the drainage area in acres (ac).
1.
Typical runoff coefficients (C values) are provided in the Technical
Manual for Stream Encroachment, prepared by the New Jersey Department
of Environmental Protection (NJDEP), page 51, Table 3.1-2(B1). Runoff
coefficient C used in the rational formula shall be weighted if there
is more than one (1) kind of land use within the drainage basin under
consideration.
2.
The time of concentration (tc) is defined
as the time required for water to reach the point in question from
the most hydraulically distant point in the basin. Time of concentration
(tc) shall be estimated from the Nomograph
for the Determination of Time of Concentration, prepared by the State
of New Jersey Highway Authority. The analysis shall also consider
the procedure outline in Section 3.12(c) for Technical Release (TR)
Number 55, Urban Hydrology for Small Watersheds, United States Department
of Agriculture, Soil Conservation Series, as supplemented and amended
(SCS method).
3.
Rainfall intensity as a function of duration and storm recurrence
frequency shall be based upon geographically appropriate data as depicted
in the plates in Technical Paper Number 25, Rainfall Intensity Duration-Frequency
Curves, United States Department of Commerce, Weather Bureau, as supplemented
and amended. Intensity curves may be based on local rainfall frequency
data, where available. In all instances, a minimum time of concentration
of five (5) minutes should be used.
4.
The peak rate of runoff for areas greater than twenty (20) acres
shall be calculated by hydrograph analysis method as outlined in the
latest edition of Urban Hydrology for Small Watersheds Technical Release
Number 55 (TR55).
F.
Runoff Volume Calculation. Runoff volume shall be calculated by the
hydrograph analysis method as outlined in the latest edition of Urban
Hydrology for Small Watershed Technical Release Number 55 (SCS method).
This method shall be used for watersheds having drainage areas greater
than twenty (20) acres. For drainage areas of less than twenty (20)
acres, the rational method triangular hydrograph approximation with
the peak rate occurring at the time of concentration and the end of
the hydrograph at three (3) times the time of concentration may be
used as an alternative.
G.
System Design.
1.
Collection systems shall be designed to accommodate the intensity
for a storm frequency of once in ten (10) years for storm drainage
facilities located in or affecting streets of the rural, local and
minor collector classifications. A storm frequency of once in twenty-five
(25) years shall be utilized for systems affecting secondary arterial
and major collector streets as well as all open channels.
2.
Hydraulic capacity for open channel or closed conduit flow shall
be determined by the Manning equation or charts/nomographs based on
the Manning equation. The hydraulic capacity is termed "Q" and is
expressed as discharge in cubic feet per second. The Manning equation
is as follows:
|
Qp
|
=
|
1.486 AR 2/3 S1/2
n
|
|
Where
| ||
|
n
|
=
|
Manning's roughness coefficient.*
|
|
A
|
=
|
Cross-sectional area of flow in square feet.
|
|
R
|
=
|
Hydraulic radius in feet (R = Q/P, where P is equal to the wetted
perimeter).
|
|
S
|
=
|
Slope of conduit in feet per foot.
|
|
*NOTE: The Manning roughness coefficients to be utilized are
shown in the Technical Manual for Stream Encroachment, NJDEP, Table
3.2-11 (A-1).
|
3.
Velocities in open channels at design flow shall not be less than
five-tenths (0.5) foot per second and not greater than that velocity
which will begin to cause erosion or scouring of the channel. Permissible
velocities for swales, open channels and ditches are allowed for the
appropriate soil type based on the Soil Conservation Service Standards
for Soil Erosion and Sediment Control in New Jersey, as amended.
4.
Velocities in closed conduits at design flow shall be at least two
(2) feet per second but not more than ten (10) feet per second.
5.
No pipe size in the storm drainage system shall be less than fifteen
(15) inches in diameter.
6.
All discharge pipes shall terminate with a precast concrete flared
end section or a cast-in-place concrete headwall with or without wingwalls
as conditions dictate.
7.
The spacing of inlets shall be such that surface water shall not
flow for more than five hundred (500) feet or the quantity of water
is such that it caused ponding of water deeper than two (2) inches
at Type B and Type E inlets, whichever is the lesser distance. If
due to the slope of the approach prior to the inlet, eighty percent
(80%) of the stormwater does not enter the inlet, decreased spacing
and depth of water permissible shall be required. Sufficient inlets
will be placed to eliminate any flow exceeding two (2) cubic feet
per second across any roadway intersections or pedestrian crosswalk.
8.
Dished gutters shall be permitted at any street intersection on rural
and local streets and at the intersection of rural and local streets
with minor collector streets and at the intersection of minor collector
streets with major collector streets where the street of the lower
classification is to be officially designated and signed as a stop
street. In such case, the dished gutter shall cross only the street
of the lower classification. At the intersections of primary and secondary
arterial streets and major collector streets, sufficient catch basins,
at the discretion of the reviewing agency, shall be installed at each
street intersection to avoid gutter overflow and at low points in
the street grade, and dished gutters shall not be permitted.
9.
Manhole spacing shall increase with pipe size. The maximum spacing
shall be five hundred (500) feet for fifteen (15) to eighteen (18)
inches; six hundred (600) feet for twenty-one (21) to thirty-six (36)
inches; and seven hundred (700) feet for forty-two (42) inches and
greater.
H.
Construction Standards for Pipe.
1.
Materials used in the construction of storm sewers shall be constructed
of reinforced concrete, ductile iron, corrugated aluminum or corrugated
steel unless site and other conditions dictate otherwise. Reinforced
concrete pipe shall be used unless the applicant can demonstrate that
the use of other materials will be more beneficial due to the proposed
installation. Cost will not be a consideration in this analysis. Specifications
referred to, such as American Standards Association, American Society
for Testing and Materials, American Water Works Association, etc.,
should be the latest revision.
2.
Reinforced Concrete Pipe.
a.
Circular reinforced concrete pipe and fittings shall meet the
requirements of ASTM C-76.
b.
Elliptical reinforced concrete pipe shall meet the requirements
of ASTM C-507.
c.
Joint design and joint material for circular pipe shall conform
to ASTM C-443.
d.
Joints for elliptical pipe shall be bell and spigot or tongue
and groove, sealed with butyl, rubber tape or external sealing bands
conforming to ASTM C-877.
e.
All pipe shall be Class III unless a stronger pipe (i.e., higher
class) is indicated to be necessary.
f.
The minimum depth of cover over the concrete pipe shall be as
designated by the American Concrete Pipe Association.
3.
Ductile Iron Pipe. Ductile iron pipe shall be centrifugally cast
in metal or sand-lined molds to ANSI A 21.51-1976 (AWWA C151-76).
The joints shall conform to AWWA Cl11. Pipe shall be furnished with
flanges where connections to flange fittings are required. Pipe should
be Class 50 (minimum). The outside of the pipe should be coated with
a uniform thickness of hot-applied coal tar coating and the inside
line cement in accordance with AWWA C104. Ductile iron pipe shall
be installed with Class C ordinary bedding.
4.
Corrugated Aluminum Pipe. Within the public right-of-way and where
severe topographic conditions or the desire to minimize the destruction
of trees and vegetation exist, corrugated aluminum pipe, pipe arch
or helical corrugated pipe may be used. The material shall comply
with the Standard Specifications for Corrugated Aluminum Alloy Culvert
and Under Drain AASHTO destination M196 or the Standard Specification
for Aluminum Alloy Helical Pipe AASHTO Designation M-211. The minimum
thickness of the aluminum pipe to be used shall be:
a.
Less than twenty-four (24) inch diameter or equivalent, seventy-five
thousandths (0.075) inch (14-gauge).
b.
Twenty-four-inch diameter and less than forty-eight-inch diameter
or equivalent, one hundred five thousandths (0.105) inch (12-gauge).
c.
Forty-eight-inch but less than seventy-two-inch diameter or
equivalent, one hundred thirty-five thousandths (0.135) inch (10-gauge).
d.
Seventy-two-inch diameter or equivalent and larger, one hundred
sixty-four thousandths (0.164) inch (8-gauge).
5.
Corrugated Steel Pipe. Corrugated steel pipe may be used in place
of corrugated aluminum and shall meet the requirements of AASHTO Specification
M36. Coupling bands and special sections shall also conform to AASHTO
M-36. All corrugated steel pipe shall be bituminous coated in accordance
with AASHTO M-190 Type A minimum.
6.
Pipe bedding shall be provided as specified in Design and Construction
of Sanitary and Storm Sewers, ASCE Manuals and Reports on Engineering
Practice Number 37, prepared by A Joint Committee of the Society of
Civil Engineers and the Water Pollution Control Federation, New York,
1969.
I.
Construction Standards for Inlets, Catch Basins and Manholes. Inlets,
catch basins and manholes shall be designed in accordance with State
Highway Department Standard Plans and Specifications. Frames shall
be Campbell Foundry Company Pattern Number 2541, 2548, with eight-inch
curb face, and 3432, 3440, for Type E inlets, or approved equal. All
grates shall be bicycle grates.
1.
Manholes and catch basins shall be precast concrete, brick or concrete
block, coated with two (2) coats of portland cement mortar.
2.
If precast manhole barrels and cones are used, they shall conform
to ASTM Specification C-473 with round rubber gasketed joints, conforming
to ASTM Specification C-923. Maximum absorption shall be eight percent
(8%) in accordance with ASTM Specification C-478, Method A.
3.
If precast manholes are utilized, the top riser section shall terminate
less than one (1) foot below the finished grade and the manhole cover
shall be flush with the finished grade.
4.
Manhole frames and covers shall be of cast iron conforming to ASTM
Specification A-48 Class 30 and be suitable for H-20 loading capacity.
All manhole covers in rights-of-way or in remote areas shall be provided
with a locking device. The letters "Year 20 __ " and the words "STORM
SEWER" shall be cast integrally in the cover.
J.
Detention Facilities.
1.
Development shall use the best available technology to accommodate
stormwater management by natural drainage strategies as indicated
in subsection D of this section.
2.
Detention and all other stormwater management facilities shall conform
to the standards under the New Jersey Stormwater Management Act, N.J.S.A.
40:55D-93 et seq.
3.
Where detention facilities are deemed necessary, they shall accommodate
site runoff generated from two-year, ten-year and one hundred-year
storms considered individually, unless the detention basin is classified
as a dam, in which case the facility must also comply with the Dam
Safety Standards, N.J.A.C. 7:20. These "design storms" shall be defined
as either a twenty-four-hour storm using the rainfall distribution
recommended by the United States Soil Conservation Service (such as
United States Soil Conservation Service, Urban Hydrology for Small
Watersheds, Technical Release Number 55) or as the estimated maximum
rainfall for the estimated time of concentration of runoff at the
site when using a design method such as the modified rational method.
Runoff greater than that occurring from the one hundred-year, twenty-four-hour
storm will be passed over an emergency spillway.
Detention will be provided such that, after development, the
peak rate of flow from the site will not exceed that by similar storms
prior to development.
4.
In calculating the site runoff to be accommodated by a detention
facility, the method to be used is a tabular hydrograph method as
presented in TR Number 55 (SCS method), as supplemented and amended.
The pre-developed lands in the site shall be assumed to be in good
condition, if the lands are woods, or with conservation treatment,
if the land is cultivated, regardless of conditions existing at the
time of concentration.
5.
Detention facilities shall be located as far horizontally from surface
water and as far vertically from groundwater as is practicable. A
complete soils report for the detention basins and surrounding areas
shall be submitted. The report should address the effect groundwater
will have on the construction and maintenance of the detention basins.
6.
Only one-half (1/2) of the area devoted to detention or retention
facilities shall be considered non-impervious surfaces in calculating
the maximum percentages as set forth in other sections of this chapter.
The area devoted shall be the area encompassed by the depth of water
to the emergency spillway, plus one (1) foot.
7.
The top of the excavation or the toe of the outside slope shall be
set back twenty-five (25) feet from adjoining nonresidential property
lines and fifty (50) feet from an adjoining property line of a lot
on which there is a residential use. The edge of the design high water
for the detention basins shall be set back one hundred (100) feet
existing or proposed dwelling units.
8.
The top of the excavation or the toe of the outside slope shall be
set back fifty (50) feet from the edge of the pavement from adjoining
roads and shall be set back twenty-five (25) feet from the adjoining
right-of-way line for any right-of-way dedicated for use as a public
road.
9.
Dry Detention Basins. The following design standards shall apply
to all dry detention basins:
a.
The maximum embankment side slopes shall have the ratio of one
(1) vertical to three (3) horizontal.
b.
Basin bottom shall meet the following specifications:
c.
An area ten (10) feet wide with a maximum slope of two percent
(2%) shall be constructed at the top of the bank surrounding the basin.
d.
Vegetation stabilization cover shall be provided throughout
the basin and landscaping shall be provided on the perimeter of the
basin as approved by the Board's landscape architect.
e.
The basin floor shall lie a minimum of two (2) feet above the
seasonal high groundwater table.
10.
Wet detention/retention basins are discouraged. Wet basins may
be permitted only if no other above ground stormwater management facility
is feasible.
11.
Underground detention/retention basins are discouraged. Underground
detention/retention basins may be permitted only if no other above
ground stormwater management facility is feasible.
K.
Protecting Water Quality.
1.
In addition to addressing water quantity generated by development,
a stormwater management system shall also enhance the water quality
of stormwater runoff.
2.
In order to enhance water quality of stormwater runoff, stormwater
management shall provide for the control of a water quality design
storm. The water quality design storm shall be defined as the one-year
frequency SCS Type III twenty-four-hour storm or a one and twenty-five-hundredths-inch
two-hour rainfall.
3.
The water quality design storm shall be controlled by best management
practices. These include but are not limited to the following:
a.
In dry detention basins, provisions shall be made to ensure
that the runoff from the water quality design storm is retained such
that not more than ninety percent (90%) will be evacuated prior to
thirty-six (36) hours for all nonresidential projects or eighteen
(18) hours for all residential project. The retention time shall be
considered a brim-drawdown storage. The retention time shall be reduced
in any case which would require an outlet size diameter of three (3)
inches or less. Therefore, three-inch diameter orifices shall be the
minimum allowed. The depth of the water quality storm should not exceed
two (2) feet in depth.
b.
In permanent ponds or wet basins, the water quality requirements
of this section shall be satisfied where the volume of permanent water
is at least three (3) times the volume of runoff produced by the water
quality design storm.
L.
Principal Outlets Quantity Control.
1.
All principal outlet structures shall be concrete block or reinforced
concrete. All construction joints are to be watertight. The outlet
structure can consist of a riser, culvert pipe and/or weir outlet
and must be accessible from the buffer area/access road when the basin
is operational at full design flow for the 100-year design storm event.
To minimize the chance of clogging and to facilitate cleaning, outlet
openings, other than subsection K3a above, shall be at least six (6)
inches in diameter. Similarly, riser pipes, if utilized, shall be
at least eight (8) inches in diameter. All pipe joints are to be watertight,
reinforced concrete pipe. In addition, trash racks and/or antivortex
devices may be required where deemed necessary by the City. Outlet
control structures should be protected by maintenance free trash racks.
Trash racks should be designed to be on an incline with a clear opening
area large enough so that debris buildup does not impede the area
of the opening it protects. The trash rack should be a hinged rack
and should avoid moving parts. It should be able to be opened to gain
access for cleaning the outlet pipe, and should be made of a noncorrosive
material (stainless steel or aluminum).
2.
Eight-inch thick antiseep collars are to be installed along outlet
pipes. Such collars shall be constructed of reinforced concrete with
minimum Number 5 bars, each way, and two (2) inches of cover.
3.
Where applicable, a concrete cradle shall be provided for outlet
pipes.
4.
Suitable lining shall be placed upstream and downstream of principal
outlets as necessary to prevent scour and erosion. Such lining shall
conform to the criteria contained in Standards for Soil Erosion and
Sediment Control in New Jersey, published by the New Jersey State
Soil Conservation Committee.
5.
All outlet facilities shall be designed to prevent the potential
hazard of a child's or an adult's either being carried into the opening
or being held against the outlet by the pressure of the flowing stream
waters, even during a one hundred-year storm.
6.
Safe outlet structure design can encompass either outlet risers,
gratings, trash racks or other means that, in the opinion of the Planning
or Zoning Board, provide the desired level of safety.
7.
Outlet structures should be designed to facilitate outlet operation
and maintenance as the water level rises and to permit clearing either
during or after a storm. Structural support members, steps, rungs
or ladders should be provided to allow easy escape opportunities for
a child or an adult without having these support members, ladders,
etc., impede the clearing of trash from the outlet structure or the
upward movement of trash from the outlet structure or the upward movement
of trash as the water level rises.
8.
The use of thin metal plates for trash rack bars, hand hold supports,
sharp crested weirs or orifices are prohibited because of the potential
for accidents. Wire mesh fabric is similarly prohibited due to its
poor suitability for trash clearance.
9.
Any outlet protective facility should have lockable hinged connections
providing adequate access to thoroughly clean the area enclosed by
the structure and to facilitate removal of accumulated debris and
sediment around the outlet structure.
10.
The outlet protective structure should have negligible influence
upon the hydraulic performance of the outlet structure.
11.
All outlet structures shall be structurally sound and shall
be designed to withstand, without failure or permanent deformation,
all structural loads, hydrostatic, dynamic or otherwise, which impact
upon it during the design life of the installation. They shall be
maintenance free to the maximum extent possible.
12.
The detention/retention basin side slope walls shall be graded
to slopes no greater than three (3) horizontal to one (1) vertical
for a distance no less than twenty-five (25) feet on all sides of
the outlet structure.
13.
Other means of attaining the same outlet safety condition, such
as inaccessible outlet locations, weirs, cascades, etc., will be considered
as approvable if the same goals were attained.
14.
Existing basins and outlet structures shall be revised by the
respective responsible owners to comply with the above-defined goals
within one (1) year of the enactment of this amendment.
M.
Principal Outlets Quality Control.
1.
Based upon the requirement limiting the size of the outlet to a minimum
of six (6) inches in diameter, water quality control shall be maintained
by providing an amount of storage equal to the total amount of runoff
which will be produced by the one-year frequency SCS Type III twenty-four-hour
storm or a one and twenty-five-hundredths-inch, two-hour rainfall
at the bottom of the proposed detention basin along with a minimum
three-inch diameter outlet.
2.
The invert(s) of the principal outlet(s) used to control the larger
storms for flood control purposes should be set at the elevation of
the water surface elevation required to produce the water quality
storage volume. Therefore, the principal outlets would be utilized
for storms in excess of the one and twenty-five-hundredths-inch, two-hour
event which, in turn, would be completely controlled by the lower
three (3) inch outlet. If the above requirements would result in a
pipe smaller than three (3) inches in diameter, the period of retention
shall be waived so that three (3) inches will be the minimum pipe
size used. It should be remembered that, in all cases, the basin should
be considered initially empty (i.e., the storage provided for the
quality requirements and the discharge capacity of its outlet should
be utilized during the routing of the larger flood control storms).
N.
Emergency Spillways.
1.
Vegetated emergency spillways shall have side slopes not exceeding
three (3) horizontal to one (1) vertical.
2.
Emergency spillways not excavated from noncompacted soil shall be
suitably lined and shall comply with criteria contained in Standards
for Soil Erosion and Sediment Control.
3.
Maximum velocities in emergency spillways shall be checked based
on the velocity of the peak flow in the spillway resulting from the
routed emergency spillway hydrograph. Where maximum velocities exceed
those contained in Standards for Soil Erosion and Sediment Control
in New Jersey, suitable lining shall be provided.
O.
Dams and Embankments.
1.
The minimum top widths of all dams and embankments are listed below.
These values have been adopted from the Standards for Soil and Sediment
Control in New Jersey, published by the New Jersey State Soil Conservation
Committee.
|
MINIMUM TOP WIDTHS FOR DAMS & EMBANKMENTS
| |
|---|---|
|
Height (feet)
|
Top Width (feet)
|
|
0-15
|
10
|
|
15-20
|
12
|
|
20-25
|
14
|
2.
The design top elevation of all dams and embankments after all settlement
has taken place shall be equal to or greater than the maximum water
surface elevation in the basin resulting from the routed freeboard
hydrograph. Therefore, the design height of the dam or embankment,
defined as the vertical distance from the top down to the bottom of
the deepest cut, shall be increased by the amount needed to ensure
the design top elevation will be maintained following all settlement.
This increase shall not be less than five percent (5%). Where necessary,
the Engineer shall require consolidation tests of the undisturbed
foundation soil to more accurately determine the necessary increase.
3.
Maximum side slopes for all dams and embankments are three (3) horizontal
to one (1) vertical.
4.
All earth fill shall be free from brush, roots and other organic
material subject to decomposition.
5.
Cutoff trenches are to be excavated along the dam or embankment center
line to impervious subsoil or bedrock.
6.
Safety ledges shall be constructed on the side slopes of all detention
basins having a permanent pool of water. The ledges shall be four
(4) to six (6) feet in width and located approximately two and one-half
(2-1/2) to three (3) feet below and one (1) to one and one-half (1-1/2)
feet above the permanent water surface.
7.
The fill material in all earth dams and embankments shall be compacted
to at least ninety-five percent (95%) of the maximum density obtained
from compaction tests performed by the appropriate method in ASTM
D698.
8.
The top of bank for facilities constructed in cut and the toe of
slope for facilities constructed in fill shall be located no closer
than ten (10) feet to an existing or proposed property line.
9.
Detention basins shall be sodded, attractively buffered and landscaped
and designed as to minimize propagation of insects, particularly mosquitoes.
All landscaping and buffering shall be approved by the City.
P.
Detention Facilities in Flood Hazard Areas. There will be no detention
basins in the floodway except for those on-stream and shall comply
with all applicable regulations under the Flood Hazard Control Act,
N.J.S.A. 58:16A-50 et seq., and the New Jersey Stormwater Management
Act, N.J.S.A. 40:55D-93 et seq.
Q.
Detention facilities in freshwater wetlands. Detention basins located
in freshwater wetlands may be allowed only in accordance with the
Freshwater Wetlands Protection Act, N.J.S.A. 13:9B-1 et seq. and any
rules adopted pursuant thereto.
R.
Detention Facilities; Maintenance and Repair.
1.
Responsibility for operation and maintenance of detention facilities,
including periodic removal and disposal of accumulated particulate
material and debris, shall remain with the owner or owners of the
property with permanent arrangements that it shall pass to any successive
owner, unless assumed by a government agency. If portions of the land
are to be sold, legally binding arrangements shall be made to pass
the basic responsibility to successors in title. These arrangements
shall designate for each project the property owner, governmental
agency or other legally established entity to be permanently responsible
for maintenance, hereinafter in this section referred to as the "responsible
person."
2.
Prior to granting final approval to any project subject to review
under this section, the applicant shall enter into an agreement with
the municipality (or County) to ensure the continued operation and
maintenance of the detention facility. This agreement shall be in
a form satisfactory to Corporation Counsel and may include, but may
not necessarily be limited to, personal guaranties, deed restrictions,
covenants and bonds. In cases where property is subdivided and sold
separately, a homeowners, association or similar permanent entity
should be established as the responsible entity, absent an agreement
by a governmental agency to assume responsibility.
a.
An applicant seeking approval for construction of a detention
facility shall provide the funds necessary to permanently maintain
the facility. The amount necessary to permanently maintain the facility
shall be calculated by the Planning Board Engineer based upon current
estimates for maintenance with an annual increase of four percent
(4%). The Planning Board Engineer shall also assume that the investment
will yield a return equal to the ninety-day certificate of deposit
interest rate paid by the City fiduciary institution or its successor
on the date the calculation is made.
b.
The form of security for the maintenance of the facility shall
be approved by Corporation Counsel.
3.
In the event that the detention facility becomes a danger to public
safety or public health or if it is in need of maintenance, the municipality
shall so notify in writing the responsible person. From that notice,
the responsible person shall have fourteen (14) days to effect such
maintenance and repair of the facility in a manner that is approved
by the City Engineer or his designee. If the responsible person fails
or refuses to perform such maintenance and repair, the municipality
may proceed to do so and shall bid the cost thereof to the responsible
person.
S.
Division of Coastal Resources.
1.
All projects containing stream encroachments within the flood hazard
area and one hundred-year floodplain, at locations having a drainage
area of over fifty (50) acres and all projects of special concern,
as defined in N.J.A.C. 7:13-5, are subject to the approval of NJDEP,
Division of Coastal Resources.
2.
All projects containing a drainage area over fifty (50) acres must
establish the one hundred-year floodplain zone in accordance with
N.J.A.C. 7:13-1.8.
T.
The approval of any map of land delineating streets by the Planning
Board of the City of Plainfield shall be in no way construed as an
acceptance of any street indicated thereon.
U.
For both major and minor subdivisions, blocks and lots shall be graded
to secure proper drainage away from buildings and to prevent the collection
of stormwater in pools.
V.
For both major and minor subdivisions, land subject to periodic or
occasional flooding (floodplain areas) shall not be plotted for residential
occupancy nor for any other purpose which may endanger life or property
or aggravate the flood hazard. Such land within a plat shall be considered
for open spaces or other similar uses.
W.
Where a minor or major subdivision is traversed by a watercourse,
surface or underground drainage way or drainage system, channel or
stream, there shall be provided and dedicated a drainage right-of-way
easement to the City conforming substantially with the lines of such
watercourse and of such further width or construction, or both, as
will be adequate to accommodate expected stormwater runoff, fifteen
(15) feet beyond the bank top on at least one (1) side for access
to the drainage right-of-way and, in any event, meeting any minimum
widths and locations shown on the adopted official map or master plan.
Such easement dedication shall be expressed on the plat as follows:
"Drainage and utility right-of-way easement granted to the City of
Plainfield." No relocation, construction or reconstruction shall take
place within the area of the easement, nor shall any structures be
located within such area, nor shall any action be taken which may
alter or impair the effectiveness of present or future drainage facilities
or cause soil erosion without prior approving authority or City Council
approval.
X.
Prohibitions on the Discharge of Storm Drainage and Groundwater.
1.
Stormwater, groundwater, rainwater, street drainage, subsurface drainage
or yard drainage shall not be discharged through direct or indirect
connections of a sump pump, cellar drain or any other means of conveyance
into a community sanitary sewer owned or operated by the Plainfield
City Sewer Utility or any sewerage authority.[1]
[1]
Editor's Note: The Municipal Utilities Authority was dissolved
by Ord. No. MC 2022-21 and a Sewer Utility and Solid Waste Utility
were created by Ord. No. MC 2022-22.
2.
Any person who is convicted of violating any provision of this section
shall be fined not less than fifty ($50.00) dollars for a first offense
and not less than one hundred ($100.00) dollars for each subsequent
offense.
[Added 4-12-2021 by Ord.
No. MC 2021-14]
A.
Policy Statement. Flood control, groundwater recharge, and pollutant
reduction shall be achieved through the use of stormwater management
measures, including green infrastructure best management practices
(GI BMPs) and nonstructural stormwater management strategies. GI BMPs
and low-impact development (LID) should be utilized to meet the goal
of maintaining natural hydrology to reduce stormwater runoff volume,
reduce erosion, encourage infiltration and groundwater recharge, and
reduce pollution. GI BMPs and LID should be developed based upon physical
site conditions and the origin, nature and the anticipated quantity,
or amount, of potential pollutants. Multiple stormwater management
BMPs may be necessary to achieve the established performance standards
for water quality, quantity, and groundwater recharge.
B.
Purpose. The purpose of this section is to establish minimum stormwater management requirements and controls for "major development," as defined in § 17:12-2.2.
C.
D.
Compatibility with Other Permit and Ordinance Requirements. Development
approvals issued pursuant to this section are to be considered an
integral part of development approvals and do not relieve the applicant
of the responsibility to secure required permits or approvals for
activities regulated by any other applicable code, rule, act, or ordinance.
In their interpretation and application, the provisions of this section
shall be held to be the minimum requirements for the promotion of
the public health, safety, and general welfare. This section is not
intended to interfere with, abrogate, or annul any other ordinances,
rule or regulation, statute, or other provision of law except that,
where any provision of this section imposes restrictions different
from those imposed by any other ordinance, rule or regulation, or
other provision of law, the more restrictive provisions or higher
standards shall control.
[Added 4-12-2021 by Ord.
No. MC 2021-14]
For the purpose of this section, the following terms, phrases,
words and their derivations shall have the meanings stated herein
unless their use in the text of this section clearly demonstrates
a different meaning. When not inconsistent with the context, words
used in the present tense include the future, words used in the plural
number include the singular number, and words used in the singular
number include the plural number. The word "shall" is always mandatory
and not merely directory. The definitions below are the same as or
based on the corresponding definitions in the Stormwater Management
Rules at N.J.A.C. 7:8-1.2.
Those areas with boundaries incorporated by reference or
revised by the Department in accordance with N.J.A.C. 7:7-13.16.
The map used by the Department to identify the location of
Coastal Planning Areas, CAFRA centers, CAFRA cores, and CAFRA nodes.
The CAFRA Planning Map is available on the Department's Geographic
Information System (GIS).
An infiltration system, sand filter designed to infiltrate,
standard constructed wetland, or wet pond, established in accordance
with N.J.A.C. 7:8-4.2(c)14, that is designed and constructed in accordance
with the New Jersey Stormwater Best Management Practices Manual, or
an alternate design, approved in accordance with N.J.A.C. 7:8-5.2(g),
for an infiltration system, sand filter designed to infiltrate, standard
constructed wetland, or wet pond and that complies with the requirements
of this section.
The increase in soil bulk density.
The area from which stormwater runoff drains to a stormwater
management measure, not including the area of the stormwater management
measure itself.
A pedestrian-oriented area of commercial and civic uses serving
the surrounding municipality, generally including housing and access
to public transportation.
An agency designated by the County Commissioners to review
municipal stormwater management plans and implementing ordinance(s).
The county review agency may either be:
The Department of Environmental Protection.
A person professionally qualified and duly licensed in New
Jersey to perform engineering services that may include, but not necessarily
be limited to, development of project requirements, creation and development
of project design and preparation of drawings and specifications.
A State Development and Redevelopment Plan Center as designated
by the State Planning Commission such as urban, regional, town, village,
or hamlet.
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, for which
permission is required under the Municipal Land Use Law, N.J.S.A.
40:55D-1 et seq. In the case of development of agricultural land,
"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. 4:1C-1
et seq.
The placement or reconstruction of impervious surface or
motor vehicle surface, or exposure and/or movement of soil or bedrock
or clearing, cutting, or removing of vegetation. Milling and repaving
is not considered disturbance for the purposes of this definition.
A geographic area within which stormwater, sediments, or
dissolved materials drain to a particular receiving waterbody or to
a particular point along a receiving waterbody.
Neighborhoods designated by the Urban Coordinating Council
"in consultation and conjunction with" the New Jersey Redevelopment
Authority pursuant to N.J.S.A 55:19-69.
The following areas where the physical alteration of the
land is in some way restricted, either through regulation, easement,
deed restriction or ownership such as: wetlands, floodplains, threatened
and endangered species sites or designated habitats, and parks and
preserves. Habitats of endangered or threatened species are identified
using the Department's Landscape Project as approved by the Department's
Endangered and Nongame Species Program.
An area or feature which is of significant environmental
value, including but not limited to: stream corridors, natural heritage
priority sites, habitats of endangered or threatened species, large
areas of contiguous open space or upland forest, steep slopes, and
well head protection and groundwater recharge areas. Habitats of endangered
or threatened species are identified using the Department's Landscape
Project as approved by the Department's Endangered and Nongame Species
Program.
The detachment and movement of soil or rock fragments by
water, wind, ice, or gravity.
A stormwater management measure that manages stormwater close
to its source by:
An area within which water drains to a particular receiving
surface water body, also known as a subwatershed, which is identified
by a 14-digit hydrologic unit boundary designation, delineated within
New Jersey by the United States Geological Survey.
A surface that has been covered with a layer of material
so that it is highly resistant to infiltration by water.
The process by which water seeps into the soil from precipitation.
One or more public entities having stormwater management
planning authority designated by the regional stormwater management
planning committee pursuant to N.J.A.C. 7:8-3.2, that serves as the
primary representative of the committee.
An individual "development," as well as multiple developments
that individually or collectively result in:
The disturbance of one or more acres of land since February
2, 2004;
The creation of 10,000 square feet or more of regulated impervious
surface since February 2, 2004;
The creation of 10,000 square feet or more of regulated motor
vehicle surface since March 2, 2021;
A combination of B and C above that totals an area of 10,000
square feet or more. The same surface shall not be counted twice when
determining if the combination area equals 10,000 square feet or more.
|
Major development includes all developments that are part of
a common plan of development or sale (for example, phased residential
development) that collectively or individually meet any one or more
of paragraphs A, B, C or D above. Projects undertaken by any government
agency that otherwise meet the definition of "major development" but
which do not require approval under the Municipal Land Use Law, N.J.S.A.
40:55D-1 et seq., are also considered major development.
|
Land vehicles propelled other than by muscular power, such
as automobiles, motorcycles, autocycles, and low speed vehicles. For
the purposes of this definition, "motor vehicle" does not include
farm equipment, snowmobiles, all-terrain vehicles, motorized wheelchairs,
go-carts, gas buggies, golf carts, ski-slope grooming machines, or
vehicles that run only on rails or tracks.
Any pervious or impervious surface that is intended to be
used by "motor vehicles" and/or aircraft, and is directly exposed
to precipitation including, but not limited to, driveways, parking
areas, parking garages, roads, racetracks, and runways.
Any city, borough, town, township, or village.
The manual maintained by the Department providing, in part, design specifications, removal rates, calculation methods, and soil testing procedures approved by the Department as being capable of contributing to the achievement of the stormwater management standards specified in this section. The BMP Manual is periodically amended by the Department as necessary to provide design specifications on additional best management practices and new information on already included practices reflecting the best available current information regarding the particular practice and the Department's determination as to the ability of that best management practice to contribute to compliance with the standards contained in this section. Alternative stormwater management measures, removal rates, or calculation methods may be utilized, subject to any limitations specified in this section, provided the design engineer demonstrates to the municipality, in accordance with § 17:12-2.4F and N.J.A.C. 7:8-5.2(g), that the proposed measure and its design will contribute to achievement of the design and performance standards established by this section.
An area designated by the State Planning Commission concentrating
facilities and activities which are not organized in a compact form.
A chemical element or compound, such as nitrogen or phosphorus,
which is essential to and promotes the development of organisms.
Any dredged spoil, solid waste, incinerator residue, filter
backwash, sewage, garbage, refuse, oil, grease, sewage sludge, munitions,
chemical wastes, biological materials, medical wastes, radioactive
substance (except those regulated under the Atomic Energy Act of 1954,
as amended (42 U.S.C. Section 2011 et seq.)), thermal waste, wrecked
or discarded equipment, rock, sand, cellar dirt, industrial, municipal,
agricultural, and construction waste or runoff, or other residue discharged
directly or indirectly to the land, ground waters or surface waters
of the State, or to a domestic treatment works. "Pollutant" includes
both hazardous and nonhazardous pollutants.
The amount of water from precipitation that infiltrates into
the ground and is not evapotranspired.
Any of the following, alone or in combination:
A net increase of impervious surface;
The total area of impervious surface collected by a new stormwater
conveyance system (for the purpose of this definition, a "new stormwater
conveyance system" is a stormwater conveyance system that is constructed
where one did not exist immediately prior to its construction or an
existing system for which a new discharge location is created);
The total area of impervious surface proposed to be newly collected
by an existing stormwater conveyance system; and/or
The total area of impervious surface collected by an existing
stormwater conveyance system where the capacity of that conveyance
system is increased.
Any of the following, alone or in combination:
The total area of motor vehicle surface that is currently receiving
water;
A net increase in motor vehicle surface; and/or quality treatment
either by vegetation or soil, by an existing stormwater management
measure, or by treatment at a wastewater treatment plant, where the
water quality treatment will be modified or removed.
Solid material, mineral or organic, that is in suspension,
is being transported, or has been moved from its site of origin by
air, water or gravity as a product of erosion.
The lot or lots upon which a major development is to occur
or has occurred.
All unconsolidated mineral and organic material of any origin.
An area delineated on the State Plan Policy Map and adopted
by the State Planning Commission that is intended to be the focus
for much of the State's future redevelopment and revitalization efforts.
The geographic application of the State Development and Redevelopment
Plan's goals and statewide policies, and the official map of these
goals and policies.
Water resulting from precipitation (including rain and snow)
that runs off the land's surface, is transmitted to the subsurface,
or is captured by separate storm sewers or other sewage or drainage
facilities, or conveyed by snow removal equipment.
An excavation or embankment and related areas designed to
retain stormwater runoff. A stormwater management BMP may either be
normally dry (that is, a detention basin or infiltration system),
retain water in a permanent pool (a retention basin), or be planted
mainly with wetland vegetation (most constructed stormwater wetlands).
Any practice, technology, process, program, or other method
intended to control or reduce stormwater runoff and associated pollutants,
or to induce or control the infiltration or groundwater recharge of
stormwater or to eliminate illicit or illegal non-stormwater discharges
into stormwater conveyances.
A public body authorized by legislation to prepare stormwater
management plans.
The geographic area for which a stormwater management planning
agency is authorized to prepare stormwater management plans, or a
specific portion of that area identified in a stormwater management
plan prepared by that agency.
Water flow on the surface of the ground or in storm sewers,
resulting from precipitation.
A flood hazard area in which the flood elevation resulting
from the two-, 10-, or 100-year storm, as applicable, is governed
by tidal flooding from the Atlantic Ocean. Flooding in a tidal flood
hazard area may be contributed to, or influenced by, stormwater runoff
from inland areas, but the depth of flooding generated by the tidal
rise and fall of the Atlantic Ocean is greater than flooding from
any fluvial sources. In some situations, depending upon the extent
of the storm surge from a particular storm event, a flood hazard area
may be tidal in the 100-year storm, but fluvial in more frequent storm
events.
A neighborhood given priority access to State resources through
the New Jersey Redevelopment Authority.
A zone designated by the New Jersey Enterprise Zone Authority
pursuant to the New Jersey Urban Enterprise Zones Act, N.J.S.A. 52:27H-60
et. seq.
Previously developed portions of areas:
A structure within, or adjacent to, a water, which intentionally
or coincidentally alters the hydraulic capacity, the flood elevation
resulting from the two-, 10-, or 100-year storm, flood hazard area
limit, and/or floodway limit of the water. Examples of a water control
structure may include a bridge, culvert, dam, embankment, ford (if
above grade), retaining wall, and weir.
The ocean and its estuaries, all springs, streams, wetlands,
and bodies of surface or groundwater, whether natural or artificial,
within the boundaries of the State of New Jersey or subject to its
jurisdiction.
An area that is inundated or saturated by surface water or
ground water at a frequency and duration sufficient to support, and
that under normal circumstances does support, a prevalence of vegetation
typically adapted for life in saturated soil conditions, commonly
known as hydrophytic vegetation.
[Added 4-12-2021 by Ord.
No. MC 2021-14]
A.
Stormwater management measures for major development shall be designed
to provide erosion control, groundwater recharge, stormwater runoff
quantity control, and stormwater runoff quality treatment as follows:
1.
The minimum standards for erosion control are those established
under the Soil and Sediment Control Act, N.J.S.A. 4:24-39 et seq.,
and implementing rules at N.J.A.C. 2:90.
2.
The minimum standards for groundwater recharge, stormwater quality,
and stormwater runoff quantity shall be met by incorporating green
infrastructure.
B.
The standards in this section apply only to new major development
and are intended to minimize the impact of stormwater runoff on water
quality and water quantity in receiving water bodies and maintain
groundwater recharge. The standards do not apply to new major development
to the extent that alternative design and performance standards are
applicable under a regional stormwater management plan or Water Quality
Management Plan adopted in accordance with Department rules. The stormwater
management requirements within this section, as they relate to "major
development" supersede other design requirements stipulated in the
City Code, including but not limited to the following sections:
[Added 4-12-2021 by Ord. No. MC 2021-14]
A.
The development shall incorporate a maintenance plan for the stormwater management measures incorporated into the design of a major development in accordance with § 17:12-2.10.
B.
Stormwater management measures shall avoid adverse impacts of concentrated
flow on habitat for threatened and endangered species as documented
in the Department's Landscape Project or Natural Heritage Database
established under N.J.S.A. 13:1B-15.147 through 15.150, particularly
Helonias bullata (swamp pink) and/or Clemmys muhlnebergi (bog turtle).
C.
The following linear development projects are exempt from the groundwater recharge, stormwater runoff quality, and stormwater runoff quantity requirements of § 17:12-2.4P, Q and R.
1.
The construction of an underground utility line provided that
the disturbed areas are revegetated upon completion;
2.
The construction of an aboveground utility line provided that
the existing conditions are maintained to the maximum extent practicable;
and
3.
The construction of a public pedestrian access, such as a sidewalk
or trail with a maximum width of 14 feet, provided that the access
is made of permeable material.
D.
A waiver from strict compliance from the green infrastructure, groundwater recharge, stormwater runoff quality, and stormwater runoff quantity requirements of § 17:12-2.4O, P, Q and R may be obtained for the enlargement of an existing public roadway or railroad; or the construction or enlargement of a public pedestrian access, provided that the following conditions are met:
1.
The applicant demonstrates that there is a public need for the
project that cannot be accomplished by any other means;
2.
The applicant demonstrates through an alternatives analysis, that through the use of stormwater management measures, the option selected complies with the requirements of § 17:12-2.4O, P, Q and R to the maximum extent practicable;
3.
The applicant demonstrates that, in order to meet the requirements of § 17:12-2.4O, P, Q and R existing structures currently in use, such as homes and buildings, would need to be condemned; and
4.
The applicant demonstrates that it does not own or have other rights to areas, including the potential to obtain through condemnation lands not falling under § 17:12-2.4D3 above within the upstream drainage area of the receiving stream, that would provide additional opportunities to mitigate the requirements of § 17:12-2.4O, P, Q and R that were not achievable onsite.
E.
Tables 1 through 3 below summarize the ability of stormwater best management practices identified and described in the New Jersey Stormwater Best Management Practices Manual to satisfy the green infrastructure, groundwater recharge, stormwater runoff quality and stormwater runoff quantity standards specified in § 17:12-2.4O, P, Q and R. When designed in accordance with the most current version of the New Jersey Stormwater Best Management Practices Manual, the stormwater management measures found at N.J.A.C. 7:8-5.2(f) Tables 5-1, 5-2 and 5-3 and listed below in Tables 1, 2 and 3 are presumed to be capable of providing stormwater controls for the design and performance standards as outlined in the tables below. Upon amendments of the New Jersey Stormwater Best Management Practices to reflect additions or deletions of BMPs meeting these standards, or changes in the presumed performance of BMPs designed in accordance with the New Jersey Stormwater BMP Manual, the Department shall publish in the New Jersey Registers a notice of administrative change revising the applicable table. The most current version of the BMP Manual can be found on the Department's website at: <https://njstormwater.org/bmp_manual2.htm>.
F.
Where the BMP tables in the NJ Stormwater Management Rule are different
due to updates or amendments with the tables in this section the BMP
Tables in the Stormwater Management rule at N.J.A.C. 7:8-5.2(f) shall
take precedence.
|
Table 1
Green Infrastructure BMPs for Groundwater Recharge, Stormwater
Runoff Quality, and/or Stormwater Runoff Quantity
| ||||
|---|---|---|---|---|
|
Best Management Practice
|
Stormwater Runoff Quality TSS Removal Rate
(percent)
|
Stormwater Runoff Quantity
|
Groundwater Recharge
|
Minimum Separation from Seasonal High Water Table
(feet)
|
|
Cistern
|
0
|
Yes
|
No
|
—
|
|
Dry Well(a)
|
0
|
No
|
Yes
|
2
|
|
Grass Swale
|
50 or less
|
No
|
No
|
2(e)
1(f)
|
|
Green Roof
|
0
|
Yes
|
No
|
—
|
|
Manufactured Treatment Device(a)(g)
|
50 or 80
|
No
|
No
|
Dependent upon the device
|
|
Pervious Paving System(a)
|
80
|
Yes
|
Yes(b)
No(c)
|
2(b)
1(c)
|
|
Small-Scale Bioretention Basin(a)
|
80 or 90
|
Yes
|
Yes(b)
No(c)
|
2(b)
1(c)
|
|
Small-Scale Infiltration Basin(a)
|
80
|
Yes
|
Yes
|
2
|
|
Small-Scale Sand Filter
|
80
|
Yes
|
Yes
|
2
|
|
Vegetative Filter Strip
|
60-80
|
No
|
No
|
—
|
|
(Notes corresponding to annotations (a) through (g) are found below Table 3)
|
|
Table 2
Green Infrastructure BMPs for Stormwater Runoff Quantity
(or for Groundwater Recharge and/or Stormwater Runoff Quality
with a Waiver or Variance from N.J.A.C. 7:8-5.3)
| ||||
|---|---|---|---|---|
|
Best Management Practice
|
Stormwater Runoff Quality TSS Removal Rate
(percent)
|
Stormwater Runoff Quantity
|
Groundwater Recharge
|
Minimum Separation from Seasonal High Water Table
(feet)
|
|
Bioretention System
|
80 or 90
|
Yes
|
Yes(b)
No(c)
|
2(b)
1(c)
|
|
Infiltration Basin
|
80
|
Yes
|
Yes
|
2
|
|
Sand Filter(b)
|
80
|
Yes
|
Yes
|
2
|
|
Standard Constructed Wetland
|
90
|
Yes
|
No
|
N/A
|
|
Wet Pond(d)
|
50-90
|
Yes
|
No
|
N/A
|
|
(Notes corresponding to annotations (b) through (d) are found below Table 3)
|
|
Table 3
BMPs for Groundwater Recharge, Stormwater Runoff Quality, and/or
Stormwater Runoff Quantity
only with a Waiver or Variance from N.J.A.C. 7:8-5.3
| ||||
|---|---|---|---|---|
|
Best Management Practice
|
Stormwater Runoff Quality TSS Removal Rate
(percent)
|
Stormwater Runoff Quantity
|
Groundwater Recharge
|
Minimum Separation from Seasonal High Water Table
(feet)
|
|
Blue Roof
|
0
|
Yes
|
No
|
N/A
|
|
Extended Detention Basin
|
40-60
|
Yes
|
No
|
1
|
|
Manufactured Treatment Device(h)
|
50 or 80
|
No
|
No
|
Dependent upon the device
|
|
Sand Filter(c)
|
80
|
Yes
|
No
|
1
|
|
Subsurface Gravel Wetland
|
90
|
No
|
No
|
1
|
|
Wet Pond
|
50-90
|
Yes
|
No
|
N/A
|
|
Notes to Tables 1, 2, and 3:
| |
|
(a)
|
Subject to the applicable contributory drainage area limitation
specified at § 17:12-2.4O2;
|
|
(b)
|
Designed to infiltrate into the subsoil;
|
|
(c)
|
Designed with underdrains;
|
|
(d)
|
Designed to maintain at least a 10-foot-wide area of native
vegetation along at least 50% of the shoreline and to include a stormwater
runoff retention component designed to capture stormwater runoff for
beneficial reuse, such as irrigation;
|
|
(e)
|
Designed with a slope of less than 2%;
|
|
(f)
|
Designed with a slope of equal to or greater than 2%;
|
|
(g)
|
Manufactured treatment devices that meet the definition of green infrastructure at § 17:12-2.2;
|
|
(h)
|
Manufactured treatment devices that do not meet the definition of green infrastructure at § 17:12-2.2.
|
G.
An alternative stormwater management measure, alternative removal rate, and/or alternative method to calculate the removal rate may be used if the design engineer demonstrates the capability of the proposed alternative stormwater management measure and/or the validity of the alternative rate or method to the municipality. A copy of any approved alternative stormwater management measure, alternative removal rate, and/or alternative method to calculate the removal rate shall be provided to the Department in accordance with § 17:12-2.6B. Alternative stormwater management measures may be used to satisfy the requirements at § 17:12-2.4O only if the measures meet the definition of green infrastructure at § 17:12-2.2. Alternative stormwater management measures that function in a similar manner to a BMP listed at § 17:12-2.4O2 are subject to the contributory drainage area limitation specified at § 17:12-2.4O2 for that similarly functioning BMP. Alternative stormwater management measures approved in accordance with this subsection that do not function in a similar manner to any BMP listed at § 17:12-2.4O2 shall have a contributory drainage area less than or equal to 2.5 acres, except for alternative stormwater management measures that function similarly to cisterns, grass swales, green roofs, standard constructed wetlands, vegetative filter strips, and wet ponds, which are not subject to a contributory drainage area limitation. Alternative measures that function similarly to standard constructed wetlands or wet ponds shall not be used for compliance with the stormwater runoff quality standard unless a variance in accordance with N.J.A.C. 7:8-4.6 or a waiver from strict compliance in accordance with § 17:12-2.4D is granted from § 17:12-2.4O.
H.
Whenever the stormwater management design includes one or more BMPs
that will infiltrate stormwater into subsoil, the design engineer
shall assess the hydraulic impact on the groundwater table and design
the site, so as to avoid adverse hydraulic impacts. Potential adverse
hydraulic impacts include, but are not limited to, exacerbating a
naturally or seasonally high water table, so as to cause surficial
ponding, flooding of basements, or interference with the proper operation
of subsurface sewage disposal systems or other subsurface structures
within the zone of influence of the groundwater mound, or interference
with the proper functioning of the stormwater management measure itself.
I.
Design standards for stormwater management measures are as follows:
1.
Stormwater management measures shall be designed to take into
account the existing site conditions, including, but not limited to,
environmentally critical areas; wetlands; flood-prone areas; slopes;
depth to seasonal high water table; soil type, permeability, and texture;
drainage area and drainage patterns; and the presence of solution-prone
carbonate rocks (limestone);
2.
Stormwater management measures shall be designed to minimize maintenance, facilitate maintenance and repairs, and ensure proper functioning. Trash racks shall be installed at the intake to the outlet structure, as appropriate, and shall have parallel bars with one-inch spacing between the bars to the elevation of the water quality design storm. For elevations higher than the water quality design storm, the parallel bars at the outlet structure shall be spaced no greater than one-third the width of the diameter of the orifice or one-third the width of the weir, with a minimum spacing between bars of one inch and a maximum spacing between bars of six inches. In addition, the design of trash racks must comply with the requirements of § 17:12-2.8C;
3.
Stormwater management measures shall be designed, constructed,
and installed to be strong, durable, and corrosion resistant. Measures
that are consistent with the relevant portions of the Residential
Site Improvement Standards at N.J.A.C. 5:21-7.3, 7.4, and 7.5 shall
be deemed to meet this requirement;
4.
Stormwater management BMPs shall be designed to meet the minimum safety standards for stormwater management BMPs at § 17:12-2.8; and
5.
The size of the orifice at the intake to the outlet from the
stormwater management BMP shall be a minimum of two and one-half inches
in diameter.
J.
Manufactured treatment devices may be used to meet the requirements of this subchapter, provided the pollutant removal rates are verified by the New Jersey Corporation for Advanced Technology and certified by the Department. Manufactured treatment devices that do not meet the definition of green infrastructure at § 17:12-2.2 may be used only under the circumstances described at § 17:12-2.4O4;
K.
Any application for a new agricultural development that meets the definition of major development at § 17:12-2.2 shall be submitted to the Soil Conservation District for review and approval in accordance with the requirements at § 17:12-2.4O, P, Q and R and any applicable Soil Conservation District guidelines for stormwater runoff quantity and erosion control. For purposes of this subsection, "agricultural development" means land uses normally associated with the production of food, fiber, and livestock for sale. Such uses do not include the development of land for the processing or sale of food and the manufacture of agriculturally related products.
L.
If there is more than one drainage area, the groundwater recharge, stormwater runoff quality, and stormwater runoff quantity standards at § 17:12-2.4P, Q and R shall be met in each drainage area, unless the runoff from the drainage areas converge onsite and no adverse environmental impact would occur as a result of compliance with any one or more of the individual standards being determined utilizing a weighted average of the results achieved for that individual standard across the affected drainage areas.
M.
Any stormwater management measure authorized under the municipal stormwater management plan or ordinance shall be reflected in a deed notice recorded in the County Clerk's office. A form of deed notice shall be submitted to the municipality for approval prior to filing. The deed notice shall contain a description of the stormwater management measure(s) used to meet the green infrastructure, groundwater recharge, stormwater runoff quality, and stormwater runoff quantity standards at § 17:12-2.4O, P, Q and R and shall identify the location of the stormwater management measure(s) in NAD 1983 State Plane New Jersey FIPS 2900 US Feet or Latitude and Longitude in decimal degrees. The deed notice shall also reference the maintenance plan required to be recorded upon the deed pursuant to § 17:12-2.10B5. Prior to the commencement of construction, proof that the above required deed notice has been filed shall be submitted to the municipality. Proof that the required information has been recorded on the deed shall be in the form of either a copy of the complete recorded document or a receipt from the clerk or other proof of recordation provided by the recording office. However, if the initial proof provided to the municipality is not a copy of the complete recorded document, a copy of the complete recorded document shall be provided to the municipality within 180 calendar days of the authorization granted by the municipality.
N.
A stormwater management measure approved under the municipal stormwater management plan or ordinance may be altered or replaced with the approval of the municipality, if the municipality determines that the proposed alteration or replacement meets the design and performance standards pursuant to§ 17:12-2.4 of this section and provides the same level of stormwater management as the previously approved stormwater management measure that is being altered or replaced. If an alteration or replacement is approved, a revised deed notice shall be submitted to the municipality for approval and subsequently recorded with the County Clerk's office and shall contain a description and location of the stormwater management measure, as well as reference to the maintenance plan, in accordance with § 17:12-2.4M above. Prior to the commencement of construction, proof that the above required deed notice has been filed shall be submitted to the municipality in accordance with § 17:12-2.4M above.
O.
Green Infrastructure Standards.
1.
This subsection specifies the types of green infrastructure
BMPs that may be used to satisfy the groundwater recharge, stormwater
runoff quality, and stormwater runoff quantity standards.
2.
To satisfy the groundwater recharge and stormwater runoff quality standards at § 17:12-2.4P and Q, the design engineer shall utilize green infrastructure BMPs identified in Table 1 at § 17:12-2.4F and/or an alternative stormwater management measure approved in accordance with § 17:12-2.4G. The following green infrastructure BMPs are subject to the following maximum contributory drainage area limitations:
|
Best Management Practice
|
Maximum Contributory Drainage Area
|
|---|---|
|
Dry Well
|
1 acre
|
|
Manufactured Treatment Device
|
2.5 acres
|
|
Pervious Pavement Systems
|
Area of additional inflow cannot exceed three times the area
occupied by the BMP
|
|
Small-scale Bioretention Systems
|
2.5 acres
|
|
Small-scale Infiltration Basin
|
2.5 acres
|
|
Small-scale Sand Filter
|
2.5 acres
|
3.
To satisfy the stormwater runoff quantity standards at § 17:12-2.4R, the design engineer shall utilize BMPs from Table 1 or from Table 2 and/or an alternative stormwater management measure approved in accordance with § 17:12-2.4G.
4.
If a variance in accordance with N.J.A.C. 7:8-4.6 or a waiver from strict compliance in accordance with § 17:12-2.4D is granted from the requirements of this subsection, then BMPs from Table 1, 2, or 3, and/or an alternative stormwater management measure approved in accordance with § 17:12-2.4G may be used to meet the groundwater recharge, stormwater runoff quality, and stormwater runoff quantity standards at § 17:12-2.4P, Q and R.
5.
For separate or combined storm sewer improvement projects, such as sewer separation, undertaken by a government agency or public utility (for example, a sewerage company), the requirements of this subsection shall only apply to areas owned in fee simple by the government agency or utility, and areas within a right-of-way or easement held or controlled by the government agency or utility; the entity shall not be required to obtain additional property or property rights to fully satisfy the requirements of this subsection. Regardless of the amount of area of a separate or combined storm sewer improvement project subject to the green infrastructure requirements of this subsection, each project shall fully comply with the applicable groundwater recharge, stormwater runoff quality control, and stormwater runoff quantity standards at § 17:12-2.4P, Q and R unless the project is granted a waiver from strict compliance in accordance with § 17:12-2.4D.
P.
Groundwater Recharge Standards.
1.
This subsection contains the minimum design and performance
standards for groundwater recharge as follows.
2.
The design engineer shall, using the assumptions and factors for stormwater runoff and groundwater recharge calculations at § 17:12-2.5, either:
a.
Demonstrate through hydrologic and hydraulic analysis that the
site and its stormwater management measures maintain 100% of the average
annual pre-construction groundwater recharge volume for the site;
or
b.
Demonstrate through hydrologic and hydraulic analysis that the
increase of stormwater runoff volume from pre-construction to post-construction
for the 2-year storm is infiltrated.
3.
This groundwater recharge requirement does not apply to projects
within the "urban redevelopment area," or to projects subject to § 17:12-2.4P4
below.
4.
The following types of stormwater shall not be recharged:
a.
Stormwater from areas of high pollutant loading. High pollutant
loading areas are areas in industrial and commercial developments
where solvents and/or petroleum products are loaded/unloaded, stored,
or applied, areas where pesticides are loaded/unloaded or stored;
areas where hazardous materials are expected to be present in greater
than "reportable quantities" as defined by the United States Environmental
Protection Agency (EPA) at 40 CFR 302.4; areas where recharge would
be inconsistent with Department approved remedial action work plan
or landfill closure plan and areas with high risks for spills of toxic
materials, such as gas stations and vehicle maintenance facilities;
and
b.
Industrial stormwater exposed to "source material." "Source
material" means any material(s) or machinery, located at an industrial
facility, that is directly or indirectly related to process, manufacturing
or other industrial activities, which could be a source of pollutants
in any industrial stormwater discharge to groundwater. Source materials
include, but are not limited to, raw materials; intermediate products;
final products; waste materials; by-products; industrial machinery
and fuels, and lubricants, solvents, and detergents that are related
to process, manufacturing, or other industrial activities that are
exposed to stormwater.
Q.
Stormwater Runoff Quality Standards.
1.
This subsection contains the minimum design and performance
standards to control stormwater runoff quality impacts of major development.
Stormwater runoff quality standards are applicable when the major
development results in an increase 1/4 of an acre or more of regulated
motor vehicle surface.
2.
Stormwater management measures shall be designed to reduce the
post-construction load of total suspended solids (TSS) in stormwater
runoff generated from the water quality design storm as follows:
a.
Eighty percent TSS removal of the anticipated load, expressed
as an annual average shall be achieved for the stormwater runoff from
the net increase of motor vehicle surface.
b.
If the surface is considered regulated motor vehicle surface
because the water quality treatment for an area of motor vehicle surface
that is currently receiving water quality treatment either by vegetation
or soil, by an existing stormwater management measure, or by treatment
at a wastewater treatment plant is to be modified or removed, the
project shall maintain or increase the existing TSS removal of the
anticipated load expressed as an annual average.
3.
The requirement to reduce TSS does not apply to any stormwater
runoff in a discharge regulated under a numeric effluent limitation
for TSS imposed under the New Jersey Pollutant Discharge Elimination
System (NJPDES) rules, N.J.A.C. 7:14A, or in a discharge specifically
exempt under a NJPDES permit from this requirement. Every major development,
including any that discharge into a combined sewer system, shall comply
with paragraph 2 above, unless the major development is itself subject
to a NJPDES permit with a numeric effluent limitation for TSS or the
NJPDES permit to which the major development is subject exempts the
development from a numeric effluent limitation for TSS.
4.
The water quality design storm is 1.25 inches of rainfall in
two hours. Water quality calculations shall take into account the
distribution of rain from the water quality design storm, as reflected
in Table 4, below. The calculation of the volume of runoff may take
into account the implementation of stormwater management measures.
|
Table 4 - Water Quality Design Storm Distribution
| |||||
|---|---|---|---|---|---|
|
Time
(Minutes)
|
Cumulative Rainfall
(Inches)
|
Time
(Minutes)
|
Cumulative Rainfall
(Inches)
|
Time
(Minutes)
|
Cumulative Rainfall
(Inches)
|
|
1
|
0.00166
|
41
|
0.1728
|
81
|
1.0906
|
|
2
|
0.00332
|
42
|
0.1796
|
82
|
1.0972
|
|
3
|
0.00498
|
43
|
0.1864
|
83
|
1.1038
|
|
4
|
0.00664
|
44
|
0.1932
|
84
|
1.1104
|
|
5
|
0.00830
|
45
|
0.2000
|
85
|
1.1170
|
|
6
|
0.00996
|
46
|
0.2117
|
86
|
1.1236
|
|
7
|
0.01162
|
47
|
0.2233
|
87
|
1.1302
|
|
8
|
0.01328
|
48
|
0.2350
|
88
|
1.1368
|
|
9
|
0.01494
|
49
|
0.2466
|
89
|
1.1434
|
|
10
|
0.01660
|
50
|
0.2583
|
90
|
1.1500
|
|
11
|
0.01828
|
51
|
0.2783
|
91
|
1.1550
|
|
12
|
0.01996
|
52
|
0.2983
|
92
|
1.1600
|
|
13
|
0.02164
|
53
|
0.3183
|
93
|
1.1650
|
|
14
|
0.02332
|
54
|
0.3383
|
94
|
1.1700
|
|
15
|
0.02500
|
55
|
0.3583
|
95
|
1.1750
|
|
16
|
0.03000
|
56
|
0.4116
|
96
|
1.1800
|
|
17
|
0.03500
|
57
|
0.4650
|
97
|
1.1850
|
|
18
|
0.04000
|
58
|
0.5183
|
98
|
1.1900
|
|
19
|
0.04500
|
59
|
0.5717
|
99
|
1.1950
|
|
20
|
0.05000
|
60
|
0.6250
|
100
|
1.2000
|
|
21
|
0.05500
|
61
|
0.6783
|
101
|
1.2050
|
|
22
|
0.06000
|
62
|
0.7317
|
102
|
1.2100
|
|
23
|
0.06500
|
63
|
0.7850
|
103
|
1.2150
|
|
24
|
0.07000
|
64
|
0.8384
|
104
|
1.2200
|
|
25
|
0.07500
|
65
|
0.8917
|
105
|
1.2250
|
|
26
|
0.08000
|
66
|
0.9117
|
106
|
1.2267
|
|
27
|
0.08500
|
67
|
0.9317
|
107
|
1.2284
|
|
28
|
0.09000
|
68
|
0.9517
|
108
|
1.2300
|
|
29
|
0.09500
|
69
|
0.9717
|
109
|
1.2317
|
|
30
|
0.10000
|
70
|
0.9917
|
110
|
1.2334
|
|
31
|
0.10660
|
71
|
1.0034
|
111
|
1.2351
|
|
32
|
0.11320
|
72
|
1.0150
|
112
|
1.2367
|
|
33
|
0.11980
|
73
|
1.0267
|
113
|
1.2384
|
|
34
|
0.12640
|
74
|
1.0383
|
114
|
1.2400
|
|
35
|
0.13300
|
75
|
1.0500
|
115
|
1.2417
|
|
36
|
0.13960
|
76
|
1.0568
|
116
|
1.2434
|
|
37
|
0.14620
|
77
|
1.0636
|
117
|
1.2450
|
|
38
|
0.15280
|
78
|
1.0704
|
118
|
1.2467
|
|
39
|
0.15940
|
79
|
1.0772
|
119
|
1.2483
|
|
40
|
0.16600
|
80
|
1.0840
|
120
|
1.2500
|
5.
If more than one BMP in series is necessary to achieve the required
80% TSS reduction for a site, the applicant shall utilize the following
formula to calculate TSS reduction:
|
R = A + B - (AxB)/100
|
|
Where:
| ||
|
R
|
=
|
total TSS percent load removal from application of both BMPs
|
|
A
|
=
|
the TSS percent removal rate applicable to the first BMP
|
|
B
|
=
|
the TSS percent removal rate applicable to the second BMP
|
If there is more than one on-site drainage area, the
80% TSS removal rate shall apply to each drainage area, unless the
runoff from the subareas converge on site in which case the removal
rate can be demonstrated through a calculation using a weighted average.
6.
Stormwater management measures shall also be designed to reduce, to the maximum extent feasible, the post-construction nutrient load of the anticipated load from the developed site in stormwater runoff generated from the water quality design storm. In achieving reduction of nutrients to the maximum extent feasible, the design of the site shall include green infrastructure BMPs that optimize nutrient removal while still achieving the performance standards in § 17:12-2.4P, Q and R.
7.
In accordance with the definition of FW1 at N.J.A.C. 7:9B-1.4,
stormwater management measures shall be designed to prevent any increase
in stormwater runoff to waters classified as FW1.
8.
The Flood Hazard Area Control Act Rules at N.J.A.C. 7:13-4.1(c)1
establish 300-foot riparian zones along Category One waters, as designated
in the Surface Water Quality Standards at N.J.A.C. 7:9B, and certain
upstream tributaries to Category One waters. A person shall not undertake
a major development that is located within or discharges into a 300-foot
riparian zone without prior authorization from the Department under
N.J.A.C. 7:13.
9.
Pursuant to the Flood Hazard Area Control Act Rules at N.J.A.C.
7:13-11.2(j)3.i, runoff from the water quality design storm that is
discharged within a 300-foot riparian zone shall be treated in accordance
with this subsection to reduce the post-construction load of total
suspended solids by 95% of the anticipated load from the developed
site, expressed as an annual average.
10.
This stormwater runoff quality standards do not apply to the
construction of one individual single-family dwelling, provided that
it is not part of a larger development or subdivision that has received
preliminary or final site plan approval prior to December 3, 2018,
and that the motor vehicle surfaces are made of permeable material(s)
such as gravel, dirt, and/or shells.
11.
Special water resource protection areas shall be established
along all waters designated Category One at N.J.A.C. 7:9B, and perennial
or intermittent streams that drain into or upstream of the Category
One waters as shown on the USGS Quadrangle Maps or in the County Soil
Surveys, within the associated HUC14 drainage area. These areas shall
be established for the protection of water quality, aesthetic value,
exceptional ecological significance, exceptional recreational significance,
exceptional water supply significance, and exceptional fisheries significance
of those established Category One waters. These areas shall be designated
and protected as follows:
a.
The applicant shall preserve and maintain a special water resource
protection area in accordance with one of the following:
(1)
A 300-foot special water resource protection area
shall be provided on each side of the waterway, measured perpendicular
to the waterway from the top of the bank outwards or from the center
line of the waterway where the bank is not defined, consisting of
existing vegetation or vegetation allowed to follow natural succession
is provided.
(2)
Encroachment within the designated special water
resource protection area under paragraph (1) above shall only be allowed
where previous development or disturbance has occurred (for example,
active agricultural use, parking area or maintained lawn area). The
encroachment shall only be allowed where applicant demonstrates that
the functional value and overall condition of the special water resource
protection area will be maintained to the maximum extent practicable.
In no case shall the remaining special water resource protection area
be reduced to less than 150 feet as measured perpendicular to the
top of bank of the waterway or center line of the waterway where the
bank is undefined. All encroachments proposed under this subparagraph
shall be subject to review and approval by the Department.
b.
All stormwater shall be discharged outside of and flow through
the special water resource protection area and shall comply with the
Standard for Off-Site Stability in the "Standards for Soil Erosion
and Sediment Control in New Jersey," established under the Soil Erosion
and Sediment Control Act, N.J.S.A. 4:24-39 et seq.
c.
If stormwater discharged outside of and flowing through the
special water resource protection area cannot comply with the Standard
for Off-Site Stability in the "Standards for Soil Erosion and Sediment
Control in New Jersey," established under the Soil Erosion and Sediment
Control Act, N.J.S.A. 4:24-39 et seq., then the stabilization measures
in accordance with the requirements of the above standards may be
placed within the special water resource protection area, provided
that:
d.
A stream corridor protection plan may be developed by a regional
stormwater management planning committee as an element of a regional
stormwater management plan, or by a municipality through an adopted
municipal stormwater management plan. If a stream corridor protection
plan for a waterway subject to § 17:12-2.4G8 has been approved
by the Department of Environmental Protection, then the provisions
of the plan shall be the applicable special water resource protection
area requirements for that waterway. A stream corridor protection
plan for a waterway subject to § 17:12-2.4G8 shall maintain
or enhance the current functional value and overall condition of the
special water resource protection area as defined in § 17:12-2.4G8a(1)
above. In no case shall a stream corridor protection plan allow the
reduction of the Special Water Resource Protection Area to less than
150 feet as measured perpendicular to the waterway subject to this
subsection.
R.
Stormwater Runoff Quantity Standards.
1.
This subsection contains the minimum design and performance
standards to control stormwater runoff quantity impacts of major development.
2.
In order to control stormwater runoff quantity impacts, the design engineer shall, using the assumptions and factors for stormwater runoff calculations at § 17:12-2.5 complete one of the following:
a.
Demonstrate through hydrologic and hydraulic analysis that for
stormwater leaving the site, post-construction runoff hydrographs
for the 2-, 10-, and 100-year storm events do not exceed, at any point
in time, the pre-construction runoff hydrographs for the same storm
events;
b.
Demonstrate through hydrologic and hydraulic analysis that there
is no increase, as compared to the pre-construction condition, in
the peak runoff rates of stormwater leaving the site for the 2-, 10-
and 100-year storm events and that the increased volume or change
in timing of stormwater runoff will not increase flood damage at or
downstream of the site. This analysis shall include the analysis of
impacts of existing land uses and projected land uses assuming full
development under existing zoning and land use ordinances in the drainage
area;
c.
Design stormwater management measures so that the post-construction
peak runoff rates for the 2-, 10- and 100-year storm events are 50%,
75% and 80%, respectively, of the pre-construction peak runoff rates.
The percentages apply only to the post-construction stormwater runoff
that is attributable to the portion of the site on which the proposed
development or project is to be constructed; or
d.
In tidal flood hazard areas, stormwater runoff quantity analysis
in accordance with paragraphs 2a, 2b and 2c above is required unless
the design engineer demonstrates through hydrologic and hydraulic
analysis that the increased volume, change in timing, or increased
rate of the stormwater runoff, or any combination of the three will
not result in additional flood damage below the point of discharge
of the major development. No analysis is required if the stormwater
is discharged directly into any ocean, bay, inlet, or the reach of
any watercourse between its confluence with an ocean, bay, or inlet
and downstream of the first water control structure.
3.
The stormwater runoff quantity standards shall be applied at
the site's boundary to each abutting lot, roadway, watercourse, or
receiving storm sewer system.
[Added 4-12-2021 by Ord.
No. MC 2021-14]
A.
Stormwater runoff shall be calculated in accordance with the following:
1.
The design engineer shall calculate runoff using one of the
following methods:
a.
The USDA Natural Resources Conservation Service (NRCS) methodology, including the NRCS Runoff Equation and Dimensionless Unit Hydrograph, as described in Chapters 7, 9, 10, 15 and 16 Part 630, Hydrology National Engineering Handbook, incorporated herein by reference as amended and supplemented. This methodology is additionally described in Technical Release 55 - Urban Hydrology for Small Watersheds (TR-55), dated June 1986, herein by reference as amended and supplemented. Information regarding the methodology is available from the Natural Resources Conservation Service website at: <https://www.nrcs.usdagov/Internet/FSE_DOCUMENTS/ste1044171pdf%20> or at United States Department of Agriculture Natural Resources Conservation Service, 220 Davison Avenue, Somerset, New Jersey 08873; or
b.
The Rational Method for peak flow and the Modified Rational
Method for hydrograph computations. The rational and modified rational
methods are described in "Appendix A-9 Modified Rational Method" in
the Standards for Soil Erosion and Sediment Control in New Jersey,
January 2014. This document is available from the State Soil Conservation
Committee or any of the Soil Conservation Districts listed at N.J.A.C.
2:90-1.3(a)3. The location, address, and telephone number for each
Soil Conservation District is available from the State Soil Conservation
Committee, PO Box 330, Trenton, New Jersey 08625. The document is
also available at: <http://www.nj.gov/agriculture/divisions/anr/pdf/2014NJSoilErosionControlStandardsComplete.pdf>.
2.
For the purpose of calculating runoff coefficients and groundwater
recharge, there is a presumption that the pre-construction condition
of a site or portion thereof is a wooded land use with good hydrologic
condition. The term "runoff coefficient" applies to both the NRCS
methodology above at § 17:12-2.5a1 and the Rational and
Modified Rational Methods at § 17:12-2.5a2. A runoff coefficient
or a groundwater recharge land cover for an existing condition may
be used on all or a portion of the site if the design engineer verifies
that the hydrologic condition has existed on the site or portion of
the site for at least five years without interruption prior to the
time of application. If more than one land cover have existed on the
site during the five years immediately prior to the time of application,
the land cover with the lowest runoff potential shall be used for
the computations. In addition, there is the presumption that the site
is in good hydrologic condition (if the land use type is pasture,
lawn, or park), with good cover (if the land use type is woods), or
with good hydrologic condition and conservation treatment (if the
land use type is cultivation).
3.
In computing pre-construction stormwater runoff, the design
engineer shall account for all significant land features and structures,
such as ponds, wetlands, depressions, hedgerows, or culverts, that
may reduce pre-construction stormwater runoff rates and volumes.
4.
In computing stormwater runoff from all design storms, the design
engineer shall consider the relative stormwater runoff rates and/or
volumes of pervious and impervious surfaces separately to accurately
compute the rates and volume of stormwater runoff from the site. To
calculate runoff from unconnected impervious cover, urban impervious
area modifications as described in the NRCS Technical Release 55 -
Urban Hydrology for Small Watersheds or other methods may be employed.
5.
If the invert of the outlet structure of a stormwater management
measure is below the flood hazard design flood elevation as defined
at N.J.A.C. 7:13, the design engineer shall take into account the
effects of tailwater in the design of structural stormwater management
measures.
B.
Groundwater recharge may be calculated in accordance with the following:
The New Jersey Geological Survey Report GSR-32, A Method for Evaluating
Groundwater-Recharge Areas in New Jersey, incorporated herein by reference
as amended and supplemented. Information regarding the methodology
is available from the New Jersey Stormwater Best Management Practices
Manual; at the New Jersey Geological Survey website at: <https://www.nj.gov/dep/njgs/pricelst/gsreport/gsr32.pdf>
or at New Jersey Geological and Water Survey, 29 Arctic Parkway, PO
Box 420 Mail Code 29-01, Trenton, New Jersey 08625-0420.
[Added 4-12-2021 by Ord.
No. MC 2021-14]
A.
Technical guidance for stormwater management measures can be found
in the documents listed below, which are available to download from
the Department's website at: <http://www.nj.gov/dep/stormwater/bmp_manual2.htm>.
1.
Guidelines for stormwater management measures are contained
in the New Jersey Stormwater Best Management Practices Manual, as
amended and supplemented. Information is provided on stormwater management
measures such as, but not limited to, those listed in Tables 1, 2,
and 3.
2.
Additional maintenance guidance is available on the Department's
website at: <https://www.njstormwater.org/maintenance_guidance.htm>.
B.
Additional technical guidance for stormwater management measures
can be obtained from the following:
1.
The "Standards for Soil Erosion and Sediment Control in New
Jersey" promulgated by the State Soil Conservation Committee and incorporated
into N.J.A.C. 2:90. Copies of these standards may be obtained by contacting
the State Soil Conservation Committee or any of the Soil Conservation
Districts listed in N.J.A.C. 2:90-1.3(a)4. The location, address,
and telephone number of each Soil Conservation District may be obtained
from the State Soil Conservation Committee, P.O. Box 330, Trenton,
New Jersey, 08625; (609) 292-5540;
2.
The Rutgers Cooperative Extension Service, 732-932-9306; and
3.
The Soil Conservation Districts listed in N.J.A.C. 2:90-1.3(a)4.
The location, address, and telephone number of each Soil Conservation
District may be obtained from the State Soil Conservation Committee,
P.O. Box 330, Trenton, New Jersey, 08625, (609) 292-5540.
[Added 4-12-2021 by Ord.
No. MC 2021-14]
A.
Site design features identified under § 17:12-2.4F above, or alternative designs in accordance with § 17:12-2.4G above, to prevent discharge of trash and debris from drainage systems shall comply with the following standard to control passage of solid and floatable materials through storm drain inlets. For purposes of this paragraph, "solid and floatable materials" means sediment, debris, trash, and other floating, suspended, or settleable solids. For exemptions to this standard see § 17:12-2.7a2 below.
1.
Design engineers shall use one of the following grates whenever
they use a grate in pavement or another ground surface to collect
stormwater from that surface into a storm drain or surface water body
under that grate:
a.
The New Jersey Department of Transportation (NJDOT) bicycle
safe grate, which is described in Chapter 2.4 of the NJDOT Bicycle
Compatible Roadways and Bikeways Planning and Design Guidelines; or
b.
A different grate, if each individual clear space in that grate
has an area of no more than seven square inches, or is no greater
than 0.5 inch across the smallest dimension.
(1)
Examples of grates subject to this standard include
grates in grate inlets, the grate portion (non-curb-opening portion)
of combination inlets, grates on storm sewer manholes, ditch grates,
trench grates, and grates of spacer bars in slotted drains. Examples
of ground surfaces include surfaces of roads (including bridges),
driveways, parking areas, bikeways, plazas, sidewalks, lawns, fields,
open channels, and stormwater system floors used to collect stormwater
from the surface into a storm drain or surface water body.
c.
For curb-opening inlets, including curb-opening inlets in combination
inlets, the clear space in that curb opening, or each individual clear
space if the curb opening has two or more clear spaces, shall have
an area of no more than seven square inches, or be no greater than
two inches across the smallest dimension.
2.
The standard in paragraph A1 above does not apply:
a.
Where each individual clear space in the curb opening in existing
curb-opening inlet does not have an area of more than nine (9.0) square
inches;
b.
Where the municipality agrees that the standards would cause
inadequate hydraulic performance that could not practicably be overcome
by using additional or larger storm drain inlets;
c.
Where flows from the water quality design storm as specified
in N.J.A.C. 7:8 are conveyed through any device (e.g., end of pipe
netting facility, manufactured treatment device, or a catch basin
hood) that is designed, at a minimum, to prevent delivery of all solid
and floatable materials that could not pass through one of the following:
(1)
A rectangular space four and five-eighths (4.625)
inches long and one and one-half (1.5) inches wide (this option does
not apply for outfall netting facilities); or
(2)
A bar screen having a bar spacing of 0.5 inch.
Note that these exemptions do not authorize any infringement
of requirements in the Residential Site Improvement Standards for
bicycle safe grates in new residential development (N.J.A.C. 5:21-4.18(b)2
and 7.4(b)1).
d.
Where flows are conveyed through a trash rack that has parallel
bars with one-inch (1 inch) spacing between the bars, to the elevation
of the Water Quality Design Storm as specified in N.J.A.C. 7:8; or
e.
Where the New Jersey Department of Environmental Protection
determines, pursuant to the New Jersey Register of Historic Places
Rules at N.J.A.C. 7:4-7.2(c), that action to meet this standard is
an undertaking that constitutes an encroachment or will damage or
destroy the New Jersey Register listed historic property.
[Added 4-12-2021 by Ord.
No. MC 2021-14]
A.
This section sets forth requirements to protect public safety through
the proper design and operation of stormwater management BMPs. This
section applies to any new stormwater management BMP.
B.
The provisions of this section are not intended to preempt more stringent
municipal or county safety requirements for new or existing stormwater
management BMPs. Municipal and county stormwater management plans
and ordinances may, pursuant to their authority, require existing
stormwater management BMPs to be retrofitted to meet one or more of
the safety standards in § 17:12-2.8C1, C2 and C3, for trash
racks, overflow grates, and escape provisions at outlet structures.
C.
Requirements for Trash Racks, Overflow Grates and Escape Provisions.
1.
A trash rack is a device designed to catch trash and debris
and prevent the clogging of outlet structures. Trash racks shall be
installed at the intake to the outlet from the Stormwater management
BMP to ensure proper functioning of the BMP outlets in accordance
with the following:
a.
The trash rack shall have parallel bars, with no greater than
six-inch spacing between the bars;
b.
The trash rack shall be designed so as not to adversely affect
the hydraulic performance of the outlet pipe or structure;
c.
The average velocity of flow through a clean trash rack is not
to exceed 2.5 feet per second under the full range of stage and discharge.
Velocity is to be computed on the basis of the net area of opening
through the rack; and
d.
The trash rack shall be constructed of rigid, durable, and corrosion
resistant material and designed to withstand a perpendicular live
loading of 300 pounds per square foot.
2.
An overflow grate is designed to prevent obstruction of the
overflow structure. If an outlet structure has an overflow grate,
such grate shall meet the following requirements:
a.
The overflow grate shall be secured to the outlet structure
but removable for emergencies and maintenance.
b.
The overflow grate spacing shall be no less than two inches
across the smallest dimension.
c.
The overflow grate shall be constructed and installed to be
rigid, durable, and corrosion resistant, and shall be designed to
withstand a perpendicular live loading of 300 pounds per square foot.
3.
Stormwater management BMPs shall include escape provisions as
follows:
a.
If a stormwater management BMP has an outlet structure, escape provisions shall be incorporated in or on the structure. Escape provisions include the installation of permanent ladders, steps, rungs, or other features that provide easily accessible means of egress from stormwater management BMPs. With the prior approval of the municipality pursuant to § 17:12-2.8C, a free-standing outlet structure may be exempted from this requirement;
b.
Safety ledges shall be constructed on the slopes of all new
stormwater management BMPs having a permanent pool of water deeper
than two and one-half feet. Safety ledges shall be comprised of two
steps. Each step shall be four to six feet in width. One step shall
be located approximately two and one-half feet below the permanent
water surface, and the second step shall be located one to one and
one-half feet above the permanent water surface. See § 17:12-2.8E
for an illustration of safety ledges in a stormwater management BMP;
and
c.
In new stormwater management BMPs, the maximum interior slope
for an earthen dam, embankment, or berm shall not be steeper than
three horizontal to one vertical.
d.
Variance or Exemption from Safety Standard. A variance or exemption
from the safety standards for stormwater management BMPs may be granted
only upon a written finding by the municipality that the variance
or exemption will not constitute a threat to public safety.
e.
Safety Ledge Illustration. Elevation View -Basin Safety Ledge
Configuration.
|
Elevation View - Basin Safety Ledge Configuration
 |
[Added 4-12-2021 by Ord.
No. MC 2021-14]
A.
Submission of Site Development Stormwater Plan.
1.
Whenever an applicant seeks municipal approval of a development subject to this section, the applicant shall submit all of the required components of the Checklist for the Site Development Stormwater Plan at § 17:12-2.9C below as part of the submission of the application for approval.
2.
The applicant shall demonstrate that the project meets the standards
set forth in this section.
3.
The applicant shall submit three copies of the materials listed in the checklist for site development stormwater plans in accordance with § 17:12-2.9C.
B.
Site Development Stormwater Plan Approval. The applicant's Site Development
project shall be reviewed as a part of the review process by the municipal
board or official from which municipal approval is sought. That municipal
board or official shall consult the municipality's review engineer
to determine if all of the checklist requirements have been satisfied
and to determine if the project meets the standards set forth in this
section.
C.
Submission of Site Development Stormwater Plan. The following information
shall be required:
1.
Topographic Base Map. The reviewing engineer may require upstream
tributary drainage system information as necessary. It is recommended
that the topographic base map of the site be submitted which extends
a minimum of 200 feet beyond the limits of the proposed development,
at a scale of 1"=200' or greater, showing 2-foot contour intervals.
The map as appropriate may indicate the following: existing surface
water drainage, shorelines, steep slopes, soils, erodible soils, perennial
or intermittent streams that drain into or upstream of the Category
One waters, wetlands and flood plains along with their appropriate
buffer strips, marshlands and other wetlands, pervious or vegetative
surfaces, existing man-made structures, roads, bearing and distances
of property lines, and significant natural and manmade features not
otherwise shown.
2.
Environmental Site Analysis. A written and graphic description
of the natural and man-made features of the site and its surroundings
should be submitted. This description should include a discussion
of soil conditions, slopes, wetlands, waterways and vegetation on
the site. Particular attention should be given to unique, unusual,
or environmentally sensitive features and to those that provide particular
opportunities or constraints for development.
3.
Project Description and Site Plan(s). A map (or maps) at the
scale of the topographical base map indicating the location of existing
and proposed buildings roads, parking areas, utilities, structural
facilities for stormwater management and sediment control, and other
permanent structures. The map(s) shall also clearly show areas where
alterations will occur in the natural terrain and cover, including
lawns and other landscaping, and seasonal high groundwater elevations.
A written description of the site plan and justification for proposed
changes in natural conditions shall also be provided.
4.
Land Use Planning and Source Control Plan. This plan shall provide a demonstration of how the goals and standards of § 17:12-2.3 through § 17:12-2.6 are being met. The focus of this plan shall be to describe how the site is being developed to meet the objective of controlling groundwater recharge, stormwater quality and stormwater quantity problems at the source by land management and source controls whenever possible.
5.
Stormwater Management Facilities Map. The following information,
illustrated on a map of the same scale as the topographic base map,
shall be included:
a.
Total area to be disturbed, paved or built upon, proposed surface
contours, land area to be occupied by the stormwater management facilities
and the type of vegetation thereon, and details of the proposed plan
to control and dispose of stormwater.
b.
Details of all stormwater management facility designs, during
and after construction, including discharge provisions, discharge
capacity for each outlet at different levels of detention and emergency
spillway provisions with maximum discharge capacity of each spillway.
6.
Calculations.
a.
Comprehensive hydrologic and hydraulic design calculations for the pre-development and post-development conditions for the design storms specified in § 17:12-2.4.
b.
When the proposed stormwater management control measures depend
on the hydrologic properties of soils or require certain separation
from the seasonal high water table, then a soils report shall be submitted.
The soils report shall be based on onsite boring logs or soil pit
profiles. The number and location of required soil borings or soil
pits shall be determined based on what is needed to determine the
suitability and distribution of soils present at the location of the
control measure.
7.
Maintenance and Repair Plan. The design and planning of the stormwater management facility shall meet the maintenance requirements of § 17:12-2.10.
8.
Waiver from Submission Requirements. The municipal official
or board reviewing an application under this section may, in consultation
with the municipality's review engineer, waive submission of any of
the requirements in § 17:12-2.9C1 through § 17:12-2.9C6
when it can be demonstrated that the information requested is impossible
to obtain or it would create a hardship on the applicant to obtain
and its absence will not materially affect the review process.
[Added 4-12-2021 by Ord.
No. MC 2021-14]
A.
Applicability. The projects subject to review as in § 17:12-2.1C shall comply with the requirements of § 17:12-2.10B and § 17:12-2.10C.
B.
General Maintenance.
1.
The design engineer shall prepare a maintenance plan for the
stormwater management measures incorporated into the design of a major
development.
2.
The maintenance plan shall contain specific preventative maintenance tasks and schedules; cost estimates, including estimated cost of sediment, debris, or trash removal; and the name, address, and telephone number of the person or persons responsible for preventative and corrective maintenance (including replacement). The plan shall contain information on BMP location, design, ownership, maintenance tasks and frequencies, and other details as specified in Chapter 8 of the NJ BMP Manual, as well as the tasks specific to the type of BMP, as described in the applicable chapter containing design specifics.
3.
If the maintenance plan identifies a person other than the property
owner (for example, a developer, a public agency or homeowners' association)
as having the responsibility for maintenance, the plan shall include
documentation of such person's or entity's agreement to assume this
responsibility, or of the owner's obligation to dedicate a stormwater
management facility to such person under an applicable ordinance or
regulation.
4.
Responsibility for maintenance shall not be assigned or transferred
to the owner or tenant of an individual property in a residential
development or project, unless such owner or tenant owns or leases
the entire residential development or project. The individual property
owner may be assigned incidental tasks, such as weeding of a green
infrastructure BMP, provided the individual agrees to assume these
tasks; however, the individual cannot be legally responsible for all
of the maintenance required.
5.
If the party responsible for maintenance identified under § 17:12-2.10B2
above is not a public agency, the maintenance plan and any future
revisions based on § 17:12-2.10B7 below shall be recorded
upon the deed of record for each property on which the maintenance
described in the maintenance plan must be undertaken.
6.
Preventative and corrective maintenance shall be performed to
maintain the functional parameters (storage volume, infiltration rates,
inflow/outflow capacity, etc.). of the stormwater management measure,
including, but not limited to, repairs or replacement to the structure;
removal of sediment, debris, or trash; restoration of eroded areas;
snow and ice removal; fence repair or replacement; restoration of
vegetation; and repair or replacement of non-vegetated linings.
7.
The party responsible for maintenance identified under § 17:12-2.10B2
above shall perform all of the following requirements:
a.
Maintain a detailed log of all preventative and corrective maintenance
for the structural stormwater management measures incorporated into
the design of the development, including a record of all inspections
and copies of all maintenance-related work orders;
b.
Evaluate the effectiveness of the maintenance plan at least
once per year and adjust the plan and the deed as needed; and
c.
Retain and make available, upon request by any public entity
with administrative, health, environmental, or safety authority over
the site, the maintenance plan and the documentation required by § 17:12-2.10B6
and B7 above.
8.
The requirements of § 17:12-2.10B3 and B4 do not apply
to stormwater management facilities that are dedicated to and accepted
by the municipality or another governmental agency, subject to all
applicable municipal stormwater general permit conditions, as issued
by the Department.
9.
In the event that the stormwater management facility becomes
a danger to public safety or public health, or if it is in need of
maintenance or repair, the municipality shall so notify the responsible
person in writing. Upon receipt of that notice, the responsible person
shall have fourteen (14) days to effect maintenance and repair of
the facility in a manner that is approved by the municipal engineer
or his designee. The municipality, in its discretion, may extend the
time allowed for effecting maintenance and repair for good cause.
If the responsible person fails or refuses to perform such maintenance
and repair, the municipality or County may immediately proceed to
do so and shall bill the cost thereof to the responsible person. Nonpayment
of such bill may result in a lien on the property.
C.
Nothing in this subsection shall preclude the municipality in which
the major development is located from requiring the posting of a performance
or maintenance guarantee in accordance with N.J.S.A. 40:55D-53.
[Added 4-12-2021 by Ord.
No. MC 2021-14]
Any person(s) who erects, constructs, alters, repairs, converts,
maintains, or uses any building, structure or land in violation of
this section shall be subject to the following penalties: minimum
penalty of $1,000 and maximum penalty of $5,000.
[Added 4-12-2021 by Ord.
No. MC 2021-14]
If the provisions of any section, subsection, paragraph, subdivision,
or clause of this section shall be judged invalid by a court of competent
jurisdiction, such order of judgment shall not affect or invalidate
the remainder of any section, subsection, paragraph, subdivision,
or clause of this section.
