[HISTORY: Adopted by the Township Council of the Township
of Greenwich 4-15-2021 by Ord. No. 102-2021.[1] Amendments noted where applicable.]
[1]
Editor's Note: This ordinance also repealed former Ch. 25,
Stormwater Regulations, Ord. No. 2005-6, as amended.
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 chapter is to establish minimum stormwater management requirements and controls for "major development," as defined below in § 25-2.
c.
d.
Compatibility with Other Permit and Ordinance Requirements.
1.
Development approvals issued pursuant to this chapter 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 chapter
shall be held to be the minimum requirements for the promotion of
the public health, safety, and general welfare.
2.
This chapter 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 chapter 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.
For the purpose of this chapter, the following terms, phrases,
words and their derivations shall have the meanings stated herein
unless their use in the text of this chapter 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 area where rock consisting chiefly of calcium and magnesium
carbonates such as limestone and dolomite, has been identified.
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 chapter.
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 Board of County Commissioners
to review municipal stormwater management plans and implementing ordinance(s).
The county review agency may either be:
Any United States Geological Survey fourteen-digit Hydrologic
Unit Code subwatershed area that is identified in the Highlands Regional
Master Plan as having negative net water availability, meaning that
existing consumptive and depletive water uses exceed the capacity
of the groundwater supply to sustain.
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 in 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:
All springs, wetlands, intermittent and ephemeral streams,
perennial streams and bodies of surface water, whether natural or
artificial, located wholly or partially within the boundaries of the
Highlands Region, but shall not mean swimming pools.
An area within which water drains to a particular receiving
surface water body, also known as a subwatershed, which is identified
by a fourteen-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.
Any structure, surface, or improvement that reduces or prevents
absorption of stormwater into land, and includes porous paving, paver
blocks, gravel, crushed stone, decks, patios, elevated structures,
and other similar structures, surfaces, or improvements. To be considered
an impervious surface, the structure, surface or improvement must
have the effect of reducing or preventing stormwater absorption.
The process by which water seeps into the soil from precipitation.
A distinctive topography that indicates solution of underlying
carbonate rocks (such as limestone and dolomite) by surface water
or groundwater over time, often producing surface depressions, sinkholes,
sinking streams, enlarged bedrock fractures, caves, and underground
streams.
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 1/4 acre or more of "regulated impervious surface"
since February 2, 2004;
The creation of 1/4 acre or more of "regulated motor vehicle
surface" since March 2, 2021.
A combination of Subsection a2 and 3 above that totals an area
of 1/4 acre or more. The same surface shall not be counted twice when
determining if the combination area equals 1/4 acre 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 Subsection a1, 2, 3, or 4 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.
Designing stormwater management systems so that all reasonable
opportunities for using nonstructural stormwater practices are exhausted
and a structural BMP is implemented only where absolutely necessary.
An action by an applicant providing compensation or offset
actions for on-site stormwater management requirements where the applicant
has demonstrated the inability or impracticality of strict compliance
with the stormwater management requirements set forth in N.J.A.C.
7:8, in an adopted regional stormwater management plan, or in this
chapter, and has received a waiver from strict compliance from the
municipality. Mitigation shall include the implementation of the approved
mitigation plan within the same drainage area where the subject project
is proposed, or a contribution of funding toward a municipal stormwater
control project, or provision for equivalent treatment at an alternate
location, or any other equivalent water quality benefit as approved
by the municipality.
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 chapter. 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 chapter. Alternative stormwater management measures, removal rates, or calculation methods may be utilized, subject to any limitations specified in this chapter, provided the design engineer demonstrates to the municipality, in accordance with § 25-4f of this chapter 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 chapter.
An area designated by the State Planning Commission concentrating
facilities and activities which are not organized in a compact form.
Any project not eligible for an exemption from the Highlands
Water Protection and Planning Act Rules, pursuant to N.J.A.C. 7:38-2.3.
A chemical element or compound, such as nitrogen or phosphorus,
which is essential to and promotes the development of organisms.
Any individual, corporation, company, partnership, firm,
association, political subdivision of this state and any state, interstate
or federal agency.
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. § 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, groundwaters or surface waters
of the state, or to a domestic treatment works. "Pollutant" includes
both hazardous and nonhazardous pollutants.
Lands within the Highlands Region that are located in that
portion designated by the Highlands Act as the "Preservation Area"
(see metes and bounds description at N.J.S.A. 13:20-7b.)
Lands with the best groundwater recharge rates within a HUC14
subwatershed, as indicated by GSR-32 analysis, that provide the top
40% of the total recharge volume for the subwatershed.
The amount of water from precipitation that infiltrates into
the ground and is not evapotranspired.
Land-disturbing activity that results in the creation, addition,
or replacement of impervious surface area on an already developed
or disturbed site. Redevelopment includes but is not limited to: the
expansion of a building footprint, addition or replacement of a structure,
replacement of impervious surface area that is not part of a routine
maintenance activity, and land-disturbing activities related to structural
or impervious surfaces. It does not include routine maintenance to
maintain original line and grade, hydraulic capacity, or original
purpose of facility, nor does it include emergency construction activities
required to immediately protect public health and safety.
The Highlands regional master plan or any revision thereof
adopted by the Highlands Water Protection and Planning Council pursuant
to N.J.S.A. 13:20-8.
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 nonstormwater 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-, ten-, 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-, ten-, 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
groundwater 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.
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 chapter 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.
a.
The development shall incorporate a maintenance plan for the stormwater management measures incorporated into the design of a major development in accordance with § 25-10.
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 muhlenbergii (bog turtle).
c.
The following linear development projects are exempt from the groundwater recharge, stormwater runoff quality, and stormwater runoff quantity requirements of § 25-4p, 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 § 25-4o, 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;
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 Subsection d3 above within the upstream drainage area of the receiving stream, that would provide additional opportunities to mitigate the requirements of § 25-4o, p, q and r that were not achievable on site.
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 § 25-4o, 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 chapter 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 on Page D-15)
|
|
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 on Page D-15)
|
|
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 § 25-4o2;
|
|
(b)
|
Designed to infiltrate into the subsoil;
|
|
(c)
|
Designed with underdrains;
|
|
(d)
|
Designed to maintain at least a ten-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 § 25-2;
|
|
(h)
|
Manufactured treatment devices that do not meet the definition of "green infrastructure" at § 25-2.
|
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 § 25-6b Alternative stormwater management measures may be used to satisfy the requirements at § 25-4o only if the measures meet the definition of green infrastructure at § 25-2. Alternative stormwater management measures that function in a similar manner to a BMP listed at § 25-4o2 are subject to the contributory drainage area limitation specified at § 25-4o2 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 § 25-4o2 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 § 25-4d is granted from § 25-4o.
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 1/3 the width of the diameter of the orifice or 1/3 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 § 25-8c;
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 § 25-8; and
5.
The size of the orifice at the intake to the outlet from the stormwater
management BMP shall be a minimum of 2 1/2 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 § 25-2 may be used only under the circumstances described at § 25-4o4.
k.
Any application for a new agricultural development that meets the definition of "major development" at § 25-2 shall be submitted to the Soil Conservation District for review and approval in accordance with the requirements at § 25-4o, 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 § 25-4p, q and r shall be met in each drainage area, unless the runoff from the drainage areas converge on site 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 Office of the Warren County Clerk. 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 § 25-4o, 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 § 25-10b5. 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 § 25-4 of this chapter 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 in the Office of the Warren County Clerk and shall contain a description and location of the stormwater management measure, as well as reference to the maintenance plan, in accordance with Subsection m 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 Subsection m 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 § 25-4p and q, the design engineer shall utilize green infrastructure BMPs identified in Table 1 at § 25-4f and/or an alternative stormwater management measure approved in accordance with § 25-4g. 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
|
4.
If a variance in accordance with N.J.A.C. 7:8-4.6 or a waiver from strict compliance in accordance with § 25-4d 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 § 25-4g may be used to meet the groundwater recharge, stormwater runoff quality, and stormwater runoff quantity standards at § 25-4p, 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 § 25-4p, q and r, unless the project is granted a waiver from strict compliance in accordance with § 25-4d.
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 § 25-4, 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 two-year storm is infiltrated.
(c)
For Non-Exempt Projects located in the Preservation Area and
in a Current Deficit Area as identified in the Township's Environmental
Resource Inventory, the project shall demonstrate through hydrologic
and hydraulic analysis that the site and its stormwater management
measures provide for enhanced recharge standards set forth in Subsection
p5 below.
(d)
For Non-Exempt Projects located in the Preservation Area and
in a Prime Groundwater Recharge Area as identified in the Township's
Environmental Resource Inventory, the following standards shall apply:
(1)
Where disturbance is permitted in accordance with this subsection,
it shall be limited to no greater than 15% of the Prime Groundwater
Recharge Area on the site and shall preferentially be sited on that
portion of the Prime Groundwater Recharge Area that has the lowest
groundwater recharge rates.
(2)
Where disturbance to the Prime Groundwater Recharge Area is
permitted, the project shall demonstrate through hydrologic and hydraulic
analysis that the site and its stormwater management measures provide
for enhanced recharge standards set forth in Subsection p5 below.
3.
This groundwater recharge requirement does not apply to projects
within the urban redevelopment area, or to projects subject to Subsection
p4 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.
(c)
Carbonate rock areas in the Preservation Area where surficial
or subsurface karst features have been identified and recharge facilities
cannot be designed in a manner that would eliminate the concentrated
subsurface release of stormwater (Note: The mere presence of carbonate
bedrock does not constitute a karst feature).
5.
Non-Exempt Projects that are subject to the enhanced recharge requirements
by Subsection p2(c) or (d) above, shall apply the following standards,
either:
(a)
Recharge 125% of the percentage of the average annual preconstruction
groundwater recharge volume for the site; or
(b)
In addition to complying with the recharge requirements of § 25-4p, retain on site with no discharge, the Stormwater Quality Design Volume (SWQDv), defined as the runoff from the 1.25-inch, two-hour rainfall event. Where meeting the recharge requirement will not result in retention of the full SWQDv, the major development shall retain any additional volume to meet the requirements of this section through additional infiltration, or through evapotranspiration or capture and on-site re-use of rainfall.
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 of 1/4 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 Subsection q2 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 - (A x B)/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.
|
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 § 25-4p, 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.
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 § 25-5, complete one of the following:
(a)
Demonstrate through hydrologic and hydraulic analysis that for
stormwater leaving the site, post-construction runoff hydrographs
for the two-, ten-, 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 two-,
ten- 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 two-, ten- 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 Subsection r2(a), (b) and (c) 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.
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, incorporated herein by reference as amended and supplemented. Information regarding the methodology is available from the Natural Resources Conservation Service website at: https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb1044171.pdf 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 § 25-5a1(a) and the Rational and Modified
Rational Methods at § 25-5a1(b). 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.
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.
Submissions required for review by the Department should be mailed
to: The Division of Water Quality, New Jersey Department of Environmental
Protection, Mail Code 401-02B, PO Box 420, Trenton, New Jersey 08625-0420.
a.
Site design features identified under § 25-4f above, or alternative designs in accordance with § 25-4g 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 subsection, "solid and floatable materials" means sediment, debris, trash, and other floating, suspended, or settleable solids. For exemptions to this standard see § 25-7a2 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 7.0 square inches or is no greater than
0.5 inch across the smallest dimension.
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 Subsection 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 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 4 5/8 (4.625) inches long and 1 1/2
(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 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.
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 § 25-8c1, 2 and 3 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 § 25-8c, a freestanding 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 2 1/2 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 2 1/2 feet below the permanent water surface, and the second step shall be located one to 1 1/2 feet above the permanent water surface. See § 25-8e 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.
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a.
Submission of Site Development Stormwater Plan.
1.
Whenever an applicant seeks municipal approval of a development subject to this chapter, the applicant shall submit all of the required components of the Checklist for the Site Development Stormwater Plan at § 25-9c 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 chapter.
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 chapter.
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 one inch equals 200 feet or greater, showing two-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 floodplains 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
man-made 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 Plans. 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 § 25-2 through § 25-5 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 § 25-4 of this chapter.
(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 on-site 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 § 25-10.
8.
Waiver from Submission Requirements. The municipal official or board
reviewing an application under this chapter may, in consultation with
the municipality's review engineer, waive submission of any of
the requirements in § 25-9c1 through 6 of this chapter 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.
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 § 25-10b3
above is not a public agency, the maintenance plan and any future
revisions based on § 25-10b7 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 § 25-10b3
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 § 25-10b6
and 7 above.
8.
The requirements of § 25-10b3 and 4 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 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.
a.
The municipal review agency may grant variances from the design and performance standards in § 25-4o, p, q and r as set forth in this stormwater control ordinance provided that the following conditions are met.
1.
The applicant demonstrates that it is technically impracticable to
meet any one or more of the design and performance standards on site.
For the purposes of this analysis, technical impracticability exists
only when the design and performance standard cannot be met for engineering,
environmental, or safety reasons. The municipality's approval
of a variance shall apply to an individual drainage area and design
and performance standard and shall not apply to an entire site or
project, unless an applicant provides the required analysis for each
drainage area within the site and each design and performance standard.
2.
The applicant demonstrates that the proposed design achieves the
maximum possible compliance with the design and performance standards
on site.
3.
A mitigation project in accordance with the following is implemented.
(a)
The mitigation project may be a project which has been established
by the Township or may be a project proposed by the applicant, provided
it meets the criteria in this chapter.
(b)
The mitigation project shall be approved no later than preliminary
or final site plan approval of the major development.
(c)
The mitigation project shall be located in the same HUC 14 as
the area of the major development subject to the variance.
(d)
The mitigation project shall be constructed prior to or concurrent
with the major development.
4.
If the variance that resulted in the mitigation project being required is from the green infrastructure standards in § 25-4o, then the mitigation project must use green infrastructure BMPs in Table 5-1, and/or an alternative stormwater management measure approved in accordance with § 25-4g that meets the definition of "green infrastructure" to manage an equivalent or greater area of impervious surface and an equivalent or greater area of motor vehicle surface as the area of the major development subject to the variance. Grass swales and vegetative filter strips may only be used in the mitigation project if the proposed project additionally includes a green infrastructure BMP other than a grass swale or vegetative filter strip. The green infrastructure used in the mitigation project must be sized to manage the water quality design storm, as defined at § 25-4q4 at a minimum and is subject to the applicable contributory drainage area limitations specified in § 25-4g or § 25-4o2 as applicable.
5.
A variance from the groundwater recharge standards in § 25-4p may be granted if one of the following is met:
(a)
The average annual groundwater recharge provided by the mitigation
project must equal or exceed the average annual groundwater recharge
deficit resulting from granting the variance for the major development;
or
(b)
Runoff infiltrated during the two-year storm from the mitigation
project must equal or exceed the deficit resulting from granting the
variance from the required infiltration of the increase in runoff
volume from pre-construction to post-construction from the major development.
6.
A variance from the stormwater runoff quality standards at § 25-4q may be granted if the following are met:
(a)
The total drainage area of motor vehicle surface managed by
the mitigation project(s) must equal or exceed the drainage area of
the area of the major development subject to the variance and must
provide sufficient TSS removal to equal or exceed the deficit resulting
from granting the variance for the major development; and
(b)
The mitigation project must remove nutrients to the maximum
extent feasible in accordance with § 25-4q6.
7.
A variance from the stormwater runoff quantity standards at § 25-4r may be granted if the following are met:
(a)
The applicant demonstrates, through hydrologic and hydraulic
analysis, including the effects of the mitigation project, that the
variance will not result in increased flooding damage below each point
of discharge of the major development.
(b)
The mitigation project discharges to the same watercourse and
is located upstream of the major development subject to the variance.
(c)
The mitigation project provides peak flow rate attenuation in
accordance with § 25-4r2(c) for an equivalent or greater
area than the area of the major development subject to the variance.
For the purposes of this demonstration, equivalent includes both size
of the area and percentage of impervious surface and/or motor vehicle
surface.
8.
The applicant shall be responsible for preventive and corrective maintenance (including replacement) of the mitigation project and shall be identified as such in the maintenance plan established in accordance with § 25-10. This responsibility is not transferable to any entity other than a public agency, in which case, a written agreement with that public agency must be submitted to the review agency.
9.
Any approved variance shall be submitted by the municipal review
agency to the county review agency and the Department by way of a
written report describing the variance, as well as the required mitigation,
within 30 days of the approval.
Any person(s) who erects, constructs, alters, repairs, converts,
maintains, or uses any building, structure or land in violation of
this chapter shall be subject to the following penalties: Up to $500
per day for each day the violation continues to exist.
Each section, subsection, sentence, clause and phrase of this
chapter is declared to be an independent section, subsection, sentence,
clause and phrase, and the finding or holding of any such portion
of this chapter to be unconstitutional, void, or ineffective for any
cause, or reason, shall not affect any other portion of this chapter.
This chapter shall be in full force and effect from and after
its adoption and any publication as required by law.
