[Amended by Ord. No. 644-98; 12-14-2005 by Ord. No. 903-05; 12-12-2007 by Ord.
No. 946-07; 1-27-2021 by Ord. No. 1146-2021]
A.
Policy statement.
(1)
The general intent of this article is to manage the increase
rate and velocity of surface water runoff created by alterations in
the ground cover and natural runoff patterns.
(2)
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 article is to establish minimum stormwater management requirements and controls for "major development," as defined below in § 165-224. To protect the public health, safety and welfare of the citizens of Clinton Township and the surrounding communities, this section is deemed necessary and essential in order to:
(1)
Maintain the adequacy of natural stream channels and prevent
accelerated bank erosion by controlling the rate and velocity of runoff
discharge to these watercourses so as to avoid increasing the frequency
of the bank-full stage.
(2)
Prevent degradation of the stream biota caused by excessive
flushing and sedimentation.
(3)
Prevent degradation of stream water quality due to impairment
of the stream's biological function.
(4)
Enhance the quality of nonpoint runoff by water retention measures.
(5)
Reduce public expenditures for replacement or repair of public
facilities resulting from artificially induced flood peaks.
(6)
Prevent damage to life and property from flooding resulting
from excessive rates, quantities and velocities of runoff.
(7)
Prevent the degradation of property by enhancing the environmental
character of the streams of the Township.
C.
D.
Compatibility with other permit and ordinance requirements.
(1)
Development approvals issued pursuant to this article 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 article shall be held to be the minimum requirements
for the promotion of the public health, safety, and general welfare.
(2)
This article 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 article
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.
E.
No person shall obstruct or otherwise interfere with any drainageway,
surface water, surface water runoff, or watercourse in such a manner
as to cause or result in surface water runoff damage.
For the purpose of this article, 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.
Any person, partnership, corporation or public agency requesting
permission to engage in land disturbance activity, construction or
development.
A plan to control surface water runoff, approved by the Municipal
Planning Board.
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).
A watercourse with a definite bed and banks which confine
and conduct continuously or intermittently flowing water.
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.
An agreement or covenant, attached to deed, dedicating land
to permanent open space and prohibiting all land or vegetation disturbance,
each agreement to be entered into between the applicant and the Township.
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 Board of Chosen Freeholders
to review municipal stormwater management plans and implementing ordinance(s).
The county review agency may either be:
Any area which should not be disturbed by uses incompatible
with the paramount public interest in the management of surface water
runoff and attendant environmental damage. Examples of critical impact
areas include but are not limited to lakes, ponds, floodplains and
flood hazard areas, designated stream corridors, steep slopes, highly
erodible soils, swamps, marshes, bogs, identified aquifer recharge
and discharge areas and heavily wooded areas.
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.
Any watercourse, trench, ditch, depression or other hollow
space in the ground, natural or artificial, which collects or disperses
surface water from land.
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
wellhead 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.
Any development that creates less than 1,000 square feet
of new impervious area and disturbs less than 2,500 square feet of
land. Further, an exempt development shall not meet the definition
of "minor development."
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 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.
The process by which water seeps into the soil from precipitation.
Any activity involving the clearing, grading, transporting
or filling of land, or any other activity which alters topography
or vegetative cover.
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:
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 above Subsection A(1), (2), (3), or (4) of § 165-224 for "major development." 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."
Those listed by title on Page 10 of the Regional Stormwater
Management Study and Plan and maps of the Clinton Township Natural
Resource Inventory series referenced by number, all available for
reference in the Planning Board office.
As defined by sheet RTSC — Engineer 200, sheet one
of two published by USDA-SCS February 1970.
Any development that results in the creation of 1,000 square
feet or more of new impervious area or one that disturbs more than
2,500 square feet of land area. Further, a minor development shall
not meet the definition of "major development" in N.J.A.C. 7:8 et
seq.
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 topographical pattern or system of drainage of surface
water runoff from a particular site, including the various drainageways
and watercourses which carry surface water only during periods of
heavy rains, storms or floods.
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 § 165-230F of this article 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.
Surface water entering a channel from no definable discharge
source.
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, 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.
The Regional Stormwater Management Study and Plan, Clinton
Township, Lebanon Borough, Readington Township, published August 1974,
sponsored by the Municipal Environmental Commission using local funds
plus Ford Foundation grant and matching funds.
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.
As depicted on Map 4 of the Clinton Township Natural Resource
Inventory series.
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.
All water produced by rain, flood, drainage, springs and
seeps flowing over the land or contained within a natural or artificial
watercourse.
A plan consistent with the purposes and policies of this
article which fully indicates necessary land treatment measures and
techniques, including a schedule for implementation and maintenance.
Any overland flow of water across the ground surface.
All damage or harm to property values, land, vegetation and
water supplies which results or is likely to result when the dispersion
of surface water, typical of land in a meadow of good hydrologic condition,
is increased in rate, velocity or quantity. Such damage or harm includes
but is not limited to flooding, soil erosion, siltation and other
pollution of watercourses and diminished recharge of groundwater.
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.
All rivers, streams, brooks, waterways, lakes, ponds, marches,
swamps, bogs and other bodies of water, natural or artificial, public
or private, which are contained within, flow through or border on
Clinton Township or any portion thereof.
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 of surface water runoff related to a point of concentration
as shown on the map, Watersheds Overlay, of the Regional Stormwater
Management Study and Plan or Map No. 9 of the Clinton Township Natural
Resource Inventory series.
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 article 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. Alternative
standards shall provide at least as much protection from stormwater-related
loss of groundwater recharge, stormwater quantity and water quality
impacts of major development projects as would be provided under the
standards in N.J.A.C. 7:8-5.
A.
Minor revisions to a surface water management plan may be approved
by the Township Engineer, who shall notify the Planning Board of the
nature and reason for the change.
B.
Standards for relief. Waivers from strict compliance with the design standards shall only be granted upon showing that such exceptions from the requirements may be reasonable and within the general purpose and intent of the provisions of this section if the literal enforcement of one or more provisions of this article is impracticable or will exact undue hardship because of particular conditions pertaining to the land in question. A hardship will not be considered to exist if reasonable reductions in the scope of the project would eliminate the noncompliance. Additional information for waivers from strict compliance can be found in § 165-230D below.
C.
Mitigation. If the review agency for the project determines that
a waiver is appropriate, the applicant must execute a mitigation plan.
The scope of the mitigation plan shall be commensurate with the size
of the project and the magnitude of relief required. The mitigation
project may be taken from the list of projects in the Municipal Stormwater
Management Plan or another project identified by the applicant. All
mitigation projects are subject to the approval of the Municipal Engineer,
and all mitigation projects shall be reported to the proper agency
in accordance with N.J.A.C. 7:8.
A.
If at any time the Township Engineer finds existing conditions not
as stated in the applicant's approved plan, the Planning Board or
its designated agent shall, by certified mail, return receipt requested,
order cessation of all work and seek to enjoin the violation or take
such steps looking to the enforcement of the plan as may be lawful.
A.
The applicant shall submit to the Planning Board a separate surface water management plan for any proposed lot, subdivision, cluster development, site plan review, special exception, zoning variance or any land disturbance activity except as exempted in § 165-226. This plan shall be coordinated with the soil erosion and sediment control plan required by the Soil Erosion and Sediment Control Ordinance.
B.
Such plan shall contain:
(1)
Lot and block numbers of the site as shown on the current Tax
Map of the Township.
(2)
Name and address of the owner of the land.
(3)
Size of the subwatershed and location of the site within the
subwatershed(s) as shown on the map, Watersheds Overlay, of the Regional
Stormwater Management Study and the Plan or Map No. 9 of the Clinton
Township Natural Resource Inventory.
(4)
Location, description and quantification of significant natural
and man-made features on and surrounding the site, including topography,
all impervious surfaces, soil and drainage characteristics, with particular
attention to the location and description of presently existing surface
water runoff control devices, mechanisms or areas, swamps, floodplains,
swales, woods and vegetation, steep slopes and other features critical
to the purposes of this chapter.
(5)
Size of nearest culvert or bridge downstream of discharge area,
profiles and cross section of stream channel upstream of that structure
as inventoried on the Base Map Showing Roads, Streams, Culverts and
Bridges, Clinton Township, and Appendix B of the Regional Stormwater
Management Study and Plan, as well as profiles and cross sections
of stream channel at all points of proposed surface water discharge
from the site as required by the Township Engineer.
(6)
Location, description and quantification of proposed changes
to the site, whether of a permanent or temporary nature, with particular
attention to impervious surfaces and interception of presently dispersed
flow which may impact upon the capacity of the soil, vegetative cover
and drainageways to absorb, retard, contain or control surface water
runoff.
(7)
Designation of critical or other areas to be left undisturbed,
shown in sufficient detail to be accurately marked on the land.
(8)
Computation of the total surface water runoff before, during
and after the disturbance of land and/or construction of impervious
surfaces.
(9)
Proposed measures for surface water management.
(10)
A schedule of the sequence of installation of the surface water
management plan, related to the starting and completion dates of the
project.
(11)
Proposed maintenance schedule for all surface water management
structures, stipulating current maintenance, continued maintenance
and responsibility for same.
(12)
All proposed revisions of required data as well as such additional
data as the Planning Board may require.
A.
Minor developments. Minor developments shall be designed to include
the following stormwater management measures:
(1)
Water quality. Soil erosion and sediment control measures shall
be installed in accordance with the Standards for Soil Erosion and
Sediment Control in New Jersey.
(2)
Rate/volume control. Seepage pits or other infiltration measures
shall be provided with a capacity of one inch of runoff for each square
foot of new impervious area. Stone used in the infiltration devices
shall range from three-quarter-inch to two-and-one-half-inch clean
stone and a design void ratio of 40% shall be used. The infiltration
measures shall be designed with an overflow to the surface which shall
be stabilized and directed to an existing stormwater conveyance system
or in a manner to keep the overflow on the developed property to the
greatest extent feasible. If the new impervious surface is not roof
area, an equivalent area of existing roof may be directed to the infiltration
system. This shall be permitted where the existing roof is not already
directed to infiltration devices.
[Amended 9-28-2022 by Ord. No. 1176-2022]
(3)
Location
of infiltration measures. Stormwater infiltration measures, such as
dry wells and infiltration trenches, shall be horizontally separated
from existing and/or proposed potable wells and subsurface sewage
disposal fields and existing septic seepage pits or cesspools in accordance
with Table 4.3 of N.J.A.C. 7:9A-4.3, or latest amended or revised
edition.
[Added 9-28-2022 by Ord. No. 1176-2022]
(4)
Relief from requirements. The Township Engineer may reduce or eliminate the infiltration measures required by § 165-229A(2) above if, in his or her professional judgment based on sound engineering principles, reasonable cause exists to do so.
[Added 9-28-2022 by Ord. No. 1176-2022]
A.
The development shall incorporate a maintenance plan for the stormwater management measures incorporated into the design of a major development in accordance with Section 165-236.
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 § 165-230P, 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 § 165-230O, 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 § 165-230D(3) above within the upstream drainage area of the receiving stream, that would provide additional opportunities to mitigate the requirements of § 165-230O, 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 § 165-230O, 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 New Jersey Stormwater Management Rule
are different due to updates or amendments with the tables in this
article, 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
|
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% to 80%
|
No
|
No
|
—
|
|
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
|
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% to 90%
|
Yes
|
No
|
N/A
|
|
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
|
Stormwater Runoff Quantity
|
Groundwater Recharge
|
Minimum Separation from Seasonal High Water Table
(feet)
|
|
Blue roof
|
0%
|
Yes
|
No
|
N/A
|
|
Extended detention basin
|
40% to 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% to 90%
|
Yes
|
No
|
N/A
|
|
Notes to Tables 1, 2, and 3:
| |
|---|---|
|
(a)
|
Subject to the applicable contributory drainage area limitation specified at § 165-230O(2);
|
|
(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 § 165-224;
|
|
(h)
|
Manufactured treatment devices that do not meet the definition of "green infrastructure" at § 165-224.
|
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 § 165-232B. Alternative stormwater management measures may be used to satisfy the requirements at § 165-230O only if the measures meet the definition of "green infrastructure" at § 165-224. Alternative stormwater management measures that function in a similar manner to a BMP in this Code are subject to the contributory drainage area limitation specified in this Code 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 § 165-230O(2) 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 § 165-230D is granted from § 165-230O.
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 § 165-234C;
(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 § 165-230, 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 § 165-224 may be used only under the circumstances described at § 165-230O(4).
K.
Any application for a new agricultural development that meets the definition of major development at § 165-224 shall be submitted to the Soil Conservation District for review and approval in accordance with the requirements at § 165-230O, 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 § 165-230P, 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 Office of the Hunterdon 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 § 165-230O, 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 § 165-236B(5). 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 § 165-230 of this article 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 Office of the Hunterdon County and shall contain a description and location of the stormwater management measure, as well as reference to the maintenance plan, in accordance with § 165-230M 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 § 165-230M 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 § 165-230P and Q, the design engineer shall utilize green infrastructure BMPs identified in Table 1 at § 165-230F and/or an alternative stormwater management measure approved in accordance with § 165-230G. 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 3 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 § 165-230D 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 § 165-230G may be used to meet the groundwater recharge, stormwater runoff quality, and stormwater runoff quantity standards at § 165-230P, 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 § 165-230P, Q and R, unless the project is granted a waiver from strict compliance in accordance with § 165-230D.
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 § 165-231, 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.
(3)
This groundwater recharge requirement does not apply to projects within the "urban redevelopment area," or to projects subject to § 165-230P(4) 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 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 § 165-230Q(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 - (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 § 165-230P, 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 § 165-231, 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 § 165-230R(2)(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 § 165-231A(1)(a) and the Rational and Modified Rational Methods at § 165-231A(1)(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 has 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 § 165-230F above, or alternative designs in accordance with § 165-230G 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 § 165-233A(2) 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 § 165-233A(1) 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:
(d)
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).
(e)
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
(f)
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 § 165-234C(1), (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 § 165-234C, 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 § 165-234E 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
 |
A.
Submission of site development stormwater plan.
(1)
Whenever an applicant seeks municipal approval of a development subject to this article, the applicant shall submit all of the required components of the Checklist for the Site Development Stormwater Plan at § 165-235C 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 article.
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
article.
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
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 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 the applicable sections
of this Code 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 § 165-226 of this article.
(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 § 165-236.
(8)
Waiver from submission requirements. The municipal official or board reviewing an application under this article may, in consultation with the municipality's review engineer, waive submission of any of the requirements in § 165-235C(1) through (6) of this article 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 § 165-236B(3) above is not a public agency, the maintenance plan and any future revisions based on § 165-236B(7) 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 nonvegetated linings.
(7)
The party responsible for maintenance identified under § 165-236B(3) 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 § 165-236B(6) and (7) above.
(8)
The requirements of § 165-236B(3) 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.
Limit of contract. Critical impact areas and other areas to be left
undisturbed shall be physically marked with survey stakes or protected
with temporary snow fence prior to any land disturbance.
B.
Timing. The Planning Board shall require the construction and/or
installation of surface water management improvements in accordance
with the schedule of sequence of installation as approved.
C.
Bonding. The Planning Board shall provide for the posting of performance
guaranties and maintenance bonds when necessary.
D.
Inspection.
(1)
The applicant shall bear full and final responsibility for the
installation and construction of all required surface water runoff
control measures according to the provisions of his/her approved plan
and this article. The Township Engineer shall inspect the site during
its preparation and development and certify that all surface water
management measures have been constructed in accordance with the provisions
of the applicant's approved plan under this article.
(2)
During the 12 months subsequent to the date of completion, the
Engineer periodically shall inspect the site to ascertain that the
provisions of the applicant's approved plan are complied with, including
limit of contract for areas to be left undisturbed. The Engineer shall
give the applicant, upon request, a certificate indicating the date
on which the required measures were completed and/or accepted.
(3)
No inspection shall be undertaken unless the Chief Financial
Officer shall have first certified the availability of funds in an
amount not less than $300.
F.
Maintenance.
(1)
At the time of approval of the plan, responsibility for continued
maintenance of surface water runoff control structures and measures
shall be stipulated and properly recorded.
(2)
The Township shall retain the right to enter and make repairs
and improvements where necessary to ensure that all control measures
as well as areas dedicated to surface water retention or groundwater
recharge are adequately maintained and preserved. The Township may
charge the property owner for the costs of these services if such
maintenance is his/her responsibility.
G.
Issuance of certificate of occupancy. No certificate of occupancy
shall issue unless and until the surface water management plan has
been reviewed, the improvements made in accordance with the plan,
and the inspection has been certified by the Township Engineer.
Each section, subsection, sentence, clause and phrase of this
article is declared to be an independent section, subsection, sentence,
clause and phrase, and the finding or holding of any such portion
of this article to be unconstitutional, void, or ineffective for any
cause, or reason, shall not affect any other portion of this article.
