[Ord. No. 2021-01; amended 9-5-2023 by Ord. No. 2023-16]
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 § 25-1-2, and also to establish maintenance and repair requirements for existing stormwater management BMPs, as also defined below in § 25-1-2.
[Amended 11-20-2023 by Ord. No. 2023-17]
C.
Applicability.
(2)
This chapter shall also be applicable to all major developments undertaken
by the Borough of Hightstown.
(3)
This chapter shall also be applicable to all existing stormwater
management BMPs.
[Amended 11-20-2023 by Ord. No. 2023-17]
(4)
An application required by ordinance pursuant to Subsection C(1) above that has been submitted prior to September 5, 2023, shall be subject to the stormwater management requirements in effect on September 4, 2023.
(5)
An application required by ordinance for approval pursuant to Subsection C(1) above that has been submitted on or after March 2, 2021, but prior to September 5, 2023, shall be subject to the stormwater management requirements in effect on September 4, 2023.
[Amended 11-20-2023 by Ord. No. 2023-17]
(6)
Notwithstanding any rule to the contrary, a major development for
any public roadway or railroad project conducted by a public transportation
entity that has determined a preferred alternative or reached an equivalent
milestone before July 17, 2023, shall be subject to the stormwater
management requirements in effect prior to July 17, 2023.
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.
[Ord. No. 2021-01; amended 9-5-2023 by Ord. No. 2023-16]
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 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 County Commissioners to review
municipal stormwater management plans and implementing ordinance(s).
The county review agency may either be:
The Department of Environmental Protection.
A person professionally qualified and duly licensed in New
Jersey to perform engineering services that may include, but not necessarily
be limited to, development of project requirements, creation and development
of project design and preparation of drawings and specifications.
A State Development and Redevelopment Plan Center as designated
by the State Planning Commission such as urban, regional, town, village,
or hamlet.
The division of a parcel of land into two or more parcels, the
construction, reconstruction, conversion, structural alteration, relocation
or enlarge-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 water body or
to a particular point along a receiving water body.
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.
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.
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; or
A combination of Subsection A(2) 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 A(1), (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."
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.
The Borough of Hightstown.
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 § 25-1-4G 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.
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.
A pathway for use by motor vehicles or trains that is intended
for public use and is constructed by, or on behalf of, a public transportation
entity. A public roadway or railroad does not include a roadway or
railroad constructed as part of a private development, regardless
of whether the roadway or railroad is ultimately to be dedicated to
and/or maintained by a governmental entity.
A federal, state, county, or municipal government, an independent
state authority, or a statutorily authorized public-private partnership
program pursuant to P.L. 2018, c. 90 (N.J.S.A. 40A:11-52 et seq.),
that performs a public roadway or railroad project that includes new
construction, expansion, reconstruction, or improvement of a public
roadway or railroad.
The amount of water from precipitation that infiltrates into
the ground and is not evapotranspired.
Any of the following, alone or in combination:
A net increase of impervious surface;
The total area of impervious surface collected by a new stormwater
conveyance system (for the purpose of this definition, a "new stormwater
conveyance system" is a stormwater conveyance system that is constructed
where one did not exist immediately prior to its construction or an
existing system for which a new discharge location is created);
The total area of impervious surface proposed to be newly collected
by an existing stormwater conveyance system; and/or
The total area of impervious surface collected by an existing
stormwater conveyance system where the capacity of that conveyance
system is increased.
Any of the following, alone or in combination:
The total area of motor vehicle surface that is currently receiving
water;
A net increase in motor vehicle surface; and/or quality treatment
either by vegetation or soil, by an existing stormwater management
measure, or by treatment at a wastewater treatment plant, where the
water quality treatment will be modified or removed.
Solid material, mineral or organic, that is in suspension,
is being transported, or has been moved from its site of origin by
air, water or gravity as a product of erosion.
The lot or lots upon which a major development is to occur
or has occurred.
All unconsolidated mineral and organic material of any origin.
An area delineated on the State Plan Policy Map and adopted
by the State Planning Commission that is intended to be the focus
for much of the state's future redevelopment and revitalization efforts.
The geographic application of the State Development and Redevelopment
Plan's goals and statewide policies, and the official map of these
goals and policies.
Water resulting from precipitation (including rain and snow)
that runs off the land's surface, is transmitted to the subsurface,
or is captured by separate storm sewers or other sewage or drainage
facilities, or conveyed by snow removal equipment.
An excavation or embankment and related areas designed to
retain stormwater runoff. A stormwater management BMP may either be
normally dry (that is, a detention basin or infiltration system),
retain water in a permanent pool (a retention basin), or be planted
mainly with wetland vegetation (most constructed stormwater wetlands).
Any practice, technology, process, program, or other method
intended to control or reduce stormwater runoff and associated pollutants,
or to induce or control the infiltration or groundwater recharge of
stormwater or to eliminate illicit or illegal 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 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 water 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."
[Ord. No. 2021-01; amended 9-5-2023 by Ord. No. 2023-16]
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.
[Ord. No. 2021-01; amended 9-5-2023 by Ord. No. 2023-16]
A.
The development shall incorporate a maintenance plan for the stormwater management measures incorporated into the design of a major development in accordance with § 25-1-10.
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 13:1B-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 § 25-1-4P, 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 § 25-1-4O, P, Q and R may be obtained for the enlargement of an existing public roadway or railroad; or the construction or enlargement of a public pedestrian access, provided that the following conditions are met:
(1)
The applicant demonstrates that there is a public need for the project
that cannot be accomplished by any other means;
(2)
The applicant demonstrates, through an alternatives analysis, that through the use of stormwater management measures, the option selected complies with the requirements of § 25-1-4O, P, Q and R to the maximum extent practicable;
(3)
The applicant demonstrates that, in order to meet the requirements of § 25-1-4O, P, Q and R, existing structures currently in use, such as homes and buildings, would need to be condemned; and
(4)
The applicant demonstrates that it does not own or have other rights to areas, including the potential to obtain through condemnation lands not falling under § 25-1-4D(3) above within the upstream drainage area of the receiving stream, that would provide additional opportunities to mitigate the requirements of § 25-1-4O, 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 § 25-1-4O, 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://dep.nj.gov/stormwater/bmp-manual/.
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
|
8
0
|
Yes
|
Yes
|
2
|
|
Vegetative filter strip
|
60-80
|
No
|
No
|
—
|
|
[Notes corresponding to annotations (a) through (g) are found
below Table 3.]
|
|
Table 2
| |||||
|---|---|---|---|---|---|
|
Green Infrastructure BMPs for Stormwater Runoff Quantity
(or for Groundwater Recharge and/or Stormwater Runoff Quality
with a Waiver or Variance from N.J.A.C. 7:8-5.3)
| |||||
|
Best Management Practice
|
Stormwater Runoff Quality TSS Removal Rate
(percent)
|
Stormwater Runoff Quantity
|
Groundwater Recharge
|
Minimum Separation from Seasonal High Water Table
(feet)
| |
|
Bioretention system
|
80 or 90
|
Yes
|
Yes(b)
No(c)
|
2(b)
1(c)
| |
|
Infiltration basin
|
80
|
Yes
|
Yes
|
2
| |
|
Sand filter(b)
|
80
|
Yes
|
Yes
|
2
| |
|
Standard constructed wetland
|
90
|
Yes
|
No
|
N/A
| |
|
Wet pond(d)
|
50-90
|
Yes
|
No
|
N/A
| |
|
[Notes corresponding to annotations (b) through (d) are found
below Table 3.]
|
|
Table 3
BMPs for Groundwater Recharge, Stormwater Runoff Quality, and/or
Stormwater Runoff Quantity only with a Waiver or Variance from N.J.A.C.
7:8-5.3
| |||||
|---|---|---|---|---|---|
|
Best Management Practice
|
Stormwater Runoff Quality TSS Removal Rate
(percent)
|
Stormwater Runoff Quantity
|
Groundwater Recharge
|
Minimum Separation from Seasonal High Water Table
(feet)
| |
|
Blue roof
|
0
|
Yes
|
No
|
N/A
| |
|
Extended detention basin
|
40-60
|
Yes
|
No
|
1
| |
|
Manufactured treatment device(h)
|
50 or 80
|
No
|
No
|
Dependent upon the device
| |
|
Sand filter(c)
|
80
|
Yes
|
No
|
1
| |
|
Subsurface gravel wetland
|
90
|
No
|
No
|
1
| |
|
Wet pond
|
50-90
|
Yes
|
No
|
N/A
| |
|
Notes to Tables 1, 2 and 3:
| |
|
(a)
|
Subject to the applicable contributory drainage area limitation specified at § 25-1-4O(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 § 25-1-2.
|
|
(h)
|
Manufactured treatment devices that do not meet the definition of "green infrastructure" at § 25-1-2.
|
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 § 25-1-6B. Alternative stormwater management measures may be used to satisfy the requirements at § 25-1-4O only if the measures meet the definition of "green infrastructure" at § 25-1-2. Alternative stormwater management measures that function in a similar manner to a BMP listed at Subsection O(2) are subject to the contributory drainage area limitation specified at Subsection O(2) 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 Subsection O(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 § 25-1-4D is granted from Subsection O.
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 § 25-1-8C;
(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 § 25-1-8; 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 § 25-1-2 may be used only under the circumstances described at § 25-1-4O(4).
K.
Any application for a new agricultural development that meets the definition of "major development" at § 25-1-2 shall be submitted to the Soil Conservation District for review and approval in accordance with the requirements at § 25-1-4O, 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 § 25-1-4P, 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 Mercer 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 § 25-1-4O, 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 § 25-1-10B(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 § 25-1-4 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 with the Office of the Mercer 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 § 25-1-4P and Q, the design engineer shall utilize green infrastructure BMPs identified in Table 1 at § 25-1-4F and/or an alternative stormwater management measure approved in accordance with § 25-1-4G. 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 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 § 25-1-4D 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 § 25-1-4G, may be used to meet the groundwater recharge, stormwater runoff quality, and stormwater runoff quantity standards at § 25-1-4P, 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 § 25-1-4P, Q and R, unless the project is granted a waiver from strict compliance in accordance with § 25-1-4D.
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 § 25-1-5, either:
(a)
Demonstrate through hydrologic and hydraulic analysis that the
site and its stormwater management measures maintain 100% of the average
annual preconstruction groundwater recharge volume for the site; or
(3)
This groundwater recharge requirement does not apply to projects within the urban redevelopment area, or to projects subject to Subsection P(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
approved pursuant to the Administrative Requirements for the Remediation
of Contained Sites rules, N.J.A.C. 7:26C, or Department landfill closure
plan and areas; 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 Subsection Q(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; and
|
|
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 § 25-1-4P, 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)
The 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 § 25-1-5, complete one of the following:
(a)
Demonstrate through hydrologic and hydraulic analysis that for stormwater leaving the site, post-construction runoff hydrographs for the current and projected two-, ten-, and 100-year storm events, as defined and determined in § 25-1-5C and D, respectively, do not exceed, at any point in time, the preconstruction runoff hydrographs for the same storm events;
(b)
Demonstrate through hydrologic and hydraulic analysis that there is no increase, as compared to the preconstruction condition, in the peak runoff rates of stormwater leaving the site for the current and projected two-, ten-, and 100-year storm events, as defined and determined pursuant to § 25-1-5C and D, respectively, 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 current and projected two-, ten-, and 100-year storm events, as defined and determined in § 25-1-5C and D, respectively, are 50%, 75% and 80%, respectively, of the preconstruction 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 R(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.
[Ord. No. 2021-01; amended 9-5-2023 by Ord. No. 2023-16]
A.
Stormwater runoff shall be calculated in accordance with the following:
(1)
The design engineer shall calculate runoff using the following method: 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://directives.sc.egov.usda.gov/viewerFS.aspx?hid=21422 or at United States Department of Agriculture Natural Resources Conservation Service, 220 Davidson Avenue, Somerset, New Jersey 08873.
(2)
For the purpose of calculating curve numbers and groundwater recharge, there is a presumption that the preconstruction condition of a site or portion thereof is a wooded land use with good hydrologic condition. The term "curve number" applies to the NRCS methodology above at § 25-1-5A(1). A curve number 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 preconstruction 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 preconstruction 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.
C.
The precipitation depths of the current two-, ten-, and 100-year storm events shall be determined by multiplying the values determined in accordance with Subsection C(1) and (2) below:
(1)
The applicant shall utilize the National Oceanographic and Atmospheric
Administration (NOAA), National Weather Service's Atlas 14 Point Precipitation
Frequency Estimates: NJ, in accordance with the location(s) of the
drainage area(s) of the site. This data is available at https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_map_cont.html?bkmrk=nj;
and
(2)
The applicant shall utilize Table 5: Current Precipitation Adjustment
Factors, below, which sets forth the applicable multiplier for the
drainage area(s) of the site, in accordance with the county or counties
where the drainage area(s) of the site is located. Where the major
development lies in more than one county, the precipitation values
shall be adjusted according to the percentage of the drainage area
in each county. Alternately, separate rainfall totals can be developed
for each county using the values in the table below.
|
Table 5: Current Precipitation Adjustment Factors
| |||
|---|---|---|---|
|
County
|
Two-Year Design Storm
|
Ten-Year Design Storm
|
100-Year Design Storm
|
|
Mercer
|
1.01
|
1.02
|
1.04
|
D.
Table 6: Future Precipitation Change Factors, provided below, sets forth the change factors to be used in determining the projected two-, ten-, and 100-year storm events for use in this chapter, which are organized alphabetically by county. The precipitation depth of the projected two-, ten-, and 100-year storm events of a site shall be determined by multiplying the precipitation depth of the two-, ten-, and 100-year storm events determined from the National Weather Service's Atlas 14 Point Precipitation Frequency Estimates pursuant to Subsection C(1), above, by the change factor in the table below, in accordance with the county or counties where the drainage area(s) of the site is located. Where the major development and/or its drainage area lies in more than one county, the precipitation values shall be adjusted according to the percentage of the drainage area in each county. Alternately, separate rainfall totals can be developed for each county using the values in the table below.
|
Table 6: Future Precipitation Change Factors
| |||
|---|---|---|---|
|
County
|
Two-Year Design Storm
|
Ten-Year Design Storm
|
100-Year Design Storm
|
|
Mercer
|
1.16
|
1.17
|
1.36
|
[Ord. No. 2021-01; amended 9-5-2023 by Ord. No. 2023-16]
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 https://dep.nj.gov/stormwater/bmp-manual/.
(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://dep.nj.gov/stormwater/maintenance-guidance/.
B.
Submissions required for review by the Department should be mailed
to the Division of Watershed Protection and Restoration, New Jersey
Department of Environmental Protection, Mail Code 501-02A, PO Box
420, Trenton, New Jersey 08625-0420.
[Ord. No. 2021-01; amended 9-5-2023 by Ord. No. 2023-16]
Site design features identified under § 25-1-4F above, or alternative designs in accordance with § 25-1-4G 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 section, "solid and floatable materials" means sediment, debris, trash, and other floating, suspended, or settleable solids. For exemptions to this standard see § 25-1-7B below.
A.
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:
(1)
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
(2)
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.
(3)
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.
B.
The standard in Subsection A above does not apply:
(1)
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;
(2)
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;
(3)
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:
(a)
A rectangular space 4.625 inches long and 1.5 inches wide (this
option does not apply for outfall netting facilities); or
(b)
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].
(4)
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
(5)
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.
[Ord. No. 2021-01; amended 9-5-2023 by Ord. No. 2023-16]
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 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 § 25-1-8C(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 greater 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 § 25-1-8C, 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 feet 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 foot to 1 1/2 feet above the permanent water surface. See § 25-1-8E for an illustration of safety ledges in a stormwater management BMP; and
(c)
In new stormwater management BMPs, the maximum interior slope
for an earthen dam, embankment, or berm shall not be steeper than
three horizontal to one vertical.
D.
Variance or exemption from safety standard. A variance or exemption
from the safety standards for stormwater management BMPs may be granted
only upon a written finding by the municipality that the variance
or exemption will not constitute a threat to public safety.
E.
Safety ledge illustration.
|
Elevation View - Basin Safety Ledge Configuration
 |
[Ord. No. 2021-01; amended 9-5-2023 by Ord. No. 2023-16]
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 Subsection C 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 Planning
Board Engineer from which municipal approval is sought. The Planning
Board shall consult the Planning Board 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 Planning Board 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 §§ 25-1-3 through 25-1-5 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 predevelopment and post-development conditions for the design storms specified in § 25-1-4 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 § 25-1-10.
(8)
Waiver from submission requirements. The Planning Board may, in consultation with the Planning Board Engineer, waive submission of any of the requirements in § 25-1-9C(1) 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.
[Ord. No. 2021-01; amended 9-5-2023 by Ord. No. 2023-16]
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. For existing stormwater management BMPs, a professional
engineer shall prepare an operation and maintenance plan for the stormwater
management measures incorporated into the existing stormwater management
facilities.
[Amended 11-20-2023 by Ord. No. 2023-17]
(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 Subsection B(3) above is not a public agency, the maintenance plan and any future revisions based on Subsection B(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 Subsection B(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;
[Amended 11-20-2023 by Ord. No. 2023-17]
(d)
Obtain a stormwater maintenance permit from the Borough Engineer
by June 30 of each year; and
[Added 11-20-2023 by Ord. No. 2023-17]
(e)
On an annual basis submit to the Borough Engineer a maintenance and
inspection report and certification on a form approved by the Borough
Engineer with all required maintenance logs.
[Added 11-20-2023 by Ord. No. 2023-17]
(8)
A two-year maintenance guarantee in accordance with N.J.S.A.
40:55D-53 is required for all stormwater management facilities into
a major development.
(9)
The person responsible for maintenance identified under § 25-1-10B above shall submit an annual inspection report prepared by a professional engineer licensed in New Jersey or a New Jersey certified stormwater inspector to the Borough Engineer by June 30 of each year. The inspection report and log shall include and not be limited to:
[Amended 11-20-2023 by Ord. No. 2023-17]
(10)
Copies of checklist requirements for various stormwater management
BMPs shall be available from the Borough Clerk.
[Added 11-20-2023 by Ord. No. 2023-17]
C.
Nothing in this subsection shall preclude the municipality in which
the major development or existing stormwater management BMP is located
from requiring the posting of a performance or maintenance guarantee
in accordance with N.J.S.A. 40:55D-53.
[Added 11-20-2023 by Ord. No. 2023-17]
[Ord. No. 2021-01; amended 9-5-2023 by Ord. No. 2023-16; 11-20-2023 by Ord. No. 2023-17]
A.
This
chapter shall be enforced by the Code Enforcement Officer and/or their
designee.
B.
Any person(s) who erects, constructs, alters, repairs, converts, maintains, fails to maintain or uses any building, structure or land in violation of this chapter, or who otherwise has not complied in any respect with the requirements of this chapter, shall be subject to the following penalties for each offense: any and all penalties as set forth in Chapter 1, Article 1-5, of the Revised General Ordinances of the Borough of Hightstown.
C.
Each
act or violation, and every day upon which any violation shall occur
or continues to occur, shall constitute a separate offense.
D.
In addition to the penalties prescribed by § 25-1-11B and C above, 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 Borough Engineer or his or her 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 may immediately proceed to do so and shall bill the cost thereof, along with any professional fees or other costs incurred by the municipality associated with maintenance and repair activities, to the responsible person. Nonpayment of such bill(s) may result in the imposition of a lien against the property.
[Ord. No. 2021-01; amended 9-5-2023 by Ord. No. 2023-16]
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.
