[HISTORY: Adopted by the Mayor and Council of the Borough
of Dunellen 6-19-2006 by Ord. No.
06-10. Amendments noted where applicable.]
A.
Policy statement. Flood control, groundwater recharge, and pollutant
reduction through nonstructural or low-impact techniques shall be
explored before relying on structural BMPs. Structural BMPs should
be integrated with nonstructural stormwater management strategies
and proper maintenance plans. Nonstructural strategies include both
environmentally sensitive site design and source controls that prevent
pollutants from being placed on the site or from being exposed to
stormwater. Source control plans 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. It is the purpose of this chapter to establish minimum stormwater management requirements and controls for "major development," as defined in § 253-2.
C.
D.
Compatibility with other permit and chapter requirements. Development
approvals issued for subdivisions and site plans pursuant to this
chapter are to be considered an integral part of development approvals
under the subdivision and site plan review process 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. This
chapter is not intended to interfere with, abrogate, or annul any
other ordinance, 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.
Unless specifically defined below, words or phrases used in
this chapter shall be interpreted so as to give them the meaning they
have in common usage and to give this chapter its most reasonable
application. 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 within boundaries accepted by the Department
pursuant to N.J.A.C. 7:7-13.
The geographic depiction of the boundaries for Coastal Planning
Areas, CAFRA Centers, CAFRA Cores and CAFRA Nodes pursuant to N.J.A.C.
7:7-13.16.
The increase in soil bulk density.
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:
The New Jersey 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, by any person,
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
lands, development means: any activity that requires a state permit;
any activity reviewed by the County Agricultural Board (CAB) and the
State Agricultural Development Committee (SADC), and municipal review
of any activity not exempted by the Right to Farm Act, N.J.S.A. 4:1C-1
et seq.
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.
A neighborhood 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.
An area or feature which is of significant environmental
value, including, but not limited to: stream corridors; natural heritage
priority sites; habitat of endangered or threatened species; large
areas of contiguous open space or upland forest; steep slopes; and
well head protection and groundwater recharge areas. Habitats of endangered
or threatened species are identified using the Department's Landscape
Project as approved by the Department's Endangered and Nongame
Species Program.
The detachment and movement of soil or rock fragments by
water, wind, ice or gravity.
A 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 "development" that provides for ultimately disturbing
one or more acres of land, or increases the impervious area by more
than 1/4 acre. Disturbance for the purpose of this rule is the placement
of impervious surface or exposure and/or movement of soil or bedrock
or clearing, cutting, or removing of vegetation.
Any city, borough, town, township, or village.
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, municipality, or political subdivision of this state
subject to municipal jurisdiction pursuant to the Municipal Land Use
Law, N.J.S.A. 40:55D-1 et seq.
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.A. § 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.
The amount of water from precipitation that infiltrates into
the ground and is not evapotranspired.
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 basin may either
be normally dry (that is, a detention basin or infiltration basin),
retain water in a permanent pool (a retention basin), or be planted
mainly with wetland vegetation (most constructed stormwater wetlands).
Any structural or nonstructural strategy, 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.
Water flow on the surface of the ground or in storm sewers
resulting from precipitation.
A flood hazard area, which may be influenced by stormwater
runoff from inland areas, but which is primarily caused by the Atlantic
Ocean.
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:
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.
Design and performance standards for stormwater management measures.
A.
Stormwater management measures for major development shall be developed to meet the erosion control, groundwater recharge, stormwater runoff quantity, and stormwater runoff quality standards in § 253-4. To the maximum extent practicable, these standards shall be met by incorporating nonstructural stormwater management strategies into the design. If these strategies alone are not sufficient to meet these standards, structural stormwater management measures necessary to meet these standards shall be incorporated into the design.
B.
The standards in this chapter apply only to new major development
and are intended to minimize the impact of stormwater runoff on water
quality and water quantity in receiving water bodies and maintain
groundwater recharge. The standards do not apply to new major development
to the extent that alternative design and performance standards are
applicable under a regional stormwater management plan or Water Quality
Management Plan adopted in accordance with Department rules.
A.
The development shall incorporate a maintenance plan for the stormwater management measures incorporated into the design of a major development in accordance with § 253-10.
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 muhlenbergi (bog turtle).
C.
The following linear development projects are exempt from the groundwater recharge, stormwater runoff quantity, and stormwater runoff quality requirements of Subsections F and G:
(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 groundwater recharge, stormwater runoff quantity, and stormwater runoff quality requirements of Subsections F and G may be obtained for the enlargement of an existing public roadway or railroad; or the construction or enlargement of a public pedestrian access, provided that the following conditions are met:
(1)
The applicant demonstrates that there is a public need for the project
that cannot be accomplished by any other means;
(4)
The applicant demonstrates that it does not own or have other rights to areas, including the potential to obtain through condemnation lands not falling under Subsection D(3) above within the upstream drainage area of the receiving stream, that would provide additional opportunities to mitigate the requirements of Subsections F and G that were not achievable on site.
E.
Nonstructural stormwater management strategies.
(1)
To the maximum extent practicable, the standards in Subsections F and G shall be met by incorporating nonstructural stormwater management strategies set forth at Subsection E into the design. The applicant shall identify the nonstructural measures incorporated into the design of the project. If the applicant contends that it is not feasible for engineering, environmental, or safety reasons to incorporate any nonstructural stormwater management measures identified in Subsection E(2) below into the design of a particular project, the applicant shall identify the strategy considered and provide a basis for the contention.
(2)
Nonstructural stormwater management strategies incorporated into
site design shall:
(a)
Protect areas that provide water quality benefits or areas particularly
susceptible to erosion and sediment loss;
(b)
Minimize impervious surfaces and break up or disconnect the
flow of runoff over impervious surfaces;
(c)
Maximize the protection of natural drainage features and vegetation;
(d)
Minimize the decrease in the "time of concentration" from pre-construction
to post construction. "Time of concentration" is defined as the time
it takes for runoff to travel from the hydraulically most distant
point of the watershed to the point of interest within a watershed;
(e)
Minimize land disturbance, including clearing and grading;
(f)
Minimize soil compaction;
(g)
Provide low-maintenance landscaping that encourages retention
and planting of native vegetation and minimizes the use of lawns,
fertilizers and pesticides;
(h)
Provide vegetated open-channel conveyance systems discharging
into and through stable vegetated areas;
(i)
Provide other source controls to prevent or minimize the use
or exposure of pollutants at the site, in order to prevent or minimize
the release of those pollutants into stormwater runoff. Such source
controls include, but are not limited to:
[1]
Site design features that help to prevent accumulation of trash and debris in drainage systems, including features that satisfy Subsection E(3) below;
[2]
Site design features that help to prevent discharge of trash
and debris from drainage systems;
[3]
Site design features that help to prevent and/or contain spills
or other harmful accumulations of pollutants at industrial or commercial
developments; and
[4]
When establishing vegetation after land disturbance, applying
fertilizer in accordance with the requirements established under the
Soil Erosion and Sediment Control Act, N.J.S.A. 4:24-39 et seq., and
implementing rules.
(3)
Site design features identified under Subsection E(2)(i)[2] above 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 Subsection E(3)(c) below.
(a)
Design engineers shall use either 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]
Grates.
[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
(April 1996); 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.
[2]
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 basin floors.
(b)
Whenever design engineers use a curb-opening inlet, 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 7.0 square inches, or be no greater than 2.0 inches across
the smallest dimension.
(c)
This standard does not apply:
[1]
Where the review agency determines that this standard would
cause inadequate hydraulic performance that could not practicably
be overcome by using additional or larger storm drain inlets that
meet these standards;
[2]
Where flows from the water quality design storm as specified in Subsection G(1) 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:
[3]
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 Subsection G(1); or
[4]
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.
(4)
Any land area used as a nonstructural stormwater management measure to meet the performance standards in Subsections F and G shall be dedicated to a government agency, subjected to a conservation restriction filed with the appropriate County Clerk's office, or subject to an approved equivalent restriction that ensures that measure or an equivalent stormwater management measure approved by the reviewing agency is maintained in perpetuity.
F.
Erosion control, groundwater recharge and runoff quantity standards.
(1)
This subsection contains minimum design and performance standards
to control erosion, encourage and control infiltration and groundwater
recharge, and control stormwater runoff quantity impacts of major
development.
(a)
The minimum design and performance standards for erosion control
are those established under the Soil Erosion and Sediment Control
Act, N.J.S.A. 4:24-39 et seq., and implementing rules.
(b)
The minimum design and performance standards for groundwater
recharge are as follows:
[1]
The design engineer shall, using the assumptions and factors for stormwater runoff and groundwater recharge calculations at § 253-5, either:
[a]
Demonstrate through hydrologic and hydraulic analysis
that the site and its stormwater management measures maintain 100%
of the average annual pre-construction groundwater recharge volume
for the site; or
[b]
Demonstrate through hydrologic and hydraulic analysis
that the increase of stormwater runoff volume from pre-construction
to post-construction for the two-year storm is infiltrated.
[2]
This groundwater recharge requirement does not apply to projects within the "urban redevelopment area," or to projects subject to Subsection F(1)(b)[3] below.
[3]
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.
[4]
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 and
other subsurface structures in the vicinity or down gradient of the
groundwater recharge area.
(c)
In order to control stormwater runoff quantity impacts, the design engineer shall, using the assumptions and factors for stormwater runoff calculations at § 253-5, complete one of the following:
[1]
Demonstrate through hydrologic and hydraulic analysis that for
stormwater leaving the site, post-construction runoff hydrographs
for the two-, ten-, and one-hundred-year storm events do not exceed,
at any point in time, the pre-construction runoff hydrographs for
the same storm events;
[2]
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 one-hundred-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;
[3]
Design stormwater management measures so that the post-construction
peak runoff rates for the two-, ten- and one-hundred-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. The percentages
shall not be applied to post-construction stormwater runoff into tidal
flood hazard areas if the increased volume of stormwater runoff will
not increase flood damages below the point of discharge; or
[4]
In tidal flood hazard areas, stormwater runoff quantity analysis
in accordance with F(1)(c)[1], [2] and [3] above shall only be applied
if the increased volume of stormwater runoff could increase flood
damages below the point of discharge.
(2)
Any application for a new agricultural development that meets the definition of major development at § 253-2 shall be submitted to the appropriate Soil Conservation District for review and approval in accordance with the requirements of this section and any applicable Soil Conservation District guidelines for stormwater runoff quantity and erosion control. For the purposes of this section, "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 manufacturing of agriculturally related products.
G.
Stormwater runoff quality standards.
(1)
Stormwater management measures shall be designed to reduce the post-construction
load of total suspended solids (TSS) in stormwater runoff by 80% of
the anticipated load from the developed site, expressed as an annual
average. Stormwater management measures shall only be required for
water quality control if an additional 1/4 acre of impervious surface
is being proposed on a development site. 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 Pollution Discharge Elimination System (NJPDES) rules, N.J.A.C.
7:14A, or in a discharge specifically exempt under a NJPDES permit
from this requirement. 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 1. The calculation of the volume of runoff may
take into account the implementation of nonstructural and structural
stormwater management measures.
|
Table 1: Water Quality Design Storm Distribution
| |||
|---|---|---|---|
|
Time
(minutes)
|
Cumulative Rainfall
(inches)
|
Time
(minutes)
|
Cumulative Rainfall
(inches)
|
|
0
|
0.0000
|
65
|
0.8917
|
|
5
|
0.0083
|
70
|
0.9917
|
|
10
|
0.0166
|
75
|
1.0500
|
|
15
|
0.0250
|
80
|
1.0840
|
|
20
|
0.0500
|
85
|
1.1170
|
|
25
|
0.0750
|
90
|
1.1500
|
|
30
|
0.1000
|
95
|
1.1750
|
|
35
|
0.1330
|
100
|
1.2000
|
|
40
|
0.1660
|
105
|
1.2250
|
|
45
|
0.2000
|
110
|
1.2334
|
|
50
|
0.2583
|
115
|
1.2417
|
|
55
|
0.3583
|
120
|
1.2500
|
|
60
|
0.6250
| ||
(2)
For purposes of TSS reduction calculations, Table 2 below presents the presumed removal rates for certain BMPs designed in accordance with the New Jersey Stormwater Best Management Practices Manual. The BMP Manual may be obtained from the address identified in § 253-7, or found on the Department's website at www.njstormwater.org. The BMP Manual and other sources of technical guidance are listed in § 253-7. TSS reduction shall be calculated based on the removal rates for the BMPs in Table 2 below. Alternative removal rates and methods of calculating removal rates may be used if the design engineer provides documentation demonstrating the capability of these alternative rates and methods to the review agency. A copy of any approved alternative rate or method of calculating the removal rate shall be provided to the Department at the following address: Division of Watershed Management, New Jersey Department of Environmental Protection, P.O. Box 418 Trenton, New Jersey, 08625-0418.
(3)
If more than one BMP in series is necessary to achieve the required
80% TSS reduction for a site, the applicant shall utilize the following
formula to calculate TSS reduction:
|
R = A + B - (AXB)/100
|
|
Where:
| ||
|
R
|
=
|
total TSS percent load removal from application of both BMPs,
and
|
|
A
|
=
|
the TSS percent removal rate applicable to the first BMP
|
|
B
|
=
|
the TSS percent removal rate applicable to the second BMP
|
|
Table 2: TSS Removal Rates for BMPs
| |
|---|---|
|
Best Management Practice
|
TSS Percent Removal Rate
|
|
Bioretention systems
|
90
|
|
Constructed stormwater wetland
|
90
|
|
Extended detention basin
|
40–60
|
|
Infiltration structure
|
80
|
|
Manufactured treatment device
|
See § 253-6C
|
|
Sand filter
|
80
|
|
Vegetative filter strip
|
60–80
|
|
Wet pond
|
50–90
|
(4)
If there is more than one on-site drainage area, the 80% TSS removal
rate shall apply to each drainage area unless the runoff from the
subareas converge on site, in which case the removal rate can be demonstrated
through a calculation using a weighted average.
(5)
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 nonstructural strategies and structural measures that optimize nutrient removal while still achieving the performance standards in Subsections F and G.
(6)
Additional information and examples are contained in the New Jersey Stormwater Best Management Practices Manual, which may be obtained from the address identified in § 253-7.
(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)
Special water resource protection areas shall be established along
all waters designated Category One at N.J.A.C. 7:9B, and perennial
or intermittent streams that drain into or upstream of the Category
One waters as shown on the USGS Quadrangle Maps or in the County Soil
Surveys, within the associated HUC14 drainage area. These areas shall
be established for the protection of water quality, aesthetic value,
exceptional ecological significance, exceptional recreational significance,
exceptional water supply significance, and exceptional fisheries significance
of those established Category One waters. These areas shall be designated
and protected as follows:
(a)
The applicant shall preserve and maintain a special water resource
protection area in accordance with one of the following:
[1]
A 300-foot special water resource protection area shall be provided
on each side of the waterway, measured perpendicular to the waterway
from the top of the bank outwards or from the center line of the waterway
where the bank is not defined, consisting of existing vegetation or
vegetation allowed to follow natural succession is provided.
[2]
Encroachment within the designated special water resource protection area under Subsection G(8)(a)[1] above shall only be allowed where previous development or disturbance has occurred (for example, active agricultural use, parking area or maintained lawn area). The encroachment shall only be allowed where the applicant demonstrates that the functional value and overall condition of the special water resource protection area will be maintained to the maximum extent practicable. In no case shall the remaining special water resource protection area be reduced to less than 150 feet as measured perpendicular to the top of bank of the waterway or center line of the waterway where the bank is undefined. All encroachments proposed under this subsection shall be subject to review and approval by the Department.
(b)
All stormwater shall be discharged outside of and flow through
the special water resource protection area and shall comply with the
standard for off-site stability in the "Standards For Soil Erosion
and Sediment Control in New Jersey," established under the Soil Erosion
and Sediment Control Act, N.J.S.A. 4:24-39 et seq.
(c)
If stormwater discharged outside of and flowing through the
special water resource protection area cannot comply with the standard
for off-site stability in the "Standards for Soil Erosion and Sediment
Control in New Jersey," established under the Soil Erosion and Sediment
Control Act, N.J.S.A. 4:24-39 et seq., then the stabilization measures
in accordance with the requirements of the above standards may be
placed within the special water resource protection area, provided
that:
[1]
Stabilization measures shall not be placed within 150 feet of
the Category One waterway;
[2]
Stormwater associated with discharges allowed by this section
shall achieve a 95% TSS post-construction removal rate;
[3]
Temperature shall be addressed to ensure no impact on the receiving
waterway;
[4]
The encroachment shall only be allowed where the applicant demonstrates
that the functional value and overall condition of the special water
resource protection area will be maintained to the maximum extent
practicable;
[5]
A conceptual project design meeting shall be held with the appropriate
Department staff and Soil Conservation District staff to identify
necessary stabilization measures; and
[6]
All encroachments proposed under this section shall be subject
to review and approval by the Department.
(d)
A stream corridor protection plan may be developed by a regional stormwater management planning committee as an element of a regional stormwater management plan, or by a municipality through an adopted municipal stormwater management plan. If a stream corridor protection plan for a waterway subject to Subsection G(8) has been approved by the Department of Environmental Protection, then the provisions of the plan shall be the applicable special water resource protection area requirements for that waterway. A stream corridor protection plan for a waterway subject to Subsection G(8) shall maintain or enhance the current functional value and overall condition of the special water resource protection area as defined in Subsection G(8)(a)[1] above. In no case shall a stream corridor protection plan allow the reduction of the Special Water Resource Protection Area to less than 150 feet as measured perpendicular to the waterway subject to this subsection.
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 the NRCS National Engineering Handbook Section 4 -
Hydrology and Technical Release 55 — Urban Hydrology for Small
Watersheds; or
(b)
The Rational Method for peak flow and the Modified Rational
Method for hydrograph computations.
(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 at § 253-5A(1)(a) and the Rational and Modified Rational Methods at § 253-5A(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 have existed on the site during the five years immediately prior to the time of application, the land cover with the lowest runoff potential shall be used for the computations. In addition, there is the presumption that the site is in good hydrologic condition (if the land use type is pasture, lawn, or park), with good cover (if the land use type is woods), or with good hydrologic condition and conservation treatment (if the land use type is cultivation).
(3)
In computing pre-construction stormwater runoff, the design engineer
shall account for all significant land features and structures, such
as ponds, wetlands, depressions, hedgerows, or culverts, that may
reduce pre-construction stormwater runoff rates and volumes.
(4)
In computing stormwater runoff from all design storms, the design
engineer shall consider the relative stormwater runoff rates and/or
volumes of pervious and impervious surfaces separately to accurately
compute the rates and volume of stormwater runoff from the site. To
calculate runoff from unconnected impervious cover, urban impervious
area modifications as described in the NRCS Technical Release 55 —
Urban Hydrology for Small Watersheds and 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:
(1)
The New Jersey Geological Survey Report GSR-32 A Method for Evaluating
Ground-Water 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 http://www.state.nj.us/dep/njgs/; or at New Jersey Geological
Survey, 29 Arctic Parkway, P.O. Box 427 Trenton, New Jersey 08625-0427;
(609) 984-6587.
A.
Standards for structural stormwater management measures are as follows:
(1)
Structural stormwater management measures shall be designed to take
into account the existing site conditions, including, for example,
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)
Structural 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 § 253-8D.
(3)
Structural 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, 5:21-5:21-7.4, and
5:21-7.5 shall be deemed to meet this requirement.
(4)
At the intake to the outlet from the stormwater management basin,
the orifice size shall be a minimum of 2 1/2 inches in diameter.
B.
Stormwater management measure guidelines are available in the New Jersey Stormwater Best Management Practices Manual. Other stormwater management measures may be utilized provided the design engineer demonstrates that the proposed measure and its design will accomplish the required water quantity, groundwater recharge and water quality design and performance standards established by § 253-4 of this chapter.
A.
Technical guidance for stormwater management measures can be found in the documents listed at Subsections A(1) and A(2) below, which are available from Maps and Publications, New Jersey Department of Environmental Protection, 428 East State Street, P.O. Box 420, Trenton, New Jersey, 08625; telephone (609) 777-1038.
(1)
Guidelines for stormwater management measures are contained in the
New Jersey Stormwater Best Management Practices Manual, as amended.
Information is provided on stormwater management measures such as:
bioretention systems, constructed stormwater wetlands, dry wells,
extended detention basins, infiltration structures, manufactured treatment
devices, pervious paving, sand filters, vegetative filter strips,
and wet ponds.
(2)
The New Jersey Department of Environmental Protection Stormwater
Management Facilities Maintenance Manual, as amended.
B.
Additional technical guidance for stormwater management measures
can be obtained from the following:
(1)
The "Standards for Soil Erosion and Sediment Control in New Jersey"
promulgated by the State Soil Conservation Committee and incorporated
into N.J.A.C. 2:90. Copies of these standards may be obtained by contacting
the State Soil Conservation Committee or any of the Soil Conservation
Districts listed in N.J.A.C. 2:90-1.3(a)3. The location, address,
and telephone number of each Soil Conservation District may be obtained
from the State Soil Conservation Committee, P.O. Box 330, Trenton,
New Jersey 08625; (609) 292-5540;
(2)
The Rutgers Cooperative Extension Service, 732-932-9306; and
(3)
The Soil Conservation Districts listed in N.J.A.C. 2:90-1.3(a)3.
The location, address, and telephone number of each Soil Conservation
District may be obtained from the State Soil Conservation Committee,
P.O. Box 330, Trenton, New Jersey, 08625, (609) 292-5540.
A.
This section sets forth requirements to protect public safety through
the proper design and operation of stormwater management basins. This
section applies to any new stormwater management basin.
B.
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 basin to
ensure proper functioning of the basin 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.
(d)
The trash rack shall be constructed and installed to be rigid,
durable, and corrosion resistant, and shall be designed to withstand
a perpendicular live loading of 300 lbs./ft. sq.
(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 lbs./ft. sq.
(3)
For purposes of this Subsection B(3), "escape provisions" means the permanent installation of ladders, steps, rungs, or other features that provide easily accessible means of egress from stormwater management basins. Stormwater management basins shall include escape provisions as follows:
(a)
If a stormwater management basin has an outlet structure, escape provisions shall be incorporated in or on the structure. With the prior approval of the reviewing agency identified in § 253-8C, a freestanding outlet structure may be exempted from this requirement.
(b)
Safety ledges shall be constructed on the slopes of all new stormwater management basins having a permanent pool of water deeper than 2 1/2 feet. Such 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 § 253-8D for an illustration of safety ledges in a stormwater management basin.
(c)
In new stormwater management basins, the maximum interior slope
for an earthen dam, embankment, or berm shall not be steeper than
three horizontal to one vertical.
C.
Variance or exemption from safety standards. A variance or exemption
from the safety standards for stormwater management basins may be
granted only upon a written finding by the appropriate reviewing agency
(municipality, county or Department) that the variance or exemption
will not constitute a threat to public safety.
D.
Illustration of safety ledges in a new stormwater management basin.
 |
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 § 253-9C below as part of the submission of the applicant's application for subdivision or site plan 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 subdivision
or site plan review process by the municipal board or official from
which municipal approval is sought. That municipal board or official
shall consult the engineer retained by the Planning and/or Zoning
Board (as appropriate) 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.
Checklist requirements. 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 equal 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 environs. This
description should include a discussion of soil conditions, slopes,
wetlands, waterways and vegetation on the site. Particular attention
should be given to unique, unusual, or environmentally sensitive features
and to those that provide particular opportunities or constraints
for development.
(3)
Project description and site plan(s). A map (or maps) at the scale
of the topographical base map indicating the location of existing
and proposed buildings, roads, parking areas, utilities, structural
facilities for stormwater management and sediment control, and other
permanent structures. The map(s) shall also clearly show areas where
alterations 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 of proposed
changes in natural conditions may also be provided.
(4)
Land use planning and source control plan. This plan shall provide a demonstration of how the goals and standards of Subsection C(3) through C(6) are being met. The focus of this plan shall be to describe how the site is being developed to meet the objective of controlling groundwater recharge, stormwater quality and stormwater quantity problems at the source by land management and source controls whenever possible.
(5)
Stormwater management facilities map. The following information,
illustrated on a map of the same scale as the topographic base map,
shall be included:
(a)
Total area to be 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 § 253-4 of this chapter.
(b)
When the proposed stormwater management control measures (e.g.,
infiltration basins) depends on the hydrologic properties of soils,
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 § 253-10.
(8)
Waiver from submission requirements. The municipal official or board reviewing an application under this chapter may, in consultation with the municipal engineer, waive submission of any of the requirements in Subsection C(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.
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). Maintenance guidelines for stormwater
management measures are available in the New Jersey Stormwater Best
Management Practices Manual. If the maintenance plan identifies a
person other than the developer (for example, a public agency or homeowners'
association) as having the responsibility for maintenance, the plan
shall include documentation of such person's agreement to assume
this responsibility, or of the developer's obligation to dedicate
a stormwater management facility to such person under an applicable
ordinance or regulation.
(3)
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.
(4)
If the person responsible for maintenance identified under Subsection B(2) 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.
(5)
Preventative and corrective maintenance shall be performed to maintain
the function of the stormwater management measure, including 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.
(6)
The person responsible for maintenance identified under Subsection B(2) above shall 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.
(7)
The person responsible for maintenance identified under Subsection B(2) above shall evaluate the effectiveness of the maintenance plan at least once per year and adjust the plan and the deed as needed.
(8)
The person responsible for maintenance identified under Subsection B(2) above shall 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 Subsections B(6) and B(7) above.
(10)
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.
C.
Nothing in this section 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.
Any person who erects, constructs, alters, repairs, converts,
maintains, or uses any building, structure or land in violation of
this chapter shall be subject to the following penalties:
This chapter shall take effect immediately upon the approval
by the county review agency, or 60 days from the receipt of the ordinance
by the county review agency if the county review agency should fail
to act.
