[HISTORY: Adopted by the Mayor and Borough
Council of the Borough of Gibbsboro 6-28-2006 by Ord. No. 2006-10. Amendments noted where applicable.]
[Amended 2-10-2021 by Ord. No. 2021-01]
A.
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. It is the purpose of this chapter to establish minimum stormwater management requirements and controls for major development, as defined in § 340-2 of this chapter.
B.
C.
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.
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 the
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.
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 a county planning agency; or
a county water resource association created under N.J.S.A. 58:16A-55.5,
if the ordinance or resolution delegates authority to approve, conditionally
approve, or disapprove municipal stormwater management plans and implementing
ordinances.
The New Jersey Department of Environmental Protection.
A State Development and Redevelopment Plan Center as designated
by the State Planning Commission such as urban, regional, town, village,
or hamlet.
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.
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.
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
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.
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.
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. "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, 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, the Borough of Gibbsboro, 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. § 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.
Is defined as 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.
Water flow on the surface of the ground or in storm sewers,
resulting from precipitation.
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.
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 or ground water, whether natural or artificial,
within the boundaries of the State of New Jersey or subject to its
jurisdiction.
An area that is inundated or saturated by surface water or
ground water at a frequency and duration sufficient to support, and
that under normal circumstances does support, a prevalence of vegetation
typically adapted for life in saturated soil conditions, commonly
known as "hydrophytic vegetation."
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 § 340-4. 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 § 340-10.
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
muhlnebergi (bog turtle).
C.
The following linear development projects are exempt from the groundwater recharge, stormwater runoff quantity, and stormwater runoff quality requirements of § 340-4F 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 § 340-4F 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 § 340-4F and G that were not achievable on site.
E.
Nonstructural stormwater management strategies.
(1)
To the maximum extent practicable, the standards in § 340-4F 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 preconstruction to postconstruction. "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 § 340-4E(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]
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
[2]
A different grate, if each individual clear
space in that grate has an area of no more than seven (7.0) square
inches, or is no greater than 0.5 inches 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 basin floors.
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(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 § 340-4G(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 § 340-4G(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 historic property listed in the New Jersey Register.
(4)
Any land area used as a nonstructural stormwater management measure to meet the performance standards in § 340-4F 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.
(5)
Guidance for nonstructural stormwater management strategies is available in the New Jersey Stormwater Best Management Practices Manual. The BMP Manual may be obtained from the address identified in § 340-7 or found on the Department's website at www.njstormwater.org.
(6)
Retrofitting
of storm drain inlets.
[Added 9-23-2009 by Ord. No. 2009-14]
(a)
Purpose. Requires the retrofitting of existing storm drain inlets
which are in direct contact with repaving, repairing, reconstruction,
or resurfacing or alterations of facilities on private property, to
prevent the discharge of solids and floatables (such as plastic bottles,
cans, food wrappers and other litter) to the municipal separate storm
sewer system(s) operated by the Borough of Gibbsboro so as to protect
public health, safety and welfare, and to prescribe penalties for
the failure to comply.
(b)
MUNICIPAL SEPARATE STORM SEWER SYSTEM (MS4)
PERSON
STORM DRAIN INLET
WATERS OF THE STATE
Definitions. For the purpose of this Subsection E(6), 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.
A conveyance or system of conveyances (including roads with
drainage systems, municipal streets, catch basins, curbs, gutters,
ditches, man-made channels, or storm drains) that is owned or operated
by the Borough of Gibbsboro or other public body, and is designed
and used for collecting and conveying stormwater.
Any individual, corporation, company, partnership, firm,
association, or political subdivision of this state subject to municipal
jurisdiction.
An opening in a storm drain used to collect stormwater runoff
and includes, but is not limited to, a grate inlet, curb-opening inlet,
slotted inlet, and combination inlet.
The ocean and its estuaries, all springs, streams and bodies
of surface- or groundwater, whether natural or artificial, within
the boundaries of the State of New Jersey or subject to its jurisdiction.
(c)
Prohibited conduct. No person in control of private property
(except a residential lot with one single-family house) shall authorize
the repaving, repairing (excluding the repair of individual potholes),
resurfacing (including top coating or chip sealing with asphalt emulsion
or a thin base of hot bitumen), reconstructing or altering any surface
that is in direct contact with an existing storm drain inlet on that
property unless the storm drain inlet either:
(d)
Design standard. Storm drain inlets identified in Subsection E(6)(b) 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(6)(d)[3] below.
[1]
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:
[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 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 basin
floors.
[2]
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.
[3]
This standard does not apply:
[a]
Where the municipal engineer agrees 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;
[b]
Where flows 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:
[c]
Where flows are conveyed through a trash rack that
has parallel bars with one-inch spacing between the bars; or
[d]
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.
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 § 340-5, 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
[b]
Demonstrate through hydrologic
and hydraulic analysis that the increase of stormwater runoff volume
from preconstruction to postconstruction 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 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 a 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 § 340-5, complete one of the following:
[1]
Demonstrate through hydrologic and hydraulic
analysis that for stormwater leaving the site, postconstruction runoff
hydrographs for the two- , ten- , and one-hundred-year storm events
do not exceed, at any point in time, the preconstruction runoff hydrographs
for the same storm events;
[2]
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 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; or
[3]
Design stormwater management measures so that
the postconstruction peak runoff rates for the two- , ten- and one-hundred-year
storm events are 50%, 75% and 80%, respectively, of the preconstruction
peak runoff rates. The percentages apply only to the postconstruction
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 postconstruction stormwater
runoff into tidal flood hazard areas if the increased volume of stormwater
runoff will not increase flood damages below the point of discharge.
(2)
Any application for a new agricultural development that meets the definition of major development at § 340-2 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 postconstruction 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.
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Table 1
Water Quality Design Storm Distribution
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|---|---|---|---|---|
|
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 § 340-7 or found on the Department's website at www.njstormwater.org. The BMP Manual and other sources of technical guidance are listed in § 340-7. 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 TSS reduction of 80% for a site, the applicant shall
utilize the following formula to calculate TSS reduction:
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R = A + B — (AXB)/100
|
|
Where:
| ||
|
R = total TSS percent load removal
from application of both BMPs.
| ||
|
A = the TSS percent removal rate
applicable to the first BMP.
| ||
|
B = the TSS percent removal rate
applicable to the second BMP.
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|
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 to 60
|
|
Infiltration structure
|
80
|
|
Manufactured treatment device
|
See § 340-6C.
|
|
Sand filter
|
80
|
|
Vegetative filter strip
|
60 to 80
|
|
Wet pond
|
50 to 90
|
(4)
If there is more than one on-site drainage area, the
eighty-percent 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 postconstruction 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 § 340-4F 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 § 340-7.
(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 three-hundred-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.
[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 TSS postconstruction removal rate
of 95%;
[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 § 340-4G(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 preconstruction 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 § 340-5A(1)(a) and the Rational and Modified Rational Methods at § 340-5A(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 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 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: 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 § 340-8D.
(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, 5:21-7.4, 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 that 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 § 340-4 of this chapter.
A.
Technical guidance for stormwater management measures can be found in the documents listed at Subsection A(1) and (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)4.
The location, address, and telephone number of each Soil Conservation
District may be obtained from the State Soil Conservation Committee,
P.O. Box 330, Trenton, New Jersey 08625; (609) 292-5540;
(2)
The Rutgers Cooperative Extension Service, 732-932-9306;
and
(3)
The Soil Conservation Districts listed in N.J.A.C.
2:90-1.3(a)4. The location, address, and telephone number of each
Soil Conservation District may be obtained from the State Soil Conservation
Committee, P.O. Box 330, Trenton, New Jersey 08625; (609) 292-5540.
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. Note: The provisions of this section are not intended to preempt more stringent municipal or county safety requirements for new or existing stormwater management basins. Municipal and county stormwater management plans and ordinances may, pursuant to their authority, require existing stormwater management basins to be retrofitted to meet one or more of the safety standards in Subsection B(1), (2), and (3) for trash racks, overflow grates, and escape provisions at outlet structures.
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 pounds per foot square.
(2)
An overflow grate is designed to prevent obstruction
of the overflow structure. If an outlet structure has an overflow
grate, such grate shall meet the following requirements:
(a)
The overflow grate shall be secured to the outlet
structure but removable for emergencies and maintenance.
(b)
The overflow grate spacing shall be no less
than two inches across the smallest dimension.
(c)
The overflow grate shall be constructed and
installed to be rigid, durable, and corrosion-resistant, and shall
be designed to withstand a perpendicular live loading of 300 pounds
per foot square.
(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 § 340-8C, 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 § 340-8D 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 Subsection C 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 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
environs must be submitted. This description should include a discussion
of soil conditions, slopes, wetlands, waterways and vegetation on
the site. Particular attention should be given to unique, unusual,
or environmentally sensitive features and to those that provide particular
opportunities or constraints for development.
(3)
Project description and site plan(s). A map (or maps)
at the scale of the topographical base map indicating the location
of existing and proposed buildings, roads, parking areas, utilities,
structural facilities for stormwater management and sediment control,
and other permanent structures. The map(s) shall also clearly show
areas where alterations 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 §§ 340-3 through 340-6 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 predevelopment and postdevelopment conditions for the design storms specified in § 340-4 of this chapter.
(b)
When the proposed stormwater management control
measures depends (e.g., infiltration basins) 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 § 340-10.
(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 § 340-9C(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.
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 Subsection B(6) and (7) above.
(9)
The requirements of Subsection B(3) and (4) do not apply to stormwater management facilities that are dedicated to and accepted by the municipality or another governmental agency.
(a)
The owners of stormwater management facilities,
which are privately owned, shall fund or otherwise guarantee the maintenance
and inspection program for a period of no less than 10 years. The
program shall identify the entity which is responsible for the requirements
for maintenance and action to be taken by the municipality for failure
of said maintenance, inspection process by the Borough and method
to finance the program.
(b)
The Borough shall reserve the right to require
the renewal of the program for a period of time determined by the
Borough.
(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 guaranty 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: 15% of
the construction cost; said cost is determined by the Borough Engineer.
