[HISTORY: Adopted by the Borough Council
of the Borough of Hampton 4-10-2006 by Ord. No. 4-06. Amendments noted where
applicable.]
A.
Policy statement. Stormwater management is the process
of minimizing stormwater runoff and directing stormwater appropriate
nonstructural and structural stormwater management measures so as
to control flooding, recharge groundwater and reduce pollution of
water resources. Transport of stormwater-related pollutants into local
surface and ground waters can result in: the destruction of fish,
wildlife, and habitats; threats to public health due to contaminated
food and drinking water supplies; and losses of recreational and aesthetic
values. Stormwater management shall occur with the understanding and
acceptance of stormwater as a resource; low-impact and nonstructural
measures shall be tailored to a site and applied wherever and to the
extent feasible.
B.
Purpose. The purpose of this chapter is to establish
minimum stormwater management requirements and controls for major
development and to reduce the amount of nonpoint source pollution
entering surface and ground waters. This chapter guides new development
in a manner that is proactive and minimizes harmful impacts to natural
resources. Specifically, this chapter shall:
(1)
Reduce artificially induced flood damage to public
health, life, and property;
(2)
Minimize increased stormwater runoff rates and volumes;
(3)
Minimize the deterioration of existing structures
that would result from increased rates of stormwater runoff;
(4)
Induce water recharge into the ground wherever suitable
infiltration, soil permeability, and favorable geological conditions
exist;
(5)
Prevent an increase in nonpoint source pollution;
(6)
Maintain the integrity and stability of stream channels
and buffers for their ecological functions, as well as for drainage,
the conveyance of floodwater, and other purposes;
(7)
Control and minimize soil erosion and the transport
of sediment;
(8)
Minimize public safety hazards at any stormwater detention
facility constructed pursuant to subdivision or site plan approval;
(9)
Maintain adequate baseflow and natural flow regimes
in all streams and other surface water bodies to protect the aquatic
ecosystem;
(10)
Protect all surface water resources from degradation;
and
(11)
Protect groundwater resources from degradation
and diminution.
C.
Applicability.
(1)
This chapter shall be applicable to all site plans
and subdivisions for the following major developments that require
preliminary or final site plan or subdivision review:
(a)
Nonresidential major developments; and
(b)
Aspects of residential major developments that
are not preempted by the Residential Site Improvement Standards (RSIS)
at N.J.A.C. 5:21. The provisions of both this chapter and the RSIS
are to be applied and reviewed concurrently for any residential major
development.
(c)
In the case of agricultural or horticultural
development that meets the definition of "major development" under
N.J.A.C. 7:8, a farm conservation plan that addresses the protection
of soil and water resources shall be developed and implemented. Such
a plan shall be approved by the Hunterdon County Soil Conservation
District.
(2)
This chapter shall also be applicable to all major
developments undertaken by the Borough of Hampton.
(3)
This chapter does not apply to activities of Hunterdon
County, the State of New Jersey and the government of the United States
of America when those activities are specifically exempted from municipal
regulation by relevant state or federal law.
D.
Compatibility with other permit and ordinance 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 shall be construed to assure consistency with the requirements
of New Jersey laws and acts amendatory thereof or supplementary thereto,
applicable implementing regulations, and any existing or future municipal
NJPDES permits and any amendments or revisions thereto or reissuance
thereof. This chapter is not intended to interfere with, abrogate,
or annul any other ordinance, rule or regulation, statute, or other
provision of law. Where any provision of this chapter imposes restrictions
different from those imposed by any other ordinance, rule or regulation,
or other provision of law, whichever provisions are more restrictive
or impose 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. Where common definitions exist, 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.
- AGRICULTURE or HORTICULTURE or AGRICULTURAL OR HORTICULTURAL USE
- The use of the land for common farm-site activities, including but not limited to production, harvesting, storage, grading, packaging, processing and the wholesale and retail marketing of crops, plants, animals and other related commodities and the use and application of techniques and methods of soil preparation and management, fertilization, weed, disease and pest control, disposal of farm waste, irrigation, drainage, and water management, and grazing.
- AGRICULTURAL OR HORTICULTURAL DEVELOPMENT
- Construction for the purposes of supporting common farm-site activities, including but not limited to: the production, harvesting, storage, grading, packaging, processing, and the wholesale and retail marketing of crops, plants, animals, and other related commodities and the use and application of techniques and methods of soil preparation and management, fertilization, weed, disease, and pest control, disposal of farm waste, irrigation, drainage and water management, and grazing.
- BMP
- Best management practices as contained in the New Jersey Stormwater Best Management Practices Manual dated April 2004 and as updated, available from www.njstormwater.com.
- CATEGORY 1 (C1) WATERS
- Waters of the state, including unnamed waterways that appear on soil survey and USGS Topographic Quadrangle within the same HUC 14 watershed, designated in N.J.A.C. 7:9B-1.15(c) through (h) for purposes of implementing the antidegradation policies set forth at N.J.A.C. 7:9B-1.5(d) for protection from measurable changes in water quality characteristics because of their clarity, color, scenic setting, other characteristics of aesthetic value, exceptional ecological significance, exceptional recreational significance, exceptional water supply significance, or exceptional fisheries resources(s).
- COMPACTION
- The increase in soil bulk density caused by subjecting soil to greater-than normal loading. Compaction can also decrease soil infiltration and permeability rates.
- CORE
- A pedestrian-oriented area of commercial and civic uses serving the surrounding municipality, generally including housing and access to public transportation.
- COUNTY REVIEW AGENCY
- The Hunterdon County Planning Board, as designated by the County Board of Chosen Freeholders to review municipal stormwater management plans and implementing ordinance(s).
- DEPARTMENT
- The New Jersey Department of Environmental Protection.
- DESIGNATED CENTER
- A State Development and Redevelopment Plan Center, such as urban, regional, town, village, or hamlet, as designated by the State Planning Commission.
- DESIGN ENGINEER
- 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.
- DEVELOPMENT
- 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.
- DISTURBANCE
- Any activity, including the clearing, excavating, storing, grading, filling or transportation of soil or any other activity, that causes soil to be exposed to the danger of erosion.
- DRAINAGE AREA
- 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.
- ENVIRONMENTALLY CRITICAL AREA
- 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; wellhead protection areas; and groundwater recharge areas. Habitats of endangered or threatened species are those identified by the Department's Landscape Project as approved by the Department's Endangered and Nongame Species Program, or by the Department pursuant to the Highlands Act at N.J.S.A. 13:20-32k and 13:20-34a(4).
- EROSION
- The detachment and movement of soil or rock fragments by water, wind, ice or gravity.
- GROUNDWATER
- A body of water below the surface of the land in a zone of saturation where the spaces between the soil or geological materials are fully saturated with water.
- HIGHLANDS ACT
- The Highlands Water Protection and Planning Act, P.L. 2004, c.120, codified at N.J.S.A. 13:20-1 et seq., as amended.
- HUC-14
- A watershed as defined by the United States Geological Survey, with a fourteen-digit identifier; a subwatershed.
- IMPERVIOUS SURFACE
- A surface that has been covered with a layer of material so that it is highly resistant to infiltration by water relative to natural conditions in the area.
- INFILTRATION
- The process by which water from precipitation seeps into the soil to a level below the normal root soil of plant species.
- KARST TERRAIN
- An area where karst topography, with its characteristic surface and subterranean features, is developed as a result of the dissolution of limestone, dolomite, or other soluble rock. Characteristic physiographic features present in karst terrains include but are not limited to sinkholes, sinking streams, caves, blind valleys, large springs and subterranean drainage. See also "limestone area."
- LIMESTONE AREA
- An area of Hunterdon County underlain by carbonate sedimentary rock consisting chiefly of calcium carbonate. Limestone is commonly used as a general term for the class of rocks that consist of at least 80% calcium or magnesium carbonate. See also "karst terrain."
- LOW-IMPACT DEVELOPMENT (LID)
- Methods incorporating design measures to replicate predevelopment hydrology to reduce the impacts of development at a lot-level basis, treating rainwater where it falls by creating conditions that allow the water to infiltrate back into the ground. LID emphasizes greater infiltration of stormwater on site rather than regarding the stormwater as a nuisance condition and disposable.
- MAINTENANCE PLAN
- A document required for all major development projects for stormwater management maintenance. The document shall contain specific preventive 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 preventive and corrective maintenance (including replacement).
- MAJOR DEVELOPMENT
- Any development that provides for ultimately disturbing one or more acres of land or would create 1/4 acre or more of impervious surface.
- MAXIMUM EXTENT PRACTICABLE
- Compliance with the specific objective to the greatest extent possible taking into account equitable considerations and competing factors, including but not limited to, environmental benefits, pollutant removal effectiveness, regulatory compliance, ability to implement given site-specific environmental conditions, cost and technical or engineering feasibility.
- MITIGATION
- An action by an applicant providing compensation or offset actions for on-site stormwater management requirements where the applicant has demonstrated the inability or impracticality of strict compliance with the stormwater management requirements set forth in N.J.A.C. 7:8, in an adopted regional stormwater management plan, or in this local ordinance, and has received a waiver from strict compliance from the municipality. Mitigation, for the purposes of this chapter, includes both the mitigation plan detailing how the project's failure to strictly comply will be compensated, and the implementation of the approved mitigation plan within the same HUC-14 within which the subject project is proposed (if possible and practical), or a contribution of funding toward a regional stormwater control project, or provision for equivalent treatment at an alternate location, or other equivalent water quality benefit.
- MUNICIPALITY
- Any city, Borough, town, township, or village.
- NODE
- An area designated by the State Planning Commission concentrating facilities and activities that are not organized in a compact form.
- NONSTRUCTURAL STORMWATER MANAGEMENT TECHNIQUES
- Techniques that control or reduce stormwater runoff in the absence of stormwater structures (e.g., basins and piped conveyances), such as minimizing site disturbance, preserving important site features, including but not limited to natural vegetation, reducing and disconnecting impervious cover, minimizing slopes, utilizing native vegetation, minimizing turf grass lawns, increasing time of concentration and maintaining and enhancing natural drainage features and characteristics.
- NUTRIENT
- A chemical element or compound, such as nitrogen or phosphorus, which is essential to and promotes the development of plants, algae and other organisms or vegetation.
- NUTRIENT LOAD
- The total amount of a nutrient such as nitrogen or phosphorus entering the water during a given time, such as "tons of nitrogen per year" or "pounds of phosphorus per day." Nutrients may enter the water from runoff, groundwater recharge, point-source discharges, or the air (in the form of wet deposition such as rain or snow as well as dry deposition).
- NUTRIENT CONCENTRATION
- The amount of a nutrient in a defined volume of water (such as milligrams of nitrogen per liter). The relationship between nutrient concentration and nutrient load can vary and depends on the surface water flow, the volume of water in the water body or aquifer, and watershed characteristics.
- PERMEABLE
- A surface or land cover capable of transmitting or percolating a significant amount of precipitation into the underlying soils.
- PERSON
- Any individual, corporation, company, partnership, firm, association, the Borough of Hampton, 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.
- POLLUTANT
- 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.
- POLLUTION
- The man-made or man-induced alteration of the chemical, physical, biological, and radiological integrity of water to the extent that the pollutant concentration or level violates either the Groundwater Quality Standards (N.J.A.C. 7:9-6) or the Surface Water Quality Standards (N.J.A.C. 7:9B) of New Jersey.
- RECHARGE
- The amount of water from precipitation that infiltrates into the ground and becomes part of a groundwater body.
- REVIEW AGENCY (MUNICIPAL)
- The municipal body or official that is responsible for the review of a major development project for compliance with the stormwater management requirements.
- SEDIMENT
- Solid material, mineral or organic, that is in suspension and is being transported or has been moved from its site of origin by air, water or gravity as a product of erosion.
- SITE
- The lot or lots upon which a major development is to occur or has occurred.
- SOIL
- All unconsolidated mineral and organic material of any origin.
- SOLID AND FLOATABLE MATERIALS
- Sediment, debris, trash, and other floating, suspended, or settleable solids.
- SOURCE MATERIAL
- Any material(s) or machinery, located at an industrial facility, that is directly or indirectly related to process, manufacturing, or other industrial activities, that could be a source of pollutants in any industrial stormwater discharge to ground or surface water. 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.
- SPECIAL RESOURCE WATERS
- Water bodies receiving special protections due to their drinking water status or role as high-quality habitat for threatened and endangered species or species of commercial or recreational importance. This includes waterways so designated through the New Jersey Stormwater Management Rules (N.J.A.C. 7:8) because of exceptional ecological significance, exceptional water supply significance, exceptional recreational significance, exceptional shellfish resource, or exceptional fisheries resource. Waters so designated are protected by a three-hundred-foot buffer extending on either side of the waterway measured perpendicular from top-of-bank or center of channel for waterways lacking a defined top-of-bank.
- STATE DEVELOPMENT AND REDEVELOPMENT PLAN METROPOLITAN PLANNING AREA (PA1)
- 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.
- STATE PLAN POLICY MAP
- The geographic application of the State Development and Redevelopment Plan's goals and statewide policies, and the official map of these goals and policies.
- STORMWATER
- 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.
- STORMWATER RUNOFF
- The flow of stormwater on or across the surface of the ground, in drainage facilities or in storm sewers.
- STORMWATER MANAGEMENT BASIN
- 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 (a constructed stormwater wetland).
- STORMWATER MANAGEMENT MEASURE
- 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.
- STREAM BUFFER
- A strip of land located immediately adjacent to a stream channel consisting of natural, undisturbed vegetative cover, which serves as a transition area between uplands and riparian lands. A stream buffer may encompass wetlands, may be contained within a floodplain or floodway or may extend beyond a wetland, floodplain or floodway boundary.
- STRUCTURAL STORMWATER TECHNIQUES
- A stormwater management measure that involves control of concentrated stormwater runoff or infiltration, such as stormwater basins, piped conveyance systems and manufactured stormwater devices, and can include various types of basins, filters, surfaces, and devices located on individual lots in a residential development or throughout a commercial, industrial, or institutional development site in areas not typically suited for larger, centralized structural facilities.
- THREATENED AND ENDANGERED SPECIES
- Endangered species are those whose prospects for survival in New Jersey are in immediate danger because of a loss or change in habitat, overexploitation, predation, competition, disease, disturbance or contamination. Assistance is needed to prevent future extinction in New Jersey. Threatened species are those who may become endangered if conditions surrounding them begin to or continue to deteriorate. Habitats of endangered or threatened species are those identified by the Department's Landscape Project as approved by the Department's Endangered and Nongame Species Program, or by the Department pursuant to the Highlands Act at N.J.S.A. 13:20-32k and 13:20-34a(4).
- TIME OF CONCENTRATION
- The time it takes for stormwater runoff to travel from the hydraulically most distant point of the watershed to the point of interest within a watershed.
- TRANSITION AREA
- An area of protected upland adjacent to a freshwater wetland that minimizes adverse impacts on the wetland or serves as an integral component of the wetlands ecosystem. Also called "buffer" area.
- URBAN REDEVELOPMENT AREA
- Previously developed portions of areas delineated on the State Plan Policy Map (SPPM) as the Metropolitan Planning Area (PA1), Designated Centers, Cores or Nodes.
- WATERS OF THE STATE
- 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.
- WETLANDS or WETLAND
- An area that is inundated or saturated by surface water or groundwater at a frequency and duration sufficient to support, and that under normal circumstances does support, a prevalence of vegetation typically adapted for life in saturated soil conditions, commonly known as hydrophytic vegetation.
A.
Design and performance standards for stormwater management
measures.
(1)
Stormwater management measures for major development shall be designed to meet the erosion control, groundwater recharge, and stormwater runoff quantity and quality standards in § 207-4, as described in technical guidance documents listed in § 207-7. As detailed in § 207-4, 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 along with the practicable nonstructural strategies.
(2)
The standards in this chapter apply to both new major
development and redevelopment 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 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.
Nonstructural stormwater management strategies.
(1)
To the maximum extent practicable, the standards in Subsections B and C shall be met by incorporating nonstructural stormwater management strategies set forth in this subsection into the design. The applicant shall identify the nonstructural measures incorporated into the design of the project. Documentation of the use of nonstructural stormwater management measures shall require the preparation by the applicant of the NJDEP Low-Impact Development Checklist. If the applicant contends that it is not feasible for engineering, environmental, or safety reasons to incorporate any or only specific nonstructural stormwater management measures identified in Subsection A(2) below into the design of a particular project, the applicant shall identify the strategy or strategies considered and provide a basis for the contention. In both cases, the applicant bears the burden of proving any impracticability.
(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 the creation of new impervious surfaces
and reduce, break up or otherwise disconnect the flow of runoff over
impervious surfaces;
(c)
Maximize the protection of natural drainage
features and vegetation, except where native or natural vegetation
is considered invasive;
(d)
Minimize the decrease in the time of concentration
from preconstruction to postconstruction;
(e)
Minimize land clearing and disturbance and overall
site grading;
(f)
Minimize soil compaction;
(g)
Retain native, noninvasive vegetation, plant
low-maintenance landscaping, plant native vegetation, and minimize
the creation of lawns and the use of plantings and vegetation that
require the excessive use of fertilizers, pesticides and irrigation;
(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, exposure and/or mobilization of pollutants and prevent
or minimize the release and transport 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 A(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,
application of 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. Prior to applying fertilizer, soil
tests must be conducted on site to determine the type of fertilization
necessary.
(3)
Site design features identified under Subsection A(2)(i)[2] above shall comply with the following standard to control passage of solid and floatable materials through storm drain inlets. For exemptions to this standard see Subsection A(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 7.0 square inches,
or is no greater than 0.5 inches across the smallest dimension.
(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 C(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 C(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 B and C shall be:
(a)
Dedicated to a government agency;
(b)
Subjected to a conservation restriction filed
with the Hunterdon County Clerk's office; or
(c)
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.
B.
Erosion control, groundwater recharge and stormwater
runoff quantity control standards.
(1)
This subsection contains minimum design and performance
standards to control erosion, maintain groundwater recharge, and control
stormwater runoff quantity impacts of major development projects.
(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]
Using the criteria for calculating stormwater runoff and groundwater recharge in § 207-5B, the design engineer shall comply with at least one of the following standards:
[a]
Demonstrate through hydrologic and hydraulic
analysis that the postdeveloped project site maintains 100% of the
site's predeveloped average annual groundwater recharge volume; or
[b]
Demonstrate through hydrologic and hydraulic
analysis that any increase in the project site's projected stormwater
runoff volume produced by the two-year, twenty-four-hour storm from
predeveloped to postdeveloped conditions is fully infiltrated.
[2]
Groundwater recharge is not required at major development projects located within an "urban redevelopment area" as defined in § 207-2 or from those portions of major development projects that produce stormwater runoff described in Subsection B(1)(b)[3] below.
[3]
The following two types of stormwater runoff
shall not be recharged:
[a]
Stormwater runoff from areas of high pollutant
loading. High pollutant loading areas are:
[i]
Areas in industrial and commercial
developments where solvents and/or petroleum products are loaded/unloaded,
stored, or applied;
[ii]
Areas where pesticides are loaded/unloaded
or stored;
[iii]
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; and
[iv]
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]
Stormwater runoff from industrial areas exposed
to "source material."
[4]
The design engineer shall assess and certify
the hydraulic impact on the groundwater table and design the project
site and all site groundwater recharge measures so as to avoid adverse
hydraulic impacts. Adverse hydraulic impacts include, but are not
limited to, raising the groundwater table so as to cause surface ponding,
flooding of basements and other subsurface facilities, and interference
with the proper operation of subsurface sewage disposal systems and
other subsurface structures in the vicinity of a groundwater recharge
measure.
(c)
The minimum design and performance standards
for the control of stormwater runoff quantity are as follows:
[1]
Using the criteria for calculating stormwater runoff and groundwater recharge in § 207-5, the design engineer shall comply with at least one of the following standards:
[a]
Demonstrate through hydrologic and hydraulic
analysis that the postdeveloped stormwater runoff hydrographs from
the project site for the two-, ten-, and one-hundred-year storms do
not exceed, at any point in time, the site's predeveloped runoff hydrographs
for the same storms;
[b]
Demonstrate through hydrologic and hydraulic
analysis that under postdeveloped site conditions:
[i]
There is no increase in predeveloped
stormwater runoff rates from the project site for the two-, ten- and
one-hundred-year storms; and
[ii]
Any increased stormwater runoff
volume or change in stormwater runoff timing for these storms will
not increase flood damage at or downstream of the project site. When
performing this analysis for predeveloped site conditions, all off-site
development levels shall reflect existing conditions. When performing
this analysis for postdeveloped site conditions, all off-site development
levels shall reflect full development in accordance with current zoning
and land use ordinances.
[c]
Design on-site stormwater management measures
so that the peak postdeveloped stormwater runoff rates from the project
site for the two-, ten- and one-hundred-year storms are 50%, 75% and
80%, respectively, of the site's peak predeveloped stormwater runoff
rates. Peak stormwater outflow rates for these storms shall be adjusted
where necessary to account for the discharge of increased stormwater
runoff rates and/or volumes from project site areas not controlled
by the on-site measures. The percentages do not have to be applied
to those portions of the project site that are not proposed for development
at the time of application, provided that such areas are:
(2)
Any application for a new agricultural or horticultural development that meets the definition of major development in § 207-2 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.
C.
Stormwater runoff quality standards.
(1)
Stormwater management measures shall be designed to reduce by 80% the anticipated postconstruction load of total suspended solids (TSS) in stormwater runoff from the developed site, expressed as pounds per year. Stormwater management measures shall also be in conformance with § 207-4C(9)(c) of this chapter. Stormwater management measures shall only be required for water quality control if an additional 1/4 acre or more 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. Daily limits of TSS (TMDL) may apply to the site development based on conditions of regulatory approvals.
(2)
The water quality design storm shall be 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, subject to revision due to subsequent rule
changes. 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
|
(3)
For purposes of TSS reduction calculations, Table 2 below presents the presumed removal rates for certain BMPs designed, constructed and maintained in accordance with the New Jersey Stormwater Best Management Practices Manual, subject to revision due to subsequent rule changes. The current edition of the BMP Manual may be obtained from the address identified in § 207-7, or found on the Department's Web site at www.njstormwater.org. The BMP Manual and other sources of technical guidance are listed in § 207-7. TSS reduction shall be calculated based on the removal rates for the BMPs in Table 2 below. Alternative BMPs, removal rates and methods of calculating removal rates may be approved if the design engineer provides documentation demonstrating the capability of these alternative BMPs, removal rates and computational methods to the review agency. Documentation for alternative rates and methods shall consist of published (peer-reviewed) journal article or scientific paper. A copy of any approved alternative rate or method of calculating the removal rate, including documentation, shall be provided to the Department at the following address: Division of Watershed Management, New Jersey Department of Environmental Protection, PO Box 418, Trenton, New Jersey, 08625-0418.
(4)
If more than one BMP in series is necessary to achieve
the required eighty-percent 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 (expressed as
a whole number) from application of both BMPs, and
| |
A =
|
the TSS percent removal rate (whole number)
applicable to the first (upstream) BMP
| |
B =
|
the TSS percent removal rate (whole number)
applicable to the second (downstream) BMP
| |
In cases where three (or more) BMPs are used
in series, the applicant shall calculate the TSS reduction for the
two most upstream BMPs in the series using the above formula, then
substitute the result (R) of that calculation in the formula for "A"
when calculating the combined result with the next BMP in the series.
|
Table 2: TSS Removal Rates for BMPs
(Source: New Jersey Stormwater
Best Management Practices Manual)
| ||
---|---|---|
Best Management Practice
|
TSS Percent Removal Rate
| |
Bioretention systems
|
90
| |
Wetland
|
90
| |
Extended detention basin
|
40-60
| |
Infiltration structure
|
80
| |
Manufactured treatment device
|
See § 207-6C
| |
Sand filter
|
80
| |
Vegetative filter strip
|
60-80
| |
Wet pond
|
50-90
|
(5)
If there is more than one on-site drainage area, the
eighty-percent TSS removal rate shall apply to the discharge of each
drainage subarea, unless the runoff from the subareas converge on
site, in which case the removal rate can be demonstrated through a
calculation using an area-weighted average.
(6)
Stormwater management measures shall also be designed to reduce, to the maximum extent practicable, the postconstruction nutrient load from the developed site in stormwater runoff generated from the water quality design storm. In achieving reduction of nutrients to the maximum extent practicable, the design of the site shall include nonstructural strategies and structural measures that optimize nutrient removal while still achieving the performance standards in Subsections B and C. This standard may be superseded by a more stringent numeric effluent limitation 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. Daily limits for nutrient loading (TMDL) may apply to the site development based on conditions of regulatory approvals.
(7)
Additional information and examples are contained in the New Jersey Stormwater Best Management Practices Manual, which may be obtained from the address identified in § 207-7.
(8)
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 and any new stormwater discharge
point to waters classified as FW1.
(9)
Special water resource protection areas shall be established
along all waters designated Category One at N.J.A.C. 7:9B, and along
all 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 HUC-14 drainage
area. Other authoritative sources of stream delineation may be utilized,
such as a delineation that is part of the municipal or regional stormwater
management plan or a stream delineation overlay prepared by the Department.
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, unless superseded by a local stream corridor protection
ordinance:
[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 C(9)(a)[1] above shall only be allowed where previous development or disturbance has occurred (for example, preexisting active agricultural use, parking area or maintained lawn area). The encroachment shall only be allowed where the applicant demonstrates to the satisfaction of the review agency 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 subparagraph 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 discharges allowed by this section
shall achieve a ninety-five-percent TSS postconstruction removal rate;
[3]
Thermal pollution by stormwater discharges shall
be addressed to ensure no significant increase or decrease in temperature
occurs in the receiving waterway outside of the mixing zone;
[4]
The encroachment shall only be allowed where
the applicant demonstrates to the satisfaction of the review agency
that the ecological value and 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 reviewed and approved by the Department prior to approval
by the review agency.
(d)
A stream corridor protection plan for a waterway subject to Subsection C(9) shall maintain or enhance the current ecological value and condition of the special water resource protection area as defined in Subsection C(9)(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.
(e)
Subsection C(9) does not apply to the construction of one individual single-family dwelling that is not part of a larger development and is on a lot receiving preliminary or final subdivision approval on or before February 2, 2004, provided that the construction begins on or before February 2, 2009.
D.
Maintenance plan. The development shall incorporate a maintenance plan for the stormwater management measures incorporated into the design of a major development in accordance with § 207-10.
E.
Exemptions. The following linear development projects are exempt from the groundwater recharge, stormwater runoff quantity, and stormwater runoff quality requirements of § 207-4B and C:
F.
Waivers from strict compliance.
(1)
A waiver from strict compliance with the groundwater recharge, stormwater runoff quantity, and stormwater runoff quality requirements of § 207-4B and C 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:
(a)
The applicant demonstrates that there is a public
need for the project that cannot be accomplished by any other means;
(d)
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 F(1)(c) above within the upstream drainage area of the receiving stream, that would provide additional opportunities to mitigate the requirements of § 207-4B and C that were not achievable on site.
(2)
A waiver from strict compliance with the requirements of § 207-4B and C may be issued in those cases where an applicant has demonstrated the inability or impracticality of strict compliance, other than projects addressed under Subsection F(1), with the stormwater management requirements set forth in N.J.A.C. 7:8, in an adopted regional stormwater management plan, or in a local ordinance which is as strict as N.J.A.C. 7:8. A waiver from strict compliance for such projects can only be obtained if the applicant agrees to undertake a suitable mitigation measure identified in the mitigation section of the municipality's stormwater management plan. In such cases, the applicant must submit a mitigation plan detailing how the project's failure to strictly comply will be compensated. In cases where a waiver is granted, an applicant should provide mitigation, if possible and/or practical within the same HUC-14 watershed within which the subject project is proposed, or contribute funding toward a regional stormwater control project, or provide for equivalent treatment at an alternate location, or other equivalent water quality benefit, in lieu of implementing the required stormwater control measures on their specific site.
G.
Threatened and endangered species. When habitat for threatened and endangered species (see definition for "environmental critical areas" in § 207-2), is present on a site, stormwater management measures shall be implemented to avoid adverse impacts caused by pollutant discharge, the creation of concentrated flow, or the alteration of recharge.
A.
Stormwater runoff calculations.
(1)
In complying with the design and performance standards in § 207-4, the design engineer shall calculate stormwater runoff using one of the following methods:
(a)
The USDA Natural Resources Conservation Service
(NRCS) methodology, including the NRCS Runoff Equation, NRCS Dimensionless
Unit Hydrograph, and appropriate NRCS twenty-four-hour design storm,
as described in the current NRCS National Engineering Handbook Part
630 - Hydrology, and the current Technical Release 55 - Urban Hydrology
for Small Watersheds or superseding document; or
(b)
The Rational Method for peak stormwater runoff
rate calculations and the Modified Rational Method for stormwater
runoff hydrograph calculations. Use of the Rational Method and Modified
Rational Method are limited to drainage areas of 20 acres or less.
Neither the Rational Method nor Modified Rational Method shall be
used to calculate runoff volumes for groundwater recharge or stormwater
runoff infiltration purposes.
(2)
When selecting or calculating runoff coefficients
for predeveloped project site conditions using any of the above methods,
the project site's land cover shall be assumed to be woods. However,
another land cover may be used to calculate runoff coefficients if:
(a)
Such land cover has existed at the site or portion
of the site without interruption for at least five years immediately
prior to the time of application; and
(b)
The design engineer can document the character
and extent of such land cover through the use of photographs, affidavits,
and/or other acceptable land use records. If more than one land cover
other than woods has existed on the site during the five years immediately
prior to the time of application, the land cover with the lowest runoff
potential (including woods) shall be used for the computations. All
predeveloped land covers shall be assumed to be in good hydrologic
condition and, if cultivated, shall be assumed to have applied appropriate
conservation practices.
(3)
In calculating predeveloped site stormwater runoff,
the design engineer shall include the effects of all land features
and structures, such as ponds, wetlands, depressions, hedgerows and
culverts, that reduce predeveloped site stormwater runoff rates and/or
volumes.
(4)
In calculating stormwater runoff using the NRCS methodology,
the design engineer shall use appropriate twenty-four-hour rainfall
depths as developed for the project site by the National Oceanic and
Atmospheric Administration.
(5)
In calculating stormwater runoff using the NRCS methodology,
the design engineer shall separately calculate and then combine the
runoff volumes from pervious and directly connected impervious surfaces
within a drainage area.
(6)
Calculation of stormwater runoff from unconnected
impervious surfaces shall be based, as applicable, upon the two-step
methodology as described in the Department's current Stormwater Best
Management Practices Manual or the NRCS methodology described in the
current Technical Release 55 - Urban Hydrology for Small Watersheds.
B.
Groundwater recharge calculations.
(1)
In complying with the design and performance standards in § 207-4, the design engineer may calculate groundwater recharge in accordance with the New Jersey Groundwater Recharge Spreadsheet (NJGRS) computer program as described in the Department's current Stormwater Best Management Practices Manual. Alternative groundwater recharge calculation methods may be used upon approval by the Municipal Engineer.
(2)
In complying with the design and performance standards in § 207-4, the design engineer shall calculate stormwater runoff infiltration volumes in accordance with the USDA Natural Resources Conservation Service (NRCS) methodology, including the NRCS Runoff Equation, as described in the current NRCS National Engineering Handbook, Part 630 - Hydrology, and the current Technical Release 55 - Urban Hydrology for Small Watersheds. In addition, the design engineer shall use appropriate two-year, twenty-four-hour rainfall depths as developed for the project site by the National Oceanic and Atmospheric Administration.
(3)
When selecting or calculating runoff coefficients
for predeveloped project site conditions for groundwater recharge
or stormwater runoff infiltration calculations, the project site's
land cover shall be assumed to be woods. However, another land cover
may be used to calculate runoff coefficients if:
(a)
Such land cover has existed at the site or portion
of the site without interruption for at least five years immediately
prior to the time of application; and
(b)
The design engineer can document the character
and extent of such land cover through the use of photographs, affidavits,
and/or other acceptable land use records. If more than one land cover
other than woods has existed on the site during the five years immediately
prior to the time of application, the land cover with the lowest runoff
potential (including woods) shall be used for the computations. All
predeveloped land covers shall be assumed to be in good hydrologic
condition and, if cultivated, shall be assumed to have conservation
treatment.
A.
Structural management measures. Standards for structural
stormwater management measures are as follows:
(1)
Structural stormwater management measures shall be
designed to factor into the design the existing site conditions which
may cause the measure to fail, have an adverse effect on water quality
or quantity, or cause harm or damage to persons or property, 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; existing or former
mines; significant land filling; and the presence of solution-prone
carbonate rocks (limestone) and related Karst topography.
(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 § 207-8B.
(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,
7.4, and 7.5 shall be deemed to meet this requirement. The measures
are to be sequenced in the site development process so that erosion
control standards are met and so the measure is not compromised or
impaired by construction runoff.
(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.
(5)
Stormwater management basins shall be designed to meet the minimum safety standards for stormwater management basins at § 207-8.
(6)
Where tailwater will affect the hydraulic performance
of a stormwater management measure, the design engineer shall include
such effects in the measure's design.
B.
Guidelines for management measures. Stormwater management measure guidelines are available in the New Jersey Stormwater Best Management Practices Manual and other documents as described in § 207-7. Other stormwater management measures may be utilized, provided the design engineer demonstrates to the satisfaction of the review agency that the proposed measure and its design will accomplish the required water quantity, groundwater recharge and water quality design and performance standards established by § 207-4 of this chapter.
C.
Manufactured treatment devices.
(1)
Manufactured treatment devices may be used to meet the requirements of § 207-4 of this chapter, provided the pollutant removal rates are verified by the New Jersey Corporation for Advanced Technology and certified by the Department.
(2)
Nonverified manufactured treatment devices may also
be used for purposes other than underground discharge of stormwater,
where such devices provide a clear benefit to stormwater quality or
flow control in a manner that facilitates improved nonstructural stormwater
management controls on the site or avoids the need for approval of
off-site mitigation. The benefits of proposed nonverified manufactured
treatment devices must be proved to the satisfaction of the review
agency.
(3)
Manufactured treatment devices may be used only where the maintenance plan required by § 207-10 ensures that the manufactured device will be properly maintained for its functional lifespan and will be replaced as needed with management measures that are at least as effective as the original manufactured treatment device working in accordance with manufacturers' specifications.
A.
Primary technical guidance. 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. This document is also available at www.njstormwater.org.
(2)
The New Jersey Department of Environmental Protection
Stormwater Management Facilities Maintenance Manual (NJDEP Ocean County
Demonstration Study, Stormwater Management Facilities Maintenance
Manual, dated June 1989), as amended.
B.
Additional technical guidance. 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, P.O.
Box 330, Trenton, New Jersey 08625; (609) 292-5540, or the Hunterdon
County Soil Conservation District, 687 Pittstown Road, Suite 1, Frenchtown,
New Jersey 08825, (908) 788-1397.
(2)
The Rutgers Cooperative Extension Service, (732) 932-9306.
(3)
The Hunterdon County Soil Conservation District, 687
Pittstown Road, Suite 1, Frenchtown, New Jersey 08825, (908) 788-1397.
(4)
The United States Environmental Protection Agency,
including the National Management Measures to Control Nonpoint Source
Pollution from Urban Areas, available at the Web site: http://www.epa.gov/owow/nps/urbanmm/index.html.
(5)
Field guides of the United States Department of Agriculture, Natural Resources Conservation Service, where supplemental to and not conflicting with a source of primary guidance in § 207-7A.
(6)
Other similarly authoritative governmental or trade
association sources acceptable to the municipality.
A.
General scope. 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 intended to intercept runoff-borne
trash and debris that might otherwise block the hydraulic openings
in the outlet structure of a structural stormwater management measure.
Trash racks shall be installed upstream of such outlet structure openings
to ensure proper functioning of the structural stormwater management
measure in accordance with the following:
(a)
The trash rack should be constructed primarily
of bars aligned in the direction of flow with a maximum bar spacing
of approximately 1/2 the diameter or width of the hydraulic opening
it is protecting. Transverse bars aligned perpendicular to flow should
be sized and spaced as necessary for rack stability and strength.
(b)
The trash rack shall not adversely affect the
hydraulic performance of either the outlet structure opening it is
protecting or the overall outlet structure.
(c)
The trash rack shall have sufficient net open
area under clean conditions to limit the peak design storm velocity
through it to a maximum of 2.5 feet per second.
(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 square
foot.
(2)
An overflow grate is a device intended to protect
the opening in the top of a stormwater management measure outlet 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 more
than two inches across the smallest dimension;
(c)
The overflow grate shall be constructed and
installed to be rigid, durable, and corrosion resistant and shall
be designed to withstand a perpendicular live loading of 300 pounds
per square foot.
(3)
Structural stormwater management measures shall include
escape provisions as follows:
(a)
If a structural stormwater management measure
has an outlet structure, escape provisions shall be incorporated in
or on the structure. Escape provisions means the permanent installation
of ladders, steps, rungs, or other features that provide readily accessible
means of ingress and egress from the outlet structure.
(b)
Safety ledges shall be constructed on the slopes of all new structural stormwater management measures 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 § 207-8D for an illustration of safety ledges in a stormwater management basin.
(c)
In new stormwater management basins, the maximum
slope of the interior and exterior of an earthen dam, embankment,
or berm shall not be steeper than five horizontal to one vertical
in accordance with N.J.A.C. 7:8-6(c)3.
(d)
An emergency drawdown method for detention basins
is required where the permanent pool will be more than 2 1/2
feet deep. This drawdown method must consider downstream or off site
stability at the outfall in accordance with the Standards for Soil
Erosion and Sediment Control in New Jersey.
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.
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 § 207-9C below as part of the submission of the applicant's application for subdivision or site plan approval.
(2)
The applicant shall demonstrate through submission
requirements 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 (the review agency). That review
agency 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.
Submission requirements. The information in Subsections C(1) through C(7) below shall be provided unless a waiver is approved through Subsection C(8) below:
(1)
Existing site conditions base map, including topography,
streams, roads and current built environment. 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 300 feet beyond the limits of the proposed
development, at a scale appropriate to show site details, showing
two-foot contour intervals.
(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 critical
areas and to those that provide particular opportunities or constraints
for development.
(3)
Project description and site plan(s). A map (or maps)
at a scale appropriate for the site 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)
Stormwater site planning and design summary. This plan shall provide a demonstration of how the goals and standards of §§ 207-3 through 207-6 are being met, including both nonstructural and structural approaches. The focus of this plan shall be to describe how the site is being managed or 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. Refer to the municipal stormwater management plan and/or the municipal stormwater pollution prevention plan for additional requirements. It should explain in full the maps required by this section.
(5)
Stormwater management facilities map(s). The following
information, illustrated on a map at a scale appropriate for the site,
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, land area to remain
in natural vegetation, and details of the proposed plan to infiltrate,
manage, 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 and discharge stability calculations for the predevelopment and postdevelopment conditions for the design storms specified in § 207-4 of this chapter.
(b)
When the proposed stormwater management control
measures (e.g., infiltration basins) depend 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. The municipality
shall be notified of site investigation activities and given the opportunity
to have a witness, either prior to approval or as a condition of approval,
as appropriate for the specific type of measure. Subsequent to approval
of the major development, postconstruction bulk soil density and infiltration
testing shall be required for all infiltration measures that were
used as justification for meeting the recharge standard, to ensure
that they were properly constructed.
(7)
Maintenance and repair plan. The design and planning of the stormwater management facility shall meet the maintenance requirements of § 207-10.
(8)
Waiver from submission requirements. The review agency may, in consultation with the Municipal Engineer, waive submission of any of the requirements in § 207-9C(1) through C(6) of this chapter when it can be demonstrated that the information requested is impossible to obtain or it would create a significant economic 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. This plan shall be separate from all other
documents and designed for ongoing use by the site owners or operators
in performing and documenting maintenance and repair, and by the municipality
in ensuring implementation of the maintenance plan. The final maintenance
plan shall be updated and provided to the municipality postconstruction
to include an evaluation based on the specifications of the initial
maintenance plan and as-built conditions.
(2)
The maintenance plan shall contain specific preventive maintenance tasks and schedules; cost estimates, including estimated cost of sediment, debris, or trash removal and disposal; safety needs; identification of methods and disposal sites for materials removed during maintenance; maintenance requirements for created wetlands and other ecological systems; safety devices and systems; warranty and operational standards from the manufacturers of any manufactured treatment devices (See § 207-6C); and the name, address, and telephone number of the person or persons responsible for preventive and corrective maintenance (including replacement), using maintenance guidelines for Stormwater management measures from § 207-7, the municipal stormwater management plan and any relevant regional stormwater management plan. If the maintenance plan identifies a person other than the developer (for example, a public agency or homeowners' association) as having the responsibility for continuing 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)
Preventive and corrective maintenance shall be performed
to maintain the function of the stormwater management measures, including
repairs or replacement to the structures; 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 preventive 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. The log shall be kept on site and be made available for inspection by any review agency having jurisdiction.
(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. Adjustments to the plan and/or deed must be submitted to the Township Committee for review and approval.
(8)
The person responsible for maintenance identified under Subsection B(2) above shall retain, submit annually to the municipality 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 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 a fine not exceeding $2,000, imprisonment
for a period not exceeding 90 days and/or a period of community service
not exceeding 90 days. After notification of violation, each day of
continuance thereof may, in the discretion of the court, be treated
as a separate and distinctive violation hereof.
A.
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 Hunterdon County Planning Board if the Hunterdon
County Planning Board, as county review agency, should fail to act.
B.
The Borough Clerk shall publish notice of the passage
of the ordinance after the public hearing and adoption, as well as
filing a copy of the ordinance as finally adopted with the Hunterdon
County Planning Board as required by N.J.S.A. 40:55D-16. In addition,
the Borough Clerk shall also transmit a copy of the Ordinance after
final passage to the Borough Tax Assessor as required by N.J.S.A.
40:49-2.1.
This chapter shall supersede all applicable
ordinances in conflict.