New Jersey Administrative Code › Title 5 - COMMUNITY AFFAIRS › Chapter 21 - RESIDENTIAL SITE IMPROVEMENT STANDARDS › Subchapter 7 - STORMWATER MANAGEMENT › Appendix B

Current through Register Vol. 56, No. 14, July 15, 2024
DEP Stormwater Management Rules Referenced in N.J.A.C. 5:21-7:
				  N.J.A.C. 7:8-5 and 6 and other Relevant Portions of the Stormwater Rules
Definitions of words and terms used in N.J.A.C. 7:8-5 and 6
"CAFRA Planning Map" means the geographic depiction of the
				  boundaries for Coastal Planning Areas, CAFRA Centers, CAFRA Cores and CAFRA Nodes
				  pursuant to N.J.A.C. 7:7E-5B.3.
"CAFRA Centers, Cores or Nodes" means those areas within
				  boundaries accepted by the Department pursuant to N.J.A.C. 7:8E-5B.
"Compaction" means the increase in soil bulk density.
"Core" means a pedestrian-oriented area of commercial and civic
				  uses serving the surrounding municipality, generally including housing and access to
				  public transportation.
"Department" means the Department of Environmental
				  Protection.
"Designated Center" means a State Development and Redevelopment
				  Plan Center as designated by the State Planning Commission such as urban, regional,
				  town, village, or hamlet.
"Design engineer" means 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" means the division of a parcel of land into two or
				  more parcels, the construction, reconstruction, conversion, structural alteration,
				  relocation or enlargement of any building or structure, any mining excavation or
				  landfill, and any use or change in the use of any building or other structure, or
				  land or extension of use of land, for which permission is required under the
				  Municipal Land Use Law,
				  N.J.S.A. 40:55D-1 et
				  seq.
In the case of development on agricultural land, development
				  means: any activity that requires a State permit; any activity reviewed by the
				  County Agricultural Boards (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.
"Drainage area" means a geographic area within which stormwater
				  runoff, sediments, or dissolved materials drain to a particular receiving waterbody
				  or to a particular point along a receiving waterbody.
"Environmentally critical area" means an area or feature which is
				  of significant environmental value, including, but not limited to: stream corridors;
				  natural heritage priority sites; habitats of endangered or threatened species; large
				  areas of contiguous open space or upland forest; steep slopes; and well head
				  protection and groundwater recharge areas. Habitats of endangered or threatened
				  species are identified using the Department's Landscape Project as approved by the
				  Department's Endangered and Nongame Species Program.
"Empowerment Neighborhoods" means neighborhoods designated by the
				  Urban Coordinating Council "in consultation and conjunction with" the New Jersey
				  Redevelopment Authority pursuant to
				  N.J.S.A.
				  55:19-69.
"Erosion" means the detachment and movement of soil or rock
				  fragments by water, wind, ice or gravity.
"Impervious surface" means a surface that has been covered with a
				  layer of material so that it is highly resistant to infiltration by water.
"Infiltration" is the process by which water seeps into the soil
				  from precipitation.
"Municipality" means any city, borough, town, township, or
				  village.
"Node" means an area designated by the State Planning Commission
				  concentrating facilities and activities which are not organized in a compact
				  form.
"Nutrient" means a chemical element or compound, such as nitrogen
				  or phosphorus, which is essential to and promotes the development of
				  organisms.
"Person" means any individual, corporation, company, partnership,
				  firm, association, political subdivision of this State and any state, interstate or
				  Federal agency.
"Pollutant" means any dredged spoil, solid waste, incinerator
				  residue, filter backwash, sewage, garbage, refuse, oil, grease, sewage sludge,
				  munitions, chemical wastes, biological materials, medical wastes, radioactive
				  substance (except those regulated under the Atomic Energy Act of 1954, as amended (
				  42 U.S.C. §§
										2011 et seq.)), thermal waste, wrecked or
				  discarded equipment, rock, sand, cellar dirt, industrial, municipal, agricultural,
				  and construction waste or runoff or other residue discharged directly or indirectly
				  to the land, ground waters or surface waters of the State, or to a domestic
				  treatment works. "Pollutant" includes both hazardous and nonhazardous
				  pollutants.
"Recharge" means the amount of water from precipitation that
				  infiltrates into the ground and is not evapotranspired.
"Sediment" means 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.
"Site" means the lot or lots upon which a major development is to
				  occur or has occurred.
"Soil" means all unconsolidated mineral and organic material of
				  any origin.
"State Development and Redevelopment Plan Metropolitan Planning
				  Area (PA1)" means 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" 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.
"Stormwater" means 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" means water flow on the surface of the ground
				  or in storm sewers, resulting from precipitation.
"Stormwater management basin" means 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).
"Stormwater management measure" means 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.
"Tidal Flood Hazard Area" means a flood hazard area, which may be
				  influenced by stormwater runoff from inland areas, but which is primarily caused by
				  the Atlantic Ocean.
"Urban Coordinating Council Empowerment Neighborhood" means a
				  neighborhood given priority access to State resources through the New Jersey
				  Redevelopment Authority.
"Urban Enterprise Zones" means a zone designated by the New Jersey
				  Urban Enterprise Zone Authority pursuant to the New Jersey Urban Enterprise Zones
				  Act,
				  N.J.S.A. 52:27H-60 et
				  seq.
"Urban Redevelopment Area" is defined as previously developed
				  portions of areas:
1. Delineated on the State Plan Policy Map (SPPM) as the
				  Metropolitan Planning Area (PA1), Designated Centers, Cores or Nodes;
2. Designated as CAFRA Centers, Cores or Nodes;
3. Designated as Urban Enterprise Zones; and
4. Designated as Urban Coordinating Council Empowerment
				  Neighborhoods.
"Waters of the State" means 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" means 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.
SUBCHAPTER 5. DESIGN AND PERFORMANCE STANDARDS FOR STORMWATER
				  MANAGEMENT MEASURES
7:8-5.1 Scope
(a) This subchapter establishes design and performance standards
				  for stormwater management measures for major development intended to minimize the
				  adverse impact of stormwater runoff on water quality and water quantity and loss of
				  groundwater recharge in receiving water bodies.
(b) The standards specified in this subchapter do not apply to
				  major development if alternative design and performance standards that are at least
				  as protective as would be achieved through this subchapter when considered on a
				  regional stormwater management area basis are applicable under a regional stormwater
				  management plan adopted in accordance with this chapter or a water quality
				  management plan adopted in accordance with N.J.A.C. 7:15.
7:8-5.2 Stormwater management measures for major
				  development
(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 at
				  N.J.A.C.
				  7:8-5.4 and 5.5. To the maximum extent
				  practicable, these standards shall be met by incorporating nonstructural stormwater
				  management strategies at
				  N.J.A.C.
				  7:8-5.3 into the design. If these measures alone
				  are not sufficient to meet these standards, structural stormwater management
				  measures at
				  N.J.A.C.
				  7:8-5.7 necessary to meet these standards shall be
				  incorporated into the design.
(b) The development shall incorporate a maintenance plan under
				  N.J.A.C.
				  7:8-5.8 for the stormwater management
				  measures.
(c) 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-15.1 47 through 15.150, particularly
				  Helonias bullata (swamp pink) and/or Clemmys muhlnebergi (bog turtle).
(d) The following linear development projects are exempt from the
				  groundwater recharge, storm-water runoff quantity, and stormwater runoff quality
				  requirements at
				  N.J.A.C.
				  7:8-5.4 and 5.5:
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.
(e) A waiver from strict compliance from the groundwater recharge,
				  stormwater runoff quantity, and stormwater runoff quality requirements at
				  N.J.A.C.
				  7:8-5.4 and 5.5 may be obtained for the
				  enlargement of an existing public roadway or railroad, or the construction or
				  enlargement of a public pedestrian access, provided that the following conditions
				  are met:
1. The applicant demonstrates that there is a public need for the
				  project that cannot be accomplished by any other means;
2. The applicant demonstrates through an alternatives analysis,
				  that through the use of nonstructural and structural stormwater management
				  strategies and measures, the option selected complies with the requirements of
				  N.J.A.C.
				  7:8-5.4 and 5.5 to the maximum extent
				  practicable;
3. The applicant demonstrates that, in order to meet the
				  requirements at
				  N.J.A.C.
				  7:8-5.4 and 5.5 existing structures currently in
				  use, such as homes and buildings would need to be condemned; and
4. The applicant demonstrates that it does not own or have other
				  rights to areas, including the potential to obtain through condemnation lands not
				  falling under (e)3 above within the upstream drainage area of the receiving stream,
				  that would provide additional opportunities to mitigate for requirements of
				  N.J.A.C.
				  7:8-5.4 and 5.5 that were not achievable on-site.
N.J.A.C.
				  7:8-5.3 Nonstructural stormwater management
				  strategies
(a) To the maximum extent practicable, the standards in
				  N.J.A.C.
				  7:8-5.4 and 5.5 shall be met by incorporating
				  nonstructural stormwater management strategies at
				  N.J.A.C.
				  7:8-5.3into the design. The persons submitting an
				  application for review shall identify the nonstructural strategies 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 strategies identified in (b) below into the design of a
				  particular project, the applicant shall identify the strategy and provide a basis
				  for the contention.
(b) Nonstructural stormwater management strategies incorporated
				  into site design shall:
1. Protect areas that provide water quality benefits or areas
				  particularly susceptible to erosion and sediment loss;
2. Minimize impervious surfaces and break up or disconnect the
				  flow of runoff over impervious surfaces;
3. Maximize the protection of natural drainage features and
				  vegetation;
4. Minimize the decrease in the "time of concentration" from
				  pre-construction to post-construction. "Time of concentration" is defined as the
				  time it takes for runoff to travel from the hydraulically most distant point of the
				  drainage area to the point of interest within a watershed;
5. Minimize land disturbance including clearing and
				  grading;
6. Minimize soil compaction;
7. Provide low-maintenance landscaping that encourages retention
				  and planting of native vegetation and minimizes the use of lawns, fertilizers and
				  pesticides;
8. Provide vegetated open-channel conveyance systems discharging
				  into and through stable vegetated areas; and
9. 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. These source controls include, but are not
				  limited to:
i. Site design features that help to prevent accumulation of trash
				  and debris in drainage systems;
ii. Site design features that help to prevent discharge of trash
				  and debris from drainage systems;
iii. Site design features that help to prevent and/or contain
				  spills or other harmful accumulations of pollutants at industrial or commercial
				  developments; and
iv. 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.
(c) Any land area used as a nonstructural stormwater management
				  measure to meet the performance standards in
				  N.J.A.C.
				  7:8-5.4 and 5.5 shall be dedicated to a government
				  agency, subjected to a conservation restriction filed with the County Clerk's
				  office, or subject to Department approved or equivalent restriction that ensures
				  that measure or an equivalent stormwater management measure approved by the
				  reviewing agency is maintained in perpetuity.
(d) Guidance for nonstructural stormwater management strategies is
				  available in the New Jersey Stormwater Best Management Practices Manual available
				  from the Department through the address listed at
				  N.J.A.C. 7:8-1.3.
7:8-5.4 Erosion control, groundwater recharge, and runoff quantity
				  standards
(a) This section 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.
1. 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.
2. The minimum design and performance standards for groundwater
				  recharge are as follows:
i. The design engineer shall, using the assumptions and factors
				  for stormwater runoff and groundwater recharge calculations at
				  N.J.A.C.
				  7:8-5.6, either:
(1) Demonstrate through hydrologic and hydraulic analysis that the
				  site and its stormwater management measures maintain 100 percent of the average
				  annual pre-construction groundwater recharge volume for the site; or
(2) Demonstrate through hydrologic and hydraulic analysis that the
				  increase of stormwater runoff volume from pre-construction to post-construction for
				  the two-year storm is infiltrated.
ii. This groundwater recharge requirement does not apply to
				  projects within the "urban redevelopment area," or to projects subject to (a)2iii
				  below.
iii. The following types of stormwater shall not be
				  recharged:
(1) 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 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
(2) 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.
iv. 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 downgradient of
				  the groundwater recharge area.
3. In order to control stormwater runoff quantity impacts, the
				  design engineer shall, using the assumptions and factors for stormwater runoff
				  calculations at
				  N.J.A.C.
				  7:8-5.6, complete one of the following:
i. Demonstrate through hydrologic and hydraulic analysis that for
				  stormwater leaving the site, post-construction runoff hydrographs for the two, 10,
				  and 100-year storm events do not exceed, at any point in time, the pre-construction
				  runoff hydrographs for the same storm events;
ii. Demonstrate through hydrologic and hydraulic analysis that
				  there is no increase, as compared to the pre-construction condition, in the peak
				  runoff rates of stormwater leaving the site for the two, 10, and 100-year storm
				  events and that the increased volume or change in timing of stormwater runoff will
				  not increase flood damage at or downstream of the site. This analysis shall include
				  the analysis of impacts of existing land uses and projected land uses assuming full
				  development under existing zoning and land use ordinances in the drainage
				  area;
iii. Design stormwater management measures so that the
				  post-construction peak runoff rates for the two, 10 and 100-year storm events are
				  50, 75 and 80 percent, respectively, of the pre-construction peak runoff rates. The
				  percentages apply only to the post-construction stormwater runoff that is
				  attributable to the portion of the site on which the proposed development or project
				  is to be constructed; or
iv. In tidal flood hazard areas, stormwater runoff quantity
				  analysis in accordance with (a)3i, ii and iii above shall only be applied if the
				  increased volume of stormwater runoff could increase flood damages below the point
				  of discharge.
(b) Any application for a new agricultural development that meets
				  the definition of major development at
				  N.J.A.C. 7:8-1.2 shall be
				  submitted to the 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 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 manufacture of
				  agriculturally related products.
7:8-5.5 Stormwater runoff quality standards
(a) Stormwater management measures shall be designed to reduce the
				  post-construction load of total suspended solids (TSS) in stormwater runoff
				  generated from the water quality design storm by 80 percent 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
				  one-quarter acre of impervious surface is being proposed on a development site.
				  (Department of Community Affairs Note: Consistent with
				  N.J.A.C.
				  7:8-4.2, municipal stormwater management plan and
				  elements, the Residential Site Improvement Standard requirements only are triggered
				  by residential developments that disturb one or more acres of land.) The requirement
				  to reduce TSS does not apply to any stormwater runoff in a discharge regulated under
				  a numeric effluent limitation for TSS imposed under the New Jersey Pollutant
				  Discharge Elimination System (NJPDES) rules, N.J.A.C. 7:14A, or in a discharge
				  specifically exempt under a NJPDES permit from this requirement. 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 below. The calculation of the volume of runoff may
				  take into account the implementation of non-structural and structural stormwater
				  management measures.
Table 1: Water Quality Design Storm
						  Distribution
Cumulative
Cumulative
Time
Rainfall
Time
Rainfall
(Minutes)
(Inches)
(Minutes)
(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
--
(b) 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
				  N.J.A.C. 7:8-1.3
				  or found on the Department's website at
http://www.njstormwater.org
. The BMP
				  manual and other sources of technical guidance are listed in
				  N.J.A.C.
				  7:8-5.9(a). 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. Where the Department is not 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 address at
				  N.J.A.C.
				  7:8-1.3.
(c) If more than one BMP in series is necessary to achieve the
				  required 80 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 from application of both BMPs,
				  and
A = the TSS percent removal rate applicable to the first
				  BMP
B = the TSS percent removal rate applicable to the second BMP
Table 2: TSS Removal Rates for BMPs
Best Management Practice
TSS
						  Percent Removal Rate
Bioretention Systems
90
Constructed Stormwater Wetland
90
Extended Detention Basin
40-60
Infiltration Structure
80
Manufactured Treatment Device
See
						  N.J.A.C.
						  7:8-5.7(d)
Sand Filter
80
Vegetative Filter Strip
60-80
Wet Pond
50-90
(d) If there is more than one onsite drainage area, the 80 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.
(e) Stormwater management measures shall also be designed to
				  reduce, to the maximum extent feasible, the post-construction nutrient load of the
				  anticipated load from the developed site in stormwater runoff generated from the
				  water quality design storm. In achieving reduction of nutrients to the maximum
				  extent feasible, the design of the site shall include nonstructural strategies and
				  structural measures that optimize nutrient removal while still achieving the
				  performance standards in
				  N.J.A.C.
				  7:8-5.4 and 5.5.
(f) Additional information and examples are contained in the New
				  Jersey Stormwater Best Management Practices Manual, which may be obtained from the
				  address identified in
				  N.J.A.C.
				  7:8-1.3.
(g) 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.
(h) 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 HUC
				  14 drainage. 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:
1. The applicant shall preserve and maintain a special water
				  resource protection area in accordance with one of the following:
i. A 300-foot special water resource protection area shall be
				  provided on each side of the waterway, measured perpendicular to the waterway from
				  the top of bank outwards, or from the centerline of the waterway where the bank is
				  not defined, consisting of existing vegetation or vegetation allowed to follow
				  natural succession is provided.
ii. Encroachment within the designated special water resource
				  protection area under (h)1i 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 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
				  centerline of the waterway where the bank is undefined. All encroachments proposed
				  under this subparagraph shall be subject to review and approval by the
				  Department.
2. All stormwater shall be discharged outside of but may 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.
				  (see
				  N.J.A.C.
				  2:90-1.3 ).
3. 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.,
				  (see
				  N.J.A.C.
				  2:90-1.3 ), 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:
i. Stabilization measures shall not be placed within 150 feet of
				  the waterway;
ii. Stormwater associated with discharges allowed by this
				  paragraph shall achieve a 95 percent TSS post construction removal rate;
iii. Temperature shall be addressed to ensure no impact on
				  receiving waterway;
iv. 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;
v. A conceptual project design meeting shall be held with the
				  appropriate Department staff and Soil Conservation District staff to identify
				  necessary stabilization measures; and
vi. All encroachments proposed under this section shall be subject
				  to review and approval by the Department.
4. 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 this subsection has been approved by the Department, 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 this subsection shall maintain or enhance the current functional value
				  and overall condition of the special water resource protection area as defined above
				  in (h)1i. In no case shall a stream corridor protection plan allow reduction of the
				  Special Water Resource Protection Area to less than 150 feet as measured
				  perpendicular to the waterway subject to this subsection.
5. This subsection does not apply to the construction of one
				  individual single family dwelling that is not part of a larger development 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.
7:8-5.6 Calculation of stormwater runoff and groundwater
				  recharge
(a) Stormwater runoff shall be calculated in accordance with the
				  following:
1. The design engineer shall calculate runoff using one of the
				  following methods:
i. The USDA Natural Resources Conservation Service (NRCS)
				  methodology, including the NRCS Runoff Equation and Dimensionless Unit Hydrograph,
				  as described in Section 4, National Engineering Handbook (NEH-4), dated July 2002,
				  incorporated herein by reference as amended and supplemented. This methodology is
				  additionally described in Technical Release 55-Urban Hydrology for Small Watersheds
				  (TR-55), dated June 1986, incorporated herein by reference as amended and
				  supplemented. Information regarding the methodology is available from the Natural
				  Resources Conservation Service website at
http://www.wcc.nrcs.usda.gov/water/quality/common/neh603/4content.html
or at Natural Resources Conservation Service, 220 Davidson Avenue, Somerset, New
				  Jersey 08873; (732) 537-6040; or
ii. The Rational Method for peak flow and the Modified Rational
				  Method for hydrograph computations.The rational and modified rational methods are
				  described in "Appendix A-9 Modified Rational Method" in the Standards for Soil
				  Erosion and Sediment Control in New Jersey, July 1999. This document is available
				  from the State Soil Conservation Committee or any of the Soil Conservation Districts
				  listed at
				  N.J.A.C.
				  2:90-1.3(a)4. The location,
				  address, and telephone number of each Soil Conservation District is available from
				  the State Soil Conservation Committee, PO Box 330, Trenton, NJ 08625, (609)
				  292-5540.
2. For the purpose of calculating runoff coefficients and
				  groundwater recharge, there is a presumption that the pre-construction condition of
				  a site or portion thereof is a wooded land use with good hydrologic condition. The
				  term "runoff coefficient" applies to both the NRCS methodology at
				  N.J.A.C.
				  7:8-5.6(a)1  i and the Rational
				  and Modified Rational Methods at
				  N.J.A.C.
				  7:8-5.6(a)1  i. A runoff
				  coefficient or a groundwater recharge land cover for an existing condition may be
				  used on all or a portion of the site if the design engineer verifies that the
				  hydrologic condition has existed on the site or portion of the site for at least
				  five years without interruption prior to the time of application. If more than one
				  land cover have existed on the site during the five years immediately prior to the
				  time of application, the land cover with the lowest runoff potential shall be used
				  for the computations. In addition, there is the presumption that the site is in good
				  hydrologic condition (if the land use type is pasture, lawn, or park), with good
				  cover (if the land use type is woods), or with good hydrologic condition and
				  conservation treatment (if the land use type is cultivation.)
3. In computing pre-construction stormwater runoff, the design
				  engineer shall account for all significant land features and structures, such as
				  ponds, wetlands, depressions, hedgerows, or culverts, that may reduce
				  pre-construction stormwater runoff rates and volumes.
4. In computing stormwater runoff from all design storms, the
				  design engineer shall consider the relative stormwater runoff rates and/or volumes
				  of pervious and impervious surfaces separately to accurately compute the rates and
				  volume of stormwater runoff from the site. To calculate runoff from unconnected
				  impervious cover, urban impervious area modifications as described in the NRCS
				  Technical Release-55, Urban Hydrology for Small Watersheds or other methods may be
				  employed.
5. If the invert of the outlet structure of a stormwater
				  management measure is below the flood hazard design flood elevation as defined at
				  N.J.A.C. 7:13, the design engineer shall take into account the effects of tailwater
				  in the design of structural stormwater management measures.
(b) Groundwater recharge may be calculated in accordance with the
				  following:
1. The New Jersey Geological Survey 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 New Jersey Geological Survey website at http://
http://www.state.nj.us/dep/njgs/
, or
				  at New Jersey Geological Survey, 29 Arctic Parkway, PO Box 427, Trenton, NJ
				  08625-0427; (609) 984-6587.
7:8-5.7 Standards for structural stormwater management
				  measures
(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 one-third the width of the diameter of the orifice or
				  one-third 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
				  N.J.A.C.
				  7:8-6.2(a).
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.
4. At the intake to the outlet from the stormwater management
				  basin, the orifice size shall be a minimum of two and one-half inches in
				  diameter.
5. Stormwater management basins shall be designed to meet the
				  minimum safety standards for stormwater management basins at N.J.A.C. 7:8-6
(b) Stormwater management measure guidelines are available in the
				  New Jersey Stormwater Best Management Practices Manual. Other stormwater management
				  measures may be utilized provided the design engineer demonstrates that the proposed
				  measure and its design will accomplish the required water quantity, ground water
				  recharge and water quality design and performance standards established by this
				  subchapter.
(c) Manufactured treatment devices may be used to meet the
				  requirements of this subchapter, provided the pollutant removal rates are verified
				  by the New Jersey Corporation for Advanced Technology and certified by the
				  Department.
7:8-5.8 Maintenance requirements
(a) The design engineer shall prepare a maintenance plan for the
				  stormwater management measures incorporated into the design of a major
				  development.
(b) 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.
(c) 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.
(d) If the person responsible for maintenance identified under (b)
				  above is not a public agency, the maintenance plan and any future revisions based on
				  (h) below shall be recorded upon the deed of record for each property on which the
				  maintenance described in the maintenance plan must be undertaken.
(e) 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.
(f) The person responsible for maintenance identified under (b)
				  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.
(g) The person responsible for maintenance identified under (b)
				  above shall evaluate the effectiveness of the maintenance plan at least once per
				  year and adjust the plan and the deed as needed.
(h) The person responsible for maintenance identified under (b)
				  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 (f) and (g) above.
(i) 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.
7:8-5.9 Sources for technical guidance
(a) Technical guidance for stormwater management measures can be
				  found in the documents listed at (a)1 and 2 below, which are available from Maps and
				  Publications, Department of Environmental Protection, 428 East State Street, PO 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, 2002 as amended.
				  (Department of Community Affairs Note: The effective version of the New Jersey
				  Stormwater Best Management Practices Manual is the April 2004 edition.) Information
				  is provided on stormwater management measures such as:
i. Bioretention systems;
ii. Constructed stormwater wetlands;
iii. Dry wells;
iv. Extended detention basins;
v. Infiltration structures;
vi. Manufactured treatment devices;
vii. Pervious paving;
viii. Sand filters;
ix. Vegetative filter strip, and
x. Wet pond.
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, PO 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, PO Box 330, Trenton, New Jersey 08625,
				  609-292-5540.
SUBCHAPTER 6. SAFETY STANDARDS FOR STORMWATER MANAGEMENT
				  BASINS
7:8-6.1 Scope
(a) This subchapter sets forth requirements to protect public
				  safety through the proper design and operation of stormwater management basins. This
				  subchapter applies to any new stormwater management basin.
(b) The provisions of this subchapter 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
				  N.J.A.C.
				  7:8-6.2(a), (b) and (c)1 for
				  trash racks, overflow grates, and escape provisions at outlet structures.
N.J.A.C.
				  7:8-6.2Requirements for trash racks, overflow
				  grates and escape provisions
(a) 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:
1. The trash rack shall have parallel bars, with no greater than
				  six-inch spacing between the bars;
2. The trash rack shall be designed so as not to adversely affect
				  the hydraulic performance of the outlet pipe or structure;
3. The average velocity of flow through a clean trash rack is not
				  to exceed 2.5 feet per second under the full range of stage and discharge. Velocity
				  is to be computed on the basis of the net area of opening through the rack;
				  and
4. The trash rack shall be constructed of rigid, durable, and
				  corrosion resistant material and designed to withstand a perpendicular live loading
				  of 300 lbs./ft sq.
(b) An overflow grate is designed to prevent obstruction of the
				  overflow structure. If an outlet structure has an overflow grate, the grate shall
				  comply with the following requirements:
1. The overflow grate shall be secured to the outlet structure but
				  removable for emergencies and maintenance;
2. The overflow grate spacing shall be no greater than two inches
				  across the smallest dimension; and
3. The overflow grate shall be constructed of rigid, durable, and
				  corrosion resistant material and designed to withstand a perpendicular live loading
				  of 300 lbs./ft sq.
(c) Stormwater management basins shall include escape provisions
				  as follows:
1. If a stormwater management basin has an outlet structure,
				  escape provisions shall be incorporated in or on the structure. Escape provisions
				  include the installation of permanent ladders, steps, rungs, or other features that
				  provide easily accessible means of egress from stormwater management basins. With
				  the prior approval of the reviewing agency pursuant to
				  N.J.A.C.
				  7:8-6.3(a), a free-standing
				  outlet structure may be exempted from this requirement;
2. Safety ledges shall be constructed on the slopes of all new
				  stormwater management basins having a permanent pool of water deeper than two and
				  one-half feet. Safety ledges shall be comprised of two steps. Each step shall be
				  four to six feet in width. One step shall be located approximately two and one-half
				  feet below the permanent water surface, and the second step shall be located one to
				  one and one-half feet above the permanent water surface. See N.J.A.C. 7:8-6 Appendix
				  A for an illustration of safety ledges in a stormwater management basin; and
3. 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.
7:8-6.3 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.
Appendix A:
Illustration of safety ledges in a new detention basin.
Depicted is an elevational view.
Data in
				  image