Borough of Highland Park, NJ Stormwater Management

This article shall be applicable to all site plans and subdivisions for the following major developments that require preliminary or final site plan or subdivision review:

Nonresidential major developments; and

Aspects of residential major developments that are not preempted by the Residential Site Improvement Standards at N.J.A.C. 5:21.

This article shall also be applicable to all major developments undertaken by the Borough of Highland Park.

Compatibility with other permit and ordinance requirements. Development approvals issued for subdivisions and site plans pursuant to this article 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 article shall be held to be the minimum requirements for the promotion of the public health, safety and general welfare. This article is not intended to interfere with, abrogate or annul any other ordinance, rule or regulation, statute or other provision of law, except that, where any provision of this article imposes restrictions different from those imposed by any other ordinance, rule or regulation, or other provision of law, the more restrictive provisions or higher standards shall control.

Consistency with state rules. This article is consistent with all relevant sections of NJDEP's Stormwater Management Rules at N.J.A.C. 7:8.

[Added 5-1-2007 by Ord. No. 07-1720]

§ 230-177 Definitions.

Unless specifically defined below, words or phrases used in this article shall be interpreted so as to give them the meaning they have in common usage and to give this article its most reasonable application. The definitions below are the same as or based on the corresponding definitions in the Stormwater Management Rules at N.J.A.C. 7:8-12.

CAFRA CENTERS, CORES or NODES: Those areas within boundaries accepted by the Department pursuant to N.J.A.C. 7:8E-5B.

CAFRA PLANNING MAP: 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.

COMPACTION: The increase of soil bulk density.

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: An agency designated by the County Board of Chosen Freeholders to review municipal stormwater management plans and implementing ordinance(s). The county review agency may either be:

DEPARTMENT: The New Jersey Department of Environmental Protection.

DESIGNATED CENTER: A state development and redevelopment plan center as designated by the State Planning Commission, such as urban, regional, town, village or hamlet.

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.

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 AREAS: An area or feature which is of significant environmental value, including but not limited to stream corridors; natural heritage priority sites; habitat of endangered or threatened species; large areas of contiguous open space or upland forest; steep slopes; and wellhead protection and groundwater recharge areas. Habitats of endangered or threatened species are identified using the Department's Landscape Project as approved by the Department's Endangered and Nongame Species Program.

EMPOWERMENT NEIGHBORHOOD: A neighborhood designated by the Urban Coordinating Council in consultation and conjunction with the New Jersey Redevelopment Authority pursuant to N.J.S.A. 55:19-69.

EROSION: The detachment and movement of soil or rock fragments by water, wind, ice or gravity.

IMPERVIOUS SURFACE: A surface that has been covered with a layer of material so that it is highly resistant to infiltration by water.

INFILTRATION: The process by which water seeps into the soil from precipitation.

MAJOR DEVELOPMENT: Any development that provides for ultimately disturbing one or more acres of land. "Disturbance" for the purpose of this rule is the placement of impervious surface or exposure and/or movement of soil or bedrock or clearing, cutting or removing of vegetation.

MUNICIPALITY: Any city, borough, town, township or village.

NODE: An area designated by the State Planning Commission concentrating facilities and activities which are not organized in a compact form.

NUTRIENT: A chemical element or compound, such as nitrogen or phosphorus, which is essential to and promotes the development of organisms.

PERSON: Any individual, corporation, company, partnership, firm, association, Borough of Highland Park, or political subdivision of this state subject to municipal jurisdiction pursuant to 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.

RECHARGE: The amount of water from precipitation that infiltrates into the ground and is not evapotranspired.

SEDIMENT: 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: 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.

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 MANAGEMENT BASIN: An excavation or embankment and related areas designed to retain 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.

STORMWATER RUNOFF: Water flow on the surface of the ground or in storm sewers resulting from precipitation.

TIDAL FLOOD HAZARD AREA: 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: A neighborhood given priority access to state resources through the New Jersey Redevelopment Authority.

URBAN ENTERPRISE ZONES: A zone designated by the New Jersey Enterprise Zone Authority pursuant to the New Jersey Urban Enterprise Zones Act, N.J.S.A. 52:27H-60 et seq.

URBAN REDEVELOPMENT AREA: Previously developed portions of areas:

WATERS OF THE STATE: The ocean and its estuaries, all springs, streams, wetlands, and bodies of surface water or groundwater, whether natural or artificial, within the boundaries of the State of New Jersey or subject to its jurisdiction.

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."

§ 230-178 General standards.

Design and performance standards for stormwater management measures.

Stormwater management measures for major development shall be developed to meet the erosion control, groundwater recharge, stormwater runoff quantity, and stormwater runoff quality standards in §§ 230-179 and 230-180 of this article 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.

The standards in the article apply only to new major development and are intended to minimize the impact of stormwater runoff on water quality and water quantity in receiving water bodies and maintain groundwater recharge.

The standards do not apply to new major development to the extent that alternative design and performance standards are applicable under a regional stormwater management plan or water quality management plan adopted in accordance with Department rules.

§ 230-179 Stormwater management requirements for major development.

[Amended 5-1-2007 by Ord. No. 07-1720]

The development shall incorporate a maintenance plan for the stormwater management measures incorporated in to design of a major development in accordance with § 230-186 of this article.

Stormwater management measures shall avoid adverse impacts of concentrated flow on habitat for threatened and endangered species as documented in the Department's Landscape Project or Natural Heritage Database established under N.J.S.A. 13:1B-15.147 through 13:1B-15.150, particularly Helonias bullata (swamp pink) and/or Clemmys muhlenbergii (bog turtle).

The following linear development projects are exempt from the groundwater recharge, stormwater runoff quantity, and stormwater runoff quality requirements of §§ 230-179F and 230-180 of this article:

The construction of an underground utility line, provided that the disturbed areas are revegetated upon completion;

The construction of an aboveground utility line, provided that the existing conditions are maintained to the maximum extent practicable; and

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.

A waiver from strict compliance from the groundwater recharge, stormwater runoff quantity, and stormwater runoff quality requirements of §§ 230-179F and 230-180 of this article 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:

The applicant demonstrates that there is a public need for the project that cannot be accomplished by any other means;

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 §§ 230-179F and 230-180 of this article to the maximum extent practicable;

The applicant demonstrates that, in order to meet the requirements of §§ 230-179F and 230-180 of this article, existing structures currently in use, such as homes and buildings, would need to be condemned; and

The applicant demonstrates that it does not own or have other rights to areas, including the potential to obtain through condemnation, lands not falling under Subsection D(3) above within the upstream drainage area of the receiving stream that would provide additional opportunities to mitigate the requirements of §§ 230-179F and 230-180 of this article that were not achievable on site.

Nonstructural stormwater management strategies.

To the maximum extent practicable, the standards in §§ 230-179F and 230-180 of this article shall be met by incorporating nonstructural stormwater management strategies set forth at § 230-179E of this article into the design. The applicant shall identify the nonstructural measures incorporated into the design of the project. If the applicant contends that it is not feasible for engineering, environmental, or safety reasons to incorporate any nonstructural stormwater management measures identified in Subsection E(2) below into the design of a particular project, the applicant shall identify the strategy considered and proved a basis for the contention.

Nonstructural stormwater management strategies incorporated into site design shall:

Protect areas that provide water quality benefits or areas particularly susceptible to erosion and sediment loss;

Minimize impervious surfaces and break up or disconnect the flow of runoff over impervious surfaces;

Maximize the protection of natural drainage features and vegetation;

Minimize the decrease in the time of concentration from preconstruction to post construction. "Time of concentration" is defined as the time it takes for runoff to travel from the hydraulically most distant point of the watershed to the point of interest within a watershed;

(e)

Minimize land disturbance including clearing and grading;

(f)

Minimize soil compaction;

(g)

Provide low-maintenance landscaping that encourages retention and planting of native vegetation and minimizes the use of lawns, fertilizers and pesticides;

(h)

Provide vegetated open-channel conveyance systems discharging into and through stable vegetated areas; and

(i)

Provide other source controls to prevent or minimize the use or exposure of pollutants at the site in order to prevent or minimize the release of those pollutants into stormwater runoff. Such sources controls include, but are not limited to;

Site design features that help to prevent accumulation of trash and debris in drainage systems, including features that satisfy Subsection E(3) below;

Site design features that help to prevent discharge of trash and debris from drainage systems;

Site design features that help to prevent and/or contain spills or other harmful accumulations of pollutants at industrial or commercial developments; and

[4]

When establishing vegetation after land disturbance, applying fertilizer in accordance with the requirements established under the Soil Erosion and Sediment Control Act, N.J.S.A. 4:24-39 et seq., and implementing rules.

Site design features identified under Subsection E(2)(i) above shall comply with the following standard to control passage of solid and floatable materials through storm drain inlets. For purposes of this paragraph, "solid and floatable materials" mean sediment, debris, trash and other floating, suspended or settleable solids. For exemptions to this standard see Subsection E(3)(c) below.

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 the grate:

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

A different grate, if each individual clear space in that grate has an area of no more that seven square inches or is no greater than 0.5 inches across the smallest dimension.

Examples of grates subject to this standard include grates in grate inlets, the grate portion (non-curb-opening portion) of combination inlets, grates on storm sewer manholes, ditch grates, trench grates, and grates of spacer bars in slotted drains. Examples of ground surfaces include surfaces of roads (including bridges), driveways, parking areas, bikeways, plazas, sidewalks, lawns, fields, open channels, and stormwater basin floors.

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 seven square inches or be no greater than two inches across the smallest dimension.

This standard does not apply:

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;

Where flows from the water quality design storm as specified in § 230-180A below are conveyed through any device (e.g., end-of-pipe netting facility, manufactured treatment device, or a catch basin hood) that is designed, at a minimum, to prevent delivery of all solid and floatable materials that could not pass through one of the following:

[a]

A rectangular space 4 5/8 inches long and 1 1/2 inches wide (this option does not apply for outfall netting facilities); or

[b]

A bar screen having a bar spacing of 0.5 inches.

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 § 230-180A below; 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.

Any land area used as a nonstructural stormwater management measure to meet the performance standards in §§ 230-179F and 230-180 shall be dedicated to a government agency, subject to a conservation restriction filed with the appropriate county clerk's office or subject to an approved equivalent restriction that ensures that measure or an equivalent stormwater management measure approved by the reviewing agency is maintained in perpetuity.

Guidance for nonstructural stormwater management strategies is available in the New Jersey Stormwater Best Management Practices Manual. The BMP Manual may be obtained from the address identified in § 230-180 of this article or found on the Department's website at www.njstormwater.org.

Erosion control, groundwater recharge and runoff quantity standards.

This subsection contains minimum design and performance standards to control erosion, encourage and control infiltration and groundwater recharge, and control stormwater runoff quantity impacts of major development.

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.

The minimum design and performance standards for groundwater recharge are as follows:

The design engineer shall, using the assumptions and factors for stormwater runoff and groundwater recharge calculations at § 230-181 of this article, either:

[a]

Demonstrates through hydrologic and hydraulic analysis that the site and its stormwater management measures maintain 100% of the average annual preconstruction groundwater recharge volume for the site; or

[b]

Demonstrate through hydrologic and hydraulic analysis that the increase of stormwater runoff volume from preconstruction to post construction for the two-year storm is infiltrated.

This groundwater recharge requirement does not apply to projects within the urban redevelopment area or to projects subject to Subsection F(1)(b)[3] below.

The following types of stormwater shall not be recharged:

[a]

Stormwater from areas of high pollutant loading. High pollutant loading areas are areas in industrial and commercial developments where solvents and/or petroleum products are loaded/unloaded, stored or applied; areas where pesticides are loaded/unloaded or stored; areas where hazardous materials are expected to be present in greater than "reportable quantities," as defined by the United States Environmental Protection Agency (EPA) at 40 CFR 302.4; areas where recharge would be inconsistent with Department-approved remedial action work plan or landfill closure plan; and areas with high risks for spills of toxic materials, such as gas station and vehicle maintenance facilities; and

[b]

Industrial stormwater exposed to source material. "Source material" means any material(s) or machinery, located at an industrial facility, that is directly or indirectly related to process, manufacturing or other industrial activities, which could be a source of pollutants in any industrial stormwater discharge to groundwater. Source materials include, but are not limited to, raw materials; intermediate products; final products; waste material; by-products; industrial machinery and fuels, and lubricants, solvents, and detergents that are related to process, manufacturing, or other industrial activities that are exposed to stormwater.

[4]

The design engineer shall assess the hydraulic impact on the groundwater table and design the site so as to avoid adverse hydraulic impacts. Potential adverse hydraulic impacts include, but are not limited to, exacerbating a naturally or seasonally high water table so as to cause surficial ponding, flooding of basements, or interference with the proper operation of subsurface sewage disposal systems and other subsurface structures in the vicinity or downgradient of the groundwater recharge area.

In order to control stormwater runoff quantity impacts, the design engineer shall, using the assumptions and factors for stormwater runoff calculations at § 230-181 of this article, complete one of the following:

Demonstrate through hydrologic and hydraulic analysis that for stormwater leaving the site, post-construction runoff hydrographs for the two-, ten-, and one-hundred-year storm events do not exceed, at any point in time, the preconstruction runoff hydrographs for the same storm events;

Demonstrate through hydrologic and hydraulic analysis that there is no increase, as compared to the preconstruction condition, in the peak runoff rates of stormwater leaving the site for two-, ten-, and one-hundred-year storm events and that the increased volume or change in timing of stormwater runoff will not increase flood damage at or downstream of the site. This analysis shall include the analysis of impacts of existing land uses and projected land uses assuming full development under existing zoning and land use ordinances in the drainage area; or

Design stormwater management measures so that the post-construction peak runoff rates for the two-, ten- and one-hundred-year storm events are 50%, 75% and 80%, respectively, of the preconstruction peak runoff rates. The percentages apply only to the post-construction stormwater runoff that is attributable to the portion of the site on which the proposed development or project is to be constructed. The percentages shall not be applied to post-construction stormwater runoff into tidal flood hazard areas if the increased volume of stormwater runoff will not increase flood damages below the point of discharge.

In tidal flood and hazard areas, stormwater runoff quantity analysis in accordance with Subsection F(1)(c)[1], [2] and [3] above shall only be applied if the increased volume of stormwater runoff could increase flood damages below the point of discharge.

Any application for a new agricultural development that meets the definition of major development at § 230-177 of this article shall be submitted to the appropriate Soil Conservation District for review and consideration in accordance with the requirements of this article and any applicable Soil Conservation District guidelines for stormwater runoff rate and erosion control. For the purposes of this article, "agricultural development' means land uses normally associated with the production of food, fiber and livestock for sale. Such uses do not include the development of land for the processing or sale of food and the manufacturing of agriculturally related products.

§ 230-180 Stormwater runoff quality standards.

Stormwater management measures shall be designed to reduce the post-construction load of total suspended solids (TSS) in stormwater runoff by 80% of the anticipated load from the developed site, expressed as an annual average. Stormwater management measures shall only be required for water quality control if an additional 1/4 acre of impervious surface is being proposed on a development site. The requirement to reduce TSS does not apply to any stormwater runoff in a discharge regulated under a numeric effluent limitation for TSS imposed under the New Jersey Pollution Discharge Elimination System (NJPDES) rules, N.J.A.C. 7:14A or in a discharge specifically exempt under a NJPDES permit from this requirement. The water quality design storm is 1.25 inches of rainfall in two hours. Water quality calculations shall take into account the distribution of rain from the water quality design storm, as reflected in Table 1. The calculation of the volume of runoff may take into account the implementation of nonstructural and structural stormwater management measures.

Table 1: Water Quality Design Storm Distribution
Time (minutes)	Cumulative Rainfall (inches)	Time (minutes)	Cumulative Rainfall (inches)
0	0.0000	65	0.8917
5	0.0083	70	0.9917
10	0.0166	75	1.0500
15	0.0250	80	1.0840
20	0.0500	85	1.1170
25	0.0750	90	1.1500
30	0.1000	95	1.1750
35	0.1330	100	1.2000
40	0.1660	105	1.2250
45	0.2000	110	1.2334
50	0.2583	115	1.2417
55	0.3583	120	1.2500
60	0.6250

For purposes of TSS reduction calculations, Table 2 below presents the presumed removal rated 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 § 230-183 of this article or found on the Department's website at www.njstormwater.org. The BMP Manual and other sources of technical guidance are listed in § 230-183 of this article. TSS reduction shall be calculated based on the removal rates for the BMPs in Table 2 below. Alternative removal rates and methods of calculating removal rates may be used if the design engineer provides documentation demonstrating the capability of these alternative rates and methods to the review agency. A copy of any approved alternative rate or method of calculating the removal rate shall be provided to the Department at the following address: Division of Watershed Management, New Jersey Department of Environmental Protection, P.O. Box 418, Trenton, New Jersey 08625-0418.

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 from application of the both BMPs
	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% to 60%
	Infiltration structure	80%
	Manufactured treatment device	See § 230-182C
	Sand filter	80%
	Vegetative filter strip	60% to 80%
	Wet pond	50% to 90%

If there is more than one on-site drainage area, the eighty-percent TSS removal rate shall apply to each drainage area, unless the runoff from the subareas converge on site, in which case the removal rate can be demonstrated through calculation using a weighted average.

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 §§ 230-179F and 230-180 of this article.

Additional information and examples are contained in the New Jersey Stormwater Best Management Practices Manual, which may be obtained from the address identified in § 230-183 of this article.

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.

Special water resources protection areas shall be established along all waters designated Category One at N.J.A.C. 7:9B, and perennial or intermittent streams that drain into or upstream of the Category One waters as shown on the USGS Quadrangle Maps or in the county soil surveys, within the associated HUC14 drainage area. These areas shall be established for the protection of water quality, aesthetic value, exceptional ecological significance, exceptional recreational significance, exceptional water supply significance, and exceptional fisheries significance of those established Category One waters. These areas shall be designated and protected as follows:

The applicant shall preserve and maintain a special water resource protection area in accordance with one of the following:

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.[1]

Editor's Note: Amended at time of adoption of Code (see Ch. 1, General Provisions, Art. I).

Encroachment within the designated special water resource protection area under Subsection H(1)(a) 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 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.

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.

If stormwater discharge 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:

Stabilization measures shall not be placed within 150 feet of the Category One waterway;

Stormwater associated with discharge allowed by this article shall achieve a ninety-five-percent TSS post-construction removal rate;

Temperature shall be addressed to ensure no impact on the receiving waterway;

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;

(e)

A conceptual project design meeting shall be held with the appropriate Department staff and Soil Conservation District staff to identify necessary stabilization measures; and

(f)

All encroachments proposed under this article shall be subject to review and approval by the Department.

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 waterway subject to § 230-180H of this article has been approved by the Department of Environmental Protection, then the provisions of the plan shall be the applicable special water resource protection area requirements for that waterway. A stream corridor protection plan for a waterway subject § 230-180H shall maintain or enhance the current functional value and overall condition of the special water resource protection area as defined in Subsection H(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.

Subsection H 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.

§ 230-181 Calculation of stormwater runoff and groundwater recharge.

Stormwater runoff shall be calculated in accordance with the following:

The design engineer shall calculate runoff using one of the following methods:

The USDA Natural Resources Conservation Service (NRCS) methodology, including the NRCS Runoff Equation and Dimensionless Unit Hydrograph, as described in the NRCS National Engineering Handbook Part 630— Hydrology and Technical Release 55 — Urban Hydrology for Small Watersheds; or

The Rational Method for peak flow and the Modified Rational Method for hydrograph computations.

For the purpose of calculating runoff coefficients and groundwater recharge, there is a presumption that the preconstruction condition of a site or portion thereof is a wooded land use with good hydrologic condition. The term "runoff coefficient" applies to both the NRCS methodology at Subsection A(1)(a) and the Rational and Modified Rational Methods at Subsection A(1)(b). A runoff coefficient or a groundwater recharge land cover for an existing condition may be used on all or a portion of the site if the design engineer verifies that the hydrologic condition has existed on the site or portion of the site for at least five years without interruption prior to the time of application. If more than one land cover have existed on the site during the five years immediately prior to the time of application, the land cover with the lowest runoff potential shall be used for the computations. In addition, there is the presumption that the site is in good hydrologic condition (if the land use type is pasture, lawn or park), with good cover (if the land use type is woods), or with good hydrologic condition and conservation treatment (if the land type is cultivation).

In computing preconstruction stormwater runoff, the design engineer shall account for all significant land features and structures, such as ponds, wetlands, depressions, hedgerows or culverts, that may reduce preconstruction stormwater runoff rates and volumes.

In computing stormwater runoff from all design storms, the design engineer shall consider the relative stormwater runoff rates and/or volumes of pervious and impervious surfaces separately to accurately compute the rates and volume of stormwater runoff from the site. To calculate runoff from unconnected impervious cover, urban impervious area modifications as described in the NRCS Technical Release 55 — Urban Hydrology for Small Watersheds and other methods may be employed.

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.

Groundwater recharge may be calculated in accordance with the following:

The New Jersey Geological Survey Report GSR-32, A Method for Evaluating Ground-Water Recharge Areas in New Jersey, incorporated herein by reference, as amended and supplemented. Information regarding the methodology is available from the New Jersey Stormwater Best Management Practices Manual at http:/www.state.nj.us/dep/njgs/ or at New Jersey Geological Survey, 29 Arctic Parkway, P.O. Box 427, Trenton, New Jersey 08625-0427; (609) 984-6587.

§ 230-182 Standards for structural stormwater management measures.

Standard for structural stormwater management measures are as follows:

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).

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 § 230-184B of this article.

Structural stormwater management measures shall be designed, constructed, and installed to be strong, durable, and corrosion resistant. Measures that are consistent with the relevant portions of the Residential Site Improvement Standards at N.J.A.C. 5:21-7.3, 5:21-7.4, and 5:21-7.5 shall be deemed to meet this requirement.

At the intake to the outlet from the stormwater management basin, the orifice size shall be minimum of 2 1/2 inches in diameter.

Stormwater management basins shall be designed to meet the minimum safety standards for stormwater management basins at § 230-184 of this article.

Stormwater management measure guidelines are available in the New Jersey Stormwater Best Management Practices Manual. Other stormwater management measures may be utilized, provided the design engineer demonstrates that the proposed measure and its design will accomplish the required water quantity, groundwater recharge and water quality design and performance standards established by §§ 230-179 and 230-180 of this article.

Manufactured treatment devices may be used to meet the requirements of §§ 230-179 and 230-180 of this article, provided the pollutant removal rates are verified by the New Jersey Corporation for Advanced Technology and certified by the Department.

§ 230-183 Sources for technical guidance.

Technical guidance for stormwater management measures can be found in the documents listed at Subsection A(1) and (2) below, which are available from Maps and Publications, New Jersey Department of Environmental Protection, 428 East State Street, P.O. Box 420, Trenton, New Jersey, 08625; (609) 777-1038.

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 filter, vegetative filter strips, and wet ponds.

The New Jersey Department of Environmental Protection Stormwater Management Facilities Maintenance Manual, as amended.

Additional technical guidance for stormwater management measures can be obtained from the following:

The Standard for Soil Erosion and Sediment Control in New Jersey promulgated by the State Soil Conservation Committee and incorporated into N.J.A.C. 2:90. Copies of these standards may be obtained by contacting the State Soil Conservation Committee or any of the soil conservation districts listed in N.J.A.C. 2:90-1.3(a)4. The location, address, and telephone number of each soil conservation district may be obtained from the State Soil Conservation Committee, P.O. Box 330, Trenton, New Jersey 08625; (609) 292-5540;

The Rutgers Cooperative Extension Service, (732) 932-9306; and

The Soil Conservation District listed in N.J.A.C. 2:90-1.3(a)4. The location, address, and telephone number of each soil conservation district may be obtained from the State Soil Conservation Committee, P.O. Box 330, Trenton, New Jersey 08625; (609) 292-5540.

§ 230-184 Safety standards for stormwater management basins.

This article sets forth requirements to protect public safety through the proper design and operation of stormwater management basins. This article applies to any new stormwater management basin.

Requirements for trash racks, overflow grates and escape provisions.

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:

The trash rack shall have parallel bars, with no greater than six-inch spacing between the bars.

The trash rack shall be designed so as not to adversely affect the hydraulic performance of the outlet pipe or structure.

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.

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.

An overflow grate is designed to prevent obstruction of the overflow structure. If an outlet structure has an overflow grate, such grate shall meet the following requirements:

The overflow grate shall be secured to the outlet structure but removable for emergencies and maintenance.

The overflow grate spacing shall be no less than two inches across the smallest dimension.

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.

For purposes of this Subsection B(3), "escape provisions" means the permanent installation of ladders, steps, rungs or other features that provide easily accessible means of egress from stormwater management basin. Stormwater management basins shall include escape provisions as follows:

If a stormwater management basin has an outlet structure, escape provisions shall be incorporated in or on the structure. With the prior approval of the reviewing agency identified in § 230-184C of this article, a freestanding outlet structure may be exempted from this requirement.

Safety ledges shall be constructed on the slopes of all new stormwater management basins having a permanent pool of water deeper than 2 1/2 feet. Such safety ledges shall be comprised of two steps. Each step shall be four to six feet in width. One step shall be located approximately 2 1/2 feet below the permanent water surface, and the second step shall be located one to 1 1/2 feet above the permanent water surface. See § 230-184D of this article for an illustration of safety ledges in a stormwater management basin.

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.

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.

Illustration of safety ledges in a new stormwater management basin. See Figure 1 below.

	Figure 1: Required Safety Ledges for a Stormwater Management Wet Pond

§ 230-185 Requirements for a site development stormwater plan.

Submission of site development stormwater plan.

Whenever an applicant seeks municipal approval of a development subject to this article, the applicant shall submit all of the required components of the Checklist for the Site Development Stormwater Plan at Subsection C below as part of the submission of the applicant's application for subdivision or site approval.

The applicant shall demonstrate that the project meets the standard set forth in this article.

The applicant shall submit (specify number) copies of the material listed in the checklist for site development stormwater plans in accordance with Subsection C of this article.

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 municipal board of official shall consult the engineer retained by the Planning and/or Zoning Board (as appropriate) to determine if the project meets the standards set forth in this article.

Checklist requirements. The following information shall be required:

Topographic base map. The reviewing engineer may require upstream tributary drainage system information. It is recommended that the topographic base map of the site be submitted which extends a minimum of 200 feet beyond the limits of the proposed development, at a scale of one inch equals 200 feet or greater, showing two-foot contour intervals. The map, as appropriate, may indicate the following; existing surface water drainage, shorelines, steep slopes, soils, erodible soils, perennial or intermitted streams that drain into or upstream of the Category One waters, wetlands and floodplains along with their appropriate buffer strips, marshlands and other wetlands, pervious or vegetative surfaces, existing man-made structures, roads, bearing and distances of property lines, and significant natural and man-made features not otherwise shown.

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 environmental sensitive features and to those that provide particular opportunities or constraints for development.

Project description and site plan(s). A map (or maps) at the scale of the topographic base map, indicating the location of existing and proposed buildings, roads, parking areas, utilities, structural facilities for stormwater management and sediment control, and other permanent structures. The map(s) shall also clearly show areas where alterations occur in the natural terrain and cover, including lawns and other landscaping, and seasonal high groundwater elevations. A written description of the site plan and justification of proposed changes in natural conditions may also be provided.

Land use planning and source control plan. This plan shall provide a demonstration of how the goals and standards of §§ 230-178 through 230-182 of this article are being met. The focus of this plan shall be to describe how the site is being developed to meet the objective of controlling groundwater recharge, stormwater quality and stormwater quantity problems at the source by land management and source controls whenever possible.

Stormwater management facilities map. The following information, illustrated on a map of the same scale as the topographic base map, shall be included:

Total area to be paved or built upon, proposed surface contours, land area to be occupied by the stormwater management facilities and the type of vegetation thereon, and details of the proposed plan to control and dispose of stormwater.

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.

Comprehensive hydrologic and hydraulic design calculations for the predevelopment and post-development conditions for the design storms specified in § 230-180 of this article.

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.

(7)

Maintenance and repair plan. The design and planning of the stormwater management facility shall meet the maintenance requirements of § 230-186 of this article.

(8)

Waiver form submission requirements. The municipal official or board reviewing an application under this article may, in consultation with Municipal Engineer, waive submission of any of the requirements in § 230-185C(1) through (6) of this article when it can be demonstrated that the information requested is impossible to obtain or it would create a hardship on the applicant to obtain, and its absence will not materially affect the review process.

§ 230-186 Maintenance and repair.

Applicability. Projects subject to review as in § 230-176C of this article shall comply with the requirements of Subsections B and C in this section.

General maintenance.

The design engineer shall prepare a maintenance plan for the stormwater management measures incorporated into the design of a major development.

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.

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.

If the person responsible for maintenance identified under § 230-186B(2) above is not a public agency, the maintenance plan and any future revisions based on § 230-186B(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.