[2] For purposes of TSS reduction calculations, Table 2 below presents the presumed removal rates for certain BMPs designed in accordance with the New Jersey Stormwater Best Management Practices Manual. The BMP Manual may be obtained from the address identified in Subsection G below, or found on the Department's website at www.njstormwater.org. The BMP Manual and other sources of technical guidance are listed in
[3] 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
[4] 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 sub-areas converge on site in which case the removal rate can be demonstrated through a calculation using a weighted average.
(b) Nutrients. 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
(c) Additional information. Additional information and examples are contained in the New Jersey Stormwater Best Management Practices Manual, which may be obtained from the address identified in
(d) FW 1 waters. In accordance with the definition of FW 1 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 FW 1 .
(e) Category 1 waters. Special water resource protection areas shall be established along all waters designated Category One at N.J.A.C. 7:913, 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:
[1] The applicant shall preserve and maintain a special water resource protection area in accordance with one of the following:
[a] A 300-foot special water resource protection area shall be provided on each side of the waterway, measured perpendicular to the waterway from the top of the bank outwards or from the centerline of the waterway where the bank is not defined, consisting of existing vegetation or vegetation allowed to follow natural succession is provided.
[b] Encroachment within the designated special water resource protection area under Paragraph [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 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 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.
[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., 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:
[a] Stabilization measures shall not be placed within 150 feet of the Category One waterway;
[b] Stormwater associated with discharges allowed by this section shall achieve a 95 percent TSS post-construction removal rate;
[c] Temperature shall be addressed to ensure that there is no detrimental impact on the receiving waterway;
[d] 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 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 the Village through an adopted municipal stormwater management plan. If such a stream corridor protection plan for a waterway subject to
[5]
(7) Standards for structural stormwater management measures.
Standards for structural stormwater management measures are as follows:
(a) General.
[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.
[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] Stormwater management basins shall be designed to meet the minimum safety standards for stormwater management basins at
[5] Manufactured treatment devices may be used to meet the requirements of
[6] 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
(b) Trash racks. A trash rack is a device designed to catch trash and debris and prevent 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] Trash racks shall have parallel bars with one-inch (1 ") spacing between the bars to the elevation of the water quality design storm.
[2] 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.
[3] At the intake to the outlet from the stormwater management basin, the orifice size shall be a minimum of two and one-half (2.5) inches in diameter.
[4] The design of trash racks must also comply with the requirements of
(c) Grates and inlets to prevent discharge of trash and debris from drainage systems. Site design features identified ,under
[1] Design engineers shall use either of the following grates whenever they use a grate in pavement or another ground surface to collect stormwater from that surface into a storm drain or surface water body under that grate:
[a] The New Jersey Department of Transportation (NJDOT) bicycle safe grate, which is described in Chapter 2.4 of the NJDOT Bicycle Compatible Roadways and Bikeways Planning and Design Guidelines (April 1996); or
[b] A different grate, if each individual clear space in that grate has an area of no more than seven (7) square inches, or is no greater than one-half (0.5) inch across the smallest dimension.
Examples of grates subject to this standard include grates in grate inlets, the grate portion (non-curb-opening portion) of combination inlets, grates on storm sewer manholes, ditch grates, trench grates, and grates of spacer bars in slotted drains. Examples of ground surfaces include surfaces of roads (including bridges), driveways, parking areas, bikeways, plazas, sidewalks, lawns, fields, open channels, and stormwater basin floors.
[2] Whenever design engineers use a curb70pening 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 (7) square inches, or be no greater than two (2) inches across the smallest dimension.
[3] This standard does not apply:
[a] 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;
[b] Where flows from the water quality design storm as specified in
[i] A rectangular space four and five-eighths inches long and one and one-half (1 .5) inches wide (this option does not apply for outfall netting facilities); or
[ii] A bar screen having a bar spacing of one-half (0.5) inch.
[c] 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
[d] Where the New Jersey Department of Environmental Protection determines, pursuant to the New Jersey Register of Historic Places Rules at N.J.A.C. 7:4-7.2(c), that action to meet this standard is an undertaking that constitutes an encroachment or will damage or destroy the New Jersey Register listed historic property.
(d) Safety standards for stormwater management basins.
The following requirements are intended to protect public safety through the proper design and operation of stormwater management basins. These requirements apply to any new stormwater management basin.
[1] Requirements for trash racks. A trash rack is a device designed to catch trash and debris and prevent the clogging of outlet structures. Trash racks shall be installed at the intake to the outlet from the stormwater management basin to ensure proper functioning of the basin outlets in accordance with the following:
[a] The trash rack shall have parallel bars, with no greater than six inch spacing between the bars.
[b] The trash rack shall be designed so as not to adversely affect the hydraulic performance of the outlet pipe or structure.
[c] The average velocity of flow through a clean trash rack is not to exceed 2.5 feet per second under the full range of stage and discharge. Velocity is to be computed on the basis of the net area of opening through the rack.
[d] The trash rack shall be constructed and installed to be rigid, durable, and corrosion resistant, and shall be designed to withstand a perpendicular live loading of 300 Ibs/ft. sq.
[2] Requirements for overflow grates. An overflow grate is designed to prevent obstruction of the overflow structure. If an outlet structure has an overflow grate, such grate shall meet the following requirements:
[a] The overflow grate shall be secured to the outlet structure but removable for emergencies and maintenance.
[b] The overflow grate spacing shall be no less than two inches across the smallest dimension.
[c] The overflow grate shall be constructed and installed to be rigid, durable, and corrosion resistant, and shall be designed to withstand a perpendicular live loading of 300 Ibs./ft. sq.
[3] Requirements for escape provisions. For purposes of this paragraph, "escape provisions" means the permanent installation of ladders, steps, rungs, or other .features that provide easily accessible means of egress from stormwater management basins. Stormwater management basins shall include escape provisions as follows:
[a] If a stormwater management basin has an outlet structure, escape provisions shall be incorporated in or on the structure. With the prior approval of the reviewing agency a freestanding outlet structure may be exempted from this requirement.
[b] Safety ledges shall be constructed on the slopes of all new stormwater management basins having a permanent pool of water deeper than two and one-half 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 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 below for an illustration of safety ledges in a stormwater management basin.
[c] In new stormwater management basins, the maximum interior slope for an earthen dam, embankment, or berm shall not be steeper than 3 horizontal to 1 vertical.
[4] Relief 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.
(8) Maintenance and repair.
(a) Maintenance plan required. The design engineer shall prepare a maintenance plan for the stormwater management measures incorporated into the design of the development. Maintenance guidelines for stormwater management measures are available in the New Jersey Stormwater Best Management Practices Manual.
(b) Plan contents. 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). 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) Maintenance responsibility. 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) Recording of plan. If the person responsible for maintenance identified under paragraph (b) above is not a public agency, the maintenance plan and any future revisions based on paragraph (g) 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) Plan implementation. 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) Maintenance log. The person responsible for maintenance identified under paragraph (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) Ongoing evaluation. The person responsible for maintenance identified under paragraph 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) Record-keeping. The person responsible for maintenance identified under paragraph (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 paragraphs (f) and (g) above.
(i) Governmental facilities exempted. The requirements of paragraphs (c) and (d) above do not apply to stormwater management facilities that are dedicated to and accepted by the Village or another governmental agency.
(j) Failure to maintain. In the event that the stormwater management facility becomes a danger to public safety or public health, or if it is in need of maintenance or repair, the Village shall so notify the responsible person in writing. Upon receipt of that notice, the responsible person shall have fourteen (14) days to effect maintenance and repair of the facility in a manner that is approved by the Village Engineer or his/her approved designee. The Village, in its discretion, may extend the time allowed for effecting maintenance and repair for good cause. If the responsible person fails or refuses to perform such maintenance and repair, the Village or County may immediately proceed to do so and shall bill the cost thereof to the responsible person.
(k) Guarantees. Nothing in this section shall preclude the Village from requiring the posting of a performance or maintenance guarantee in accordance with N.J.S.A. 40:55D-53.
(9) Sources for technical guidance.
(a) Department sources. Technical guidance for stormwater management measures can be found in the documents listed below, which are available from Maps and Publications, New Jersey Department of Environmental Protection, 428 East State Street, P.O. Box 420, Trenton, New Jersey, 08625; telephone (609) 777-1038.
[1] Guidelines for stormwater management measures are contained in the New Jersey Stormwater Best Management Practices Manual, as amended. Information is provided on stormwater management measures such as: bioretention systems, constructed stormwater wetlands, dry wells, extended detention basins, infiltration structures, manufactured treatment devices, pervious paving, sand filters, vegetative filter strips, and wet ponds.
[2] The New Jersey Department of Environmental Protection Stormwater Management Facilities Maintenance Manual, as amended.
(b) Additional sources. 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 Bergen County Soil Conservation District is located at 700 Kinderkamack Road, Suite 106, Oradell, New Jersey 07649 telephone number (201) 261-4407, FAX (201) 261-7573;
[2] The Rutgers Cooperative Extension Service, 732-932-9306; and
[3] The Soil Conservation Districts listed in N.J.A.C. 2:90-1.3(a)4. The location, address, and telephone number of each Soil Conservation District may be obtained from the State Soil Conservation Committee, P.O. Box 330, Trenton, New Jersey, 08625, (609) 292-5540.
E. Requirements for minor development.
The following requirements shall apply to all minor development as defined by
(1) Erosion control standards.
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) Groundwater recharge standards.
(a) Applicability.
Stormwater runoff from the following areas shall be recharged, provided that the types of runoff indicated in
[1] All roof areas of buildings having an area of at least 200 square feet.
[2] Any impervious surface(s) that that represent an increase of at least two hundred (200) square feet of such surfaces from the pre-development condition.
(b) Groundwater recharge calculations.
Groundwater recharge calculations, when required, shall be prepared in accordance with the New Jersey Geological Survey Report GSR-32, A Method for Evaluating Groundwater Recharge Areas in New Jersey.
(c) Roof drain connections.
Stormwater runoff that must be recharged from roof areas shall drain to leaders that are connected to seepage pits/tanks or equivalent structures with schedule 40' or SDR 35 PVC pipe having a minimum six-inch (6") diameter.
(d) Seepage tank/retention system design.
[1] Storage capacity.
[a] When the amount of impervious surfaces that drains to the tank/system is at least two hundred (200) square feet but less than two thousand (2,000) square feet, the storage volume of the tank/system must be at least one gallon for each square foot of impervious cover. The volume of the air voids in the clean stone surrounding a tank/system shall not be counted toward the required volume.
[b] When the amount of impervious surfaces that drains to the tank/system is at least two thousand (2,000) square feet, the tank/system must be designed by a professional engineer so that the stormwater runoff from the site is no greater after than in the pre-development condition for the following storms:
1 hour - 3 inch rainfall
24 hours - 7 inch rainfall
[c] Soil tests. Soil percolation tests results shall be submitted to support design calculations when required by the Village Engineer.
[2] Tanks/systems shall be located a minimum of fifteen (15) feet from proposed or existing structure foundations, and located outside the required building envelope (i.e., area formed by the minimum setback lines for the principal building) whenever possible.
[3] Tanks/systems shall be located at least five (5) feet from the property line, provided that the Village Engineer may require a greater setback when it is determined that such location is not sufficient to avoid significant detriments to adjacent lands.
[4] At least two (2) feet of cover shall be provided over tanks/systems.
(3) Runoff quantity standards.
(a) Applicability. All development that results in an increase of at least two hundred (200) square feet of impervious cover from the predevelopment condition shall be designed so that there is no increase in the rate of stormwater runoff from the pre-development condition.
(b) Runoff calculation methodology. All runoff calculations shall be based on the two (2), ten (10) and one hundred (100) year storm events. Runoff shall be calculated using either the Rational Method (modified for hydrograph computations) or the USDA Natural Resources Conservation Service (NRCS) methodology, including the NRCS Runoff Equation and Dimensionless Unit Hydrograph, as described in the NRCS National Engineering Handbook, Section 4 -Hydrology and Technical Release 55 Urban Hydrology for Small Watersheds.
(4) Technical guidance. Technical guidance is available on a limited basis with the Engineering Division during normal office hours.
(5) Soil movement permits. A soil movement permit in accordance with Chapter 246 is required on a separate application whenever more than one hundred (100) cubic yards of soil is proposed to be moved.
F. Retrofitting of existing storm drain inlets. No person in control of private property (except a residential lot with one single family house) shall authorize the repaving, repairing (excluding the repair of individual potholes), resurfacing (including top coating or chip sealing with asphalt emulsion or a thin base of hot bitumen), reconstructing or altering any surface that is in direct contact with an existing storm drain inlet on that property unless the storm drain inlet either:
(1) Already meets the design standard described under § 190-83D(7)(c) for the control of the passage of solid and/or floatable materials; or
(2) Is retrofitted or replaced to meet the design standard under § 190-83D(7)(c) prior to the completion of the project.
**Webmasters Note: The previous subsection, F., has been added as per Ordinance No. 3223.
