Public Township Council Meeting — Packet

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 one hundred fifty (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. (b) All stormwater shall be discharged outside of and flow through the special water resource protection area and shall comply with the Standard for Off-Site Stability in the "Standards for Soil Erosion and Sediment Control in New Jersey," established under the Soil Erosion and Sediment Control Act, N.J.S.A. 4:24-39 et seq. (c) If stormwater discharged outside of and flowing through the special water resource protection area cannot comply with the Standard for Off-Site Stability in the, "Standards for Soil Erosion and Sediment Control in New Jersey," established under the Soil Erosion and Sediment Control Act, N.J.S.A. 4:24-39 et seq., then the stabilization measures in accordance with the requirements of the above standards may be placed within the special water resource protection area, provided that: (1) Stabilization measures shall not be placed within one hundred fifty (150) feet of the Category One waterway; (2) Stormwater associated with discharges allowed by this section shall achieve a ninety-five (95%) percent TSS post-construction removal rate; 167

DRAFT PROPOSED REVISIONS – OCTOBER 2011 (3) Temperature shall be addressed to ensure no impact on receiving waterway; (4) The encroachment shall only be allowed where the applicant demonstrates that the functional value and overall condition of the special water resource protection area will be maintained to the maximum extent practicable; (5) A conceptual project design meeting shall be held with the appropriate Department staff and Soil Conservation District staff to identify necessary stabilization measures; and (6) All encroachments proposed under this subsection shall be subject to review and approval by the Department. (d) A stream corridor protection plan may be developed by a regional stormwater management planning committee as an element of a regional stormwater management plan, or by a municipality through an adopted municipal stormwater management plan. If a stream corridor protection plan for a waterway subject to subsection 25- 29.4g,8. has been approved by the Department of Environmental Protection, then the provisions of the plan shall be the applicable special water resource protection area requirements for that waterway. A stream corridor protection plan for a waterway subject to paragraph g,8. shall maintain or enhance the current functional value and overall condition of the special water resource protection area as defined in paragraph g,8(a)(1) above. In no case shall a stream corridor protection plan allow the reduction of the Special Water Resource Protection Area to less than one hundred fifty (150) feet as measured perpendicular to the waterway subject to this subsection. (e) This subsection does not apply to the construction of one (1) individual single family dwelling that is not part of a larger development on a lot receiving preliminary or final subdivision approval on or before the effective date of the

family dwelling that is not part of a larger development on a lot receiving preliminary or final subdivision approval on or before the effective date of the Stormwater Management Rules*, provided that the construction begins on or before five (5) years from effective date of the Stormwater Management Rules.* (Ord. No. 2063-06 § 4) 25-29.5 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: (a) The USDA Natural Resources Conservation Service (NRCS) methodology, including the NRCS Runoff Equation and Dimensionless Unit Hydrograph, as described in the NRCS National Engineering Handbook Section 4-Hydrology and Technical Release 55 - Urban Hydrology for Small Watersheds; or (b) The Rational Method for peak flow and the Modified Rational Method for hydrograph computations. 2. For the purpose of calculating runoff coefficients and groundwater recharge, there is a presumption that the preconstruction condition of a site or portion thereof is a wooded land use with good hydrologic condition. The term "runoff coefficient" applies to both the NRCS methodology at subsection 25-29.5a,1(a) and the Rational and Modified Rational Methods at subsection 25-29.5a,1(b). A runoff coefficient or a groundwater recharge land cover for an existing condition may be used on all or a portion of the site if the design engineer verifies that the hydrologic condition has existed on the site or portion of the site for at least five (5) years without interruption prior to the time of application. If more * Editor's Note: Ordinance No. 2063-06 codified herein was adopted March 21, 2006. 168

DRAFT PROPOSED REVISIONS – OCTOBER 2011 than one (1) land cover have existed on the site during the five (5) years immediately prior to the time of application, the land cover with the lowest runoff potential shall be used for the computations. In addition, there is the presumption that the site is in good hydrologic condition (if the land use type is pasture, lawn, or park), with good cover (if the land use type is woods), or with good hydrologic condition and conservation treatment (if the land use type is cultivation). 3. In computing preconstruction stormwater runoff, the design engineer shall account for all significant land features and structures, such as ponds, wetlands, depressions, hedgerows, or culverts that may reduce preconstruction stormwater runoff rates and volumes. 4. In computing stormwater runoff from all design storms, the design engineer shall consider the relative stormwater runoff rates and/or volumes of pervious and impervious surfaces separately to accurately compute the rates and volume of stormwater runoff from the site. To calculate runoff from unconnected impervious cover, urban impervious area modifications as described in the NRCS Technical Release-55, Urban Hydrology for Small Watersheds and other methods may be employed. 5. If the invert of the outlet structure of a stormwater management measure is below the flood hazard design flood elevation as defined at N.J.A.C. 7:13, the design engineer shall take into account the effects of tailwater in the design of structural stormwater management measures. b. Groundwater recharge may be calculated in accordance with the following: 1. 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. (Ord. No. 2063-06 § 5) 25-29.6 Standards for

jgs/; or at New Jersey Geological Survey, 29 Arctic Parkway, P.O. Box 427, Trenton, New Jersey 08625-0427; (609) 984-6587. (Ord. No. 2063-06 § 5) 25-29.6 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 (1) 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 (1/3) the width of the diameter of the orifice or one-third (1/3) the width of the weir, with a minimum spacing between bars of one (1) inch and a maximum spacing between bars of six (6) inches. In addition, the design of trash racks must comply with the requirements of subsection 25-29.8d. 3. Structural stormwater management measures shall be designed, constructed, and installed to be strong, durable, and corrosion resistant. Measures that are consistent with the relevant portions of the Residential Site Improvement Standards at N.J.A.C. 5:21-7.3, 7.4, and 7.5 shall be deemed to meet this requirement. 169

DRAFT PROPOSED REVISIONS – OCTOBER 2011 4. At the intake to the outlet from the stormwater management basin, the orifice size shall be a minimum of two and one-half (2 1/2) inches in diameter. 5. Stormwater management basins shall be designed to meet the minimum safety standards for stormwater management basins at subsection 25-29.8. 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, groundwater recharge and water quality design and performance standards established by this section. c. Manufactured treatment devices may be used to meet the requirements of this section, provided the pollutant removal rates are verified by the New Jersey Corporation for Advanced Technology and certified by the Department. (Ord. No. 2063-06 § 6) 25-29.7 Sources for Technical Guidance. a. Technical guidance for stormwater management measures can be found in the documents listed at paragraphs 1. and 2. below, which are available from Maps and Publications, Department of Environmental Protection, 428 East State Street, P.O. Box 420, Trenton, New Jersey, 08625; (609) 777-1038. 1. Guidelines for stormwater management measures are contained in the New Jersey Stormwater Best Management Practices Manual, as amended. Information is provided on stormwater management measures such as: bioretention systems, constructed stormwater wetlands, dry wells, extended detention basins, infiltration structures, manufactured treatment devices, pervious paving, sand filters, vegetative filter strips, and wet ponds. 2. The New Jersey Department of Environmental Protection Stormwater Management Facilities Maintenance Manual, as amended. b. Additional technical guidance for stormwater management measures can be obtained from the following: 1. The "Standards for Soil Erosion and Sediment Control in New Jersey" promulgated by the State Soil Conservation Committee and incorporated into N.J.A.C. 2:90. Copies of these standards may be obtained by contacting the

ediment Control in New Jersey" promulgated by the State Soil Conservation Committee and incorporated into N.J.A.C. 2:90. Copies of these standards may be obtained by contacting the State Soil Conservation Committee or any of the Soil Conservation Districts listed in N.J.A.C. 2:90-1.3(a)4. The location, address, and telephone number of each Soil Conservation District may be obtained from the State Soil Conservation Committee, P.O. Box 330, Trenton, New Jersey, 08625; (609) 292-5540; 2. The Rutgers Cooperative Extension Service, (732)932-9306; and 3. The Soil Conservation Districts listed in N.J.A.C. 2:90-1.3(a)4. The location, address, and telephone number of each Soil Conservation District may be obtained from the State Soil Conservation Committee, P.O. Box 330, Trenton, New Jersey, 08625, (609) 292-5540. (Ord. No. 2063-06 § 7) 25-29.8 Safety Standards for Stormwater Management Basins. a. This subsection sets forth requirements to protect public safety through the proper design and operation of stormwater management basins. This section applies to any new stormwater management basin. 170

DRAFT PROPOSED REVISIONS – OCTOBER 2011 b. The provisions of this subsection are not intended to preempt more stringent municipal or County safety requirements for new or existing stormwater management basins. c. Requirements for Trash Racks, Overflow Grates and Escape Provisions. 1. A trash rack is a device designed to catch trash and debris and prevent the clogging of outlet structures. Trash racks shall be installed at the intake to the outlet from the stormwater management basin to ensure proper functioning of the basin outlets in accordance with the following: (a) The trash rack shall have parallel bars, with no greater than six (6) 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 two and one-half (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 three hundred (300) lbs./ft. sq. 2. An overflow grate is designed to prevent obstruction of the overflow structure. If an outlet structure has an overflow grate, such grate shall meet the following requirements: (a) The overflow grate shall be secured to the outlet structure but removable for emergencies and maintenance. (b) The overflow grate spacing shall be no less than two (2) 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 three hundred (300) lbs./ft. sq. 3. For purposes of this subsection, escape provisions means the permanent installation of ladders, steps, rungs, or other features that provide easily accessible means of egress from stormwater management basins.

on, escape provisions means the permanent installation of ladders, steps, rungs, or other features that provide easily accessible means of egress from stormwater management basins. Stormwater management basins shall include escape provisions as follows: (a) If a stormwater management basin has an outlet structure, escape provisions shall be incorporated in or on the structure. With the prior approval of the reviewing agency identified in subsection 25-29.8d. 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 (2 1/2) feet. Such safety ledges shall be comprised of two (2) steps. Each step shall be four (4) to six (6) feet in width. One (1) step shall be located approximately two and one-half (2 1/2) feet below the permanent water surface, and the second step shall be located one (1) to one and one-half (1 1/2) feet above the permanent water surface. See subsection 25-29.8e. 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. d. Variance or Exemption from Safety Standards. 171

DRAFT PROPOSED REVISIONS – OCTOBER 2011 1. 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. e. Illustration of Safety Ledges in a New Stormwater Management Basin. (Ord. No. 2063-06 § 8) 25-29.9 Requirements for a Site Development Stormwater Plan. a. Submission of Site Development Stormwater Plan. 1. Whenever an applicant seeks municipal approval of a development subject to this ordinance, the applicant shall submit all of the required components of the Checklist for the Site Development Stormwater Plan at subsection 25-29.9c. below as part of the submission of the applicant's application for subdivision or site plan approval. 2. The applicant shall demonstrate that the project meets the standards set forth in this ordinance. 3. The applicant shall submit [specify number] copies of the materials listed in the checklist for site development stormwater plans in accordance with subsection 25-29.9c. of this ordinance. b. Site Development Stormwater Plan Approval. The applicant's site development project shall be reviewed as a part of the subdivision or site plan review process by the municipal board or official from which municipal approval is sought. That municipal board or official shall consult the engineer retained by the Planning and/or Zoning Board (as appropriate) to determine if all the checklist requirements have been satisfied and to determine if the project meets the standards set forth in this ordinance. 172