Melanie Martin Hunterdon County Planning Department

Transcription

1 HUNTERDON COUNTY SAMPLE MUNICIPAL STORMWATER MANAGEMENT PLAN AND GUIDANCE DOCUMENT Although not mandatory it is highly recommended that municipalities submit their Municipal Stormwater Management Plans (MSWMP) to the Hunterdon County Planning Board as the Hunterdon County Board of Chosen Freeholders designated County Review Agency in both paper and electronic format (preferably an unlocked Adobe pdf) as soon as a draft version is available. This document has been prepared by the County Planning Board staff to facilitate and assist municipalities in developing their Municipal Stormwater Management Plans (MSWMP) and Ordinance required by the latest New Jersey Department of Environmental Protection (NJDEP) Stormwater Phase II Permitting Regulations and the Stormwater Management Rules. The links and resources provided within will enable you to meet the requirements outlined in N.J.A.C. 7: Additionally, you should become familiar with the Checklist for County Review of Municipal Stormwater Plans and Stormwater Control Ordinances provided by the NJDEP (posted on our website listed below). Please use this document in addition to the NJDEP checklist, listed above, for the formatting of your MSWMP. The County has prepared this model to incorporate County specific data and parameters into the Sample Municipal Stormwater Management Plan provided by the NJDEP. County additions, comments and changes have been added to the NJDEP Sample Municipal Stormwater Management Plan to tailor it to our region. Comments and phrases provided in italics are informational and instructional only and should not be included in the MSWMP. The County Review Agency will use the aforementioned documents as templates to ensure that the minimum requirements are met for the NJDEP. The County Review Agency encourages all municipalities to consider the MSWMP elements and ordinances of all neighboring communities in the creation of your MSWMP to ensure the highest level of effective plan implementation. Please see the Hunterdon County Stormwater Management website for helpful links and additional information. Melanie Martin Hunterdon County Planning Department Hunterdon County Planning Department would like to thank the following organizations for their assistance with the creation of this document: New Jersey Department of Environmental Protection, Division of Watershed Management County of Somerset Hunterdon County Soil Conservation District Hunterdon County Roads, Bridges and Engineering Department Princeton Hydro, LLC Additionally, we would like to thank the City of Lambertville s Stormwater Committee for allowing us to share their MSWMP on our website. 1

2 SAMPLE MUNICIPAL STORMWATER MANAGEMENT PLAN INTRODUCTION This Municipal Stormwater Management Plan (MSWMP) provides the strategies and implementation tools for Municipality s stormwater management program. The creation of this plan is required by N.J.A.C. 7:14A-25 Municipal Stormwater Regulations and the contents and format of this document are consistent with the requirements of N.J.A.C. 7:8 Municipal Stormwater Management Rules. The plan provides the options and strategies available to improve the management of stormwater throughout Municipality (Borough, City, Town or Township). Issues of groundwater recharge, impacts of stormwater runoff quantity and quality, water quality degradation associated with new development, design and performance standards and low impact / sustainable stormwater management practices are addressed. The standards and practices provided within are intended to incorporate better methods and advance the science of managing stormwater by relying less on traditional structural stormwater management techniques for all development projects and more on non-structural techniques that mimic existing hydrology. These standards are intended to minimize the adverse impact of stormwater runoff on water quality and quantity and the loss of groundwater recharge that provides baseflow in receiving water bodies. This transition in stormwater management ideology will result in less obtrusive facilities that are more aesthetic to the community and less laborious on those responsible for long-term operations and maintenance. This plan also addresses the review and update of the municipal Master Plan, existing ordinances and other related planning documents to facilitate municipal administrative consistency. Additionally, this plan includes a mitigation strategy for special circumstances resulting in a waiver, variance or exemption from the design and performance standards detailed within. The mitigation plan will identify the requisite measures required to offset the impact created by granting a waiver, variance or exemption and to lessen the impact of existing development. STORMWATER MANAGEMENT GOALS The goals of this MSWMP are to: (Be sure to include the nine basic goals of municipal stormwater management planning provided in N.J.A.C. 7:8-2.2: Safely convey floodwaters and reduce flood damage, including damage to life and property; Minimize, to the extent practical, any increase in stormwater runoff from any new development; Reduce soil erosion from any development or construction project; Assure the adequacy of existing and proposed culverts and bridges, and other in stream structures; Maintain groundwater recharge and quality; Prevent, to the greatest extent feasible, an increase in nonpoint pollution; Decrease overbank flooding (overbank flooding occurs when excess water overloads the stream channels and flows out into the floodplain) and maintain the integrity of stream channels for their biological functions, as well as for drainage and habitat, through the development of riparian buffer zones; 2

3 Minimize pollutants in stormwater from new and existing development to restore, enhance and maintain the chemical, physical and biological integrity of the waters of the State, to protect the public health, to safeguard fish and aquatic life and scenic and ecological values and to enhance the domestic, municipal, recreational, industrial, and other uses of water; Protect public safety through the proper design and operation of stormwater basins; Preserve and protect the environmentally sensitive areas, including but not limited to steep slopes, wetlands, floodplains, groundwater recharge areas as defined by the N.J.A.C. 7:8, and wildlife habitats; and Educate the public about and generate acceptance for the stormwater control measures detailed in the MSWMP. To achieve these goals, this plan outlines specific stormwater design and performance standards for new development. Additionally, the plan proposes stormwater management controls to address impacts from existing development. Preventative and corrective maintenance strategies are included in the plan to ensure long-term effectiveness of stormwater management facilities. The plan also outlines safety standards for stormwater infrastructure to be implemented to protect public safety. GENERAL STORMWATER DISCUSSION As provided in the New Jersey Stormwater Best Management Practices Manual: Land development can dramatically alter the hydrologic cycle (Figure #) of a site and, ultimately, an entire watershed. Prior to development, native vegetation can either directly intercept precipitation or draw that portion that has infiltrated into the ground and return it to the atmosphere through evapotranspiration. Development can remove this beneficial vegetation and replace it with lawn or impervious cover, reducing the site s evapotranspiration and infiltration rates. Clearing and grading a site can remove depressions that store rainfall. Construction activities may also compact the soil and diminish its infiltration ability, resulting in increased volumes and rates of stormwater runoff from the site. Impervious areas that are connected to each other through gutters, channels, and storm sewers can transport runoff more quickly than natural areas. This shortening of the transport or travel time quickens the rainfall-runoff response of the drainage area, causing flow in downstream waterways to peak faster and higher than natural conditions. These increases can create new and aggravate existing downstream flooding and erosion problems and increase the quantity of sediment in the channel. Filtration of runoff and removal of pollutants by surface and channel vegetation is eliminated by storm sewers that discharge runoff directly into a stream. Increases in impervious area can also decrease opportunities for infiltration that, in turn, reduces stream base flow and groundwater recharge. Reduced base flows and increased peak flows produce greater fluctuations between normal and storm flow rates, which can increase channel erosion. Reduced base flows can also negatively impact the hydrology of adjacent wetlands and the health of biological communities that depend on base flows. Finally, erosion and sedimentation can destroy habitat from which some species cannot adapt. [Figure #: Include Hydrologic Cycle diagram], please see the Hunterdon County Stormwater Management website for a word document containing a hydrologic cycle diagram and source that can be cut and pasted into your document (Source: NJDEP Division of Stormwater and Nonpoint Source Pollution). In addition to increases in runoff peaks, volumes, and loss of groundwater recharge, land development often results in the accumulation of pollutants on the land surface that runoff can 3

4 mobilize and transport to streams. New impervious surfaces and cleared areas created by development can accumulate a variety of pollutants from the atmosphere, fertilizers, animal wastes, and leakage and wear from vehicles. Pollutants can include metals, suspended solids, hydrocarbons, pathogens, and nutrients. In addition to increased pollutant loading, land development can adversely affect water quality and stream biota in more subtle ways. For example, stormwater falling on impervious surfaces or stored in detention or retention basins can become heated and raise the temperature of the downstream waterway, adversely affecting cold water fish species such as trout. Development can remove trees along stream banks that normally provide shading, stabilization, and leaf litter that falls into streams and becomes food for the aquatic community. MUNICIPAL BACKGROUND Please utilize the charts in Appendices A and B for the following paragraph inclusions; charts taken from Hunterdon County Databook, 2003 or can be found at Municipality encompasses square miles (use Appendix A) in the part of Hunterdon County, New Jersey. The predominant land use throughout the municipality is (describe land use and development trends observed throughout the municipality). The existing land use map is depicted in Figure # and is based on the (provide data year and source, i.e Municipal Land Use and/or Zoning). The various zoning districts found in the township/borough/city/town and the current zoning map is shown in Figure #. Please feel free to contact the County for mapping assistance. The undeveloped areas that exist in Municipality are located and can be seen on the (year) aerial photo with parcel lot lines (Figure #). Figure # illustrates the hydrology of Municipality and Figure # identifies the topography as depicted on the USGS 7.5 Minute Quadrangle Maps. USGS 7.5 Minute Quadrangle Maps can be located at: or you can contact the County for further mapping questions and assistance. According to the 2000 census, Municipality has residents. The population rose approximately percent since the 1990 census (use Appendix B). Population increases have resulted in considerable demand for new development throughout Hunterdon County; these changes in the landscape have most likely increased stormwater runoff volumes and pollutant loads to the waterways of the municipality. Additionally, this population increase/decrease is significant and is/but more than/less than the overall state and county increases of approximately 9 and 13 percent respectively over the same period. Give a brief description of the development potential of Municipality. [e.g., Municipality has a small/moderate/significant (choose one) amount of developable land. and/or Municipality is almost fully developed., refer to your build-out / land use analysis section of MSWMP]. It was determined through the 2004 Cross-Acceptance III process that Municipality is mostly/partially (choose one) within the (provide New Jersey State Planning Area Designation) and/or our township has assigned (list all applicable areas) as a designated center where the groundwater recharge requirements are not applicable according to N.J.A.C. 7:8-5.4(a)2ii. 4

5 Give a hydrologic location of the Municipality. The Township is situated along the side of the River in the Basin. It is located in the Watershed Management Area (WMA) and contains portions of Hydrologic Unit Code (HUC) areas for (add HUC14 areas within township). These HUC-14 areas are shown in Figure #. [Although not required by the rule, a map showing the watershed boundaries in your Municipality is beneficial for impact location and assessment, funding searches and grant applications. To find your watershed address" and links to GIS data go to Additionally, the following watershed groups serve our Municipality (list any non-profit, volunteer or other watershed groups that assist your Municipality). A brief overview of the HUC and WMA designations: The United States Geological Service has developed a method for identifying and inventorying watersheds in the U.S. called the hydrologic unit code system. Through this system all U.S. watersheds have a name and a corresponding number, this number is called the hydrologic unit code (HUC) or watershed address. (Source: USGS) The term "HUC-14" is from the hydrologic unit code system for delineating and identifying drainage areas. The system starts with the largest possible drainage area (basin) and progressively breaks it down into smaller subdivisions (subbasins, watersheds and subwatersheds respectively). These subdivisions are delineated and numbered in a nested fashion (see example below). A drainage area with a 14 numbered address, or HUC-14, is a subwatershed of a larger watershed with 11 numbers, or a HUC-11, see the table below. There are 921 HUC-14 subwatersheds in New Jersey that average 8.5 square miles. There are 150 HUC-11 watersheds in New Jersey with an average size of 51.9 square miles. To see a graphic depiction of the breakdown of New Jersey go to: (Source: NJDEP Division of Watershed Management) Example of how a USGS hydrologic unit code system works: DESCRIPTION ADDRESS Basin Watershed Region (Subbasin) Watershed HUC Subwatershed HUC The dephuc14 is NJDEP's version of the USGS HUC-14 that delineates the extent of the DEP watershed management regions and areas to be used for the statewide watershed initiative. The NJDEP Watershed Management Area (WMA) and dephuc14 area are very similar; both were created from the USGS HUC-14 data. (Source: NJDEP Division of Watershed Management) WATER QUALITY ISSUES In 1992, the New Jersey Department of Environmental Protection (NJDEP) has established an Ambient Biomonitoring Network (AMNET) to document the health of the state s waterways. Monitoring the effects of stormwater pollution on the health of our waterways enables us to determine the best strategies to improve water quality for residents locally and throughout the State. There are over 800 AMNET sites (referred to as Site # in Appendix C, also available on our website) throughout New Jersey. These sites are sampled for benthic macroinvertebrates 5

6 (biological indicators of stream health) by NJDEP on a five-year cycle. Streams are classified as non-impaired, moderately impaired, or severely impaired based on the AMNET data. (Appendix C lists the impairments as IMPAIR1 or IMPAIR2 with a rating of no sample, none, moderate or severe.) Non-impaired: Benthic community comparable to other undisturbed streams within the region. A community characterized by a maximum taxa richness, balanced taxa groups and good representation of intolerant individuals. Moderately Impaired: Macroinvertebrate richness is reduced, in particular EPT taxa. Taxa composition changes result in reduced community balance and intolerant taxa become absent. Severely Impaired: A dramatic change in the benthic community has occurred. Macroinvertebrates are dominated by a few taxa that are very abundant. Tolerant taxa are the only individuals present. Source: New Jersey Department of Environmental Protection Bureau of Freshwater and Biological Monitoring (NJDEP/BFBM): The data is used to generate a New Jersey Impairment Score or NJIS, (refer to NJIS 1 ( sampling) and NJIS 2 ( sampling) on Appendix C; this is the Biological Impairment Rating for the first and second rounds of sampling), which is based on a number of biometrics related to benthic macroinvertebrate community dynamics in the waterways. Biological Assessment Total Score Non-impaired Moderately Impaired 9-21 Severely Impaired 0-6 Source: NJDEP/BFBM: The AMNET table (Appendix C) was modified from the NJDEP data to include only those sites located in Hunterdon County. For clarification the following information is provided to explain the column labeled HABITAT2. Definition: Habitat Score for second round of sampling. Parameters evaluated included in-stream substrate, channel morphology, bank structural features, and riparian vegetation. The area evaluated included the sample site and its immediate surroundings (usually within a foot radius). The qualitative habitat assessment involves four condition categories, rating each parameter as optimal, suboptimal, marginal or poor based on recently revised EPA criteria (Barbour et. Al, 1997 Revision to Rapid Bioassessment Protocols for Use in Streams and Rivers: Periphyton, Benthic Macroinvertebrates, and Fish. USEPA 841-D ). Note: a score of 999 indicates the site was not assessed for habitat. Source: NJDEP/BFBM 6

7 Based on the AMNET data, the waterbodies bordering/within/throughout Municipality are significantly impaired/moderately impaired/not impaired. If none are present include the following statement: The closest AMNET site is located. There are also AMNET sites upstream/downstream on the River at (provide location from Appendix C). Please see the following website for additional AMNET information and data: Historic AMNET data can be downloaded from: Please see Appendix C for a listing of the NJDEP AMNET Reference Sites with Ecoregion Sections in Hunterdon County. Stream health can be determined from a variety of factors, e.g. biological, chemical, physical, etc The most common testing parameters include but are not limited to: fecal coliform, e. coli, total phosphorous, dissolved oxygen, total suspended solids, temperature, nitrates/nitrites, ph, and turbidity (United States Environmental Protection Agency, USEPA). For a list and thorough description of why the individual parameters should be monitored go to In addition to the AMNET data, the NJDEP and other regulatory agencies collect water quality chemical data on the streams in the state. Provide the following information if applicable to your Municipality: These data show that the instream total phosphorus concentrations and fecal coliform concentrations of the Raritan and Millstone Rivers frequently exceed the state s criteria. This means that these rivers are impaired waterways and the NJDEP is required to develop a Total Maximum Daily Load (TMDL) for these pollutants for each waterway. A TMDL is the amount of a pollutant that can be accepted by a waterbody without causing an exceedance of water quality standards or interfering with the ability to use a waterbody for one or more of its designated uses. The allowable load is allocated to the various sources of the pollutant, such as stormwater and wastewater discharges, which require an NJPDES permit to discharge, and nonpoint source, which includes stormwater runoff from agricultural areas and residential areas, along with a margin of safety. Provisions may also be made for future sources in the form of reserve capacity. An implementation plan is developed to identify how the various sources will be reduced to the designated allocations. Implementation strategies may include improved stormwater treatment plants, adoption of ordinances, reforestation of stream corridors, retrofitting stormwater systems, and other BMP s. The New Jersey Integrated Water Quality Monitoring and Assessment Report (305(b) and 303(d)) (Integrated List) is required by the federal Clean Water Act to be prepared biennially and is a valuable source of water quality information. This combined report presents the extent to which New Jersey waters are attaining water quality standards, and identifies waters that are impaired. Sublist 5 of the Integrated List constitutes the list of waters impaired or threatened by pollutants, for which one or more TMDL s are needed. The (Stream/Brook/Creek/Tributary/Lake/Reservoir) is/are listed on Sublist 5. The Delaware, Lamington, Musconetcong, Neshanic and Raritan River are also listed on the 2004 Integrated List. The integrated list is available from the NJDEP website at: or you may contact the NJDEP for a specific listing. Note: The USEPA Guidance for developing Integrated Reports (USEPA 2001, USEPA 2003) of water quality and listings of impaired water segments recommends placing the assessment results into one of five specific categories. The USEPA s Guidance defines the five categories in which a waterbody may be placed. The NJDEP has renamed Category 1-5 (USEPA designation) to Sublist 1-5 to avoid confusion with Category 1 Waterbody Designation. The following list is how the Sublists were determined: 7

8 Sublist 1: Attaining a water quality standard and no use is threatened. Sublist 2: Attaining some of the designated uses; no use is threatened; and insufficient or no data and information is available to determine if the remaining uses are attained or threatened. Sublist 3: Insufficient or no data and information to determine if any designated use is attained. Sublist 4: Impaired or threatened for one or more designated uses but does not require the development of a TMDL. (Three Categories). 1. TMDL has been completed. 2. Other enforceable pollution control requirements are reasonably expected to result in the attainment of the water quality standard in the near future. 3. Impairment is not caused by a pollutant. Sublist 5: The water quality standard is not attained. The waterbody is impaired or threatened for one or more designated uses by a pollutant(s), and requires a TMDL. Source NJDEP: WATER QUANTITY ISSUES In addition to water quality problems, the Township has occasional/severe water quantity problems including but not limited to flooding, stream bank erosion and diminished base flow. Describe flooding impacts to communities, [e.g. Flooding occurs on the River(s) and on (Stream/Brook). Flooding on the River(s) affects properties on the side of the Township. While flooding along (Stream/Brook) affects properties along its length]. The 100-year floodplain, shown in Figure #, depicts the River, Stream/Brook, and Stream/Brook floodplains. Water quantity impacts in the municipality extend further than the floodplains. Many of the existing structural stormwater management facilities cannot sustain the flow of water created from severe storm events. During these events, the existing facilities do not have adequate capacity, thereby causing a backwater effect and increased flooding upstream. The increased amounts of water result in stream bank erosion, under-cutting, scouring, overbank erosion, habitat loss and degradation of roadways and bridge crossings. The capacity deficit in existing facilities is a direct result of the increased amount of impervious surfaces throughout Municipality. (Although not required, Municipalities are highly encouraged to inventory and list site-specific examples.) Additionally, the high imperviousness of the Township has significantly decreased groundwater recharge, decreasing base flows in streams during dry weather periods. Lower base flows can have a negative impact on instream habitat during the summer months. Groundwater recharge rates for native soils in this area are generally between and inches annually. The average annual groundwater recharge rates are shown graphically in Figure #. Groundwater recharge rates can be found at under Digital Data: Groundwater, DGS99-2 MS Excel Workbook Implementing the NJGS Ground-Water-Recharge Methodology. New Jersey Geologic Survey (NJGS) estimates groundwater recharge using 8

9 methodology from NJGS Report GSR-32 "A Method for Evaluation of Ground-Water-Recharge Areas in New Jersey. Land-use/land-cover, soil and municipality-based climatic data were combined and used to produce an estimate of ground-water recharge in inches/year. Recharge was then ranked by volume (billions of gallons/year) using natural breaks in the percentage of total volume. According to the NJDEP, A Well Head Protection Area (WHPA) in New Jersey is a map area calculated around a Public Community Water Supply (PCWS) well in New Jersey that delineates the horizontal extent of ground water captured by a well pumping at a specific rate over a two, five, and twelve-year period of time for unconfined wells. The confined wells have a fifty foot radius delineated around each well serving as the well head protection area to be controlled by the water purveyor in accordance with Safe Drinking Water Regulations (see NJAC 7: (b) 1). Wellhead protection areas, also required as part of the MSWMP, are shown in Figure #. (Contact the County for mapping assistance.) Well Head Protection Area delineations are conducted in response to the Safe Drinking Water Act Amendments of 1986 and 1996 as part of the Source Water Area Protection Program (SWAP). The delineations are the first step in defining the sources of water to a public supply well. Within these areas, potential contamination will be assessed and appropriate monitoring will be undertaken as subsequent phases of the NJDEP SWAP. As shown in Figure #, a portion of the Township is/is not (choose one) in a tier 3 wellhead protection area. This area is located. (The NJDEP defines a tier as the following: Tier 1, 2 and 3 is defined by the time of water travel to the well. Tier 1 is 2 years, Tier 2 is 5 years and Tier 3 is 12 years). In addition to the rivers and streams that run through and along the Township, there are a number of wetland areas. These wetland areas, shown in Figure #, are a very valuable resource for Municipality. In addition to being a very environmentally sensitive part of the landscape; wetlands provide erosion and pollution control by serving as a sedimentation area and filtering basin, absorbing silt, organic matter and pollutants. They are valuable as water storage, as many aquifers are located beneath wetlands, also wetlands can provide flood alleviation for waterways that have overtopped their banks during periods of heavy rainfall. (USEPA) DESIGN AND PERFORMANCE STANDARDS Municipality will adopt the design and performance standards for stormwater management measures as presented in N.J.A.C. 7:8-5 to minimize the adverse impact of stormwater runoff on water quality and water quantity and loss of groundwater recharge in receiving water bodies. The design and performance standards include the language for maintenance of stormwater management measures consistent with the stormwater management rules at N.J.A.C. 7:8-5-8 Maintenance Requirements, and language for safety standards consistent with N.J.A.C. 7:8-6 Safety Standards for Stormwater Management Basins. The Stormwater Management Ordinances will be submitted to the County for review and approval on or before April 1, The Stormwater Management Ordinance will establish minimum stormwater management requirements and controls for major development and reduce the amount of non-point source pollution entering waterways. The ordinance will guide new development that is proactive and minimally impacts natural resources. Specifically, the Stormwater Management Ordinance ordinance shall: Reduce artificially induced flood damage to public health, life, and property; Minimize increased stormwater runoff rates and volumes; 9

10 Minimize the deterioration of existing structures that would result from increased rates of stormwater runoff; Induce water recharge into the ground wherever suitable infiltration, soil permeability, and favorable geological conditions exist; Prevent an increase in nonpoint source pollution; Maintain the integrity and stability of stream channels for their biological functions, as well as for drainage, the conveyance of floodwater, and other purposes; Control and minimize soil erosion and the transport of sediment; Minimize public safety hazards at any stormwater detention facility constructed pursuant to subdivision or site plan approval; Maintain high water in all streams and other surface water bodies; Protect all surface water resources from degradation; and Protect ground water resources from degradation. This plan and the adopted ordinance(s) in no way abrogates any other ordinance, rule or regulation, statute, or other provision of law imposed by local, county, state or federal entities. Where any provision of this ordinance imposes restrictions different from those imposed by any other ordinance, rule or regulation, or other provision of law, whichever provisions are more restrictive or impose higher standards shall control. During construction, Township inspectors will observe the construction of the project to ensure that the stormwater management measures are constructed and function as designed. (This statement is verbatim from the NJDEP Sample Municipal Stormwater Management Plan; it is advised that this statement be tailored to reflect your municipal management plan and staffing requirements.) PLAN CONSISTENCY The MSWMP must be consistent with all adopted Regional SWMP s and TMDLs. Contact the NJDEP Division of Watershed Management for information. Additionally, this MSWMP must be coordinated with the Hunterdon County Soil Conservation District and must follow the guidelines set forth by the New Jersey Department of Agriculture (NJDA) Soil Erosion and Sediment Control Standards, of the Soil Erosion and Sediment Control Act: L C. 251 and the New Jersey Department of Community (NJDCA) Affairs Residential Site Improvement Standards, N.J.A.C. 5:21. The following links are provided for your convenience: NJDA Soil Erosion and Sediment Control Act: NJDCA Residential Site Improvement Standards: If neither of the above apply it is sufficient to include the following paragraphs: Municipality is not within a Regional Stormwater Management Planning Area and no TMDLs have been developed for waters within the Township; therefore this plan does not need to be consistent with any regional stormwater management plans (RSWMPs) nor any TMDLs. If any RSWMPs or TMDLs are developed in the future, this MSWMP will be updated to be consistent. The MSWMP is consistent with the Residential Site Improvement Standards (RSIS) at N.J.A.C. 5:21. The Municipality will utilize the most current update of the RSIS in the stormwater 10

11 management review of residential areas. This Municipal Stormwater Management Plan will be updated to be consistent with any future updates to the RSIS. The NJDEP implements the Stormwater Management Rules N.J.A.C. 7:8 through the Land Use Regulation Programs (LURP): Additionally, local authorities implement the Stormwater Management Rules through the Municipal Land Use Law (MLUL) and the RSIS. The RSIS are applicable to any residential application that goes before a local planning board. Through RSIS the Stormwater Management Rules are enforced whenever a municipality requires the control of stormwater runoff from a site that is part of a site plan or subdivision application. Therefore, consistent with its duly adopted ordinances, a municipality may require compliance with the Stormwater Management Rules through the RSIS whether or not a development is a major development as defined in N.J.A.C. 7:8. Source: NJDEP - intro1 The Municipal Stormwater Management Ordinance will require all major development to comply with New Jersey s Soil Erosion and Sediment Control Standards. During construction, Township inspectors will observe on-site soil erosion and sediment control measures and report any inconsistencies to and cooperate with the Hunterdon County Soil Conservation District. NONSTRUCTURAL STORMWATER BEST MANAGEMENT PRACTICES Deciding which stormwater control method to use is a very complicated task. Municipalities are encouraged to seek professional assistance when developing this portion of their MSWMPs. Several factors must be considered when choosing a nonstructural stormwater best management practice (BMP); e.g. soil permeability, underlying geology, terrain, watershed factors, municipal and County goals, pollution levels, location, maintenance and cost. A written and graphic description of the natural and man-made features of the site and its environs should be included with this section. The description should include a discussion of soil conditions, slopes, wetlands, waterways and vegetation of the site. Particular attention should be given to unique, unusual, or environmentally sensitive features and to those that provide particular opportunities or constraints for development. (Hunterdon County Soil Conservation District). To reiterate, BMP selection is very site dependent and thus the selection process should be site specific. Site conditions to consider when selecting BMP s (please contact the Hunterdon County Soil Conservation District with further questions (908) ): Deeply fractured bedrock, depth to bedrock Limestone, karst features,soluble bedrock Mining or quarry operations, blasting areas Areas subject to dynamic compaction Acid producing soils and soil ph Acid or other mine waste or runoff Seasonal high water table Compacted soils, colloidal soils Flood plains Soil permeability and transivity Soil shrink swell potential Threatened and endangered species habitat Areas of fill Shallow or eroded soils Buried stumps construction debris Subsurface utility lines Leaking sanitary lines Groundwater mounding Septic and wells of adjacent lots Stream buffers Wetlands and their buffers Adjacent landuse 11

12 Hardpans or plough pans Excessive manure use Invasive plant species Subsurface pipelines Deer, geese, beaver potential Soil health Historic agricultural practices (fertilizer/pesticide use) Field applications of biosolids, meadow life, aglime The township has reviewed its Master Plan and Ordinances and has provided a list of the sections in the Municipal Land Use and Zoning Ordinances that are to be modified to incorporate nonstructural stormwater management strategies. Once the Land Use Code revisions are completed, they will be submitted to the County Review Agency for review and approval on or before April 1, A copy will be sent to the NJDEP at the time of submission to the County. F.Y.I. When submitting the plan and ordinances to the County for review, and a copy to the NJDEP, all revised land use codes, ordinances, master plans and maps must be attached along with a schedule of adoption. The NJDEP provides the following list of example ordinances that should be evaluated: buffers, cluster development, Special Water Resource Protection Areas, curbs and gutters, off-site/off-tract improvements, stream corridors and Stream Corridor Protection Plans, performance standards, landscaping and natural features, sidewalks, soil erosion and sediment control, etc Please see the NJDEP Sample Municipal Stormwater Management Plan: Appendix C of the New Jersey Stormwater Best Management Practices Manual for sample formatting and content. LAND USE / BUILD-OUT ANALYSIS If a municipality can document that it has a combined total of less than one square mile of vacant or agricultural lands, the municipality is not required to complete the following build-out analysis. Otherwise a build-out analysis must be conducted assuming full development under existing zoning for each HUC-14 drainage area in the municipality. To satisfy the minimum requirements, the result of the build-out analysis is acreage of impervious cover by HUC-14 and associated non-point pollution loadings attributed to the build-out of the municipality. Additional information on the build-out is provided in Chapter 3 of the New Jersey Stormwater Best Management Practices Manual. There are four steps to preparing a build-out analysis that satisfies the requirements for the Municipal Stormwater Management Plan (NJDEP Sample MSWMP): 1. Determine the total land area within each of the HUC-14s of the municipality. NOTE: See the HCPB calculations of HUC-14 s by municipality posted on our stormwater website. 2. Determine the area of constrained lands within each HUC-14 of the municipality. NOTE: Constrained lands can include: A) Water and wetlands as calculated in the NJDEP 1995 Land Use/Land Cover, B) Steep slopes greater than 20 percent, available from the HCPB, and C) Municipal open space and preserved farms. 12

13 NOTE: In the Highlands Preservation Area additional environmental constraints were added consistent with the Highlands Water Protection and Planning Act, i.e., upland forests and 300 buffer around all open water and wetlands. 3. Determine the land available for development by simply subtracting the constrained lands from the total land area for each HUC-14. In essence, the land available for development is the agricultural, forest and/or barren lands available within each HUC-14. Existing residential, commercial, and industrial areas are also eligible for redevelopment and should be considered as land available for development. 4. For each HUC-14, complete a build-out analysis by using the municipal zoning map and applicable ordinances to determine the acreage of new development. Once the build-out acreage of each land use is determined for each HUC-14, nonpoint source loadings can be determined for the buildout scenario. Shown below are examples of build-out analyses for two HUC-14s located in the municipality. A detailed land use analysis for the Township was conducted. Figure # illustrates the existing land use in the township/borough/city/town, based on data provided by. The municipal zoning districts are shown on Figure #. Figure # illustrates the HUC-14s (see our website for a listing of the HUC-14 acreages by municipality) and Figure # illustrates the constrained lands within the township/borough/city/town. The build-out calculations for impervious cover are shown in Table #. As expected when developing agricultural and forested lands, the build-out of the HUC-14s will result in a significant increase in impervious surfaces. Table # presents the pollutant loading coefficients by land cover. The pollutant loads at full buildout are presented in Table #. It is important to note that, although the pollutant loads for agricultural lands are higher than those for low density residential for the parameters in the pollutant loading coefficients by land cover table listed above, converting agricultural lands to residential typically results in an increase in pollutant loads for metals and petroleum hydrocarbons. It is recommended that each municipality calculate build-out pollutant loads for each. Also, total suspended solid loads due to stormwater runoff may decrease due to the conversion of agricultural lands to low density residential, but the percentage of impervious surfaces increases dramatically. If, due to the increase of impervious surfaces, increases in stormwater runoff flows are not managed properly, these high flows will increase streambank erosion, thereby increasing sediment loads to the receiving waters. There are a number of resources available for assistance with preparing the build-out analysis, including the Association of New Jersey Environmental Commissions (ANJEC), the Stony Brook- Millstone Watershed Association, Rutgers University s Center for Remote Sensing and Spatial Analysis, the Nonpoint Education of Municipal Officials (NEMO), and USEPA (Green Communities: How to do a Build-Out Analysis at The mapping and querying ability of GIS software such as ESRI s ArcView is essential for preparing a build-out analysis in a cost-effective manner. 13

14 The Hunterdon County Planning Board (HCPB) calculated population projections maximum residential build-out to the year 2020 and total build-out. The calculations were based on the 2000 Census and factored in recent growth trends, pending development applications and recent land preservation efforts. Zoning requirements and environmental constraints were utilized to guide and/or constrain development. The environmental constraints used were slopes of 20 percent and greater, wetlands and buffers and Category One waters and buffers. In the Highlands Preservation Area additional environmental constraints were added consistent with the Highlands Water Protection and Planning Act, i.e. upland forests and 300 buffer around all open water and wetlands. The projections and build-out calculations were given in total households and population. While the rule requires that each municipality calculate the total acreage in the municipality of impervious surface and associated future nonpoint source pollutant load assuming full build-out of the projected land uses; municipalities are encouraged to utilize the HCPB Build-Out totals in conjunction with the NJDEP method. See our Stormwater website for the Total Build-Out and 2020 Projections data. For more information on Build-Out methodology, please see the Hunterdon County Cross Acceptance Report Preliminary Draft: Volume I of January 13, 2005 located on the HCPB Smart-Growth website: MITIGATION PLANS In the event that it is deemed impracticable or impossible to meet the requirements of N.J.A.C. 7:8 a variance or exemption from strict compliance may be granted. At 7:8-4.2c(11): In order to grant a variance or exemption from the design and performance standards in N.J.A.C. 7:8-5, include a mitigation plan that identifies what measures are necessary to offset the deficit created by granting the variance or exemption. The mitigation plan shall ensure that mitigation is completed within the drainage area and for the performance standard for which the variance or exemption was granted; At 7:8-4.6: Variance or exemption from the design and performance standards for stormwater management measures A municipality may grant a variance or exemption from the design and performance standards for stormwater management measures set forth in its approved municipal stormwater management plan and stormwater control ordinance(s), provided the municipal plan includes a mitigation plan in accordance with N.J.A.C. 7:8 4.2(c)11 and the municipality submits a written report to the county review agency and the Department describing the variance or exemption and the required mitigation. Chapter 3 of the New Jersey Stormwater Best Management Practices Manual (BMP Manual) provides detailed information on what the NJDEP requires for mitigation strategies There are many options available for mitigation and they vary greatly for each municipality. The following 3 examples work off of the mitigation options as presented in the BMP Manual and have been presented by Princeton Hydro, LLC at various Stormwater seminars and presentations. 14

15 Example 1: An example of equivalent, i.e. in-kind or direct, mitigation as per Chapter 3 of BMP Manual: SCENARIO Due to natural site constraints, an applicant is unable to fully satisfy the recharge criteria, this results in a net recharge deficit of 50,000 ft 3. MITIGATION STRATEGY Mitigation is achieved by collecting and recharging equal volume of runoff at an off-site, impervious area, located within the same HUC-14 Site selection based on the direction and approval of municipality; e.g., the selected site must be a known location with inadequate existing recharge. The applicant is responsible for securing the land and easements necessary to implement the mitigation project. Example 2: An example of non-equivalent mitigation as per Chapter 3 of BMP Manual: SCENARIO The project fails to fully satisfy the recharge requirement. Recharge options within same watershed (HUC-14) are non-existent. MITIGATION STRATEGY The applicant is directed to address a non-point source pollution problem, e.g., reduction of fecal coliform levels. The applicant is responsible for all elements of the project including land acquisition, maintenance, and reporting. Example 3: An example of a funding mitigation as per Chapter 3 of BMP Manual: SCENARIO Due to the site constraints, the applicant is unable to fully meet the design and performance standards and equivalent and non-equivalent mitigation is not possible. MITIGATION STRATEGY The applicant can provide funding to the municipality for an environmental enhancement project that has been identified in the Municipal Stormwater Management Plan. This option is available only if the MSWMP includes a list of environmental enhancement projects for recharge, flood control, and/or non-point source pollution control. The contributed funds must be equal to or greater than cost to implement the required on-site stormwater measure for which relief is requested, including the costs of land, easements, and long-term maintenance. A mitigation plan is required to grant a variance or exemption from the design and performance standards of a municipal stormwater management plan. The mitigation requirements should offer a hierarchy of options that clearly offset the effect on groundwater recharge, stormwater quantity control, and/or stormwater quality control that was created by granting the variance or exemption. The following fictional example is one of the means a municipality can select for a mitigation plan. This mitigation plan is provided for a proposed development that may be granted a variance or exemption from the stormwater management design and performance standards. Any variance, 15

16 waiver or exemption granted shall be subject to site-specific analysis and the approval of an acceptable mitigation plan. Presented below is a hierarchy of options. Mitigation Project Criteria 1. The mitigation project must be implemented in the same drainage area as the proposed development. The project must provide additional groundwater recharge benefits, or protection from stormwater runoff quality and quantity from previously developed property that does not currently meet the design and performance standards outlined in the Municipal Stormwater Management Plan. The developer must ensure the long-term maintenance of the project, including the maintenance requirements under Chapters 8 and 9 of the NJDEP Stormwater BMP Manual. a. The applicant can select one of the following projects listed to compensate for the deficit from the performance standards resulting from the proposed project. More detailed information on the projects can be obtained from the Township Engineer. Listed below are specific projects that can be used to address the mitigation requirement. Groundwater Recharge Retrofit the L.B. Middle School site and detention basin to provide an additional 300,000 cf of average annual groundwater recharge. Replace the existing deteriorated 20,000 sf overflow impervious parking lot at Children s Memorial Soccer Complex with permeable paving to provide 150,000 cf of additional average annual groundwater recharge. Water Quality Retrofit the existing stormwater management facility at Matisse Elementary School to provide the removal of 80 percent of total suspended solids from the parking lot runoff. Retrofit the existing parking area at the West Side Municipal Complex to provide the removal of 80 percent of total suspended solids. Due to site constraints, the retrofit BMP must be installed underground and cannot reduce the existing number of parking spaces. Water Quantity Install stormwater management measures in the open space in the Woodlot Development to reduce the peak flow from the upstream development on the receiving stream by 20 cfs, 35 cfs, and 100 cfs for the 2, 10, and 100-year storms respectively. 2. If a suitable site cannot be located in the same drainage area as the proposed development, as discussed in Option 1, the mitigation project may provide mitigation that is not equivalent to the impacts for which the variance or exemption is sought, but that addresses the same issue. For example, if a variance is given because the 80 percent TSS requirement is not met, the 16