Municipal Stormwater Management Planning

Municipal Stormwater Management Planning Christopher C. Obropta, Ph.D., P.E. Water Resources Extension Specialist with Rutgers Cooperative Extension Assistant Professor with Department of Environmental Sciences 732-932-4917 obropta@envsci.rutgers.edu

WHY? It s not just the law, it s the right thing to do. By March 3, 2005, all 566 municipalities must submit their stormwater management plans to their County for review. Of the 2,308 assessed river miles, 1,913 river miles (83%) did not meet the surface water quality standards for at least one parameter. Approximately 2,063 river miles were assessed for recreational designated use attainment. Only 22% of the assessed sites were fully attaining and meeting the standards for recreational activity.

Goals of SW Mgt Plan 1. Reduce flooding damage, including damage to life and property; 2. Minimize, to the maximum extent practical, any increase in stormwater runoff from any new development; 3. Reduce soil erosion from any development or construction project; 4. Assure the adequacy of existing and proposed culverts and bridges, and other instream structures; 5. Maintain groundwater recharge;

Goals of SW Mgt Plan 6. Prevent, to the greatest extent feasible, an increase in nonpoint source pollution; 7. Maintain the integrity of stream channels for their biological functions, as well as for drainage;

Goals of SW Mgt Plan 8. Minimize pollutants in stormwater runoff from new and existing development in order to restore, enhance and maintain the chemical, physical, and biological integrity of the waters of the State, to protect 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; and 9. Protect public safety through the proper design and operation of stormwater management facilities.

Municipal SW Mgt. Plan shall address: Stormwater-related water quality impacts Groundwater recharge impacts Water quantity impacts of major development. Major development is limited to projects that ultimately disturb one or more acres of land.

Municipal SW Mgt. Plan may also address: Stormwater-related water quality Groundwater recharge impacts Water quantity impacts of existing land uses.

Municipal Stormwater Management Plans must conform with applicable Regional Stormwater Management Plans

Introduction Stormwater Some of the readers of the plan may have limited knowledge of stormwater related issues. A brief description of the hydrologic cycle and how development affects the cycle may be useful to the reader. Natural conditions promotes infiltration and limits runoff runoff Development results in less infiltration and more runoff

Background The plan should include some basic background information on the municipality to help the reader understand its characteristics size in square miles, population, population changes, waterways, and health of these waterways. For example, is the municipality a rural community that is rapidly becoming developed or is it an older established community where land use is fairly stable? Is the health of the waterways in the municipality impaired? Are there flooding concerns in the municipality? Also, maps should be included to help the reader visualize the municipality and its physical features.

References The New Jersey Integrated Water Quality Monitoring and Assessment Report (305(b) and 303(d)) is available from the NJDEP website at www.nj.gov/dep/wmm/sgwqt/wat/index.html Specific data on biological monitoring (AMNET data) is available from the NJDEP web site at www.state.nj.us/dep/wmm/bfbm Additional data can be found on the United States Geological Survey (USGS) site at www.usgs.gov. Each municipality should have population statistics. This information is available from the NJ Department of Labor at www.wnjpin.net/onestopcareercenter/labormarketinformation/ lmi25/index.html

Municipal SW Mgt. Plan shall,, at a minimum: 1. Describe how the plan will achieve the nine goals discussed earlier; 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.

Municipal SW Mgt. Plan shall,, at a minimum: 2. Mapping of the municipality s waterways;

or:

Municipal SW Mgt. Plan shall,, at a minimum: 3. Mapping of the groundwater recharge areas and well head protection areas;

and:

References Mapping required for a municipal plan is fairly simple, but requires Geographic Information System (GIS) software. Mapping information is available at http://www.nj.gov/dep/gis/lists.html as well as a link to a free version of GIS software, ArcExplorer. Many local watershed associations and environmental commissions have GIS and can help create maps for an MSWMP. Rutgers University Center for Remote Sensing and Spatial Analysis can also assist in preparing these maps. The GIS Center at Stony Brook Millstone Watershed Assoc.: www.giscenter.org Detailed direction on how to create these maps is provided at http://rwqp.rutgers.edu.

Municipal SW Mgt. Plan shall,, at a minimum: 4. Describe how the plan incorporates design and performance standards in N.J.A.C. 7:8-5 or alternative standards adopted as part of a regional stormwater management plan or water quality management plan;

Municipal SW Mgt. Plan shall,, at a minimum: 5. Describe how adequate long-term operation as well as preventative and corrective maintenance (including replacement) of selected stormwater management measures will be ensured;

Municipal SW Mgt. Plan shall,, at a minimum: 6. Describe how the plan will ensure compliance with Safety Standards for Stormwater Management Basins at N.J.A.C. 7:8-6;

Addressing items 4, 5, and 6: The Township 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 ordinances will be submitted to the county for review and approval within [24 months of the effective date of the Stormwater Management Rules.] During construction, Township inspectors will observe the construction of the project to ensure that the stormwater management measures are constructed and function as designed.

Municipal SW Mgt. Plan shall,, at a minimum: 7. Describe how the plan is coordinated with the appropriate Soil Conservation District and any other stormwater management plans, including any adopted regional stormwater management plan, prepared by any stormwater management planning agency related to the river basins or drainage areas to which the plans and/or ordinances apply;

Dealing with Item 7: Are there regional stormwater management plans being developed for waterways in your municipality? Have TMDLs been completed for any of the waterways in your Township? Check: www.state.nj.us/dep/watershedmgt/index.htm

Statements to address Item 7: The Municipal Stormwater Management Plan is consistent with the Residential Site Improvement Standards (RSIS) N.J.A.C. 5:21. The municipality will utilize the most current update of the RSIS in the stormwater management review of residential areas. This Municipal Stormwater Management Plan will be updated to be consistent with any future updates to the RSIS. The Township s Stormwater Management Ordinance requires all new development and redevelopment plans 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 the local Soil Conservation District.

Municipal SW Mgt. Plan shall,, at a minimum: 8. Evaluate the extent to which the municipality s entire master plan (including the land use plan element), official map and development regulations (including the zoning ordinances) implement the principles expressed in N.J.A.C. 7:8-5.3(b).

7:8-5.3(b) = Low Impact Development (LID) Development (LID) See Appendix B of the BMP Manual for the Municipal Regulations Checklist. This Checklist will guide you through a review of your master plan and development regulations to determine where nonstructural stormwater management strategies can be incorporated.

Engineer and Planner have to work together to review master plan and municipal development code Lots of Coffee will be needed!

Municipal SW Mgt. Plan shall,, at a minimum: 9. Include a map of the municipality showing: i. Projected land use assuming full development under existing zoning, and ii. HUC 14 drainage areas; and an estimate for each HUC 14, of 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.

Mapping zoning maps tax maps huc14 permanently preserved open space floodplains, wetlands wellhead protection areas soil maps

Municipal Map of Hydrologic Unit Codes 14 HUC14

Municipal Zoning

Mapping Information & Assistance existing GIS layers at http://www.state.nj.us/dep/gis counties watershed associations soil conservation districts universities

Pollutant Loading Analysis Export data from gis for full build-out for each huc14 Provide a pollutant load for each land use Pollutant load analysis should be done for total suspended solids, total nitrogen, and total phosphorous at a minimum

Pollutant Loads By Land Cover Land Cover TP TN TSS lbs/acre/yr lbs/acre/yr lbs/acre/yr High, Medium Density Residential 1.4 15 140 Low Density, Rural Residential 0.6 5 100 Commercial 2.1 22 200 Industrial 1.5 16 200 Urban 1.0 10 120 Agriculture 1.3 10 300 Forest, Water, Wetlands 0.1 3 40

Pollutant Loading Analysis Other values may be used that are more detailed or more reflective of local Consideration should be given to additional pollutants associated with development petroleum hydrocarbons fecal coliform metals

Does the plan need to address Items 8 (master plan review) and 9 (build out analysis)? Does your municipality have a combined total of less than one square mile of vacant or agricultural lands? Permanently preserved agricultural land is excluded Vacant or agricultural land that is environmentally constrained may be excluded If yes, you can skip Items 8 and 9.

Municipal SW Mgt. Plan shall,, at a minimum: 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.

First, let s recall Goal #8: Minimize pollutants in stormwater runoff from new and existing development in order to restore, enhance and maintain the chemical, physical, and biological integrity of the waters of the State, to protect 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

The Mitigation Plan is the best opportunity to deal with runoff from existing development

Mitigation Plan Options a. Developer responsible for identification and construction of mitigation projects, b. Developer selects from locations under municipal authority, c. Municipality has a list of projects from which developer may select, or d. Developer provides funding for municipal stormwater management measures.

Types of Mitigation Direct Mitigation of Impacts Recharge: provide deficit volume of recharge that was not achieved Quantity: provide peak control at other locations Quality: using a weighted average, reduce TSS as existing developed areas

Types of Mitigation Indirect (or Non-Equivalent) Mitigation of Impacts Address existing issues of concern Quality: instead of TSS, address existing impairment (fecal, phosphorous, listed impairements) Quantity: flooding at specific location within drainage area Caution: long-term impacts of cumulative exemptions without mitigation

Other Types of Mitigation Require funding to address municipal issues of stormwater quality, quantity, and loss of recharge Least preferred Funding for development or implementation of regional stormwater management plans Banking, trading

Sample Mitigation Projects Groundwater Recharge Retrofit the detention basin at School A (approximately one acre in size) to provide 40,000 cubic feet of annual groundwater recharge. Retrofit the traffic islands at the municipal parking lot to provide 100,000 cubic feet of annual groundwater recharge. Water Quality Retrofit the detention basin at School B to remove 80% of the TSS from the stormwater runoff. Install NJDEP verified manufactured treatment device or other retrofit BMP to remove total suspended solids and petroleum hydrocarbons from the discharge of stormwater from the parking lot at the municipal complex. Water Quantity Install stormwater detention and infiltration systems within the disturbed area of the open space in the Housing A development to decrease flooding on Overtopped Lane.

How do you identify mitigation projects? Perform a Characterization and Assessment of the Municipality by: Identify potential sources of water quality problems including development, roads, storm sewer outfalls, agricultural, geese infested basins, etc. Identify water quantity problems within the municipality including flooding, baseflow reduction, groundwater depletion, The Mitigation Plan should be based on selecting stormwater management measures that enhance, protect, and/or improve water quality, groundwater recharge, and address flooding issues. An analysis of the feasibility and costs of each stormwater management measure should be considered.

Mitigation Plans - Considerations On-site compliance should always be the first option Location of mitigation projects Must consider receiving stream issues Long-term maintenance must be addressed

How do you get started? Step 1 Prepare the maps first (Items 2 and 3) Look to the environmental commissions, watershed associations, county offices, colleges, and consultants for help

Step 2 Look at NJDEP s web site Are any of your streams or lakes are impaired? Have TMDLs been developed for any of these waters? Are regional stormwater mgt. plans being developed? Do you have one square mile (640 acres) or less of developable land?

Step 3 If you have more than one square mile of developable land: Review master plan and development code (Item 8) Prepare build out analysis and perform loading calculations (Item 9)

Step 4 Prepare the Mitigation Plan including conducting the characterization and assessment to identify problem areas Look to the environmental commissions, watershed associations, county offices, colleges, and consultants for help Tools that are available to help: USDA s Stream Visual Assessment Protocol

Last Step Assemble the Municipal Stormwater Management Plan including the stormwater control ordinances and optional stream corridor protection plan (i.e., riparian buffer ordinance) Submit to the County for review and send a copy to NJDEP