Green Infrastructure Stormwater Management Applications in the Pines Frequently Asked Questions and Example Projects Stephen J. Souza, Ph.D Princeton Hydro, LLC 1108 Old York Road Suite 1, P.O. Box 720 Ringoes, NJ 08551 New Jersey Agricultural Experiment Station - Office of Continuing Professional Education
Thanks To New Jersey Future Pineland Preservation Alliance Pinelands Commission And our host New Jersey Manufacturers
NJDEP s Take on Green Infrastructure Reduce volume, flow rates and pollutant characteristics of wet weather flows. Promote stormwater infiltration, treatment and reuse. Examples - pervious paving, bioretention basins, vegetated swales, and cisterns.
USEPA s Take on Green Infrastructure Green infrastructure - an adaptable term Array of products, technologies, and practices that use natural systems or engineered systems to mimic natural stormwater management processes. Use of vegetation, soils, and natural processes to infiltrate, evapotranspirate, and/or recycle stormwater runoff and create healthier environments. Stormwater management systems that mimic nature by soaking up and storing water.
Green Infrastructure in the Pinelands Pinelands Commission, New Jersey Future and Pinelands Preservation Alliance all recognize the importance of green infrastructure stormwater management measures Promote recharge of surficial aquifer Decrease runoff volumes Decrease flooding Treat and remove pollutants from runoff
What s The Fuss About a Little Runoff? Increased volume and velocity Altered baseflow and stream hydrology Increased non-point source pollutant mobilization, transport and loading Degraded water quality Impaired wetland, riparian and aquatic habitats Compromised ecosystem functions
Hydraulic Impacts Erosion Bank Subsidence
Hydrologic Impacts Flooding Altered Baseflow
Floodplain / Riparian Degradation Riparian buffers intact and stream banks stable Riparian buffers disturbed and stream banks unstable
Impacted/Impaired Water Quality Over 70% of water quality problems in US due to nonpoint source pollution Impacts recreation, aesthetics, drinking water quality.
Lost Services and Functions Eutrophication Fish Kills
So Yes A Little Stormwater Runoff Leads to a Lot of Problems
Development Driven Hydrologic Changes www.mass.gov
Rainfall/Stream Flow Relationship
Effect of Watershed Urbanization On Storm Hydrograph
These problems can t be solved by only managing peak flows we also need to: Reduce runoff volume Maintain or replicate existing hydrology and flow paths Maintain baseflow Remove or reduce pollutant loads THIS CAN T BE ACCOMPLISHED USING A DETENTION BASIN
Typical Dry Detention Basin Compacted bottom Low flow channel Lack of vegetation
Successful Stormwater Management via Green Infrastructure 1. Treat stormwater as a resource 2. Don t make stormwater management an afterthought 3. Attack the cause not the symptoms 4. Turn your watershed inside out 5. Think small to achieve big results 6. Use nature as your model
Typically we try to get rid of stormwater as quickly as possible as is evidenced in site plans, lot grading, and design and operation of stormwater collection systems Reuse Recharge Stormwater Is A Resource Preserve existing hydrology and hydrologic properties of water and wetland resources
In the Good Old Days Quickly collect and move SW away from structures Route it to the lowest point on site Contain and detain and then discharge from site, SW management focus on peak flow control No consideration given to reducing runoff volume, removing pollutants, or recharging groundwater
Low Impact Development Techniques Reduce and/or prevent adverse runoff impacts by preserving or closely mimicking pre-developed hydrologic response to precipitation. Manage runoff close to source. Promote the concept of designing with nature. Use both structural and non-structural BMPs As per NJDEP LID can be applied to virtually any development site, regardless of impervious coverage, to produce enhanced site designs and decreased stormwater impacts.
Turn Your Watershed Inside Out Don t rely on end of pipe solutions. Start close to point of runoff generation and identify opportunities to collect and treat runoff.this includes stormwater capture and reuse. Understand the natural limits and constraints of the watershed (e.g., steep slopes, clayey soils).
Think Small to Achieve Big Results Divide and conquer. Work with small catchments. Tame small chunks of runoff, deal with small volumes. Think small footprint BMPs. Create multiple treatment opportunities and treatment trains. Increase level of treatment by linking BMPs and have them work in series. Courtesy Stone Age Pavers
Let Nature Be Your Model Biodetention, Bioretention, Biofiltration, Alternative Landscaping Focus on BMPs that emphasize runoff reduction, stormwater infiltration, and pollutant removal.not simply peak flow attenuation.
Turn Down The Volume!!! Common to most green infrastructure techniques is the reduction in the volume of runoff generated from a site. Starts with proper site planning, and site preparation. Complimented by proper BMP selection and construction. By generating less runoff volume achieve better control of rate, amount and quality of discharged stormwater.
Frequently Asked Questions Isn t this only applicable for new development, how can I make it work in areas already developed? Isn t this only for large development sites? You can t expect to use this on small lot subdivisions. Don t the stormwater rules preclude the use of on-lot stormwater management?
Frequently Asked Questions Don t the Pineland Rules restrict recharge and infiltration practices? What about our soils? not all the soils in the Pines are sandy, some are actually very restrictive and inhibit recharge.
Frequently Asked Questions Don t I need specialized equipment to maintain these BMPs? Site restoration part of LID strategy.maintenance of good soil health Prevention of compaction Loss of organic content Post-restoration of soil permeability Regular inspection and proper maintenance of any BMP is critical to its longevity and performance
Frequently Asked Questions Aren t LID and green infrastructure BMPs too costly to implement? In Philadelphia green infrastructure BMPs actually save property owners money by decreasing impervious coverage fees 2013 EPA LID Barrier Busters Fact Sheet Series
On-Lot and Small Foot Print Techniques
Soil Health. Healthy soils have good porosity the greater the porosity the less runoff less runoff means less flooding, less pollutant transport and less need for structural stormwater management. Ocean County Soil Conservation District
Guidance available through Ocean County SCD, NRCS, DRKN, American Littoral Society and Rutgers Avoid compacting soils Regularly aerate lawns Use native plants Soil Health. Test soils and amend accordingly usually ph too low Minimize pesticide and fertilizer use
Alternative Landscaping Pinelands Preservation Alliance American Littoral Society Delaware River Keeper Network Replace unnecessary lawn with native trees, shrubs and perennials Native plants increase habitat for beneficial insects, butterflies and birds Choose plants that are correct for your yard know the plant s sun, shade, soil and water requirements. Use low maintenance and drought tolerant plants Construct rain gardens, vegetated swales and other small footprint BMPs to manage runoff before it exists lot
Rainwater Harvesting Use stored rainfall to irrigate foundation and related landscape plantings Irrigate vegetable gardens Aid in fire suppression Grey water supply Rain Barrels
Drywells
Rain Gardens http://water.rutgers.edu/rain_gardens/raingardensymp/1_coffman.pdf
Rain Gardens The first rain gardens for residential use were developed in 1990 in Prince George's County, Maryland. Designed to mimic the water retention areas that occurred naturally before development of an area. http://www.lid-stormwater.net/biolowres_home.htm http://water.rutgers.edu/rain_gardens/raingardensymp/1_coffman.pdf
Green Roofs and Porous Pavement Recognized as effective stormwater management techniques for new and existing development. Scalable can be utilized in large and small applications. Provide storage and detention opportunities. Require a good design data. www.philywatersheds.com www.njaes.rutgers.edu
Large Scale Green Infrastructure Techniques
Bioretention Systems BMPs that use filtration and/or infiltration to treat stormwater runoff. Also make use of an engineered soil media. Soil media and vegetation capitalize on natural processes to remove particulate and dissolved pollutants including N, P and heavy metals.
Bioretention Basins and Swales Can be used for large or small application Can be used to retrofit existing standard detention basins Requires engineered soil media similar to that used to construct rain garden (high % sand and organic amendments) Can be planted with trees Construct w/w out underdrain, pre-treatment forebay, and other features that decrease scour, capture trash and reduce maintenance needs of basin/swale
Vegetated Swales Design details provided in 9.12 GRASS SWALES NJDEP BMP Manual
Vegetated Swales
Bioretention Swales w and w/o Underdrain Dry Swale As Per (Claytor & Schueler, 1996) Wet Swale
Curb-Side Bio-Retention
Urban Green Infrastructure Retrofits Michael Clar, P.E. Ecosite, Inc., 2003
Tree Box Installation
Tree Boxes Provides filtration and some infiltration prior to discharge
Bioretention Parking Lot Swale Runoff routed to swale via curb-cuts or standard inlets
Parking Lot Bio-Infiltration Swale
Parking Lot Buffer/Swale
Retrofitted Conventional Detention Basin
Converted Detention Basin
Converted Detention Basin
After Two Months of Grow-In Time
After Two Years of Grow-In Time
Seasonal Succession - Summer
Seasonal Succession Fall/Winter
Large Bio-infiltration Basin NJM Hammonton, NJ
Dig and drop down to 8 Finished grade Place leaf compost Seeded and stabilized Dig and drop, again to 3
Expanded Rain Garden Application - DRBC
Initial Grading
Seeding / Planting
One year later
One year later
Pennswood Village - Integrated Bioretention System A bioretention system that functions like riparian corridor / floodplain Integrated elements of system Sedimentation basin Grassed waterway Vegetated riparian buffers Stormwater infiltration system Created wetland/wet-pond
Courtesy - Wells-Appel Land Strategies
Form, Function, Aesthetics Courtesy - Wells-Appel Land Strategies
Functions As A Riparian Corridor
Central Bio-Retention Area
Riparian Corridor and Lower Wet Pond / Wetland Area
Lower Wet Pond / Wetland Area
In Summary Improperly managed stormwater is the cause of numerous environmental and ecological impacts. Standard detention techniques can t properly address these impacts. Green infrastructure techniques provide functional solutions with potential for ecological uplift.
In Summary Don t make SW management an after thought. Begin by treating stormwater as a resource not as a waste. Success of green infrastructure SW techniques linked to knowledge of site need good hydrologic and soils data. Over arching goal is volume reduction tame it, recharge it, reuse it!
In Summary LID and non-structural techniques part of solution. These approaches work very well in Pines Work with conditions look for opportunities to manage runoff as close to point of generation as possible. Divide and conquer.where possible use linked small foot print BMPs See PPA Guide. Replicate natural processes in design.
Sources of Information Rutgers (2016) Green Infrastructure Guidance Manual For New Jersey Pinelands Preservation Alliance Barnegat Bay LID http://www.pinelandsalliance.org/downloads/pinelandsalliance _816.pdf NJ Future - http://www.njfuture.org/issues/environment-andagriculture/water-sewer/water-infrastructure/gi_resources/ Philadelphia Water Department Stormwater Guidance Manual (Version 3) and Green City Clean Waters. www.phillywatersheds.org NJDEP Green Infrastructure in New Jersey http://www.nj.gov/dep/gi/
Stephen J. Souza, Ph.D. Princeton Hydro, LLC 1108 Old York Rd, Suite 1 P.O. Box 720 Ringoes, NJ 08551 908-237-5660 Ssouza@princetonhydro.com New Jersey Agricultural Experiment Station - Office of Continuing Professional Education