Frequently asked questions and example projects. Presented by Steve Souza from Princeton Hydro, at Workshop for Design Professionals, May 24, 2016

1. New Jersey Agricultural Experiment Station - Office of Continuing Professional Education
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

2. • New Jersey Future
• Pineland Preservation Alliance
• Pinelands Commission
And our host…
New Jersey Manufacturers
Thanks To…

3. • 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.
NJDEP’s Take on Green Infrastructure

4. • 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.
USEPA’s Take on Green Infrastructure

5. 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
Green Infrastructure in the Pinelands

6. • 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
What’s The Fuss About a Little Runoff?

7. Hydraulic Impacts
Erosion Bank Subsidence

8. Hydrologic Impacts
Flooding Altered Baseflow

9. Floodplain / Riparian Degradation
Riparian buffers intact and
stream banks stable
Riparian buffers disturbed
and stream banks unstable

10. Impacted/Impaired Water Quality
Over 70% of water quality
problems in US due to non-
point source pollution
Impacts recreation,
aesthetics,
drinking water quality.

11. Lost Services and Functions
Eutrophication Fish Kills

12. So Yes…A Little Stormwater Runoff Leads
to a Lot of Problems

13. Development Driven Hydrologic Changes
www.mass.gov

14. Rainfall/Stream Flow Relationship

15. Effect of
Watershed
Urbanization
On Storm
Hydrograph

16. • 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
These problems can’t be solved by only
managing peak flows…we also need to:

17. Typical “Dry” Detention Basin
Compacted bottom
Low flow channel
Lack of vegetation

18. 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
Successful Stormwater Management via Green
Infrastructure

19. 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
• Preserve existing hydrology and hydrologic
properties of water and wetland resources
Stormwater Is A Resource

20. • 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
In the “Good Old Days”

21. 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”.
Low Impact Development Techniques

23. • 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).
Turn Your Watershed Inside Out

24. • Think “small footprint” BMPs.
• Create multiple treatment
opportunities and “treatment
trains”.
• Increase level of treatment by
linking BMPs and have them
work in series.
Think Small to Achieve Big Results
Courtesy Stone Age Pavers
• “Divide and conquer”. Work with small catchments.
• Tame small “chunks” of runoff, deal with small
volumes.

25. • Biodetention, Bioretention, Biofiltration, Alternative
Landscaping…
• Focus on BMPs that emphasize runoff reduction,
stormwater infiltration, and pollutant removal ….not
simply peak flow attenuation.
Let Nature Be Your
Model

26. • 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.
Turn Down The Volume!!!

27. • 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 sub-
divisions.
• Don’t the stormwater rules preclude the use of
on-lot stormwater management?
Frequently Asked Questions

28. • 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

29. 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

30. Frequently Asked Questions
Aren’t LID and green infrastructure BMPs too costly to implement?
2013 EPA LID Barrier Busters Fact Sheet Series
In Philadelphia green infrastructure BMPs actually save property
owners money by decreasing impervious coverage fees

31. On-Lot and
Small Foot Print
Techniques

32. 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.
Soil Health….
Ocean County Soil Conservation District

33. Guidance available through Ocean County SCD,
NRCS, DRKN, American Littoral Society and
Rutgers
• Avoid compacting soils
• Regularly aerate lawns
• Use native plants
• Test soils and amend accordingly…usually pH
too low
• Minimize pesticide and fertilizer use
Soil Health….

34. 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
Alternative Landscaping

35. • Use stored rainfall to
irrigate foundation and
related landscape
plantings
• Irrigate vegetable
gardens
• Aid in fire suppression
• Grey water supply
Rainwater Harvesting
Rain
Barrels

36. Drywells

37. Rain Gardens
http://water.rutgers.edu/Rain_Gardens/RainGardenSymp/1_coffman.pdf

38. 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://water.rutgers.edu/Rain_Gardens/RainGardenSymp/1_coffman.pdf
http://www.lid-stormwater.net/biolowres_home.htm

39. 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

40. Large Scale Green
Infrastructure
Techniques

41. 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.

42. • 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
Bioretention Basins and Swales

43. Vegetated Swales
Design details provided in
9.12 GRASS SWALES
NJDEP BMP Manual

44. Vegetated Swales

45. Bioretention Swales w and w/o Underdrain
As Per (Claytor &
Schueler, 1996)
Dry Swale
Wet Swale

46. Curb-Side Bio-Retention

47. Urban Green Infrastructure Retrofits
Michael Clar, P.E.
Ecosite, Inc., 2003

48. Tree Box
Installation

49. Tree Boxes
Provides filtration
and some infiltration
prior to discharge

50. Bioretention Parking
Lot Swale
Runoff routed to swale
via curb-cuts or
standard inlets

51. Parking Lot Bio-Infiltration
Swale

52. Parking Lot
Buffer/Swale

53. Retrofitted Conventional Detention Basin

54. Converted Detention Basin

55. Converted Detention Basin

56. After Two Months of Grow-In Time

57. After Two Years of Grow-In Time

58. Seasonal Succession - Summer

59. Seasonal Succession – Fall/Winter

60. Large Bio-infiltration Basin
NJM – Hammonton, NJ

61. Dig and drop down to 8’
Place leaf compost
Dig and drop, again to 3’
Finished grade
Seeded and stabilized

62. Expanded “Rain Garden” Application -
DRBC

63. Initial Grading

64. Seeding / Planting

65. One year later…

66. One year later…

67. • 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
Pennswood Village -
Integrated Bioretention System

68. Courtesy - Wells-Appel Land Strategies

69. Form, Function, Aesthetics
Courtesy - Wells-Appel Land Strategies

70. Functions As A Riparian Corridor

71. Central Bio-Retention Area

72. Riparian Corridor and Lower
Wet Pond / Wetland Area

73. Lower Wet Pond / Wetland Area

74. • 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…

75. • 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…

76. • 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.
In Summary…

77. • 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-and-
agriculture/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/
Sources of Information

78. New Jersey Agricultural Experiment Station - Office of Continuing Professional Education
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