green infrastructure planning for hamilton township
TRANSCRIPT
Green Infrastructure Planning forHamilton Township, Atlantic County
New Jersey
Christopher C. Obropta, Ph.D., [email protected]
www.water.rutgers.edu
September 20, 2021
Water Resources Program
Rutgers Cooperative ExtensionRutgers Cooperative Extension (RCE) helps the diversepopulation of New Jersey adapt to a rapidly changingsociety and improves their lives through an educationalprocess that uses science-based knowledge.
Water Resources Program
Our mission is to identify and address
water resourcesissues by engaging
and empowering communities toemploy practical science-based
solutions to helpcreate a more equitable and
sustainable New Jersey.
Water Resources Program
Water Resources Program
More development
More impervious surfaces
More stormwater runoff
10% 20% 30% 55%
The Impact of Development on Stormwater Runoff
Water Resources Program
The Urban Hydrologic Cycle
Reference: Tom Schueler and Lisa Fraley-McNeal, Symposium on Urbanization and Stream Ecology, May 23 and 24, 2008
Green Infrastructure- is an approach to stormwater management that is cost-effective, sustainable, and environmentally friendly. Green infrastructure projects
• capture • filter • absorb • reuse
stormwater to maintain or mimic natural systems and treat runoff as a resource.
Green Infrastructure includes:
• green roofs• rainwater harvesting• tree filter/planter boxes• rain gardens/bioretention
systems• permeable pavements• vegetated swales or bioswales• natural retention basins• trees & urban forestry• green streets
Parker Urban Greenscapes. 2009.
It is all about controlling runoff from impervious surfaces
Step 1: Depave
Step 2: Simple Disconnection
Rooftop runoff is now “disconnected” from flowing directly into the storm sewer system
Disconnect to a Rain Garden
Lots of Rain Gardens
Step 3: Convert to Permeable Pavement
ADVANTAGES• Manage stormwater runoff• Minimize site disturbance• Promote groundwater
recharge• Low life cycle costs,
alternative to costly traditional stormwater management methods
• Mitigation of urban heat island effect
• Contaminant removal as water moves through layers of system
COMPONENTS
Porous Asphalt
Grass Pavers
Water Resources Program
Impervious Cover Assessment Figures/Charts
Water Resources Program
Impervious Cover Assessment
• Analysis completed by watershed and by municipality
• Use 2015 Land Use data to determine impervious cover
• Calculate runoff volumes for water quality, 2, 10 and 100-year design storm and annual rainfall
• Contains three concept designs
Agriculture3.4%
Barren Land0.5%
Forest49.4%
Urban11.8%
Water2.1%
Wetlands32.8%
Commercial8.2% High Density
Residential5.3%
Industrial1.4%
Low Density Residential
10.4%
Medium Density
Residential10.7%
Mixed Urban9.7%Recreational Land
6.9%
Rural Residential
33.5%
Transportation/Infrastructure14.0%
Subwatershed
Total Area Land Use Area Impervious Cover
(ac) (ac) (ac) (%)
Absecon Creek South Branch 409.2 409.2 4.8 1.2%
Absecon Creek North Branch 1,420.9 1,413.2 95.9 6.8%
Babcock Creek 11,045.7 10,941.5 642.8 5.9%
Deep Run 6,060.2 6,042.6 31.2 0.5%
Great Egg Harbor River 28,036.8 26,902.6 635.1 2.4%
Gravelly Run 5,523.5 5,459.3 597.1 10.9%
Hospitality Branch 0.6 0.6 0.0 0.0%
Landing Creek 541.5 501.5 3.2 0.6%
Makepeace Stream 1,863.6 1,860.3 36.5 2.0%
Mill Branch 14.1 14.1 8.2 57.9%
Miry Run 1,204.6 1,135.8 23.5 2.1%
South River 9,292.8 9,263.8 203.0 2.2%
Stephen Creek 207.6 207.6 3.1 1.5%
Tuckahoe River 17.2 17.2 0.0 0.0%
Watering Race Branch 6,632.7 6,612.7 202.7 3.1%
Total 72,271.1 70,782.0 2487.0 3.5%
Subwatershed
Total Runoff Volume for the 1.25" NJ Water Quality Storm
(MGal)
Total Runoff Volume for
the NJ Annual Rainfall of 44"
(MGal)
Total Runoff Volume for the 2-Year
Design Storm (3.31") (MGal)
Total Runoff Volume for the 10-Year Design Storm (5.16")
(MGal)
Total Runoff Volume for the
100-Year Design Storm (8.90") (MGal)
Absecon Creek South Branch 0.2 5.7 0.4 0.7 1.2
Absecon Creek North Branch 3.3 114.6 8.6 13.5 23.2
Babcock Creek 21.8 768.0 57.6 90.8 155.3Deep Run 1.1 37.3 2.8 4.4 7.5Great Egg Harbor River 21.6 758.8 56.9 89.7 153.5Gravelly Run 20.3 713.3 53.5 84.3 144.3Hospitality Branch 0.0 0.0 0.0 0.0 0.0Landing Creek 0.1 3.9 0.3 0.5 0.8Makepeace Stream 1.2 43.6 3.3 5.2 8.8Mill Branch 0.3 9.7 0.7 1.2 2.0Miry Run 0.8 28.0 2.1 3.3 5.7South River 6.9 242.5 18.2 28.7 49.0Stephen Creek 0.1 3.7 0.3 0.4 0.7Tuckahoe River 0.0 0.0 0.0 0.0 0.0Watering Race Branch 6.9 242.1 18.2 28.6 49.0
Total 84.4 2,971.2 222.8 351.1 601.0
Water Resources Program
WE LOOK HERE FIRST:SchoolsPlaces of Worship LibrariesMunicipal BuildingPublic Works FirehousesPost OfficesElks or Moose LodgeParks/ Recreational Fields
• 20 to 40 sites are entered into a PowerPoint
• Site visits are conducted
Water Resources Program
Green Infrastructure Strategic Plan
Examples of Identified Project Sites
72
0' 50' 100'
bioretention system
pervious pavement
drainage area
property line
2015 Aerial: NJOIT, OGIS
N
H A M I LT O N T O W N S H I P M U N I C I P A L B U I L D I N G 6 1 0 1 1 3 t h S t r e e tMay s L a n d i n g , NJ 0 8 3 3 0
Impervious Cover Existing Loads fromImpervious Cover(lbs/yr)
Runoff Volume from Impervious Cover (Mgal)
% sq. ft. TP TN TSS For the 1.25" Water QualityStorm
For anAnnualRainfall of 44"
29 155,444 7.5 78.5 713.7 0.121 4.26
Recommended
Infrastructure Practices
RechargePotential(Mgal/yr)
TSSRemovalPotential(lbs/yr)
Maximum Volume ReductionPotential
(gal/storm)
Peak Discharge Reduction
Potential (cu.ft./second)
Estimated Size ( sq.ft.)
Estimated Cost
Bioretention systems 0.072 12 5,300 0.20 700 $3,500
Pervious pavement 0.859 144 63,040 2.37 7,290 $182,250
Parking spaces on the west side of the site can be converted to pervious pavement to capture stormwater from the parking lot. Two raingardens can be installed along the south end of the building by redirecting downspouts into them to capture stormwater from the rooftop.A preliminary soil assessment suggests that the soils have suitable drainage characteristics for green infrastructure.
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H A M I LT O N T O W N S H I P M U N I C I P A L B U I L D I N G 6 1 0 1 1 3 t h S t r e e tMa y s L a n d i n g , NJ 0 8 3 3 0
76
H A M I L T O N T O W N S H I P M U N I C I P A L U T I L I T I E S A U T H O R I T Y
6 0 2 4 K en S c u l l A v e n u e Ma y s L a n d i n g , NJ 0 8 3 3 0
77
H A M I L T O N T O W N S H I P M U N I C I P A L U T I L I T I E S A U T H O R I T Y
6 0 2 4 K en S c u l l A v e n u e Ma y s L a n d i n g , NJ 0 8 3 3 0
http://water.rutgers.edu/Projects/HamiltonTwp-AtlanticCo/HamiltonTwp_AtlanticCounty/index.html
Water Resources Program
Final Thoughts
• Plans promote action and earn Sustainable Jersey Points• Plans are a conduit for funding• Impervious cover reduction action plan/green
infrastructure action plan provides sites for developers to offset impacts
• Wide range in cost of projects (Eagle Scout projects to economic stimulus money projects)
• Foundation for stormwater utilities, watershed restoration plans, stormwater mitigation plans, and/or integrated water quality plans
