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What is Green Infrastructure and How Does It Reduce Wet Weather Issues?

Making natural systems work for us: using soil and vegetation - rather than concrete and pipe,to manage stormwater volume, rate, and water quality impacts

Prepared by:

Prepared for:

Onondaga County, New York

October 2008

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CombinedSewer

Interceptor Sewer to Wastewater

Treatment Facility

SanitarySewer

CreekDry Weather

Flow

During dry weather, sanitary flows are collected in combined sewers for treatment at Metro

Catch Basin

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During wet weather, inflows exceed the collection system’s capacity and trigger a CSO

CombinedSewer

Interceptor Sewer to Wastewater

Treatment Facility

SanitarySewer

Creek

Catch Basin

Combined Sewer

Overflow

Stormwater Runoff

Roof Leaders

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Green solutions intercept and reduce stormwater flows to sewers, providing storage, infiltration, and treatment

Vegetated Swale

Combined Sewer

Interceptor Sewer to Wastewater

Treatment Facility

SanitarySewer

CreekDry Weather

Flow

Porous Roadway

Stormwater Runoff

Roof Leader

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Green infrastructure reduces….

Flooding Erosion Stormwater runoff volume Stormwater pollutant loadings CSOs Gray infrastructure operation, maintenance, energy

and treatment costs

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Green Infrastructure Technologies and Example Applications

Porous pavement Parking lots Roadways Sidewalks Basketball courts

Bioretention/vegetated infiltration Rain Gardens Vegetated curb extensions Tree trenches Planter boxes Cisterns for capture/re-use Vegetated roofs

Green streets Combinations of the above

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Porous Pavement Parking Lot

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Porous Pavement Asphalt Roadway Porous Pavement Asphalt Roadway

Porous Pavement Paver Roadway

Porous Pavement Paver Roadway

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Porous Pavement

sidewalk

basketball court

10Rain Garden (bioretention/vegetative infiltration)Rain Garden (bioretention/vegetative infiltration)

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Vegetated Curb Extension – Plan View

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Vegetated Curb Extension – Profile View

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Tree Trench

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Tree Trenches along Street

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Planter Box

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Cistern for Capture/Re-use

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Vegetated Roof

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Vegetated Roof

under construction

finished roof

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Green Streets…putting it all together

Portland State University Street Planters

Image Source: A Civic Vision for the Central DelawareImage Source: A Civic Vision for the Central Delaware

Green Streets…putting it all together ~ “Catch the Rain”20

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Green Infrastructure improves:

Water quality Air quality Neighborhood aesthetics Habitat and biodiversity Recreational and transportation opportunities Property values Community health and vitality

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DEC Promoting GI Approach

Stormwater Best Management Practices (BMPs) CSO Long Term Control Plans Order on Consent Environmental Benefit Projects

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Funding Sources

Environmental Benefit Projects Water Quality Improvement Projects (WQIP) US Forestry Grants Clean Water State Revolving Fund (CWSRF)

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Demonstration Projects

GI projects should be demonstration projects» Cost / Benefit compared to gray» Actual stormwater retention/detention» Operation and Maintenance costs» Other benefits/problems

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Data Collection

Data collection to estimate transpiration rates, percent removal of contaminates, infiltration rates, and estimated volume reduction in runoff may include –

quality of the stormwater influent and effluent meterological data/ rainfall data (rain gauges) groundwater and surfacewater levels water flow monitoring devices soil pH and nutrient levels observed flora and fauna

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