Green Infrastructure:Reconnecting Water, Soils and Vegetation in the

Urban Environment

Michele Adams, P.E. LEED AP

Two important observations:

Volume: 96% of the annual rainfall

volume of 36 inches is from

storms 3 inches or less

Frequency: Most of the time, it rains 1 inch

or less

Annual Percentages of Volume from Storms

A New Paradigm for WaterVolume: Capture the Small Frequent Rainfalls

• Pennsylvania – Volume Increase for 2-Year Event (1 ½” -2”)

• City of Philadelphia: 1” from Impervious Surfaces• US Green Building Council (LEED) – 95% of Rainfall Events

EPA: Mimic Natural Hydrology

Image by Viridian Landscape Studios

The Challenge – Combined Sewers

• Cathedral and Parking on top of hill

• Surrounded by “Olmsted’s Woods”

• Point Discharges eroding hillside, creating ravines

• Lack of Recharge: Diminished Soil Moisture and Dying Trees

• Invasive Vegetation

Restoration:Washington National Cathedral

Once the Volume is reduced• Repair outfalls and ravines

with check dams• Prevent to continued loss of

groundwater• Make the structures look

natural

Infiltration Trenches

First Step:Reduce the problem by reducing the volume of

runoff

• Direct Runoff to Infiltration Trenches in Lawn

Amphitheater that is an infiltration system

• Replace Storm Sewers with Infiltration Trenches along Roadway

• Intercept Storm Sewer• Return water to woodland

soils

Stormwater in Philadelphia

• Capture first 1-inch of rainfall from impervious surfaces for new development (current rule)

• Stormwater fees restructured in 2010 -monthly charges for impervious and total site areas.

• Stormwater measures can reduce monthly fees

• “Green Streets” designs• Planter boxes, tree trenches, rain

gardens, and bioswales • Use vegetation and soils to manage

stormwater

Urban Schools:Sadie Alexander K-8 School

• Constructed in 2000• Philadelphia Water

Department• Reducing Volume to

Combined Sewers• Urban Green Space:

• Porous Playground• Playfield with

Stormwater Bed Below

• Rain Gardens• Education

Stormwater Infiltration Below Playfield

Sadie Alexander School, Philadelphia

• Roof Leaders from Building to Bed

• Old Urban Fill• Infiltration to Reduce Volume• Urban Green Space

• Education• Access• Infiltration• Urban Green Space

Rain Gardens

Porous Pavement Playground (no puddles!)

Rain Gardens

Rainwater can support the landscape and soils, reducing pipes and basins.

Porous Paving with Infiltration

Same Detail Can be Used with Standard Paving with Infiltration

Porous Asphalt Walkways

Swarthmore College

Grey TowersNational Forest Service

Greening Greenfield School

New Porous walk

Construction of Vegetated Swale

Before

After

Removal of Pavement to Create Stormwater Swale

Capture of 1-inch rainfall plus green space, education, and new play areas.

Swale to bioretention area

Independence Charter School

Before

Porous Asphalt, Stormwater Cobble Swale to Rain Garden

Independence Charter School

Waterview Recreation CenterDownspout Planter Boxes

Before

After

Before After

Passyunk Avenue

• Busy dirty street

Bio-retention

Water from the street enters through a trench drain

Overflow water exits to an inlet

Clark Park

• Constructed in 2007• Philadelphia Water

Department & PA Horticultural Society

• Infiltration Bed under Asphalt Basketball Court

Stone Infiltration Bed• Captures 1.5” of Water

from Street, Parking Lot, and Sidewalks

Street inlet designed with water quality insert and sump to prevent debris and sediment from clogging infiltration bed.

Finished Basketball Court with Subsurface Infiltration Bed

Portland Porous Streets

Porous Pavers

Porous Asphalt

Porous Concrete

East Falls: Complete Streets

Rendering by Andropogon Associates

Rendering by Andropogon Associates

• City and Delaware Horticultural partnership

• Urban Heat Island Cooling

• Capture 1” from Street and Store

Commercial and Parking Lot:Urban Grocery Store in Wilmington

Bioswales and Rain Gardens for Parking Lot water

Tree Trenches collect street water

West Hollywood Porous Pavement

– Existing Site

Planter Box(Variation on Bioretention)

Wilmington Library

Also Bioretention and Storage for Irrigation

At the Residential Level: Downspout Disconnection

Disconnect downspout from combined sanitary sewer system

•Portland, OR•Chicago, IL•Boston, MA•Minneapolis, MN•Bremerton, WA•Lynchburg, VA•Pittsburgh Nine Mile Run!•Pittsburgh: Nine Mile Run!

Portland, Oregon

• Elimination of 94% of overflows to Willamette River by 2011

• > 44,000 disconnected downspouts (>1 BGY stormwater)

• Residents can do work themselves and earn $53 per downspout

• Community groups earn $13 per downspout

Where Does The Water Go?• Lawns• Other pervious

surfaces • Vegetative swales• Rain gardens• Infiltration trenches• Rain barrels

Boston Disconnect Program

New Residential: Village at Springbrook• High Density Residential• 59 acres• 269 homes:• 146 Townhouses• 96 Quads• 17 Singles• Sinkholes and limestone

Can Water be Managed within the landscape?127 small measures, no detention basins.

• Each home manages its own runoff in a Rain Garden seepage bed, located in the right-of-way.

Patios, Terraces, Courtyards

Pervious Pavements

Paths

Driveways

At the Residential Level: Rain Barrels

Infiltration Trench – “leaky pipe”

A Private RetreatPhiladelphia PA

The property

Wissahickon Creek in Fairmount Park

Schuylkill River

The Plan

Existing

Proposed

Vegetable GardenMeadow

Compost

Lawn

Gathering Garden

Patio

Compost

Bird Feeders

Table & chairs

Rain GardenStreet TreesN

N

The Street

Street trees were obtained through Philadelphia Green & the WNCA Tree Tenders

From Lawn to MeadowNATURAL AREAMeadow Development in Progress

Roxborough Habitat Restoration Project

Beautiful Meadow Coming to your Neighborhood!

Before Before

After After

Brown Thrasher

After

The Rain Garden

Existing

Proposed

Infiltration area under bluestone

Planted swale

Lawn

Patio

Compost

Final treatment

Rain Garden and Swale Location

Before

A Private Retreat

Infiltration bed

Planted Swale

Rain Chains, Spash blocks

Restoring Panther Hollow –Restoring the Watershed