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Contemporary Issues in Designing and Managing Sustainable Cities Urban Affairs 1171

Water: Philadelphia's "Green City – Clean Water Plan"

WATER

In Philadelphia 80% of storm water falls on impermeable surfaces, parking lots, roadways, roofs

13 billion gallons of runoff per year

Philadelphia has 3,000 miles of aging water infrastructure

Source: http://www.nextgreatcity.com/actions/sewer http://www.onearth.org/article/phillywater

One inch of rain water hitting one acre of asphalt means 27,000 gallons of water is going into the sewer

Our storm water + sewage systems are old, and in many areas are beyond their life expectancy

Where did they go?

"Natural" streams still flow underground, but contained in sewers

1892

http://www.phillywatersheds.org

http://www.wplp.net/

Pennypack Creek Water Shed

Watershed A drainage basin which all water flows to a single location

City is understood as a system operating within nature

Watersheds can be very large

Majority of rainfall in urban areas is not absorbed in ground

Must be treated before it can be released to waterways

Water problem in Philadelphia:

Much of Philadelphia's underground water system has combined sewer (human+industrial waste) and storm run-off (rainwater).

During storms, system is overburdened and excess waste is deposited into native waterways (small creeks -> Schuylkill River -> Delaware River)

Dry weather

Wet weather

The green infrastructure plan would turn 1/3 of the city’s impervious surfaces, or 4,000 acres, into absorptive green spaces, avoiding the need for treatment.

Impervious: Streets, sidewalks, roofs

Solutions

"Gray" vs “Green" Infrastructure

Solutions

"Gray" Infrastructure refers to traditional infrastructure solutions to manage storm water.

Expensive to build and maintain, treats water as waste

Solutions

“Green” is the use of natural systems and passive technologies to use nature’s ability to deal with storm water.

Treats storm water as a resource, both for human use and replenishing ground water

GOAL: put water into the ground

Rain Barrels A Rain barrels collect and store storm water runoff from downspouts.

Green Roofs A green roof is a roof that is partially or completely covered with vegetation to manage storm water runoff

Infiltration systems

Grey Water Rain Harvesting System

Porous Pavement Replaces traditional pavement, allowing storm water runoff to infiltrate directly into the ground.

Permeable Paving

Rain Gardens / Vegetated Swales Swales are designed to collect storm water and slowly infiltrate back into the ground

Mt. Tabor Middle School, Portland Oregon

Mt. Tabor Middle School, Portland Oregon

Bump Outs/Curb Extensions A curb opening directs storm water runoff from the street and gutter into the bump-out.

Sidewalk Planters Sidewalk planters are vegetated with native plants that collect storm water runoff.

These methods also trap sediment, other pollutants and reducing the rate and volume of storm water runoff.

Living Wall / Green Wall A vertical arrangement of plants and other vegetation, gravity fed from roof runoff.

Gray • Reduced combined sewer overflow • Improve water quality • Jobs

Green • Reduced combined sewer overflow • Improve water quality • Jobs (green jobs) • Improve Air quality • Cooling • Reduced heat Island effect • Reduce Carbon Footprint • Increased recreation / green space • Enhance ecosystems • Improve aesthetics • Raise property values

Gray vs. Green Infrastructure