Noah Garrison, Natural Resources Defense CouncilMay 15, 2013

Greening New Orleans: Stormwater in the Urban Landscape

Land-Use in the Chino Basin

Wildermuth Environmental

Impervious Surface

Impervious Surface

Stormwater Runoff: Impairment and Flooding

Dan Marschka

LA Times

California Coastal Commission

Rooftops to Rivers II

• Demonstrates how cities use green infrastructure to improve stormwater management and achieve multiple benefits.

• The report includes:– Economic benefits of green

infrastructure– Case studies on 14 cities – Encouragement for EPA to

learn from the work of these cities and advance these solutions nationwide

NRDC’s Emerald City Metric

Philadelphia

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Green City, Clean Waters plan – creating an urban network of GI over the next 25 years -- the most comprehensive found in any U.S. city.

$2.4

Billion

The Philadelphia Story: Green City Clean Waters

• City Requires management of the first 1-inch of rainfall by infiltration

• Plan is unique among US cities because it:

o Requires that thousands of acres be retrofitted with green infrastructure, citywide. At least one-third of impervious area served by

combined sewer system transformed into “greened acres” -- nearly 10,000 acres.

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Portland, OR Retention standard – January

2011: new development and redevelopment projects must capture and treat 80% of the average annual runoff volume on site

Toronto, Canada Requires buildings over 2,000

sq meters to incorporate a green roof

Implemented a mandatory downspout disconnect program

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Los Angeles, CA Retention standard – runoff

from the 85th percentile, 24-hour storm

Development of less than one-acre (as little as 500 square feet of impervious surface) must incorporate LID BMPs

EPA / Abby Hall

Haan-Fawn Chau

NRDC: A Clear Blue Future

Feasibility of Retention

Investigation of the Feasibility and Benefits of Low-Impact Site Design Practices Applied to Meet Various Potential Stormwater Runoff Regulatory Standards – Dr. Richard Horner

Green Roofs

National Research Council's Institute for Research in Construction

Green Roofs Retain Runoff• A green roof with a 3 – 4 inch soil

layer can generally retain 0.5 – 1 inch of rainfall from a storm event.

• Estimated retention rates for green roofs across the U.S. generally range from 40 to 80 percent of total annual rainfall volume.

Green Roofs (and cool roofs) Reduce Energy for Building Cooling• Temperature on a dark,

conventional roof may exceed ambient air temperatures by 90°F or more on a sunny day.

• Green roofs provide shade and evaporative cooling that can reduce building cooling energy by 10 to 25 percent on average, or as high as 75 percent depending on building characteristics.

LID is Cost Effective

…

National Association of Home Builders: