Green Roofs and Green Infrastructure High-Performance Building Week June 16, 2010.
Green Roofs and Green Infrastructure
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Transcript of Green Roofs and Green Infrastructure
Green Roofs and Green Infrastructure
High-Performance Building WeekJune 16, 2010
Environmental Benefits of Green Roofs, Green Infrastructure, and Low-Impact Development:• Control stormwater runoff• Improve water quality• Conserve water• Reduce urban heat island effect• Store carbon• Improve air quality• Reduce building energy use• Create biohabitat
Impervious Surface and Water Quality
• Natural landscapes clean and filter water, slow and reduce runoff
• Traditional development increases impervious surfaces
• In the U.S., impervious surfaces are increasing 3% annually
• Result: Urban and suburban stormwater runoff is the #1 cause of pollution in urban watersheds
Sources: Urban Green Space: Effects on Water and Climate, Regina E. Bonsignore, University of Minnesota, 2003; Stream Corridor Restoration: Principles, Processes, and Practices, Federal Interagency Stream Restoration Working Group, 1998.
Impervious Surface and Water Quality
• Water quality begins to degrade when impervious cover exceeds 10%
• Water quality becomes “poor” when impervious cover exceeds 25%
• D.C. – 46 % impervious• NYC – over 90% impervious• Stormwater concerns:
– Pollutant load – Water temperature– Speed and quantity causes
erosion and streambed scouring
Sources: Urban Green Space: Effects on Water and Climate, Regina E. Bonsignore, University of Minnesota, 2003; Stream Corridor Restoration: Principles, Processes, and Practices, Federal Interagency Stream Restoration Working Group, 1998.
Water Quality: Combined Sewer Outflows
• Heavy storms = release of untreated sewage and runoff into watersheds.
• Nationwide, CSOs affect 772 cities, 40 million people
• Scope of problem in D.C. — 2.5 billion gallons of untreated wastewater and precipitation released annually
• In some parts of D.C., one-tenth inch of rain triggers CSOs
• Cost of fixing problem in D.C. -- $2.6 billion
Sources: U.S. Environmental Protection Agency; D.C. Water and Sewer Authority
Water Quality: Combined Sewer Outflows
• CSOs are #1 cause of beach closures around urban areas
Impervious Surface and Flooding
• As development increases, so does the amount and speed of stream flow
• As stream flow speeds increase, so does flooding
Source: U.S. Geological Survey
Houston 2001: Tropical Storm Allison
• $6.5 billion (‘08 USD) in damages• 41 deaths• 70,000 homes flooded
Traditional Development = Urban Heat Island
• = Increased air pollution and related health problems
• = Increased carbon footprint -- higher temperatures require more energy for cooling
Sources: U.S. Environmental Protection Agency; Paul R. Baumann, Department of Geography, SUNY Oneonta
Test
April 15, 2004
Image Courtesy of Michael Van Valkenburgh Associates, Inc. & ASLA
Roofs are 15-25% of surface area in cities
ASLA: Pre-Green Roof
ASLA Green Roof
ASLA Green Roof Results
• Retains 100 % of a one-inch rainfall and over 77 % of total annual rainfall
• Reduces the amount of nitrogen entering the watershed
• Building energy use reduced by 10 % in winter months
• Temperature as much as 43.5 cooler in the summer
•25% reduction in stormwater leaving site
•Bioretention planters filter and clean water
• LEED platinum • Integrated stormwater and
wastewater system
Sidwell Friends School, D.C.Image courtesy of Andropogon
• Biofilters treat building wastewater for reuse
• Uses constructed wetlands, rain gardens, bioswales, biofiltration and habitat pools
Sustainable Housing Community: High PointSustainable Housing Community: High PointSeattle, WashingtonSeattle, WashingtonPhoto courtesy of Mithun
• 120 acre residential redevelopment
• Returns clean water to an urban salmon-bearing stream
Photo courtesy of Mithun
• Rain gardens, pervious pavements, 22,000 linear feet of bioswales
• Native plants and rich vegetation
• Controls water flow for 100-year storm events
Photo courtesy of Mithun
• Incorporates “Complete Streets”
• Handles 100-year storm rainfalls
SW 12th Avenue, Portland, ORSW 12th Avenue, Portland, ORPhoto courtesy of Kevin Robert Perry, ASLA Photo courtesy of Kevin Robert Perry, ASLA
• Retail district “green street” • Retains 100% of rainfall from
a 100-year storm• Channels water from street
into stormwater planters
NE Siskiyou, Portland, ORNE Siskiyou, Portland, ORPhoto courtesy of Kevin Robert Perry, ASLA Photo courtesy of Kevin Robert Perry, ASLA
•Residential “green street”
Photo courtesy of Kevin Robert Perry, ASLAPhoto courtesy of Kevin Robert Perry, ASLA
Photo courtesy of Kevin Robert Perry, ASLAPhoto courtesy of Kevin Robert Perry, ASLA
Buffalo Bayou Promenade, Houston, TXPhoto courtesy SWA Group
•Turned derelict riverfront into 23 acres of park land•Mitigated erosion•Enhanced flood control
Buffalo Bayou Promenade, Houston, TXPhoto courtesy SWA Group
• Reduces air temperature• Provides recreation
opportunities• Creates biohabitat
Important Legislation• HR 4202 The Green Infrastructure for
Clean Water Act of 2009– Provides grants to states, localities, and other
qualified entities for plan, design and implementation of green infrastructure projects that would mitigate stormwater runoff and address other water quality and quantity issues
HR 4202 – Recommends changes to local ordinances,
permitting processes, and zoning regulation to encourage the use of Green Infrastructure solutions
– Establishes a Green Infrastructure program at EPA to promote the use of green infrastructure
– Creates up to 5 Green Infrastructure centers of excellence to conduct research and develop best management practices
Questions?Roxanne Blackwell [email protected] 202.216.2334
Kevin O’[email protected]