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  • 1. ROOFTOPS TO RIVERSGreen Strategies for Controlling Stormwaterand Combined Sewer OverflowsProject Design and DirectionNancy Stoner, Natural Resources Defense CouncilAuthorsChristopher Kloss, Low Impact Development CenterCrystal Calarusse, University of Maryland School of Public PolicyNatural Resources Defense CouncilJune 2006
  • 2. ABOUT NRDCThe Natural Resources Defense Council is a national nonprofit environmental organization with more than 1.2million members and online activists. Since 1970, our lawyers, scientists, and other environmental specialists haveworked to protect the world’s natural resources, public health, and the environment. NRDC has offices in NewYorkCity, Washington, D.C., Los Angeles, San Francisco, and Beijing. Visit us at wishes to acknowledge the support of The McKnight Foundation; The Charles Stewart Mott Foundation;The Joyce Foundation; The Geraldine R. Dodge Foundation, Inc.; The Marpat Foundation; The Morris and GwendolynCafritz Foundation; Prince Charitable Trusts; The Mary Jean Smeal Family Fund; The Brico Fund, Inc.; The SummitFund of Washington; The Naomi and Nehemiah Cohen Foundation; and The Jelks Family Foundation, Inc.NRDC Director of Communications: Phil GutisNRDC Publications Manager: Alexandra KennaughNRDC Publications Editor: Lisa GoffrediProduction: Bonnie GreenfieldCover Photo: ©2006 Corbis. View of Arlington, Virginia, seen from across the Potomac River in Washington, D.C.Copyright 2006 by the Natural Resources Defense Council.For additional copies of this report, send $5.00 plus $3.95 shipping and handling to NRDC Reports Department, 40 West 20th Street, New York, NY 10011. Californiaresidents must add 7.5% sales tax. Please make checks payable to NRDC in U.S. dollars.This report is printed on paper that is 100 percent post-consumer recycled fiber, processed chlorine free.
  • 3. CONTENTSPeer Reviewers ivExecutive Summary vChapter 1: Introduction 1Chapter 2: The Growing Problem of Urban Stormwater 2Chapter 3: Controlling Stormwater in Urban Environments 6Chapter 4: Economic Benefits of Green Solutions 11Chapter 5: Policy Recommendations for Local Decision Makers 13Chapter 6: Conclusion 16Chapter 7: Case Studies 17Chicago, Illinois 17Milwaukee, Wisconsin 20Pittsburgh, Pennsylvania 22Portland, Oregon 24Rouge River Watershed, Michigan 27Seattle, Washington 29Toronto, Ontario, Canada 31Vancouver, B.C., Canada 33Washington, D.C. 37Appendix: Additional Online Resources 40Endnotes 43 iii
  • 4. PEER REVIEWERSKatherine Baer Darla InglisAmerican Rivers Seattle Public UtilitiesTom Chapman Otto KauffmannMilwaukee Metropolitan Sewerage District City of VancouverMike Cox Jim MiddaughSeattle Public Utilities City of Portland Bureau of Environmental ServicesRobert Goo Steve ModdemeyerU.S. EPA Seattle Public UtilitiesBill Graffin Laurel O’SullivanMilwaukee Metropolitan Sewerage District Consultant to Natural Resources Defense CouncilJose Gutierrez Brad SewellCity of Los Angeles Environmental Affairs Natural Resources Defense CouncilDepartment Mike ShribergEmily Hauth Public Interest Research Group in MichiganCity of Portland Bureau of Environmental Services Heather WhitlowJonathan Helmus The Casey Trees Endowment FundCity of Vancouver David Yurkovich City of Vancouver iv
  • 5. EXECUTIVE SUMMARYA s an environmental strategy, green infrastructure addresses the root cause of stormwater andcombined sewer overflow (CSO) pollution: the con- Each year, the rain and snow that falls on urban areas in the United States results in billions of gallons of stormwater runoff and CSOs. Reducing runoff withversion of rain and snow into runoff. This pollution green infrastructure decreases the amount of pollutionis responsible for health threats, beach closings, introduced into waterways and relieves the strain onswimming and fishing advisories, and habitat stormwater and wastewater infrastructure. Efforts indegradation. Water quality standards are unlikely many cities have shown that green infrastructure canto be met without effectively managing stormwater be used to reduce the amount of stormwater dischargedand CSO discharges. Green infrastructure—trees, or entering combined sewer systems and that it canvegetation, wetlands, and open space preserved or be cost-competitive with conventional stormwatercreated in developed and urban areas—is a strategy and CSO controls. Additional environmental benefitsfor stopping this water pollution at its source. include improved air quality, mitigation of the urban The urban landscape, with its large areas of heat island effect, and better urban aesthetics.impermeable roadways and buildings—known as Green infrastructure is also unique because it offersimpervious surfaces—has significantly altered the an alternative land development approach. New devel-movement of water through the environment. Over opments that use green infrastructure often cost less100 million acres of land have been developed in to build because of decreased site development andthe United States, and with development and sprawl conventional infrastructure costs, and such develop-increasing at a rate faster than population growth, ments are often more attractive to buyers because ofurbanization’s negative impact on water quality is environmental amenities. The flexible and decentral-a problem that won’t be going away. To counteract ized qualities of green infrastructure also allow it tothe effects of urbanization, green infrastructure is be retrofitted into developed areas to provide storm-beginning to be used to intercept precipitation and water control on a site-specific basis. Green infra-allow it to infiltrate rather than being collected on structure can be integrated into redevelopment effortsand conveyed from impervious surfaces. ranging from a single lot to an entire citywide plan.Case Study Program Elements and Green Infrastructure Techniques PROGRAM ELEMENTS TYPE OF GREEN INFRASTRUCTURE USED Wetlands/ Established Rain Gardens/ Downspout Riparian Used for Municipal Vegetated Disconnection/ Protection/ Direct CSO Programs & Swales & Permeable Rainwater UrbanCity Control Public Funding Green Roofs Landscape Pavement Collection ForestsChicagoMilwaukeePittsburghPortlandRouge River WatershedSeattleTorontoVancouverWashington v
  • 6. Natural Resources Defense Council Rooftops to RiversThe aerial photograph at left of Washington, DC, shows the amount of green space and vegetation present in 2002. The photo atright shows how this same area would look in 2025 after a proposed 20-year program to install green roofs on 20% of city buildingsover 10,000 square feet. PHOTOS COURTESY OF THE CASEY TREES ENDOWMENT FUND Nonetheless, wider adoption of green infra- new development plans and preserve existingstructure still faces obstacles. Among these is the vegetation.economic investment that is required across the 2. Incorporate green infrastructure into long-termcountry for adequate stormwater and CSO control. control plans for managing combined sewer overflows.Although green infrastructure is in many casesless costly than traditional methods of stormwater Green techniques can be incorporated into plans forand sewer overflow control, some municipalities infrastructure repairs and upgrades.persist in investing only in existing conventional 3. Revise state and local stormwater regulations tocontrols rather than trying an alternative approach. encourage green design. A policy emphasis should beLocal decision makers and organizations must placed on reducing impervious surfaces, preservingtake the lead in promoting a cleaner, more vegetation, and providing water quality improvements.environmentally attractive method of reducingthe water pollution that reaches their communities. The case studies that begin on page 17 offerNRDC recommends a number of policy steps nine examples of successful communities thatlocal decision makers can take to promote the use have reaped environmental, aesthetic, and eco-of green infrastructure: nomic benefits from a number of green infrastruc- ture initiatives.1. Develop with green infrastructure and pollution The table on page v provides a summarymanagement in mind. Build green space into of information contained within the case studies. vi
  • 7. CHAPTER 1INTRODUCTIONW ater pollution problems in the United States have evolved since the days when Ohio’sCuyahoga River was on fire. Increasingly, water pol-lution from discrete sources such as factory pipes isbeing overshadowed by overland flows from streets,rooftops, and parking lots, which engorge down-stream waterways every time it rains. This storm-water has nowhere to go because the naturalvegetation and soils that could absorb it have beenpaved over. Instead, it becomes a high-speed, high-velocity conduit for pollution into rivers, lakes, andcoastal waters. Most U.S. cities have separate stormwater sewer The green roof at Ford Motor Company’s Premier Automotivesystems through which contaminated stormwater North American Headquarters in Irvine, CA, was designed to visually mimic the natural landscape. PHOTO COURTESY OF ROOFSCAPES, INC.flows directly into waterways through undergroundpipes, causing streambank scouring and erosion anddumping pet waste, road runoff, pesticides, fertilizer, local levels, but fresh thinking is needed also. Someand other pollutants directly into waterways. In U.S. cities are already taking steps to successfullyolder cities, particularly in the Northeast and Great build green infrastructure into their communities.Lakes regions, stormwater flows into the same pipes Emerging green infrastructure techniquesas sewage and causes these combined pipes to over- present a new pollution-control philosophy basedflow—dumping untreated human, commercial, and on the known benefits of natural systems thatindustrial waste into waterways. Stormwater pollu- provide multimedia pollution reduction and usetion has been problematic to some extent for as long soil and vegetation to trap, filter, and infiltrateas there have been cities, but the volume of storm- stormwater. The cities already using green infra-water continues to grow as development replaces structure are finding that it is a viable alternativeporous surfaces with impervious blacktop, rooftop, to conventional stormwater management. Althoughand concrete. used widely overseas, particularly in Germany Contaminated stormwater and raw sewage and Japan, the use of green infrastructure in thedischarges from combined sewer overflows (CSOs) United States is still in its infancy; however, dataare required to be controlled under the Clean Water indicate that it can effectively reduce stormwaterAct, but progress is slow because the problems are runoff and remove stormwater pollutants, andlarge and multi-faceted and because the solutions cities that have implemented green design areare often expensive. A substantial influx of addi- already reaping the benefits (see the case studiestional resources is needed at the federal, state, and on page 17). 1
  • 8. CHAPTER 2THE GROWING PROBLEMOF URBAN STORMWATERD evelopment as we have come to know it in the United States—large metropolitan centers sur-rounded by sprawling suburban regions—has con- landscape with impervious surfaces has significant environmental impacts. The level of imperviousness in a watershed has been shown to be directly relatedtributed greatly to the pollution of the nation’s waters. to the health of its rivers, lakes, and estuaries.As previously undeveloped land is paved over and Research indicates that water quality in receivingbuilt upon, the amount of stormwater running off roofs, water bodies is degraded when watershed impervi-streets, and other impervious surfaces into nearby ousness levels are at or above 10% and that aquaticwaterways increases. The increased volume of storm- species can be harmed at even lower levels.3water runoff and the pollutants carried within it Both the National Oceanic and Atmosphericcontinue to degrade the quality of local and regional Administration (NOAA) and Pennsylvania Statewater bodies. As development continues, nature’s University estimate that there are 25 million acres ofability to maintain a natural water balance is lost to impervious surfaces in the continental United States.4a changing landscape and new impervious surfaces. This quantity represents nearly one-quarter of the The trees, vegetation, and open space typical more than 107 million acres—almost 8% of non-of undeveloped land capture rain and snowmelt, federal land in the contiguous United States—thatallowing it to largely infiltrate where it falls. Under had been developed by 2002.5 In urban areas, it is notnatural conditions, the amount of rain that is uncommon for impervious surfaces to account forconverted to runoff is less than 10% of the rainfall 45% or more of the land cover.volume.1,2 Replacing natural vegetation and This combination of developed land and impervi- ous surfaces presents the primary challenge of storm-TABLE 1: Effects of Imperviousness on Local Water water mitigation. Existing stormwater and wastewaterBodiesa,b,c infrastructure is unable to manage stormwater in Watershed a manner adequate to protect and improve waterImpervious Level Effect quality. Standard infrastructure and controls fail to 10% • Degraded water quality reduce the amount of stormwater runoff from urban 25% • Inadequate fish and insect habitat environments or effectively remove pollutants. • Shoreline and stream channel erosion 35%–50% • Runoff equals 30% of rainfall volume >75% • Runoff equals 55% of rainfall volumea Environmental Science and Technology, Is Smart Growth Better for Water THE DEFICIENCIES OF CURRENT URBAN Quality?, August 25, 2004, STORMWATER INFRASTRUCTURE estjag-w/2004/policy/jp_smartgrowth.html (accessed December 6, 2004).b U.S. EPA, Protecting Water Quality from Urban Runoff, Nonpoint Source Stormwater management in urban areas primarily Control Branch, EPA 841-F-03-003, February 2003. consists of efficiently collecting and conveyingc Prince George’s County, Maryland Department of Environmental Resources, Low-Impact Development Design Strategies, January 2000. stormwater. Two systems are currently used: separate 2
  • 9. Natural Resources Defense Council Rooftops to RiversBioswales on Portland’s Division Streetinfiltrate and treat stormwater runoff.PHOTO COURTESY OF THE PORTLAND BUREAU OF ENVIRONMENTALSERVICESstormwater sewer systems and combined sewer pollution from combined sewer systems tends to besystems. Separate stormwater sewer systems collect a more regional problem concentrated in the olderonly stormwater and transmit it with little or no treat- urban sections of the Northeast, the Great Lakesment to a receiving stream, where stormwater andits pollutants are released into the water. Combined TABLE 2: Urban Stormwater Pollutantssewer systems collect stormwater in the same setof pipes that are used to collect sewage, sending the Pollutant Sourcemixture to a municipal wastewater treatment plant. Bacteria Pet waste, wastewater collection systems Metals Automobiles, roof shingles Nutrients Lawns, gardens, atmospheric depositionSeparate Stormwater Sewer Systems Oil and grease AutomobilesThe large quantities of stormwater that wash across Oxygen-depleting Organic matter, trashurban surfaces and discharge from separate storm- substanceswater sewer systems contain a mix of pollutants, Pesticides Lawns, gardensshown in Table 2, deposited from a number of Sediment Construction sites, roadwayssources.6,7 Stormwater pollution from separate Toxic chemicals Automobiles, industrial facilitiessystems affects all types of water bodies in the Trash and debris Multiple sourcescountry and continues to pose a largely unaddressedthreat. In 2002, 21% of all swimming beach advisories TABLE 3: Urban Stormwater’s Impact on Water Qualityand closings were attributed to stormwater runoff.8Table 3 shows the percentage of assessed (monitored) Water Body Type Stormwater’s Rank % of Impaired as Pollution Source Waters Affectedwaters in the United States for which stormwater has Ocean shoreline 1st 55% (miles)been identified as a significant source of pollution.9 Estuaries 2nd 32% (sq. miles) Great Lakes 2nd 4% (miles)Combined Sewer Systems shorelineWhile pollution from separate sewer systems is a Lakes 3rd 18% (acres) Rivers 4th 13% (miles)problem affecting a large majority of the country, 3
  • 10. Natural Resources Defense Council Rooftops to RiversTABLE 4: Pollutants in CSO DischargesaPollutant Median CSO Concentration Treated Wastewater ConcentrationPathogenic bacteria, viruses, parasites• Fecal coliform (indicator bacteria) 215,000 colonies/100 mL < 200 colonies/100mLOxygen depleting substances (BOD5) 43 mg/L 30 mg/LSuspended solids 127 mg/L 30 mg/LToxics• Cadmium 2 µg/L 0.04 µg/L• Copper 40 µg/L 5.2 µg/L• Lead 48 µg/L 0.6 µg/L• Zinc 156 µg/L 51.9 µg/LNutrients• Total Phosphorus 0.7 mg/L 1.7 mg/L• Total Kjeldahl Nitrogen 3.6 mg/L 4 mg/LTrash and debris Varies Nonea U.S. EPA, Report to Congress: Impacts and Control of CSOs and SSOs, Office of Water, EPA-833-R-04-001, August 2004.region, and the Pacific Northwest. Combined sewers, Because CSOs discharge a mix of stormwater andinstalled before the mid-twentieth century and prior sewage, they are a significant environmental andto the use of municipal wastewater treatment, are health concern. CSOs contain both expected storm-present in 746 municipalities in 31 states and the water pollutants and pollutants typical of untreatedDistrict of Columbia.10 They were originally used as sewage, like bacteria, viruses, nutrients, and oxygen-a cost-effective method of transporting sewage and depleting substances. CSOs pose a direct healthstormwater away from cities and delivering them to threat in the areas surrounding the CSO dischargereceiving streams. As municipal wastewater treat- location because of the potential exposure to bacteriament plants were installed to treat sewage and protect and viruses. Estimates indicate that CSO dischargeswater quality, the limited capacity of combined sewers are typically composed of 15–20% sewage andduring wet weather events became apparent.11 80–85% stormwater.13,14 An estimated 850 billion During dry periods or small wet weather events, gallons of untreated sewage and stormwater arecombined sewer systems carry untreated sewage discharged nationally each year as combined sewerand stormwater to a municipal wastewater treatment overflows.15 Table 4 shows the concentration ofplant where the combination is treated prior to being pollutants in CSO discharges.discharged. Larger wet weather events overwhelm acombined sewer system by introducing more storm-water than the collection system or wastewater POPULATION GROWTH AND NEW DEVELOPMENTtreatment plant is able to handle. In these situations, CREATE MORE IMPERVIOUS SURFACESrather than backing up sewage and stormwater into Current levels of development and imperviousnessbasements and onto streets, the system is designed to are a major, and largely unabated, source of waterdischarge untreated sewage and stormwater directly pollution. Projections of population growth and newto nearby water bodies through a system of com- development indicate that this problem will get worsebined sewer overflows (CSOs). In certain instances, over time and that mitigation efforts will become moredespite the presence of sewer overflow points, base- costly and difficult. Although the nation has collectivelyment and street overflows still occur. Even small failed to adequately address the current levels ofamounts of rainfall can trigger a CSO event; Wash- stormwater runoff and pollution, we have also failedington D.C.’s combined sewer system can overflow to implement emerging strategies that would minimizewith as little as 0.2 inch of rainfall.12 further pollution increases. Absent the use of state-of- 4
  • 11. Natural Resources Defense Council Rooftops to Riversthe-art stormwater controls, each new acre of land footage of buildings—200 billion square feet—willdeveloped and each new parcel of impervious surface have been built after the year 2000.19will introduce new pollution into our waterways. Much of this population growth and new devel- Recent studies also indicate that stormwater opment will occur in coastal regions, a particularpollution may soon start to increase at a higher concern because urban stormwater runoff is alreadyrate than in the past. Over the past two decades, the largest source of ocean shoreline water pollution.the rate of land development has been two times Although coastal counties comprise only 17% ofgreater than the rate of population growth. Between the total acreage of the contiguous United States1982 and 1997, while the U.S. population grew 15%, they are home to more than 50% of the U.S. popu-the amount of developed land in the continental lation. Because of high population concentrationsUnited States grew 34%, an increase of 25 million on limited land areas, coastal counties contain aacres.16,17 The 25 million acres developed during higher percentage of development than interiorthis 15-year period represent nearly 25% of the total counties. In 1997, 27 million acres of coastal countiesamount of developed land in the contiguous states. had been developed, accounting for nearly 14% ofThis rapid development pattern is alarming not only the total land area. By contrast, 71 million acres,because of the conversion of a large and growing about 4% of the total land area of interior counties,percentage of the remaining undeveloped land, but had been developed.20 Based on these trends,also because of the increase in stormwater runoff that increased population and development in theseaccompanies development. coastal environments is likely to not only lead to If the relationship between land development and greater amounts of impervious surfaces in coastalpopulation growth continues, a significant amount of watersheds, but also higher percentages of impervi-land will be developed in the coming decades. The ousness. Conventional methods of stormwateranticipated 22% growth in U.S. population from 2000 control will not be able to adequately manage theto 2025 will add an additional 68 million acres of higher amount of stormwater pollution implied bydevelopment.18 By 2030, half of the total square this increased imperviousness. 5
  • 12. CHAPTER 3CONTROLLING STORMWATERIN URBAN ENVIRONMENTST he foremost challenge of reducing stormwater pollution and CSO discharges is finding aneffective method of reducing the amount of storm- water quality. Municipalities that develop programs to actually reduce stormwater pollution are moti- vated to do so because of their proximity to uniquewater created in urban environments. Methods or valued water bodies or because of a need tocurrently used to manage stormwater largely fail to protect drinking water supplies. Some of the moreaddress the underlying problem of imperviousness. aggressive and innovative stormwater programs are Stormwater collected in separate systems typically located around sensitive or important water bodiesis not treated before being discharged. In instances like the Chesapeake Bay, the Great Lakes, or Pugetwhere treatment is provided, it usually consists of Sound. Federal regulations require states to identifyfiltration to remove suspended solids, debris, and quality-limited waterways and determine thefloatables. Because dissolved materials and nutrients reduction in the Total Maximum Daily Load (TMDL)are difficult to treat in urban stormwater and little of those pollutants necessary to meet water qualityhas been done to abate the scouring, erosion, and standards, but these pollutant load-reductionother physical impacts of stormwater discharges, requirements are not often translated into effectivetreatment efforts have been largely ineffective at stormwater management programs.2diminishing stormwater-related water pollution. Municipalities are required to implement short- Most municipal stormwater discharges are regu- term and long-term strategies to reduce overflowslated as point sources under the Clean Water Act from combined sewer systems, but significant(CWA) and require a National Pollutant Discharge numbers of overflows continue to occur. The CWAElimination System (NPDES) permit. However, end- prohibits the dry weather discharge of untreatedof-pipe treatment and control typical of other per- sewage and requires wet weather CSO dischargesmitted point-source discharges are often impractical for to be limited and to control discharges of solidsurban stormwater, because of the large volumes of and floatables. Federal regulations also require thatstormwater; generated and space constraints in urban municipalities develop long-term CSO control plansareas. Permits for urban stormwater require munici- that detail procedures and infrastructure modifica-palities to develop a stormwater management plan tions necessary to minimize wet weather overflowsand to implement best management practices.1 These and meet water quality standards.3 The long-termmanagement measures are typically used in lieu of control plans focus primarily on managing storm-specific pollutant removal requirements. “Performance- water impacts on combined sewer systems.based” standards are generally not required, and mini- Mitigating CSOs is costly. The 2000 Clean Water-mum control measures are sufficient for compliance. sheds Needs Survey (CWNS) estimated that $56 bil- As a result, compliance with urban stormwater lion (2005 dollars) in capital investment was neededpermits does not necessarily result in improved for CSO control.4 Separating combined sewer lines 6
  • 13. Natural Resources Defense Council Rooftops to Riversand building deep storage tunnels are the two cur- imperviousness). Capturing, retaining, and tryingrently preferred methods of CSO control. The costs to improve the quality of vast quantities of urbanfor separating combined sewers, disconnecting storm- stormwater runoff is often more difficult andwater inlets from the combined sewer system, and expensive than reducing the amount of stormwaterdirecting them to a newly installed separate storm generated from the outset through strategies tosewer system range from $500 to $600 per foot of sewer reduce imperviousness and maximize infiltrationseparated, or $2.6 million to $3.2 million for each mile and filtration. On a municipal level, costs can beof combined sewer to be separated.5 While sewer sep- decreased when these techniques are incorporatedaration will eliminate CSO discharges and the release into redevelopment and ongoing infrastructureof untreated sewage, the trade-off is an increase in replacement efforts. Comprehensive stormwaterthe volume of untreated stormwater discharges. management programs can be used to minimize the Deep storage systems are large underground effect of impervious surfaces and manage precipi-tunnels with millions of gallons of storage capacity tation and stormwater with the use of naturalthat are built to hold the excess surge of combined processes. These “green” approaches are often lesssewer stormwater during wet weather events. These expensive and more effective than current storm-systems eventually direct the detained wastewater water and CSO the municipal treatment plant as combined sewerflow rates subside. If sized, constructed, and oper-ated properly, deep tunnels can significantly reduce GREEN ALTERNATIVESCSO discharges. However, deep tunnels take many Newer, flexible, and more effective urban storm-years to build and are very costly. Several cities have water and CSO strategies are being adopted inbegun or plan to begin deep tunnel projects costing North America. Cities are beginning to introducehundreds of millions or billions of dollars, as out- green infrastructure as a component of compre-lined in Table 5. hensive stormwater management plans aimed at Current stormwater management for separate reducing stormwater runoff, CSOs or both. Thisand combined sewer systems is ineffective because it approach is significant in that it can be used tofocuses on the symptoms (large stormwater volumes) address the stormwater problem “at the source”rather than the problem (development patterns and through efforts aimed at restoring some of theTABLE 5: Examples of Deep Storage Tunnel ProjectsCity Project Duration Completion Date Storage Capacity CostChicago, ILa,b 40+ years 2019 18 billion gallons $3.4 billionMilwaukee, WIc,d 17 years (Phase 1) 1994 405 million gallons $2.3 billion 8 years (Phase 2) 2005 88 million gallons $130 millionPortland, ORe 20 years 2011 123 million gallons $1.4 billionWashington, DCf 20 years after construction begins n/a 193.5 million gallons (proposed) $1.9 billion (projected)a Tudor Hampton, “Chicago Engineers Move Fast to Finish Epic Tunneling Feat,” Engineering News-Record, August 18, 2003, (accessed February 16, 2005).b Metropolitan Water Reclamation District of Greater Chicago, Combined Sewer Overflow Public Notification Plan, (accessed December 15, 2005).c Milwaukee Metropolitan Sewerage District, Collection System: Deep Tunnel System, (accessed November 11, 2004).d Milwaukee Metropolitan Sewerage District, Overflow Reduction Plan, (accessed November 11, 2004).e Portland Bureau of Environmental Services, Working for Clean Rivers, (accessed November 15, 2004).f D.C. Water and Sewer Authority, “WASA Proposes Plan to Control Combined Sewer Overflows to Local Waterways: Combined Sewer Long Term Control Plan,” The Reporter, Summer 2001. 7
  • 14. Natural Resources Defense Council Rooftops to RiversStreet planters in Portland, OR, are used inhighly developed urban areas to introducegreen space and manage stormwater runoff.PHOTO COURTESY OF THE PORTLAND BUREAU OF ENVIRONMENTALSERVICESnatural hydrologic function of areas that have been system is able to infiltrate and retain a rainfallurbanized. Green infrastructure can also be used to volume greater than the 10-year storm withoutlimit development in sensitive headwaters regions discharging to the municipal storm sewer system.and groundwater recharge areas to avoid the seg- Green infrastructure can be used to restore vegeta-mentation and isolation of natural environmental tion and green space in highly impervious city areas.areas and resources. Planting street trees and other urban forestry initiatives Green infrastructure can be applied in many can reduce stormwater runoff because urban treeforms. It traditionally has been thought of as the canopies intercept rainfall before it hits the pavementinterconnected network of waterways, wetlands, and is converted to stormwater. Trees with maturewoodlands, wildlife habitats, and other natural canopies can absorb the first half-inch of rainfall.7areas that maintain natural ecological processes.6 Recently the concept of green infrastructure hasIn practice, installing green infrastructure means been broadened to include decentralized, engineeredpreserving, creating, or restoring vegetated areas stormwater controls. These green techniques areand natural corridors such as greenways, parks, con- designed to mimic the functions of the natural envi-servation easements, and riparian buffers. When ronment and are installed to offset the impacts oflinked together through an urban environment, urbanization and imperviousness. Green manage-these lands provide rain management benefits simi- ment techniques are used to minimize, capture, andlar to natural undeveloped systems, thereby reducing treat stormwater at the location at which it is createdthe volume of stormwater runoff. With green infra- and before it has the opportunity to reach the col-structure, stormwater management is accomplished lection system. Engineered systems commonly usedby letting the environment manage water naturally: in urban areas include green roofs, rain gardens, raincapturing and retaining rainfall, infiltrating runoff, barrels and cisterns, vegetated swales, pocket wet-and trapping and absorbing pollutants. For example, lands, and permeable pavements.the Village Homes community in Davis, California, Most green stormwater controls actually consistuses a system of vegetated swales and meandering of green growth, including vegetated systems likestreams to manage stormwater. The natural drainage green roofs and rain gardens, but other “green” 8
  • 15. Natural Resources Defense Council Rooftops to RiversUrban trees intercept rainfall before it hits theground and is converted to stormwater runoff.PHOTO COURTESY OF THE LOW IMPACT DEVELOPMENT CENTERcontrols, like permeable pavements, are not vege- effective stormwater pollution control. This reducestated but designed to provide the water detention the amount of stormwater discharged from separateand retention capabilities of natural systems. Green stormwater sewer systems and aids combined sewerinfrastructure also encourages downspout discon- systems by decreasing the overall volume of waternection programs that redirect stormwater from entering the system, thus reducing the number andcollection systems to vegetated areas or that capture size of overflows. Another large benefit of greenand reuse stormwater, such as rain barrels. Down- infrastructure is that nearly every green techniquespout disconnection removes stormwater volume results in the removal of stormwater pollutants. Thefrom collection systems and allows green infra- natural processes employed by green infrastructurestructure components to manage the runoff. allow pollutants to be filtered or biologically or Green infrastructure offers numerous benefits when chemically degraded, which is especially advan-used to manage stormwater runoff. Many green tech- tageous for separate storm sewer systems that doniques reduce both stormwater volume and pollutant not provide additional treatment before dischargingconcentrations and, in contrast to conventional cen- stormwater. The combination of runoff reduction andtralized controls, provide flexibility in how and pollutant removal is an effective means of reducingwhere stormwater management is accomplished. The the total mass of pollution released to the environ-use of green infrastructure protects natural resources ment. Because of this, open areas and buffer zonesand lessens the environmental impacts of develop- are often designated around urban streams andment by not only addressing stormwater, but also by rivers to provide treatment and management ofimproving air quality and community aesthetics. overland flow before it reaches the waterway.1. Stormwater volume control and pollutant removal. 2. Decentralized, flexible, site-specific solution. GreenGreen infrastructure is effective for managing storm- infrastructure differs from other stormwater manage-water runoff because it is able to reduce the volume ment methods because it provides the opportunity toof stormwater and remove stormwater pollutants. manage and treat stormwater where it is generated.Reducing the amount of urban runoff is the most This decentralized approach allows green infrastructure 9
  • 16. Natural Resources Defense Council Rooftops to Rivers aged and often inadequate infrastructure system by introducing new areas of imperviousness and addi- tional volumes of stormwater. Strategies will need to be adopted to manage urban growth and its impacts on water quality. The use of green infrastructure offers an alternative to existing development patterns and a new method of developing urban areas. Green infrastructure currently is being used to manage existing stormwater problems, but has the potential to significantly effect how future development contributes to stormwater and sewer overflow problems by preserving and incorporating green space into newly developed areas and by addressing the established connection between imperviousness and stormwater pollution. 4. Ancillary benefit. Green infrastructure is also attractive because it can be used to achieve multipleA RiverSafe RainBarrel installed at the Jane Holmes nursing environmental goals. Funds spent on conventionalresidence in Pittsburgh, PA, by the Nine Mile Run RainBarrel stormwater management are used only for waterInitiative. PHOTO COURTESY OF RIVERSIDES infrastructure. In addition to stormwater manage- ment benefits, green infrastructure improves airtechniques to be installed at numerous locations quality by filtering air pollution and helps to counter-throughout the city. Green infrastructure is flexible, act urban heat island effect by lowering surfaceallowing it to be applied in a wide range of locations temperatures. For example, many of the green infra-and circumstances, and can be tailored to newly structure projects in Chicago, while also providingdeveloped land or retrofitted to existing developed stormwater management, were initially installed toareas. This enables green infrastructure to be used mitigate urban temperature increases and improveon individual sites or in individual neighborhoods energy efficiency. Green infrastructure also improvesto address localized stormwater or CSO problems, urban aesthetics, has been shown to increase prop-or incorporated into a more widespread municipal erty values, and provides wildlife habitat and recrea-stormwater management program. tional space for urban residents. This multi-benefit environmental approach ultimately provides control3. Green design and the development problem. Projected programs that are more diverse and cost-effectivepopulation growth and development will strain an than projects aimed solely at stormwater control. 10
  • 17. CHAPTER 4ECONOMIC BENEFITSOF GREEN SOLUTIONST he cost of stormwater control is a major factor in the successful implementation of pollutioncontrol programs. A large investment is required toadequately address CSOs and stormwater runoff. Inaddition to the $56 billion necessary to control CSOs,the Environmental Protection Agency (EPA) hasidentified $6 billion of documented needs for munici-palities to develop and implement stormwater man-agement programs required by the Phase I and IIstormwater regulations, as well as $5 billion in docu-mented needs for urban runoff control.1,2 However,the EPA estimates that while $5 billion has beendocumented, up to $16 billion may be needed forurban runoff control.3 These costs present a signifi-cant burden to municipal governments challengedwith funding these programs. Of course, natural stormwater retention and filtra-tion is provided by Mother Nature for free. The highcosts associated with urban stormwater result from The Nine Mile Run RainBarrel Initiative used 500 RainBarrelsthe destruction of free, natural stormwater treatment to achieve CSO reduction for the ALCOSAN treatment plant in Pittsburgh. PHOTO COURTESY OF RIVERSIDESsystems—trees, meadows, wetlands, and other formsof soil and vegetation. For example, researchers atthe University of California at Davis have estimated developed world, protecting and enhancing thosethat for every 1,000 deciduous trees in California’s areas that have not yet been developed is often theCentral Valley, stormwater runoff is reduced nearly cheapest, most effective way to keep contaminated1 million gallons—a value of almost $7,000.4 Clearly, stormwater out of urban and suburban streams.preserving trees reduces polluted stormwater dis-charges and the need for engineered controls to replacethose lost functions. When those trees are cut down THE COSTS OF BUILDING GREEN IN NEWand their functions are lost, those costs are passed on DEVELOPMENTSto municipal governments, which then pass them on Green infrastructure in many instances is less costlyto their citizens. So, while the bulk of this report is than conventional stormwater management pro-about how to integrate green infrastructure into the grams or centralized CSO approaches and may 11
  • 18. Natural Resources Defense Council Rooftops to Riversprovide an opportunity to decrease the economic TABLE 6: Cost of Conventional Urban Stormwater andburden of stormwater management. Studies in CSO ControlsaMaryland and Illinois show that new residential Cost to Managedevelopments using green infrastructure stormwater Control Cost Equationb 10 Million Gallonscontrols saved $3,500 to $4,500 per lot (quarter- to Surface storage C = 5.184V0.826 $35 millionhalf-acre lots) when compared to new developments Deep tunnels C= 7.103V0.795 $44 millionwith conventional stormwater controls.5,6 These Detention basins C = 62,728V0.69 $300,000developments were conceived and designed to Retention basins C = 69,572V0.75 $390,000reduce and manage stormwater runoff by preserving a James Heaney, et al., Costs of Urban Stormwater Control, National Risk Management Research Laboratory, Office of Research and Development,natural vegetation and landscaping, reducing overall EPA-600/R-02/021, January 2002. b Cost equations adjusted to 2005 dollars. Volume equals millions ofsite imperviousness, and installing green stormwater gallons. Cost for surface storage and deep tunnels is millions of dollars.controls. Cost savings for these developmentsresulted from less conventional stormwater infra-structure and paving and lower site preparation some instances, municipalities believe that the addi-costs. Importantly, in addition to lowering costs, tional benefits of green controls—including the crea-each of the sites discharges less stormwater than con- tion of more aesthetic city space and the significantventional developments. Adding to the cost savings, reduction in water pollution—justify the added cost.developments utilizing green infrastructure normally In addition, green infrastructure can be incrementallyyield more lots for sale by eliminating land-consuming introduced into urban environments, allowing theconventional stormwater controls, and lots in green costs to be incurred over a longer period of time.developments generally have a higher sale price The EPA has developed cost curves for conven-because of the premium that buyers place on tional urban stormwater controls relating stormwatervegetation and conservation development.7,8 storage capacity to control cost. The costs in Table 6 do not include any associated costs for construction and infrastructure. These costs represent the gener-OUTFITTING EXISTING DEVELOPMENTS WITH ally accepted costs of stormwater control and pro-GREEN INFRASTRUCTURE vide a baseline to which green infrastructure costsThe economics of retrofitting existing urban areas can be compared.with stormwater controls differ from new develop- In many instances, green infrastructure costsment. Urban stormwater retrofits can be expensive compare favorably with the costs of conventionaland complicated by space constraints, although this controls. However, cost comparisons for individual,is not always the case. Based upon the costs of their small-scale retrofit projects are not likely to favorpilot projects, city officials in Seattle and Vancouver green controls. In urban areas, green infrastructure(discussed in the case studies on pages 29 and 33), will be most cost-effective when it is incorporatedbelieve that the costs of future green infrastructure as part of an overall redevelopment effort or wheninstallations will be similar to or slightly more than large improvements to infrastructure are required.conventional stormwater controls.9,10 The analysis In these instances, the costs of green infrastructureconducted by the city of Vancouver indicates that are minimized relative to the scope and costs ofretrofitting green infrastructure into locations with the overall project. While green infrastructure mayexisting conventional stormwater controls will cost be more costly than conventional stormwater oronly marginally more than rehabilitating the conven- CSO controls in certain instances, the added coststional system, but introducing green infrastructure should be weighed against the enhanced stormwaterinto new development will cost less.11 However, control and other environmental benefits gainedwhile green infrastructure may be more expensive in from their use. 12
  • 19. CHAPTER 5POLICY RECOMMENDATIONSFOR LOCAL DECISION MAKERSA lthough green infrastructure has been shown to reduce stormwater runoff and combined seweroverflows and improve water quality, its adoption integrated into such plans. Rather than relying solely on conventional, centralized storage projects to reduce CSO volumes, municipalities shouldacross the country has been slow. Cities that have considering using green techniques, which can beincorporated green infrastructure into their storm- integrated into redevelopment projects andwater management programs have often done so infrastructure repairs and upgrades. Each yearbecause of direct efforts to encourage alternative Portland, Oregon’s downspout disconnectionstormwater approaches. The following recommenda- program diverts 1 billion gallons of stormwater fromtions can be used to encourage the use of green the collection system and has been used to helpinfrastructure in municipalities. alleviate localized combined sewer system backups in city neighborhoods.41. Get development right the first time. Reducing orpreventing stormwater runoff is the most effective 3. Revise state and local stormwater regulations toway to minimize pollution because it prevents encourage green design. Most state and localpollutants from being transported to water bodies. stormwater regulations focus on peak flow rateIncorporating green infrastructure into the earliest control. To encourage more effective stormwaterstages of community development can negate or management, these regulations should be revised tolimit the need for larger-scale, more expensive require minimizing and reducing imperviousstormwater controls. Minimizing imperviousness, surfaces, protecting existing vegetation, maintainingpreserving existing vegetation, and incorporating predevelopment runoff volume and infiltrationgreen space into designs all decrease the impact that rates, and providing water quality improvements.urbanization has on water quality. Used in this way, These requirements encourage green infrastructuregreen infrastructure design is a more cost-effective because it can meet each of these objectives. Portland,strategy, often costing less to develop per lot while Oregon, requires on-site stormwater managementyielding more lots at an increased sale price.1,2 for new development and redevelopment in both CSO and separate sewer areas of the city and2. Incorporate green infrastructure into long-term encourages use of green infrastructure to complycontrol plans for managing combined sewer overflows. with the regulation (more details about Portland’sCities with combined sewer systems are required to development regulations can be found in the casedevelop long-term plans to reduce sewer overflows study on page 24).enough to meet water quality standards.3 Green New Jersey’s stormwater management standardsinfrastructure has proven to be valuable in reducing require 300-foot riparian buffers and stipulate ainflows into combined sewer systems and should be preference for nonstructural best management 13
  • 20. Natural Resources Defense Council Rooftops to RiversThe vegetated infiltration basins in theBuckman Heights Apartments courtyardin Portland, OR, receive and infiltratestormwater from building roofs andsidewalks.PHOTO COURTESY OF PORTLAND BUREAU OF ENVIRONMENTALSERVICESpractices (BMPs). These standards also institute To date, the U.S. federal government has declinedwater quantity as well as quality regulations. The to set performance standards for stormwater dis-water quantity standards require no change in charges from development or to add specifics to thegroundwater recharge volume following construc- “maximum extent practicable” standard set by thetion and that infiltration be used to maintain pre- Clean Water Act for discharges from municipalities.7development runoff volumes and peak flow rates. Since the federal government has failed to showAny increase in runoff volume must be offset by a leadership in this area, state and local entities mustdecrease in post-construction peak flow rate. Water do so.quality standards require a reduction in stormwaternutrient loads to the “maximum extent feasible” 4. Establish dedicated funding for stormwaterand total suspended solids (TSS) reductions of 80%. management that rewards green design. AdequateIf the receiving water body is a high-quality water funding is critical for successful stormwateror tributary, the required TSS reduction is 95%.5 management programs. The billions of dollars Berlin, Germany, has incorporated the Green Area necessary to mitigate stormwater pollution andFactor (GAF) into its regulations. Based on land use combined sewer overflows require federal fundingand zoning, the GAF sets a greening target for each to augment state and municipal funding. Toproperty that provides the required ratio of vegetated encourage its use, dedicated stormwater fundingelements to impervious surface. Once property sources could identify a preference for green infra-owners apply for a building permit, they are required structure or establish a funding scale based uponto satisfy the green target goal. Property owners the relative use of green management green infrastructure practices from an approved Many jurisdictions are creating stormwater utili-list and determine compliance by calculating the ties similar in function to water and wastewater utili-proportion of the property dedicated to the greening ties. Stormwater utilities allow for the assessmenttarget. Selected green infrastructure practices are and collection of a user fee dedicated to a stormwaterweighted according to their effectiveness at meeting management program. Other jurisdictions dedicateenvironmental goals.6 a certain portion of collected local tax revenue to a 14
  • 21. Natural Resources Defense Council Rooftops to Riversstormwater fund. Establishing a dedicated fund opportunity or incentive to use green infrastructure.removes stormwater management from general Jurisdictions should review their applicable storm-revenue funding, which is subject to variable funding water and wastewater ordinances and revise themand competes with other general taxation programs to remove barriers to green infrastructure use andfor money. Stormwater utilities, where allowed by encourage more environmentally friendly regulations.15enabling legislation, are popular because of theability to determine a user rate structure and as a 7. Preserve existing trees, open space, and streamcomplement to incentive programs.8,9 buffers. Too often, development removes nearly all existing natural features. Simply preserving trees,5. Provide incentives for residential and commercial open space, and stream buffers and incorporatinguse of green infrastructure. Various incentives are them into the community will help maintain wateralready in place to encourage green infrastructure quality and manage stormwater runoff while lessen-use in a number of cities. For example, Portland, ing the need for additional stormwater controls.Oregon, allows additional building square footage For example, New Jersey’s stormwater managementfor buildings with green roofs, and Chicago provides standards require 300-foot riparian buffers fora density bonus option for buildings with vegetative new developments and redevelopments to protectcover on the roof.10,11 The city of Chicago also pro- water quality.16vided 20 $5,000 grants to install small-scale com-mercial or residential green roofs in early 2006.12 Also 8. Encourage and use smart growth. Smart growth canbeginning in 2006, Portland will provide up to a 35% be used to limit sprawl and reduce the introductiondiscount in its stormwater utility fee for properties of impervious surfaces. Smart growth policies canwith on-site stormwater management.13 Maryland identify and protect sensitive environmental areasprovides credits for using green infrastructure when and direct development to locations with adequatedetermining compliance with its stormwater regu- infrastructure. By limiting sprawl and discouraginglatory requirements. Six different credits, all related development in sensitive areas, smart growth mayto green infrastructure design, are available.14 Several increase population densities and imperviousness incities fund or subsidize downspout disconnection previously urbanized areas. Smart growth strategiesprograms; Portland’s program pays homeowners should be coupled with green infrastructure to limit$53 per downspout disconnected or the city will the stormwater and infrastructure effects of a poten-disconnect the downspouts for free. tial increase in urbanization.6. Review and revise local development ordinances. 9. Get the community involved. Green infrastructureLocal zoning requirements and building codes often presents an opportunity for community outreach andinadvertently discourage the use of green infra- education. Downspout disconnections, rain barrels,structure. Provisions requiring downspouts to be rain gardens, and green roofs may individuallyconnected to the stormwater collection system manage a relatively small volume of stormwater butprohibit disconnection programs and the use of green collectively can have a significant impact. Portland’sspace for treatment of rooftop runoff. Mandatory downspout disconnection program, for example,street widths and building setbacks can unnecessarily now diverts 1 billion gallons of stormwater awayincrease imperviousness. Stormwater treatment from the combined sewer system each year. Greenrequirements that favor centralized collection and infrastructure can be introduced into a communitytreatment and prescribe treatment options offer little one lot at a time. 15
  • 22. CHAPTER 6CONCLUSIONW hile development, imperviousness, and urban- ization have all taken their toll on downstreamwaterways, current stormwater and combined sewer of environmental commitments, including a consent decree to limit CSO discharges, Safe Drinking Water Act standards influencing the quality of infil-overflow (CSO) mitigation efforts have failed to trated stormwater, and emerging TMDL load andadequately address the problem or improve water waste load allocations.1 Other cities with combinedquality because they are focused on end-of-pipe sewer systems, or those that discharge stormwatersolutions. Current levels of development and to sensitive receiving waters, face similar require-imperviousness have degraded the nation’s water ments. Such regulations only increase the oppor-quality, and future population growth and develop- tunities for creativity and willingness on the partment will only exacerbate the problem. Additional of municipal decision makers to actively promotedevelopment will make stormwater and CSO control and introduce green infrastructure. City leaderssolutions even more difficult and costly. are finding that when faced with the simultaneous Green infrastructure offers the opportunity to not challenges of regulatory requirements, infrastructureonly develop new areas in a more environmentally limitations, and financial constraints, green infra-efficient manner, but also to rehabilitate existing devel- structure often emerges as an appropriate meansoped areas. Urbanization and development alter how of satisfying each.water is distributed throughout the environment. Much Another commonality among cities that havegreater volumes of stormwater are generated and dis- incorporated green infrastructure into theircharged to receiving water bodies in developed areas stormwater and CSO control plans is a commitmentthan would be in the natural environment. Green from city personnel. Whether elected officials orinfrastructure is providing measurable water quality professional staff, these city leaders have recognizedimprovements, most notably in stormwater volume the benefits of green infrastructure and havereduction and CSO mitigation. successfully communicated its value to the public. Some jurisdictions and cities have chosen green These cities have also been innovative with theirinfrastructure as a preferable method of stormwater regulations and environmental policies, looking foror CSO control based upon the specific needs and existing and alternative avenues to encouragegoals of the municipality. Others have installed green adoption of new stormwater and CSO controlinfrastructure to experiment with innovative storm- strategies. These efforts are often popular because ofwater or combined sewer overflow pilot projects. But the public’s positive response to the “greenscaping”all of these efforts demonstrate how it can be success- that has accompanied the programs. As many localfully integrated into urban communities. decision makers have already found, using green A common driver among the cities using green infrastructure in place of or in combination with lessinfrastructure is compliance with regulatory require- effective conventional methods of handlingments. The catalyst for Portland, Oregon’s active stormwater runoff can have benefits beyond justprogram, for example, is a need to satisfy a number economic cost savings and reduced pollution. 16
  • 23. CHICAGOCHAPTER 7CASE STUDIEST he following nine case studies illustrate efforts in North America to incorporate green infrastructureinto urban stormwater and combined sewer overflow stormwater runoff but also to address other environmental issues, such as mitigating urban heat island effects and improving energy efficiency(CSO) control strategies, but this is not an exhaustive in buildings.list. Several factors were used to select case-study cities.Among them were extent and duration of program Stormwater Collection Through Expansion of theefforts, availability of information and quantifiable Combined Sewer Systemdata, geographic location, and the number and type While the city’s past environmental infrastructureof green infrastructure elements practiced. projects have had dubious goals, the water quality of Lake Michigan, the city’s drinking water source, has long been a concern. In the early 1900s, sewageChicago, Illinois and stockyard pollution from the Chicago RiverProgressive environmental change through creative prompted Chicago officials to reverse the courseuse of green infrastructure of the South Branch of the river away from LakePopulation: 2.9 million Michigan and to the Mississippi River in an effortType of green infrastructure used: green roofs; rain to improve the lake’s water quality.1 Water issuesgardens, vegetated swales, and landscape; perme- remain a concern for the city more than a centuryable pavement; downspout disconnection/rainwater later. The city manages one of the largest wastewatercollection collection and treatment systems in the world andProgram elements: used for direct CSO control; contends with flooding, surface water qualityestablished municipal programs and public funding impairment, and CSOs. Urban runoff challenges are Historically, Chicago has been known more exacerbated by the magnitude of infrastructurefor its industrial horsepower than for progressive needed to serve Chicago’s population. The city itselfenvironmental ideas. Rivers like Bubbly Creek still has over 4,400 miles of sewage infrastructure thatbear the names they earned from the pollution they cost about $50 million annually to maintain.2 Approx-once contained. Stories of the city’s sewage and imately 3 million people call Chicago home, andpollution problems from as early as the 1880s still the population of the entire six-county metro regionpersist as popular legends. However, recent initia- surrounding the city exceeds 8 million; the region’stives show that Chicago is emerging as a leader in population is projected to increase 20% by 2030.3green development, with an extensive green roof Impervious surfaces cover approximately 58% ofprogram, environmentally sensitive demonstration the city.4projects, and municipal policies that encourage Chicago has pursued a number of initiatives todecentralized stormwater management. The city improve stormwater collection, the most ambitioushas been particularly creative in its approach, using being a $3.4 billion project to collect and store storm-green infrastructure projects to not only manage water and sewage from the combined sewer system.5 17
  • 24. CHICAGO Natural Resources Defense Council Rooftops to Rivers The green roof at Chicago’s City Hall introduces vegetation in the heart of downtown. Temperatures above the Chicago City Hall green roof average 10° to 15°F lower than a nearby black tar roof. During the month of August this temperature difference may be as great as 50°F. The associated energy savings are estimated to be $3,600 per year. PHOTO COURTESY OF ROOFSCAPES, INC. In the 1970s, the Metropolitan Water Reclamation And, unlike the past, the Chicago River is now seen District began construction of the primary control as a public amenity rather than a liability. solution for CSOs—the Tunnel and Reservoir Plan Chicago’s thriving green roof program began with (TARP). In 2003, with only part of the system opera- a 20,300 square foot demonstration roof on its own tional, more than 44 billion gallons of stormwater city hall. The green roof retains more than 75% of the were captured; 10 billion gallons, however, were volume from a one-inch storm, preventing this water released as CSOs.6 Approximately 2.5 billion gallons from reaching the combined sewer system.9 The pro- of storage are currently available in the TARP system. gram has led to more than 80 green roofs in the city, An additional 15.6 billion gallons of storage will be totaling over one million square feet.10 A 2003 Chicago available when two more reservoirs are added to the Department of the Environment study found that run- system; construction is scheduled for completion in off from green roof test plots was less than half of the 2019.7,8 When complete, the system will handle most runoff from conventional stone and black tar roof plots; of Chicago’s CSO discharges, storing combined runoff the difference was even larger for small storms. The and sewage until it can be sent for secondary treat- city encourages the use of green roofs by sponsoring ment at a wastewater treatment plant. installations and demonstration sites and by provid- ing incentives. A density bonus is offered to developers Chicago’s Green Roof Program who cover 50% or 2,000 square feet (whichever is Although the Metropolitan Water Reclamation greater) of a roof with vegetation. In early 2006, the city District has committed to this massive public works provided 20 $5,000 grants for green roof installations on project, the city has also pursued several initiatives small-scale commercial and residential properties.11 to install green infrastructure that promotes on-site stormwater management, including green roofs, Other Green Infrastructure Innovations: Chicago’s permeable paving projects, rain barrels, and green Citywide Commitment buildings. Much of this investment in green infra- Chicago has employed other green technologies to structure has paralleled the increase in population reduce urban runoff. To address localized flooding and building within the city over the last decade. caused by runoff from one alley, the city removed the 18
  • 25. CHICAGONatural Resources Defense Council Rooftops to Riversasphalt from the 630 foot long, 16 foot wide alley and green renovations on a firehouse and police head-replaced it with a permeable paving system. Now, quarters; and the Green Bungalow Initiative, a pilotinstead of generating stormwater runoff, the alley project to affordably retrofit four of Chicago’s historicwill infiltrate and retain the volume of a three-inch, bungalows with green technologies and monitorone-hour rain event.12 The permeable pavement any corresponding energy savings. The program hasrequires little maintenance and has a life expectancy thus far shown average energy savings for the greenof 25 to 35 years.13 In this same ward, vegetated swales bungalows of 15% to 49%.17are also being used for stormwater management. The city has also pursued public outreach pro- In June 2004, Chicago has embarked on a city- grams, engaging homeowners through its recent rainwide green building effort. Chicago Mayor Richard barrel and rain garden programs. In the fall of 2004M. Daley presented The Chicago Standard, a set of city residents purchased more than 400 55-gallonconstruction principles designed for municipal rain barrels for $15 each.18 The program cost the citybuildings. The standards are based on the Leader- $40,000 excluding city labor. The Department ofship in Energy and Environmental Design (LEEDTM) Environment estimates the pilot project has theGreen Building Ration System14 and emphasize potential to divert 760,000 gallons annually from thesustainability, water efficiency, energy effects, and combined sewer system, a relatively small numberindoor air quality as well as stormwater manage- compared to the total amount of stormwater runoffment. For both the green roof and green building in the city. However, the program was targeted toefforts, Chicago has created municipal demonstration areas with a high frequency of basement flooding,projects to develop professional expertise in the city meaning the program may have a more significanton these technologies. impact in these localized areas. Since the water in rain barrels can be used for other purposes such asChicago Center for Green Technology. The centerpiece landscaping, this program has additional conserva-of the city’s green building efforts is the Chicago tion benefits as well. The city also began a comple-Center for Green Technology. The Chicago Depart- mentary rain garden program, planting four rainment of Environment transformed this property from gardens along with signage explaining benefits.a 17-acre brownfield full of construction debris to Chicago has also complemented its ground-levelthe first municipal building to receive the LEEDTM initiatives with two studies on the effectiveness ofplatinum rating.15 The 34,000 square foot center green infrastructure technologies. The first is theserves as an educational facility and rental space for monitoring study of the green roof box plots. Theorganizations and businesses with an environmental second is a 2004 Department of Environment Storm-commitment. Four 3,000 gallon cisterns capture water Reduction Practices Feasibility Study that usedstormwater that is used for watering the landscaping. hydraulic modeling to assess the effectiveness of bestThe site also features a green roof, bioswales, perme- management practices for the Norwood Park sewer-able paving, and a rain garden. Chicago Department shed. The study found that downspout disconnectionof Environment models indicate that Green Tech’s would achieve peak flow reductions in the 1,370-acrestormwater management technologies retain more area by 30% for a six-month or one-year storm if allthan 50% of stormwater on site—for a three-inch homes in the 80% residential area disconnected theirstorm, the site releases 85,000 gallons of stormwater downspouts from the sewer system.19,20 This wouldto the sewer system instead of the expected 175,000 potentially reduce peak flow in the CSO outfall pipegallons.16 The success of the Green Tech project by 20% and water levels in the sewer system by eightspurred several other green building projects, inches to two feet. The study also showed that three-including three new green libraries; a new police inch and six-inch-deep rain gardens installed at eachstation to be monitored for a national case study; home could reduce total runoff by approximately 4% 19
  • 26. Natural Resources Defense Council Rooftops to Rivers and 7%, respectively, for the same six-month or one- operate combined sewers, which make up 5% of year storm events. MMSD’s total service area. Combined sewer over- flow points are located along rivers that flow intoMILWAUKEE For Additional Information Lake Michigan.23 The $2.3 billion Deep Tunnel Chicago Department of the Environment: System project, completed by MMSD in 1994, pro- vided 405 million gallons of underground sewer storage. Begun in 1986, the 19.4-mile-long system =Environment&entityNameEnumValue=05 collects and temporarily stores the large quantities of stormwater and wastewater that are conveyed through the sewers during wet weather events.24 Milwaukee, Wisconsin Prior to the system becoming operational, Investing in green infrastructure to improve water Milwaukee averaged 50 to 60 CSO events a year, quality which discharged 8 to 9 billion gallons of sewage Population: 587,000 and stormwater. The Deep Tunnel System was Type of green infrastructure used: green roofs; rain designed to limit CSOs to 1.4 events per year; in gardens, vegetated swales, and landscape; wetlands, the first 10 years of operation, from 1994 until 2003, riparian protection, or urban forests annual average CSO discharges were 1.2 billion Program elements: used for direct CSO control; gallons from 2.5 average annual events.25,26 Heavy established municipal programs and public funding rains in the spring of 2004 resulted in 1 billion gallons Like many municipalities with a combined sewer of CSO discharges during a two-week period.27 system, Milwaukee has a history of exposure to Although the Deep Tunnel System has substantially frequent CSO events and was faced with finding a reduced CSO events, excessive quantities of storm- viable overflow control strategy. To reduce the num- water can still trigger overflows, and MMSD has ber of CSOs and their impact on the water quality of committed an additional $900 million to an overflow Lake Michigan and its tributaries, the Milwaukee reduction plan.28 Metropolitan Sewerage District (MMSD), the regional wastewater treatment agency, built a deep Milwaukee’s Green Infrastructure Approach tunnel storage system in the 1980s and 1990s. MMSD As an additional strategy to limit CSO discharges, invested $3 billion during this period to reduce over- MMSD has begun to install green infrastructure flows. As a complement to this large capital invest- within the combined sewer area to decrease the ment, MMSD is investing in green infrastructure volume of stormwater entering the system. One projects to reduce stormwater inflow into the com- of the first initiatives was a disconnection program bined sewer system and mitigate stormwater runoff. that redirected building downspouts from the com- MMSD manages wastewater from 28 municipali- bined sewer system to rain barrels. Overflow from ties with a combined population of about 1.1 million the rain barrels is directed to pervious areas and rain people in a 420 square mile service area. All 28 com- gardens. In a cooperative cost-sharing arrangement munities own and operate their own sewer systems, with public entities and private businesses in the city, which drain into 300 miles of regional sewers owned MMSD partnered with others to install more than by MMSD. The district’s two wastewater treatment 60 rain gardens to receive and treat roof runoff. The plants each process about 80 to 100 million gallons total combined cost of these pilot projects was approx- of wastewater on a dry day.21 Treated wastewater imately $170,000.29 is discharged to Lake Michigan, which also serves as the city’s drinking water supply.22 The city of The Highland Gardens housing project. Seven green Milwaukee and the village of Shorewood own and roofs have been installed in the Milwaukee region. 20
  • 27. Natural Resources Defense Council Rooftops to Rivers MILWAUKEEThe green roof atop MMSD’s head-quarters, shown just after installation,demonstrates how stormwater flow intothe city’s sewer system could be reduced.PHOTO COURTESY OF MMSDOne of these is at the Highland Gardens housing Measuring the Effectiveness of Milwaukee’sproject, a 114-unit mid-rise for senior citizens and Green Infrastructurepeople with disabilities. A 20,000 square foot green The rain gardens and MMSD-financed green roofsroof was installed at a cost of $380,000. The roof were installed in 2003 and 2004. A monitoring programwill retain 85% of a two-inch rainfall. The remain- evaluating the effectiveness of the systems at managinging 15% of the water volume is directed to rain stormwater is being conducted with initial resultsgardens and a retention basin used for on-site expected in early 2006. To determine the potentialirrigation.30 These management strategies prevent impacts of the green infrastructure program, MMSDstormwater from being discharged to the collec- conducted a modeling analysis. The modeling efforttion system. showed that application of downspout disconnection, MMSD has installed or helped finance four other rain barrels, and rain gardens in residential areas wouldgreen roofs to reduce stormwater runoff. The first reduce each neighborhood’s contribution to the annualwas a 3,500 square foot structure on the roof of CSO volume 14% to 38%. Additional modeling resultsMMSD’s headquarters building in downtown showed the volume of stormwater sent to the treatmentMilwaukee. Native species of grasses and flowering plants from the neighborhoods was reduced 31% toplants were selected for the roof vegetation. The 37% and stormwater peak flow rates were reduced 5%cost of the green roof was just under $70,000.31 A to 36%, depending upon the size of the rain event.33second green roof was installed on the University (The model assumed a high participation rate for resi-of Wisconsin-Milwaukee’s Great Lakes Water Insti- dential areas. Volume and peak flow reductions wouldtute. MMSD contributed $110,000 of the $233,000 not be as great with a lower participation rate.)needed to install the 10,000 square foot unit. A third The effect of green infrastructure in commercialgreen roof was installed on the city’s Urban Ecology areas was also modeled. The use of green roofs, rainCenter, with MMSD contributing $40,000 of the gardens, and green parking lots is predicted to reducetotal project cost. The fourth green roof is at the commercial area contributions to CSO volume byMilwaukee County Zoo, to which MMSD con- 22% to 76%, but would not decrease—and couldtributed half of the $73,000 cost.32 even increase—the volume of stormwater sent to the 21
  • 28. Natural Resources Defense Council Rooftops to Rivers treatment plants. Stormwater peak flow rates from its manufacturing past. The city’s development as a commercial areas are predicted to be reduced 13% to steel powerhouse and mining center is intrinsically 69% with the introduction of green infrastructure.34 tied to its geographic and hydrologic setting. The MMSD has allocated more than $5.5 million for city has developed around the confluence of three fiscal years 2002 through 2014 for rain water rerout- rivers—the Allegheny, the Monongahela, and the ing programs intended to prevent stormwater from Ohio. Over the past two decades Pittsburgh’s metro- entering the combined sewer system. An additional politan population has declined, partly due to the $4.5 million has been allocated for fiscal years 2003 collapse of the steel industry. The city’s population through 2009 to promote, install, and monitor green decreased by 9.5% in the 1990s and the entire metro-PITTSBURGH infrastructure practices aimed at reducing stormwater.35 politan area saw a decline of 1.5%, trends that were MMSD is also purchasing and protecting open space significantly greater than other same-size cities in to reduce stormwater runoff and improve water quality the northeastern central area.38 The “steel city” is left in its urban waterways. The capital budget designates with pollution nuisances like brownfields and slag funds to purchase privately owned wetlands to pre- heaps, as well as a shrinking urban center and a vent development and establish conservation ease- considerable sewage overflow problem. ments. More than $27 million has been allocated for It is precisely because of this industrial reputation fiscal years 2000 through 2011. As of fiscal year 2005, and declining urban center that Pittsburgh has had 775 acres had been purchased in three watersheds for the opportunity and the incentive to redevelop and just under $5.8 million.36 A greenways initiative will reclaim large land parcels and turn them into green- identify lands that compose greenway connections, ways and parks. The restoration, described as linkages between sites, delineated environmental “restorative redevelopment,” is motivated by a desire corridors, isolated natural wetlands, open space, and to restore habitat, beautify land, increase parkland, riparian wetlands. Linkages between these areas will and raise property values—in all, generally making be acquired to protect and establish greenways along Pittsburgh a more attractive city.39 Pittsburgh’s efforts jurisdictional waterways or their tributaries. Prefer- in alternative stormwater management have been a ential consideration is given to land that provides combination of government-sponsored restoration stormwater or flood management benefit.37 of green space and privately funded demonstration sites. The impetus for Pittsburgh’s green restoration For Additional Information comes largely from the private sector, charitable Milwaukee Metropolitan Sewerage District: foundations, and citizens’ groups. Water Pollution from Pittsburgh’s Sewer System Pittsburgh clearly has a need for supplemental Pittsburgh, Pennsylvania stormwater management projects. The city’s storm- “Restorative development” beautifies land and water runoff contributes to frequent CSOs. In 2003, cleans water red-flag advisories for impaired water quality were Population: 325,000 issued on 111 out of 139 summer recreation days Type of green infrastructure used: green roofs; rain (from May 15 to October 1). In 2004, 125 red-flag gardens, vegetated swales, and landscape; down- advisories were issued.40 The metropolitan area spout disconnection/rainwater collection; wetlands, contains more than 300 combined sewer outfalls riparian protection, or urban forests and over 4,000 miles of underground pipes. Many Program elements: used for direct CSO control of these outfalls are upstream of drinking water Pittsburgh is a postindustrial city struggling to intakes. Solving Pittsburgh’s wet weather sewage repair the environmental degradation wrought by problems is a complicated problem that is 22
  • 29. Natural Resources Defense Council Rooftops to Rivers PITTSBURGHThe green roof surrounding the executiveoffices on the Heinz 57 Center in Pittsburghnot only provides environmental benefits,but also creates green space for outdoormeetings and employee enjoyment 14stories above the ground.PHOTO COURTESY OF ROOFSCAPES, INC.exacerbated by the fragmented nature of the collec- roofs.42 The conservatory will capture rainwater fromtion and treatment system. While there is one treat- its glass roofs and store it in a cistern to be used laterment plant operated by the Allegheny County to regulate water levels in ornamental ponds. TheSanitary Authority (ALCOSAN) in the metro area, facility will feature a green roof test garden and athere are 83 separate municipalities, each responsible 30-by-100-foot rain garden in a low-lying site nearfor maintaining their own collection system. Many the impervious parking areas.43pipes are in a state of disrepair, and ALCOSAN esti- The McGowan Institute for Regenerative Medicine,mates that repairing the system using traditional built on a brownfield site, collects rainwater from thesewage infrastructure strategies will cost more than roof for gray water needs and irrigation. The facility$3 billion. This investment includes an expansion reuses 57% of rainwater falling on the site, retainingof the wastewater treatment plant capacity over the 168,000 gallons of stormwater annually.44next 20 years from 225 million gallons per day (mgd) As a LEEDTM Gold certified building, Pittsburgh’sto 875 mgd to reduce CSOs. However, 565 mgd David L. Lawrence Center is the world’s first certi-of this increased capacity would only provide fied green convention center. Through stormwaterprimary treatment.41 reclamation, the facility reduces its potable water Against this troubled environmental background, use by approximately 60%. It has an in-house waterthe private sector and citizens’ groups in Pittsburgh treatment plant to recycle black water and featureshave taken an active role to design and implement a stainless steel roof that reduces total suspendedgreen infrastructure projects. Several demonstration solids in stormwater runoff.45 By capturing andprojects have focused specifically on stormwater reusing rainwater on-site, each of these projectscapture or treatment. decreases the amount of stormwater that would have otherwise entered the combined sewer system.Pittsburgh’s Green Infrastructure CommitmentPittsburgh’s Phipps Conservatory and Botanical Nine Mile Run and Frick Park. One of Pittsburgh’sGardens is undergoing a major expansion and, when key restoration efforts is the $7.7 million projectcomplete, will boast over 15,000 square feet of green currently under way at Nine Mile Run, one of the 23
  • 30. Natural Resources Defense Council Rooftops to Rivers last remaining daylit streams in the city. 46 The stream weather pollution to Nine Mile Run. The municipal flows underground through several neighborhoods contribution to the project, $2.7 million, is designated and daylights in Frick Park, a 455-acre natural and to repair sewer lines, preventing leakages due to old, recreation area. Before its confluence with the failing pipes. The city has also partnered with a devel- Monongahela River, Nine Mile Run collects storm- oper to transform the slag heap, a brownfield site, into a water runoff from a seven-mile watershed with 43% 710-home residential development. Aiding in this effort impervious surfaces.47 A number of environmental are groups like 3 Rivers Wet Weather Demonstration problems contribute to the stream’s impairment. To Program and the Nine Mile Run Watershed Associa- accommodate development, Nine Mile Run was tion. The community groups commissioned an engin- culverted and no longer flows in its natural meander- eering study to determine where rain barrels would be ing pattern, inhibiting its function as a wildlife habitat. most effective in reducing the stormwater runoff that In wet weather conditions, stormwater discharges contributes to CSOs. The organizations installed 500 increased stream flow in Nine Mile Run, eroding large rain barrels (132 gallons each) in critical neighbor- much of the stream bank. The altered hydrology in hoods.49 The groups focused on the educational com- the watershed leaves little water in the stream during ponent of the project to make homeowners aware ofPORTLAND dry weather conditions, making it unable to support lot-level solutions to stormwater management. aquatic life. The stream also borders a 238-acre mountain of slag; runoff from the slag increased the For Additional Information natural pH of the stream. As with most Pittsburgh Nine Mile Run Watershed Association: waterways, Nine Mile Run is also the conduit for many combined sewer overflows. The Army Corps of Engineers is undertaking the main portion of the project to clean up Nine Mile Portland, Oregon Run under authority of Section 206 of the Water Making green infrastructure a policy priority Resources Development Act of 1996. The project is a Population: 539,000 large-scale effort that will include the construction of Type of green infrastructure used: green roofs; rain woody and herbaceous wetlands to provide both gardens, vegetated swales, and landscape; down- wildlife habitat and stormwater filtration. The spout disconnection/rainwater collection stormwater management component of the project Program elements: used for direct CSO control; takes advantage of Pittsburgh’s porous and perme- established municipal programs and public funding able soils to capture recharge and attempts to prevent Portland has actively promoted funding and edu- pollutants in stormwater from reaching the stream. cation for innovative stormwater management since In an effort to repair the stream and re-create more 1998 and boasts numerous green applications through- natural conditions, the new river design adds out the city. These projects feature many types of green meanders and pool and riffle sequences, undoing infrastructure technologies, including bioswales, green channelization. The project also fits into the city of roofs, infiltration planters, and sustainable street Pittsburgh’s larger Riverfront Development Plan, design. The city has been at the leading edge of the which includes land conservation along stream green infrastructure movement and is beginning to banks to prevent runoff and erosion and increased accumulate significant data on the effectiveness of set-asides for recreational trails along Nine Mile decentralized stormwater management technologies. Run.48 The restoration effort will add an estimated As with many cities, part of the motivation to 100 acres to Frick Park. achieve more successful stormwater strategies comes The restoration would not be as effective without from a history of pollution and a desire to repair corresponding attempts to reduce sources of wet nearby ecosystems. One of Portland’s primary 24
  • 31. Natural Resources Defense Council Rooftops to RiversVegetated curb extensions decreasestormwater runoff in Portlandneighborhoods. PORTLANDPHOTO COURTESY OF THE PORTLAND BUREAU OF ENVIRON-MENTAL SERVICESecological concerns is the Willamette River, which constructed capacity, along with other projects, hasin the course of its flow takes with it a considerable virtually eliminated CSOs to the Columbia Slough,volume of combined sewer overflow. In 2004, which discharges into the Willamette River, and hasPortland experienced 50 overflow events and eliminated or controlled eight Willamette River CSOdischarged 2.8 billion gallons of combined overflow outfalls. When the projects are completed in 2011,into local waterways.50 In some areas, undersize CSOs to the Willamette will be reduced by 94%.52combined sewers cause basement sewer backups, These strategies are estimated to cost around $1.4requiring homeowners to sanitize their basements billion and are funded by local sewer charges.53after sewage backs up into their homes. Stormwater To complement the large infrastructure projects,has also transported toxic pollution into area water Portland is installing green infrastructure as anbodies. Portland Harbor, the industrialized lower innovative stormwater management approach.portion of the Willamette, was designated an EPA Green infrastructure is gaining popularity insuperfund site for contaminated sediments. Investi- Portland for several reasons, including climate,gations into the contribution of overland stormwater development patterns, and policy institutional-flow and other sources of this heavy-metal pollution ization. Portland’s rainfall occurs mostly in smallare under way. frequent storms, exactly the type of precipitation event green infrastructure technologies are mostPortland’s Dual Approach to Managing CSOs successful at mitigating. About half of Portland’sTo alleviate these pressing CSO management land area is impervious, 25% attributable to streets,problems, Portland has pursued a dual approach, and 40% attributable to rooftops.54,55 These surfacesexpanding its public infrastructure and pursuing lot- create an opportunity and a need for green infra-level strategies to manage stormwater.51 The “Big structure development.Pipe” is Portland’s primary combined sewage control Portland has also encouraged sustainablesolution, adding capacity to the overloaded sewer stormwater management through a series of policysystem. In recent years, the city has made consider- initiatives. City code now requires on-siteable progress toward reducing overflows. The stormwater management for new development and 25
  • 32. Natural Resources Defense Council Rooftops to Rivers redevelopment. Portland’s stormwater manual extensions on Southeast Ankeny Street and is plan- encourages the use of green infrastructure techniques ning additional green street projects at the intersection to meet this objective. Together, the city of Portland’s of Southwest 12th Avenue and SW Montgomery Bureau of Environmental Services (BES) and the EPA Street and the intersection of Northeast 131st Avenue jointly fund the Innovative Wet Weather Program, a and Northeast Fremont Street. grant program for stormwater management projects that focus on water quality improvement. In 2004, Portland’s “ecoroofs.” In 1996, the first green roof in budgeted expenditures for a long list of proposed Portland was installed. In the years since, Portland projects totaled almost $3 million.56 New city-owned has begun an initiative to install and monitor green buildings are required to have a green roof that roofs at sites throughout the city. The city prefers covers at least 70% of the roof area; the remaining the term “ecoroofs” to illustrate that even in the roof area must be covered with Energy Star roofing dry season when roofs are not as green, the roofs material.57 The city offers a zoning bonus, allowing can still perform well.65 Portland also uses the term for additional square footage for buildings featuring to emphasize the economic benefits of the vegetated a green roof, and in 2006 it will begin offering a technology. The city conducted extensive monitoringPORTLAND stormwater fee discount of up to 35% for properties studies on Hamilton West Apartments, a 10-story with on-site stormwater management.58,59 These building with two ecoroof components, one measur- programs are built upon the successful participation ing 2,520 square feet and the other 2,620 square feet. in the downspout disconnection program, in which Based on two years of monitoring data, BES found homeowners can receive $53 per downspout dis- that the four- to five-inch thick, 25-pound-per-square- connected from the combined sewer system. The foot ecoroof retained 58% of rainfall, preventing it city estimates that more than 45,000 households from becoming stormwater runoff. Monitoring has participate in the program, allowing infiltration of also shown that the ecoroofs absorb almost 100% more than 1 billion gallons of stormwater annu- of the rainfall from Portland’s warm season precipi- ally.60,61 The on-site stormwater management require- tation events.66 ment, along with incentive programs for installing Some of Portland’s other interesting stormwater green infrastructure, will likely lead to more wide- sites include the Oregon Museum of Science and spread applications throughout the city. Industry, where swaled medians were installed around the museum parking lot to capture storm- Street-level stormwater management. In 2003, Portland water. The museum saved $78,000 by installing the installed the Northeast Siskiyou Street vegetated green infrastructure technology over a traditional curb extensions to capture stormwater while creating collection system.67 The Liberty Centre Parking an attractive landscaped area. To assess the effective- Garage installed infiltration planters as a stormwater ness of the technology and gather data for future retrofit. These planters accept runoff from more projects, the city conducted flow tests to ensure water than 36,000 square feet of impervious surfaces and would be infiltrated in the right-of-way. The vegetated can retain the entire volume of a storm slightly curb extensions reduced peak flow from a 25-year smaller than the typical two-year storm event. The storm event (approximately two inches in six hours) cost for this retrofit was $75,500.68 The Oregon Con- by 88%.62 This is enough retention to protect local vention Center rainwater garden collects stormwater basements from flooding. The curb extensions also from 5.5 acres of roof area.69 The garden simulates a reduced total runoff (2,000 gallons in the simulation) mountain stream, doubling as an attractive landscape to the combined sewer system by 85%.63 The project space. The project is designed to handle the runoff took about two weeks to install and cost approxi- from a 25-year storm. A recent stormwater manage- mately $15,000.64 Portland has also installed curb ment project is a ring of interconnected bioswales 26
  • 33. Natural Resources Defense Council Rooftops to Riversaround the New Seasons Market at Seven Corners The Rouge River Watershed in southeast MichiganSoutheast Division Street. This project reduces covers nearly 450 square miles and is home to theimpervious surfaces and will remove 1 million historically industrial city of Detroit. Fifty percent ofgallons of stormwater annually from the combined the watershed is urbanized, and more than 1.5 millionsewer system.70 All of these projects will be eligible people live within its boundaries.72 As a tributary andto apply for the stormwater fee discount when it is major pollution source to the Detroit River, the Rougefully implemented in mid-2006. River was designated an Area of Concern by the Inter- national Joint Commission in the Great Lakes.73,74 WithNew Directions in Portland’s Green Infrastructure: industrial and municipal wastewater dischargesThe Stormwater Trading Program believed to be effectively permitted and controlled, theThe city was recently awarded a $288,000 U.S. EPA focus of the water restoration efforts in the watershedgrant for a feasibility study to determine the viability has shifted to addressing wet weather pollution. Storm-of a stormwater trading program. As conceptualized, water runoff was responsible for creating excessive flowthe trading program would allow developers who within the river, damaging stream banks and riparianwere unable to satisfy the on-site stormwater man- habitat, introducing pollutants, and causing CSOs.agement requirement to privately finance or buy In 1992, the Wayne County, Michigan Departmentcredits for stormwater mitigation elsewhere within of the Environment initiated the Rouge River Projectthe city, provided that the purchased credit met water to address wet weather pollution within the watershed.quality and discharge volume requirements. The The project is funded by U.S. EPA grants and municipalinitial cost of the stormwater credits would likely be funding and serves as a national demonstration projectbased on the cost of a publicly financed program. The for reclaiming degraded urban rivers.75 An assessment ROUGE RIVER WATERSHEDfirst phase of the study will determine if the approach of the watershed in the mid-1990s found that storm-is economically beneficial and if the program can pro- water runoff had many deleterious effects on watervide acceptable environmental results. If the trading quality and river health. Increased river flows fromapproach is determined to be feasible, later phases of stormwater discharges had eroded 60% to 90% of thethe study will outline the model approach, determine river banks on the Rouge River’s major branches.76the geographic trading area, select appropriate best Soil washed from the river banks was deposited alongmanagement practices, and develop economic models the river bottom downstream, degrading naturalfor program valuation. In later phases, the city also stream habitats. Stormwater runoff and pollution hadplans to demonstrate the operation of the trading not only contributed to a decline in river fish popula-system through pilot program implementation.71 tions, but also a number of consumption bans and advisories. Nutrient loadings caused seasonal decreasesFor Additional Information in river oxygen levels, and increased river bacteriaPortland Bureau of Environmental Services: counts and resulted in swimming advisories.77 Evaluating the most effective means of improving the water quality of the river, the Rouge River Project adopted a watershed-based approach for wet weatherRouge River Watershed, Michigan pollution control. The first step in this approach wasCleaning up the watershed with green approaches the 1997 adoption of the Michigan NPDES Generalto stormwater management Stormwater Permit. The permit is unique becausePopulation: 1.5 million the watershed communities requested permissionType of green infrastructure used: green roofs; rain from the U.S. District Court overseeing the rivergardens, vegetated swales, and landscape; permeable cleanup to develop a draft permit acceptable to thepavement; wetlands, riparian protection, or urban forests communities and state and federal regulators. The 27
  • 34. Natural Resources Defense Council Rooftops to Rivers At more than 10 acres, the largest green roof in the world sits atop Ford’s Rouge River Manufacturing Complex. The green roof is one component of a renovation designed to make the facility more environmentally sustainable. PHOTOS COURTESY OF GREEN ROOFS FOR HEALTHY CITIES consensus effort resulted in a watershed-based wetlands at improving the quality of the stormwater permit that required each community to develop runoff. In addition to dampening stormwater flows, a watershed management plan and stormwater the wetlands reduced concentrations of total sus- pollution prevention initiative. The U.S. EPA has pended solids by 80%, total phosphorus by 70%, supported Michigan’s request to continue to use BOD by 60%, and heavy metals by 60%.83 the general permit in lieu of permits that would beROUGE RIVERWATERSHED required by the Phase II regulations.78,79 Ford Motor Company’s green roof. Located along the Rouge River, Ford Motor Company’s 88-year-old, Watershed Restoration Through Green Infrastructure 600-acre Rouge River Manufacturing Complex in Green infrastructure practices have been used as part Dearborn, Michigan, recently underwent a $2 billion of watershed management plans to address stormwater renovation. The renovation of Rouge River was pollution. Although highly urbanized, more than unique because of Ford’s decision to make the manu- 50 miles of riparian parklands are publicly maintained facturing plant a more environmentally sustainable with the watershed.80 Watershed restoration efforts facility. Green infrastructure was an important have also included the use of created and existing wet- component of this effort. The complex includes a lands for stormwater management. The Inkster Wet- 450,000 square foot green roof to retain stormwater, lands demonstration project uses 14 acres of wetlands lower energy costs, and extend roof life.84,85 At over adjacent to the Rouge River to treat stormwater before 10 acres, the green roof is the largest in the world it enters the river. Three separate wetlands areas are and is anticipated to absorb the first inch of rainfall.86 part of the project and are composed of forested, Vegetated swales, planted with indigenous species, emergent, scrub, and open water wetlands. Approxi- are used throughout the site to reduce stormwater mately nine of the 14 acres are constructed wetlands.81 discharges and encourage infiltration. New trucks Prior to the project, discharge pipes routed stormwater rolling off the assembly line are taken to an outdoor past the existing wetlands and directly to the river. In parking lot paved with permeable pavement. A two- addition to creating new wetlands for stormwater treat- to three-foot gravel storage bed beneath the lot filters ment, the demonstration project rerouted stormwater pollutants from the stormwater and provides storage through the existing wetlands. The project was com- capacity.87 The renovation of the site also included pleted in 1997 at a cost of $465,000.82 A five-year the planting of more than 1,500 trees, 20,000 bushes, monitoring study evaluated the effectiveness of the and 85,000 flowering perennials.88,89 28
  • 35. Natural Resources Defense Council Rooftops to RiversFor Additional Information The Viewlands Cascade. Early this decade four NDSRouge River Wet Weather Demonstration Project: pilot projects were completed and have since been monitored to determine their effectiveness. These projects were designed to reduce stormwater runoff to Pipers Creek, a tributary of Puget Sound andSeattle, Washington home to wild coho salmon and both steelhead andUsing green infrastructure solutions to save cutthroat trout. The Viewlands Cascade was the firstsensitive waters of these projects and uses a series of 16 stepped vege-Population: 587,000 tated cells to collect stormwater runoff from approxi-Type of green infrastructure used: green roofs; rain mately 72 acres. The system was designed to reducegardens, vegetated swales, and landscape; down- the volume and flow rate of stormwater runoff byspout disconnection/rainwater collection encouraging infiltration and vegetative uptake. TheProgram elements: used for direct CSO control; estimated construction cost was $225,000.93established municipal programs and public funding Hydrologic monitoring of the Viewlands Cascade Located along the shores of Puget Sound and indicates that the system decreases stormwater run-home to rivers and creeks that serve as salmon off volume 75% to 80% and peak flow rates by 60%.94spawning grounds, Seattle is connected to the vitality Performance is greater than average for small andof its water bodies. The 84 square mile city is highly medium storm events and considerably less thanurbanized and has an average annual rainfall of average for large events. Overall, during a three-year37 inches, which occurs primarily during the region’s monitoring period, half of the total volume of storm-wet months from November to February.90 Storm- water that entered the cascade system was retainedwater runoff has long been identified as a threat to and not discharged to Pipers Creek.95 The Viewlandsthe aquatic habitat of Puget Sound and the sensitive Cascade replaced a partially concrete drainage ditch.salmon streams. Controlling stormwater in the urban Modeling indicates that the new cascade systemwatersheds is a complicated task in a city where the retained three times as much stormwater volume andmajority of development predated stormwater regu- held stormwater in the system over 2.5 times longerlations.91 Consequently, water quality in the region when compared to the original drainage ditch.96 Inhas been impaired and the hydrology of rivers and addition, the water quality of the stormwater dis- SEATTLEcreeks has been altered because of increased storm- charged has improved because of the natural vege-water volumes and flow rates. tation’s biological and chemical removal capabilities.Using Natural Drainage Systems to Manage The SEA Street Project. The 2nd Avenue Street EdgeStormwater Runoff Alternative (SEA) Street project was the second pilotIn the late 1990s, the city decided to install green infra- project and one of the better known green infrastruc-structure in an effort to mitigate urban stormwater ture projects in the country. The project redesignedrunoff. Seattle Public Utilities (SPU), the agency respon- an entire 660-foot block of 2nd Avenue with asible for water and stormwater programs, developed number of green infrastructure techniques, with thepilot projects using the concept of natural drainage goals of reducing stormwater runoff and providing asystems (NDS). The NDS program’s goal was to livable community. SPU worked collaboratively withdevelop a stormwater management system that residents during the process to develop the finalresembled natural hydrologic functions lost to urban- street design.ization.92 The initial outcome of this program has been The original 25-foot-wide straight street wasinnovative neighborhood and stormwater system replaced with a 14-foot-wide curvilinear street.designs with results exceeding initial expectations. Vegetated swales, designed to infiltrate and treat 29
  • 36. Natural Resources Defense Council Rooftops to Rivers This private residence in Seattle, WA, incorporates stormwater controls and vegetative gardens. PHOTO COURTESY OF SEATTLE PUBLIC UTILITIES stormwater, were installed within the right-of-way expected to reduce total stormwater discharge from the on both sides of the street. Street parking was replaced site by 42% and by 66% when compared to a conven- with designated angled parking slots, and a sidewalk tional Seattle street with curb and gutter. A modeling was installed on one side of the street. The final analysis indicates that if a conventional curb and gutter constructed design reduced imperviousness more system had been installed along 2nd Avenue instead of than 18% and added 100 evergreen trees and 1,100 the SEA Street design, 98 times more stormwater would shrubs.97 The original construction cost bid was have been discharged from the site.100 The SEA Street $244,000. The final total project cost was approx- design has been so popular that local residents have imately $850,000, with the substantial increase requested that their traditional streets be retrofitted. attributed to costs associated with significant com- Both the Viewlands Cascade and 2nd Avenue SEASEATTLE munity outreach and coordination as well as design Street have been successful at managing stormwater modifications to address community concerns.98 runoff. There is, however, a large functional difference Hydrologic monitoring of the project indicates between the two projects. The Viewlands Cascade a 99% reduction in total potential surface runoff. collects and treats runoff from a designated drainage Stormwater retention capacity has increased since area once it has been generated as an end-of-pipe treat- the project was completed. Stormwater runoff has ment focused on reducing peak stormwater flows; the not been recorded at the site since December 2002, 2nd Avenue SEA Street is designed as a source control a period that included the highest ever 24-hour strategy intended to prevent the discharge of storm- recorded rainfall at SeaTac Airport. Reasons for the water from the project site. The success of both projects increased stormwater retention are unclear, but it is demonstrates that green infrastructure is adaptable speculated that the maturing vegetation takes up and may be used in various capacities. SPU has more water and increasingly aids infiltration.99 incorporated both designs into a number of projects Design estimates originally anticipated that the site recently completed or currently under construction. would attenuate up to 0.75 inches of rain. Monitoring has indicated that the site is able to attenuate a substan- The 110th Street Cascade. The 110th Street Cascade tially larger rainfall amount. The SEA Street design was is also located in the Pipers Creek Watershed and is 30
  • 37. Natural Resources Defense Council Rooftops to Riversdesigned to treat runoff from a 28-acre drainage conducted with the cooperation of 10 single-family resi-basin. Monitoring at the cascade is measuring flow dential homeowners in the combined sewer area, israte and water quality.101 Completed in early 2005, studying the effectiveness of slowly draining cisterns tothe Broadview Green Grid project reconstructed an retain peak stormwater runoff. The costs of the programentire neighborhood’s drainage system in a 32-acre will be compared to the costs of detaining an equalsub-basin in the Pipers Creek Watershed. The project volume of wastewater in centralized vaults beforeused both SEA Street designs and cascade systems. being metered out to the municipal wastewater treat-The north-south streets in the project area were ment plant. The project will also test the acceptance andreconstructed using the SEA Street design. Each of effectiveness of rain gardens in the residential area.107these streets discharges to an east-west flowing Another approach to mitigating stormwatersystem of vegetated swales and cascades.102 The runoff is green roofs. The city of Seattle has installedPinehurst Green Grid, a second neighborhood scale four green roofs over the past several years. In orderreconstruction project, is in the construction phase. to evaluate the ability of these green roofs to reduce The High Point Redevelopment is under construc- stormwater runoff, the city is embarking on ation and is one of the city’s largest recent redevelop- multiple-year data collection initiative. The goal is toment efforts. Forty blocks will be redeveloped in a provide information that can be used to modify the129-acre mixed income housing area to eventually city’s stormwater code and potentially providecontain 1,600 units. The project area is 65% impervi- incentives to encourage the construction of greenous and densely populated. The NDS design will roofs in both public and commercial applications.incorporate approximately 22,000 feet of vegetated Seattle has also begun an urban forestry initiativeand grassy swales and is scheduled for completion to reduce stormwater runoff. A master plan forin 2007.103 In 2004, the NDS program received an planting trees on city streets implemented in 1999Innovations in American Government Award from established a goal of increasing the city’s tree canopyHarvard University’s Kennedy School of Govern- from 27% of city surface area to 40%.108ment. The award, accompanied by a $100,000 grant,highlights effective government projects.104 For Additional Information In addition to the NDS design concept, the city Seattle Public Utilities Natural Drainage Systems:of Seattle also promotes rainwater harvesting. The,000 square foot King Street Center uses three Drainage_&_Sewer_System/Projects/Natural5,400 gallon tanks to collect rainwater from the _Drainage_Systems/NATURALDR_20031203121352building’s roof. The collected rainwater is filtered .aspand pumped through a dedicated piping system fortoilet flushing and landscaping needs. The systemprovides 1.4 million of the approximately 2.2 million Toronto, Ontario, Canada TORONTOgallons—60%—of the toilet flushing water needed A long-term “Water Pollution Solution” focuses onannually and reduces the stormwater discharged green infrastructurefrom the building by the same amount.105 Population: 2.5 million In March 2005, SPU began the second phase of a Type of green infrastructure used: green roofs;subsidized rain barrel and cistern program intended downspout disconnection/rainwater collection;to distribute the rainwater-harvesting devices through- wetlands, riparian protection, or urban forestsout the city. The first phase of the program distributed Program elements: established municipal programs1,500 rain barrels at a reduced rate to private home- and public fundingowners.106 In addition, SPU initiated the Freemont rain- Covering 240 square miles along the shores ofwater harvesting study on March 1, 2005. The project, Lake Ontario, Toronto is the largest city in Canada, 31
  • 38. Natural Resources Defense Council Rooftops to Rivers with 2.5 million residents. The entire Toronto metro- (1) recognizing rainwater and snowmelt as a valuable politan region has a population of 4.5 million people resource; (2) managing wet weather flows on a spread out over 560 square miles. This vast urban watershed basis; (3) implementing the hierarchy of expanse is also home to an extensive infrastructure wet weather practices beginning with “source,” then network with 2,800 miles of storm sewers and over “conveyance,” and lastly, “end-of pipe” solutions; 2,600 outfalls.109 Like the Great Lakes cities in the and (4) educating communities and involving the United States, Toronto’s urban stormwater is a lead- public.113 Capital costs for the program are estimated ing cause of water pollution in Lake Ontario and its to be around $800 million; operational and main- tributaries and necessitates expensive investments tenance costs are expected to be around $13 million directed toward CSO mitigation and stormwater annually.114 The city has earmarked $200,000 management. Toronto and its surrounding water- annually for community projects that contribute sheds are part of an Area of Concern under a Remedial to the Water Pollution Solution.115 Action Plan (RAP), a policy designation derived from Toronto’s program involves a significant down- amendments to the 1972 bilateral Canada-U.S. Great spout disconnection effort to prevent runoff from Lakes Water Quality Agreement. The Toronto RAP entering both the stormwater and combined sewer covers Toronto Bay and six watersheds: Etobicoke systems. The city will disconnect residences for free Creek, Mimico Creek, Humber River, Don River, and provide splash guards or rain barrels to protect Highland Creek, and Rouge River. Goals include the residential foundations. As of June 2000, Toronto restoration of drinkable, fishable, swimmable, and estimated that approximately 20,000 homes had been aesthetically pleasing water and habitat areas.110 disconnected.116 Downspout disconnection efforts The RAP explicitly highlights pollution from urban have been targeted at areas that either experience stormwater runoff as one of the primary sources of localized flooding or have a significant runoff impact ecosystem degradation to this region.111 on Toronto’s beaches. Faced with the difficult challenge of limiting storm- Toronto has made extensive use of the natural water runoff and pollution, Toronto has developed a filtering and flood control capacity of wetlands and unique policy approach for managing stormwater vegetated areas to help achieve the goals of the RAP. with the goal of eliminating adverse effects of wet The city has embarked on wetland and stream weather flows and achieving measurable improve- restoration programs to facilitate stormwater ment in ecosystem health within the watershed.112 In management that will achieve cleaner streams and July 2003, Toronto’s City Council approved a 25-year enhanced wildlife habitat. Toronto is committing stormwater plan, the Water Pollution Solution, for- $106 million for the capital costs to restore over merly called the Wet Weather Flow Management 40 miles of streams, and expects operation and Plan. This plan is a comprehensive strategy to deal maintenance costs for this stream restoration to be with surface water quality and quantity, sewage roughly $500,000 per year.117 Several wetlands haveTORONTO overflows, and habitat protection. Toronto’s approach already been restored, including Chester Springs includes increasing traditional methods of storm- Marsh, a 7.5 -acre wetland restored on the site of an water storage capacity and improving conveyance old landfill. This particular wetland was restored structures, but it also includes greener approaches, specifically to prevent nutrients and pollutants from especially for some short-term solutions. reaching the Don River. Wetlands originally per- formed this filtering function before the Don was Toronto’s Four Principles of Stormwater channeled in the late 19th century.118 The recovered Management area has witnessed a substantial increase in the The Wet Weather Plan is explicitly based on four number of species that visit the site, spurring city innovative principles for stormwater management: plans to build and restore several more wetlands. 32
  • 39. Natural Resources Defense Council Rooftops to RiversToronto’s green roofs. Toronto has also become The study findings estimated nearly $270 milliona center for green roof technologies. While not of municipal capital cost savings and more thanexplicitly part of the stormwater plan, the green $30 million in annual savings with this number ofroof initiatives are expected to have an impact on installed green roofs. Five primary benefits were quan-stormwater mitigation. Based on an Environment tified in the study: (1) reduced stormwater flows intoCanada study, the nonprofit industry association the separate storm sewer system, (2) reduced storm-Green Roofs for Healthy Cities estimates that water flows into the combined sewer system, (3) im-greening 6% of Toronto’s roofs would cost about proved air quality, (4) mitigated urban heat island$36 million over 10 years and would retain almost effects, and (5) reduced energy consumption. The study1 billion gallons of stormwater annually.119 In 2002, estimated more than $100 million in stormwater cap-several Canadian organizations announced the Green ital cost savings, $40 million in CSO capital cost sav-Roof Infrastructure Demonstration Project, a public- ings and nearly $650,000 in CSO annual cost savings.private partnership that will fund more than $800,000 The researchers anticipate that the only costsin green roof costs.120 to the city will be those to promote green roofs, Toronto currently has over 100 green roofs, includ- although the city will also likely incur costs toing an intensive installation on the Toronto City Hall monitor design and construction of the green roofs.and an extensive installation on the gymnasium The cost to retrofit existing roofs with green roofs isroof of the Eastview Neighbourhood Community likely to be borne by private industry during theCentre.121 The National Research Council’s Institute normal maintenance cycle. Recent green roof projectsfor Research in Construction installed a monitoring in Canada have averaged $6 to $7 per square foot,system on the Eastview roof to measure both quality suggesting a total cost of $3 billion to $3.7 billion forand quantity of stormwater runoff.122 Early findings 12,000 acres of green roofs.126,127 While the total costfrom an upcoming study to investigate the potential to install the green roofs is large, it would be spreadfor widespread green roof installations in Toronto across numerous building owners and developers.(The Municipal Cost Savings Benefits of Green Roofs) The additional cost of a green roof for the minimumindicate 57% average annual flow reductions from area roof in the study, 3,750 square feet, would bethe Eastview green roof plots compared to traditional $22,000 to $27,000.roofs.123 The plots also showed peak flow rates of25% to 60% during summer and 10% to 30% in late For Additional Informationfall of those measured from conventional roofs.124 City of Toronto—Protecting Water Quality: http://These preliminary monitoring results were achieved vegetation had reached maturity. A Ryerson University study evaluated the munici-pal level benefits and costs of wide-scale imple- Vancouver, B.C., Canadamentation of green roofs in Toronto. For the study, Creative green design for city parks and roadsa Geographic Information Systems (GIS) database Population: 600,000was used to model and aggregate environmental Type of green infrastructure used: green roofs;benefits and a methodology was developed to mone- rain gardens, vegetated swales, and landscape;tize these benefits. The study assumed that green roofs permeable pavement; wetlands, riparian protection, VANCOUVERwould be installed on all city flat roofs more than or urban forests3,750 square feet and would cover at least 75% of the Program elements: established municipal programsroof. Using this assumption, more than 12,000 acres and public fundingof green roofs, representing 8% of the total land area Situated 25 miles north of the U.S.-Canadianin the city, could be installed in Toronto.125 border and bounded on three sides by water, 33
  • 40. Natural Resources Defense Council Rooftops to Rivers Vancouver is the third largest city in Canada. While runoff have been identified as leading causes of local the city covers an area of 44 square miles, the entire water pollution. metropolitan area is nearly 1,100 square miles and home to approximately 2 million people.128 Almost Creating More Permeable, Pedestrian-Friendly 90% of the 44 square mile city center is developed.129 Green Space Often recognized as one of the best cities in the world The city has begun using green infrastructure to in which to live, Vancouver was ranked third in a address a range of environmental problems. Because 2005 survey assessing the quality of life in 215 cities Canada is a signatory of the Kyoto Protocol, many of worldwide.130 However, even one of the world’s Vancouver’s green infrastructure efforts are focused most highly regarded cities is not immune to the on climate and air benefits, but some are specifically effects of urbanization and stormwater runoff. targeted at stormwater. To address stormwater runoff Vancouver sits in the Fraser River Valley, the from roadways, Vancouver has initiated a number of most productive salmon fishery in the world. An innovative street design projects as part of the city’s estimated 800 million juvenile salmon from five Greenways Program. The program is focused on intro- different species migrate along the Fraser River each ducing pedestrian-friendly green space into the city year. Eighty additional species of fish and 79 species to connect trails, environmental areas, and urban space. of birds rely on the Fraser River and its estuary for This greenway initiative has also developed innovative critical habitat and migratory routes.131,132 With strategies to manage roadway stormwater. One of these Rocky Mountain snow melt composing the majority projects is the Crown Street redevelopment project. of the source water in Vancouver, good water quality Prior to the redevelopment project, stormwater run- has historically been an attribute of Vancouver area off from Crown Street flowed untreated into the last watersheds. But within the past half century, urbani- two remaining salmon-bearing creeks in Vancouver.133 zation and stormwater have begun to degrade the In 2001, residents along a 1,100-foot block of the street area’s waters. Combined sewers constitute more petitioned the city to rehabilitate the deteriorating than 60% of the city’s collection system, and com- street using conventional curb and gutter. In response, bined sewer overflows and separate stormwater the city recommended a naturalized streetscapeVANCOUVER Crown Street just after construction and prior to swale planting. PHOTO COURTESY OF CITY OF VANCOUVER GREENWAYS PROGRAM 34
  • 41. Natural Resources Defense Council Rooftops to RiversVancouver’s first Country Lane installedin 2002.PHOTO COURTESY OF CITY OF VANCOUVER GREENWAYSPROGRAMdesign modeled after the Seattle SEA Street design. The Results will be compared with a nearby curb andnaturalized design narrowed the impervious street gutter street to confirm modeling projections.width from 28 feet to 21 feet (certain one-way sectionsof the road were narrowed to 10 feet) and incorporated The Country Lane Program. Another example of greenroadside swales with structurally supported grass to design within Vancouver’s Streets Department is thecollect and treat stormwater through infiltration. The Country Lane Program to replace traditional highlyredesigned street will retain 90% of the annual rain- impervious alleys and lanes with a more permeablefall volume on site; the remaining 10% of runoff will alternative. Asphalt lanes are replaced with twobe treated through a system of vegetated swales before concrete or gravel strips surrounded by structuraldischarging.134,135 Construction was completed in grass (structural grass is supported by a grid and soilearly 2005 at a cost of $707,000.136 A conventional structure that prevents soil compaction and rootcurb and gutter design would have cost approx- damage). Connections from the country lane toimately $364,000; however, because Crown Street residences are constructed of permeable materials,was the first of its kind in the city, an estimated including paving blocks, broken concrete sections,$311,000 was spent on additional aesthetic design and structural grass or gravel. Three Country Lanesfeatures and consultant fees that would not be neces- were installed as a pilot project to introduce greensary for future projects. Eliminating the project-specific space and encourage on-site infiltration of storm-additional costs would bring the cost of retrofitting water. The initial cost of a Country Lane was approx-existing streets with naturalized street design imately $71 per linear foot, which is four times greaterprojects in line with conventional drainage systems; than the typical alley cost of $18 per foot.139,140 Thehowever, the city estimates that installing naturalized city estimates that the cost of a Country Lane in 2006 VANCOUVERstreet designs in new developments will be less will decrease to $30 per linear foot.141,142expensive than conventional drainage systems.137,138 The city is also installing infiltration bulges alongIn cooperation with the University of British Columbia, roadways to collect and infiltrate street stormwaterVancouver will monitor the street for the next five runoff. These installations are being done in conjunc-years to assess the quality of stormwater runoff. tion with the Greenways program’s efforts to improve 35
  • 42. Natural Resources Defense Council Rooftops to Rivers Infiltration bulges capture and infiltrate stormwater before it reaches the collection system. PHOTO COURTESY OF CITY OF VANCOUVER GREENWAYS PROGRAM transportation corridors by making them more Vancouver’s green roofs. In addition to the street ini- pedestrian friendly. The city is extending curbs at tiatives, Vancouver has also used green infrastructure intersections out into the street to lessen the crossing in other applications. Green roofs have been used distance and improve the line of sight for pedestrians. extensively in the greater Vancouver area, with more The city’s stormwater catch basins are located at road- than 30 installations.144 One of the best known of these way intersections; when the bulges were constructed, roofs is installed on the Vancouver Public Library’s the city was initially relocating these catch basins Central Branch building. The 20,000 square foot outside of the bulges. Now, in certain instances, the green roof was installed in 1995 and planted as an Streets Department is installing permeable soils and artistic representation of the Fraser River. Monitoring vegetation within these bulged sections to introduce of the roof during an eight-month period in 2003 and green space and collect stormwater. The catch basins 2004 showed a 48% reduction in the volume of storm- are left in place within the bulges and any stormwater water runoff from the roof when compared to a con- that does not infiltrate into the soil overflows into the ventional roof. Peak stormwater flows were also stormwater system. This new design not only reduces reduced between 5% and 30% during the region’s the amount of stormwater runoff, but is also less costly wet winter months; in the drier summer, peak flows for the city. Because the stormwater infiltration bulges were reduced more than 80%. As with other green are installed in conjunction with planned roadway roofs, peak reductions were the greatest for smaller, improvements, the only additional costs associated less intense storms and least for larger rain events.145 with the stormwater project are the costs of a steel curb insert to allow stormwater to enter the bulge and addi- Biofiltration in Vancouver’s parks. Vancouver has tional soil excavation costs. These additional costs are designed and installed two biofiltration systems,VANCOUVER more than offset by the $2,400 to $4,000 cost of relocat- utilizing natural and reclaimed green space to treat ing the catch basins. To date, the city has installed nine stormwater runoff. One hundred sixty-seven acres infiltration bulges, three of which are maintained by of neglected, largely paved land were reclaimed local volunteers as part of a Green Streets program and re-greened to create Hastings Park. The park where local residents adopt city green space.143 provides Vancouver residents with green space in 36
  • 43. Natural Resources Defense Council Rooftops to Riversa highly urbanized section of the city. Within the Washington, D.C., sits at the confluence of thepark is the biofiltration system referred to as the Potomac and Anacostia rivers and is home to a third,Sanctuary. This system receives stormwater runoff Rock Creek. These rivers in the nation’s capital havefrom a 300-acre residential area to the south of the historical and symbolic importance. The Potomacpark and uses natural biological processes to treat River is designated an American Heritage River andthe runoff prior to discharging it to the Burrard is often synonymous with the seat of the country’sInlet.146 The biofiltration pond was designed in federal government. Unfortunately, Washington’sconjunction with the sewer separation project that rivers are also significantly affected by the largeinstalled a new separate stormwater collection amount of urbanization surrounding them. Approxi-system in the neighborhood bordering the park. mately 65% of the District is covered with impervi-The Sanctuary also provides additional aesthetic ous surfaces.151 Development and urbanization haveand environmental benefits by serving as valuable taken a toll on the natural features within the city;habitat for wildlife and birds.147,148 over the past 30 years, the District has lost 64% of its A second biofiltration system is used in Stanley areas with heavy tree cover and experienced a 34%Park, a 1,000-acre urban park in Vancouver. The increase in stormwater runoff.152park is bisected by the Stanley Park Causeway, amajor commuter route. Prior to the construction of Cleaning Up Washington’s Most Polluted Watersthe biofiltration wetlands, causeway runoff flowed Through Green Infrastructureuntreated into the Lost Lagoon, Beaver Lake, and One-third of the city is served by a combined seweradjacent forests. To manage and treat this storm- system dating to the beginning of the 1900s andwater, runoff was directed to a wetland constructed earlier. Estimated annual CSO discharges to the city’swithin the Lost Lagoon. The wetland uses natural three rivers are 2.5 billion gallons.153,154 The Anacostiafiltration and biological processes to treat the River, which receives 60% of the CSO discharges, isstormwater before it is discharged to the lagoon. one of the most polluted in the nation. Fifty percentThe innovative stormwater wetland was built to of brown bullhead catfish collected for study fromharmonize with the existing green space of the the river had cancerous liver tumors and approxi-park and to provide habitat for plants and wildlife. mately 25% had cancerous skin tumors.155 The city’sAreas of the wetland not open to the public provide approved long-term CSO control plan (LTCP) willnecessary space for birds to remain undisturbed by cost approximately $1.9 billion and focuses primarilyhuman activity.149,150 on a deep tunnel system and sewer separation, but also recognizes the importance of incorporatingFor Additional Information green infrastructure within the city.City of Vancouver Streets Design—EnvironmentallySustainable Options: Low Impact Development at the Navy Yard on Anacostia River. The Washington Navy Yard, along the banks of the Anacostia River, has been a notori- ous source of the river’s water quality problems. TheWashington, D.C. base has been subject to decades of military pollutionUsing green infrastructure to combat years of river and has been a main source of toxic water pollution.pollution In 2001, the Navy Yard installed a number of greenPopulation: 563,000 infrastructure pilot projects to manage stormwaterType of green infrastructure used: green roofs; runoff. Downspouts were disconnected and directedrain gardens, vegetated swales, and landscape; to rain barrels, and permeable pavement, rainpermeable pavement gardens, and tree box filters were installed. These WASHINGTON, DC 37
  • 44. Natural Resources Defense Council Rooftops to Rivers The first commercial high-elevation green roof in Washington, DC, will be monitored to determine how much it lowers air temperature. PHOTO COURTESY OF THE CASEY TREES ENDOWMENT FUND retrofits cost approximately $500,000 and are pro- proposed deep tunnel storage capacity by 30 million viding on-site management of stormwater previously gallons because of the decrease in rooftop runoff.157 directed to the combined sewer system. Monitoring of the site is ongoing and is determining the storm- Incorporating green infrastructure into DC’s CSO water volume reductions, stormwater discharge and stormwater programs. The District’s efforts frequency, and water quality improvements.156 with green infrastructure have not progressed as far as those in other case-study cities. However, a Washington’s green roofs. Washington’s first commer- convergence of events presents the city with an cial high-elevation green roof was installed in 2004. opportunity to integrate green approaches into its The 3,500 square foot green roof was a collaborative overall stormwater and CSO control efforts. The effort between two nonprofit organizations and the 20-year implementation schedule to complete the real estate company that owns the building. The air LTCP provides an ideal window to incorporate temperature of the green roof is being monitored and green infrastructure into the District’s pollution compared to the temperature of a 1,000 square foot control plans. The District of Columbia Water and section of the roof that was not converted. Sewer Authority (WASA), the regional agency Installing green roofs across the District is projected responsible for implementing the LTCP, has allocated to provide a significant reduction of stormwater run- $3 million of the overall LTCP budget for advocating off and CSO volume. Based on computer modeling and assisting with green infrastructure retrofits.158 by Limno-Tech, Inc., Casey Trees has measured the Major redevelopment is also planned along the effects of installing 20 million square feet of green Anacostia River to complement the construction roofs, 20% of the roof area for all city buildings over of the city’s new baseball stadium. 10,000 square feet, over the next 20 years. Modeling Some of the most significant barriers to incor- results based on this coverage scenario show a citywide porating green infrastructure, or any stormwater or reduction in runoff of 1% and CSO discharges of 15%. CSO controls, into existing urban areas are the cost The green roofs are anticipated to retain and store and challenge of retrofitting these systems into built- 430 million gallons of rainwater annually and increase out and space-constrained areas. The LTCP work andWASHINGTON, DC 38
  • 45. Natural Resources Defense Council Rooftops to RiversAnacostia redevelopment lower these barriers an adequate incentive, the current annual stormwaterbecause of the large capital investment that will fee would need to be significantly increased. Aaccompany the projects and substantial overhaul and similar system could be adopted in the combinedupgrade of associated infrastructure. These projects sewer area as well. Private grant programs, like theoffer the opportunity to integrate green infrastructure Chesapeake Bay Foundation’s green roof grantfrom the start and take advantage of the associated program, currently exist as an incentive to installcost savings. The city will also have the opportunity green infrastructure in the city. The District shouldto learn from several major cities that have been suc- complement these efforts with a city-administeredcessfully integrating green infrastructure into financial assistance program for green infrastructure.stormwater and CSO mitigation plans. A number of the policy recommendations described For Additional Informationearlier in this report could be used effectively to Casey Trees—Green Roof Vision for DC: http://wwwencourage green infrastructure. The District currently a nominal stormwater fee to its residents and for%20DC%20-%20Full%20Report%20082405.pdfcommercial properties located in the separate sewer University of Maryland School of Public Policy,area. The stormwater fee could be restructured, Reducing Combined Sewer Overflows: Toward Cleansimilar to Portland, Oregon’s model, to allow a rate Water in Washington, D.C. (May 2002): http://wwwreduction for those properties that install green or manage stormwater on site. To be _Complete.pdf WASHINGTON, DC 39
  • 46. APPENDIXADDITIONAL ONLINE RESOURCESAG-588-02 Urban Waterways: Designing Stormwater City of Vancouver Greenways InitiativeWetlands for Small Watersheds, N.C. State University greenways/otherInitiatives.htm N.C. State University, WATERSHEDS: A DecisionAlternative Stormwater Management Support System for Non-Point Pollution Control Research and Services Center of Comprehensive Environmental, Inc., The PurerWashington, Best Management Practices (BMPs) for Innovative Stormwater Management ProgramStorm and Surface Water Management: Pollution Housekeeping Purerdesign.pdf International Stormwater Best Management (BMP) DatabaseThe Stormwater Manager’s Resource Center, http://www.bmpdatabase.orgBioretention as a Water Quality Best ManagementPractice An Internet Guide to Financing Stormwater Management110-Bioretention.pdf http://stormwaterfinance.urbancenter.iupui.eduThe Center for Watershed Protection, Stormwater U.S. Green Building Council, LEED(r) for ExistingManagement and Stormwater Management Practices Buildings & _general_file.asp?DocumentID=799Chagrin River Watershed Partners—Watershed The Low Impact Urban Development Center, LowToolkit Impact Development (LID) Urban Design Tools http://www.lid-stormwater.netCity of Portland Bureau of Environmental Services Natural Resources Defense Council, Urban Stormwater Solutions 40
  • 47. Natural Resources Defense Council Rooftops to RiversNational Stormwater Center Stormwater, A Stormwater Management Plan Your Communities, Businesses, and Residents Will SupportU.S. Environmental Protection Agency, NPDES Program for Regulated Small MS4s Stormwater Plant Materials—A Resource Guidephase2.cfm 20articles/idpmcarswpm.pdfPuget Sound Action Team, Low Impact Development Texas A&M Cooperative Extension, Stormwater ManagementRain Gardens—A How-to Manual for Home Owners The Center for Watershed Protection, Urban Stream Repair PracticesRain Gardens—Improve Stormwater Management in Yard pdf U.S. Department of Energy, Building Toolbox: Stormwater Management StrategiesScholz-Barth, Katrin, Green Roofs: Stormwater from the Top Down design/buildingsiting/stormwater.html,4120,18769,00.html U.S. EPA Urban Watershed Management Research, Stormwater Management Model (SWMM)Seattle Public Utilities, Natural Drainage Systems index.htmDrainage_&_Sewer_System/Natural_Drainage_Systems/index.asp University of Washington College of Engineering, Use of Constructed Wetlands for Improving StormwaterHome*A*Syst North Carolina, Stormwater QualityManagement for Homeowners .htmlstormwater Using Constructed Wetlands to Improve WaterNew York, New Jersey, Puerto Rico, Virgin Islands QualityRegional Water Coordination Program, Stormwater in Your Backyard pdf Regional Coordination Program, Weather Reports and Watershed Protection: A Winning CombinationThe Stormwater Management Academy Management%20Education%20Program/66issue.pdf 41
  • 48. Natural Resources Defense Council Rooftops to RiversAmerican Rivers, Catching the Rain: a Great Lakes U.S. EPA, Report to Congress: Impacts and Control ofResource Guide to Natural Stormwater Management CSOs and SSOs (Aug. 2004)(July 2004) _id=5&view=allprog&sort=name?pagename=AMR_publications U.S. EPA, National Management Measures to ControlTaxpayers for Common Sense, Banking on the Future: Nonpoint Source Pollution from Urban AreasInvesting in Smart Water Strategies for Pennsylvania and (Jan. 2006)the Nation (Aug. 2005) U.S. EPA, Using Smart Growth Techniques as Stormwater Best Management Practices (2006)U.S. Public Interest Group and American Rivers, at Risk: How Low-Impact Development CanReduce Runoff Pollution in Michigan (Oct. 2005) National Association of Local Government Environmental Professionals, et al., Smart Growth for Clean Water (2003)Environmental Integrity Project, Report: Backed Up, Up Combined Sewer Systems in the Great Lakes PublicationsDetail.cfm?LinkAdvID=42157(May 2005) The Trust for Public Land, Building Green Infra- structure (June 2000)U.S .EPA, Stormwater Best Management Practices Guide (Sept. 2004) _id=915& 42
  • 49. ENDNOTESChapter 2 Chapter 41 U.S. Environmental Protection Agency, Protecting Water Quality from 1 U.S. EPA, Report to Congress: Clean Watersheds Needs Survey 2000, OfficeUrban Runoff, Nonpoint Source Control Branch, EPA 841-F-03-003, of Wastewater Management, August 20, 2003.February 2003. 2 Costs adjusted from 2000 to 2005 dollars.2 Prince George’s County, Maryland Department of Environmental 3 See note 1.Resources, Low-Impact Development Design Strategies, January 2000. 4 USDA Forest Service, Pacific Southwest Research Station, Center for3 Dana Beach, Coastal Sprawl: The Effects of Urban Design on Aquatic Urban Forest Research, in the United States, Pew Ocean Commission, 2002. (accessed January 31, 2006).4 See note 3. 5 John Haugland, Changing Cost Perceptions: An Analysis of Conservation5 U.S. Department of Agriculture, National Resources Inventory: 2002 Development, Conservation Research Institute, February 2005.Annual NRI, Natural Resources Conservation Service, April 2004. 6 Larry Coffman, “Low Impact Development Design: A New Paradigm6 See note 1. for Stormwater Management Mimicking and Restoring the Natural Hydrologic Regime, An Alternative Stormwater Management Tech-7 U.S. EPA, Report to Congress: Impacts and Control of CSOs and SSOs, nology” (Conference Proceedings from the National Conference on ToolsOffice of Water, EPA-833-R-04-001, August 2004. for Urban Water Resource Management and Protection, February 2000).8 See note 7. 7 Rocky Mountain Institute, Green Development Services: Village Homes—9 U.S. EPA, National Water Quality Inventory, 2000 Report, Office of Water, Davis, California, (accessedEPA-841-R-02-001, August 2002. December 8, 2005).10 See note 7. 8 See note 5.11 See note 7. 9 See note 5.12 D.C. Water and Sewer Authority, CSO Overflow Predictions for Average 10 The City of Vancouver, Crown Street: Vancouver’s First EnvironmentallyYear, August 2004, Sustainable Street, TAC’s Environmental Council, March 30, 2005. (accessed 11 Personal communication with Otto Kauffmann, Engineering ProjectFebruary 18, 2005). Coordinator, City of Vancouver Streets Division, November 2005.13 Milwaukee Metropolitan Sewerage District, Overflows: CSOs, (accessed November 11, 2004). Chapter 514 Portland Bureau of Environmental Services, The Cornerstone Projects, 1 See note 5, Chapter 4.(accessed February 16, 2005). 2 See note 7, Chapter 4.15 See note 7. 3 33 U.S.C. 1342(q).16 See note 3. 4 City of Portland Bureau of Environmental Services, Downspout17 USDA, Summary Report 1997 National Resources Inventory, Natural Disconnection Program Hits the Billion Gallon Mark, 2005 News Releases,Resources Conservation Service, December 1999 (revised December June 2005,2000). (accessed June 16, 2005).18 See note 3. 5 “Stormwater Management Rule,” New Jersey Register, N.J.A.C., Vol. 7,19 Arthur C. Nelson, Toward a New Metropolis: The Opportunity to Rebuild No. 8 (February 2, 2004).America, The Brookings Institution, December 2004. 6 Melissa Keeley, “Green Roofs and the Green Area Factor: An Urban20 See note 3. Green-Infrastructure Policy Instrument” (Proceedings from the Greening Rooftops for Sustainable Communities Conference, Washington, D.C.,Chapter 3 May 4–6, 2005).1 Environmental Integrity Project, Weathering the Storm: Controlling Storm 7 69 Fed. Reg. 22472 (April 26, 2004).Water Pollution in the Great Lakes States, September 2004. 8 Peter H. Lehner, et al., Stormwater Strategies: Community Responses to2 James Salzman and Barton H. Thompson Jr., Environmental Law and Runoff Pollution, Natural Resources Defense Council, May 1999.Policy (New York: Foundation Press, 2003). 9 James W. Woodworth, Jr., Out of the Gutter: Reducing Polluted Runoff in3 “Combined Sewer Overflow (CSO) Control Policy, Final Policy,” the District of Columbia, Natural Resources Defense Council, July 2002.Federal Register, Vol. 59, No. 75 (April 19, 1994) pp. 18, 688. 10 Tom Liptan and Eric Strecker, Ecoroofs (Greenroofs)—A More Sustainable4 See note 7, Chapter 2. Infrastructure. (Proceedings from the National Conference on Urban Stormwater: Enhancing Programs at the Local Level, Chicago, IL,5 Onondaga County Department of Water Environment Protection, February 17–20, 2003).Sewer Separation, Onondaga Lake Improvement Project, (accessed February 16, 2005). 11 City of Toronto Planning Division, Making Green Roofs Happen: A Discussion Paper Presented to Toronto’s Roundtable on the Environment,6 Mark A. Benedict and Edward T. McMahon, “Green Infrastructure: November 2005, Conservation for the 21st Century,” Renewal Resources Journal, (accessed December 14, 2005).Autumn 2002. 12 City of Chicago, City Launches Green Roof Grant Program, http://7 Casey Trees Endowment, Trees Provide Us with a Variety of Benefits: (accessed December 14, 2005).Cleaner Water and Less Polluted Runoff, (accessed July 8, 2005). 13 Portland Bureau of Environmental Services, Stormwater Discount Program, =80606&c=31019 (accessed October 6, 2005). 43
  • 50. Natural Resources Defense Council Rooftops to Rivers14 Maryland Department of the Environment, 2000 Maryland Stormwater 13 Invisible Structures, Inc., Porous Alleyway Demonstration Project: WardDesign Manual, Water Management Administration, June 16, 2000. 48, City of Chicago. WhitePapers/GV2Alley.pdf (accessed January 2005).15 A legal review checklist for reviewing zoning and building coderegulations is in J. Woodworth, Out of the Gutter: Reducing Polluted Runoff 14 The LEED(tm) principles were designed by the U.S. Green Buildingin the District of Columbia 52-8 (NRDC, July 2002). Council.16 See note 5. 15 City of Chicago Department of Environment, Center for Green Technology: History. GreenTech/sub/about_history.html (accessed January 2005).Chapter 6: Conclusion 16 City of Chicago Department of Environment, Center for Green1 Personal communication with Jim Middaugh, Program Manager— Technology: Water, of Portland Endangered Species Act Program, December 2005. GreenTech/sub/water.html (accessed January 2005). 17 City of Chicago Department of Environment, Green BungalowChapter 7: Case Studies Initiative, J.R. McNeill, Something New Under the Sun: An Environmental History of +Building%2fI+Want+To&deptMainCategoryOID=-536887205the Twentieth-Century World (New York: W.W. Norton & Company, Inc., &channelId=0&programId=0&entityName=Environment&top2000). ChannelName=Dept&contentOID=536910325&Failed_Reason2 City of Chicago, Conserve Chicago Together: Combined Sewers, http:// =Invalid+timestamp,+engine+has+been+restarted& =COC_EDITORIAL& (accessed=cccdadddmlmhlidcefecelldffhdffn.0&contentOID=536910787&conten December 9, 2005).TypeName=COC_EDITORIAL&topChannelName=SubAgency&block 18 City of Chicago Department of Environment, press release, “NewName=Conserve+Chicago+Together%2FSewers+of+Chicago%2FI Rain Barrel Program Announced,” August 28, 2004, and “Grass Roots+Want+To&context=dept&channelId=0&programId=0&entityName Water Education Campaign: Rain Garden and Rain Barrel Pilot Projects.”=Conserve+Chicago+Together&deptMainCategoryOID=-536889943(accessed November 19, 2004). 19 Rainfall events are defined by estimating their probability of occur- rence. For example, a one-year storm event is predicted to occur once3 City of Chicago, Chicago’s Water Agenda 2003, http://www each year; likewise, a 25-year storm is a rainfall event large enough that (accessed is predicted to occur on average only once in 25 years or, statistically, itNovember 2004). has a 4% chance of occurring in any given year. Specific storm events are4 U.S. EPA, Urban Heat Island Pilot Project: Chicago, http://www.epa often a defining component of stormwater regulations. (U.S. (accessed December 2004). Survey, Water Science for Schools, 100yearflood.html, accessed January 31, 2006).5 Tudor Hampton, “Chicago Engineers Move Fast to Finish EpicTunneling Feat,” Engineering News-Record, August 18, 2003, http:// 20 City of Chicago Department of Environment, Stormwater (accessed Practices Feasibility Study, June 11, 2004.February 16, 2005). 21 Milwaukee Metropolitan Sewerage District, What is an Overflow?,6 Personal communication with Richard Lanyon, Director of Research (accessedand Development, Metropolitan Water Reclamation District of Greater November 11, 2004).Chicago, February 02, 2005. 22 See note 21.7 Metropolitan Water Reclamation District of Greater Chicago, Tunnel 23 Personal communication with Thomas Chapman, Section Manager,and Reservoir Plan: The Deep Tunnel, Watercourse Division, Milwaukee Metropolitan Sewerage District,plants/tarp.htm (accessed December 2004). Milwaukee, Wisconsin, November 2004.8 See note 2. 24 Milwaukee Metropolitan Sewerage District, Collection System: Deep9 City of Chicago Department of Environment, About the Rooftop Garden, Tunnel System, (accessed November 11, 2004) 25 Milwaukee Metropolitan Sewerage District, MMSD Proposes Short-=ccccadddkgejkficefecelldffhdfgn.0&contentOID=536908578&conten Term Action Plan to Reduce Volume of Sewer Overflows, http://www.mmsdTypeName=COC_EDITORIAL&topChannelName=Dept&blockName .com/news/news_detail.cfm?id=27 (accessed November 11, 2004).=Environment%2FCity+Hall+Rooftop+Garden%2FI+Want+To&context=dept&channelId=0&programId=0&entityName=Environment&dept 26 See note 21.MainCategoryOID=-536887205 (accessed January 2005). 27 Personal communication with Bill Graffin, Public Information10 City of Chicago Department of Environment, Green Roofs Open to the Manager, Milwaukee Metropolitan Sewerage District, Milwaukee,Public, Wisconsin, December 28 See note 21._EngineID=cccdadddmlmhlidcefecelldffhdffn.0&contentOID=536912340&contenTypeName=COC_EDITORIAL&topChannelName=Dept&block 29 Milwaukee Metropolitan Sewerage District, Summary of StormwaterName=Environment%2FAbout+Chicago%27s+Green+Roofs%2FI+Want Reduction BMP Demonstration Projects, November 16, 2004.+To&context=dept&channelId=0&programId=0&entityName=Environm 30 Whitney Gould, “Sky’s the Limit for ‘Green Roof’ Advocate,”ent&deptMainCategoryOID=-536887205 (accessed January 2005). Milwaukee Journal Sentinel, November 28, 2004, http://www.jsonline11 See note 11, Chapter 5. .com/news/metro/nov04/279426.asp (accessed March 1, 2005).12 City of Chicago Department of Environment, Urban Heat Island 31 Mark L. Kass, “Beyond Flood Control,” Stormwater, March/AprilInitiative Alley Reconstruction, 2004, (accessedCOCWebPortal/COC_ATTACH/UHIAlley.pdf (accessed January 2005). January 5, 2005). 32 See note 29. 44
  • 51. Natural Resources Defense Council Rooftops to Rivers33 Eric Loucks, et al., Final Summary of Stormwater Reduction Results, 62 City of Portland Bureau of Environmental Services, Flow Test Report:Memorandum Prepared for the Milwaukee Metropolitan Sewerage Siskiyou Curb Extension, August 04, 2004, http://www.portlandonlineDistrict, March 9, 2004. .com/shared/cfm/image.cfm?id=63097 (accessed January 2005).34 See note 33. 63 See note 62.35 Milwaukee Metropolitan Sewerage District, 2005 Milwaukee 64 City of Portland Bureau of Environmental Services, SustainableMetropolitan Sewerage District Annual Budget. Stormwater Management: Green Streets, shared/cfm/image.cfm?id=6593136 See note 35. 65 See note 10, Chapter 5.37 See note 35. 66 See note 55.38 National Research Council, Regional Cooperation for Water QualityImprovement in Southwestern Pennsylvania, National Academies Press, 67 See note 54.January 2005. 68 City of Portland Bureau of Environmental Services, Liberty Center39 Bruce Ferguson, et al., “Restorative Redevelopment: The Nine Mile Parking Garage, Model,” Stormwater, January 13, 2004. image.cfm?id=66824 (accessed February 2005).40 Sustainable Pittsburgh, Southwestern Pennsylvania Regional Indicators 69 City of Portland Bureau of Environmental Services, Oregon ConventionReport 2004, Fall 2004. Center Rainwater Garden, index.cfm?&a=68703&c=36848 (accessed February 2005).41 See note 38. 70 City of Portland Bureau of Environmental Services, Sustainable42 Jim Taylor, Attacking Pittsburgh’s Storm Water Problem, Environmental Stormwater Solutions: New Seasons Seven Corners Store Project,Design + Construction, May 01, 2003, (accessed (accessed February 2005).January 30, 2006). 71 See note 1, Conclusion.43 Phipps Conservatory, “Phipps Expansion Raises Region’s NationalProfile,” Momentum, Summer 2004. 72 The Rouge River Project, An Overview of the Rouge River, Rouge River National Wet Weather Demonstration Project, http://www.rougeriver44 Jim Taylor, “A ‘Green Roof’ Primer” (Presented at the Alliance .com/geninfo/overview.html (accessed October 4, 2005).Building Breakfast, Green Building Alliance, July 28, 2004). 73 Department of the Environment, Wayne County, Michigan, Rouge45 David L. Lawrence Convention Center, Green Building, River National Wet Weather Demonstration Project—CSO Basins: Getting the (accessed Most Performance for Your Pollution Control Dollar, RPO-CSO-TR52, JuneFebruary 2005). 2005.46 United States Army Corps of Engineers, Project Fact Sheet: Construction 74 See note 72.General, 75 See note 73.47 David Black, Flyer for Biohabitats, Inc., Presentation at Hydrosystems 76 U.S. EPA, Great Lakes Areas of Concern: Rouge River, http://www.epaEngineering Seminar Series. .gov/glnpo/aoc/rougriv.html (accessed October 4, 2005).48 City of Pittsburgh Department of City Planning, Pittsburgh’s Regional 77 See note 76.Parks Master Plan: A New Ethic of Stewardship, April 2001. 78 The Rouge River Project, Overview Description of Storm Water49 Personal communication with Jeffrey Bergman, Program Coordinator, Management for the Rouge River, Rouge River National Wet WeatherNine Mile Run Watershed Association, February 10, 2005. Demonstration Project, overview.html (accessed October 4, 2005).50 City of Portland Bureau of Environmental Services, Working for CleanRivers, 79 See note 76.(accessed January 2005). 80 See note 76.51 City of Portland Bureau of Environmental Services, Stormwater 81 The Rouge River Project, Inkster Wetlands Project, Rouge RiverManagement in Portland, National Wet Weather Demonstration Project, http://www.rougeriverbes/index.cfm?c=31892 (accessed December 2004). .com/wetlands/inkster/inkster/index.html (accessed October 4, 2005).52 See note 50. 82 Wayne County Rouge River National Wet Weather Demonstration53 See note 50. Project, Inkster Wetlands, Wayne County, MI, The Rouge River Project, August 2002.54 City of Portland Bureau of Environmental Services, Sustainable SiteDevelopment: Stormwater Practices for New, Redevelopment and Infill Projects, 83 See note 82.November 2003. 84 Ford Motor Company, Rouge Renovation, Doug Hutchinson, et al., Stormwater Monitoring Two Ecoroofs in goodWorks/environment/cleanerManufacturing/rougeRenovation.htmPortland, Oregon, USA, City of Portland Bureau of Environmental (accessed October 7, 2005).Services, 2003. 85 Don Hammonds, “Greener, Literally: Ford’s Better Ideas for Newer56 City of Portland Bureau of Environmental Services, Environmental Plant Include Grass-Covered Roof, Pollution-Eating Plants,” PittsburghAssessment: Innovative Wet Weather Program, April 2004. Post Gazette, November 12, 2004, 04317/410625.stm (accessed October 7, 2005).57 See note 11, Chapter 5. 86, North American Case Studies, http://www.greenroofs58 See note 10, Chapter 5. .com/north_american.htm (accessed June 21, 2005).59 See note 13, Chapter 5. 87 See note 86.60 City of Portland Bureau of Environmental Services, Downspout 88 See note 84.Disconnection Program, (accessed January 2005). 89 The Associated Press, “Ford Overhauls Historic Factory to be Green,”, (accessed October 7, 2005).61 See note 4, Chapter 5. 45
  • 52. Natural Resources Defense Council Rooftops to Rivers90 Darla Inglis, Seattle Public Utilities’ Natural Drainage System Program 120 National Research Council Institute for Research in Construction,(Proceedings from the National Low Impact Development Conference, Press Release: Government of Canada Reveals Major Greenhouse GasCollege Park, Maryland, September 21-23, 2004). Reductions and Air Quality Benefits from Widespread Use of ‘Green Roofs,’ October 9, 2002.91 See note 90. 121 Nicole Cohen, “Look Up, Look Way Up,” Eye Weekly, July 15, 2004,92 See note 90. Richard R. Horner, et al., Hydrologic Monitoring of the Seattle Ultra- (accessed January 30, 2006).Urban Stormwater Management Projects: Summary of the 2000–2003 Water 122 The Garland Company, Inc., The Green Revolution Continues onYears, University of Washington Department of Civil and Environmental Toronto, December 2003.Engineering, Water Resources Series: Technical Report No. 181, Seattle,Washington, October 2004. 123 Karen Liu and John Minor, “Performance Evaluation of an Extensive Green Roof” (Presentation at Green Rooftops for Sustainable Communi-94 See note 93. ties, Washington D.C., May 2005).95 See note 93. 124 See note 123.96 See note 93. 125 Doug Banting, et al., Report on the Environmental Benefits and Costs of97 See note 93. Green Roof Technology for the City of Toronto, City of Toronto and Ontario98 See note 93. Centres of Excellence—Earth and Environmental Technologies, October 31, 2005, See note 93. (accessed December 16, 2005).100 See note 93. 126 American dollars converted from Canadian equivalent based on101 See note 90. December 19, 2005, exchange rate.102 See note 90. 127 See note 125.103 See note 90. 128 Kimberly Pedersen, Meadows in the Sky: Contemporary Applications for Eco-roofs in the Vancouver Region, (Vancouver, B.C.: University of British104 Seattle Public Utilities, Natural Drainage Systems Receive $100,000 Columbia, 2001).Award—Harvard Recognizes Innovative City Program, 129 See note 128.(accessed December 16, 2005). 130 Canadian Broadcasting Corporation, Vancouver 3rd in World in105 Puget Sound Action Team, Rooftop Rainwater Harvesting, Natural Quality of Life Survey, CBC News, March 13, 2005.Approaches to Stormwater Management, March 2003. 131 See note 128.106 Personal communication with Steve Moddemeyer, Senior Strategic 132 River Works, Fraser Facts: The Importance of the Fraser River,Advisor, Seattle Department of Planning and Development, February (accessed April 20, 2005.2005. 133 Scott Deveau, “Street in for Crowning Touch,” The Vancouver Courier,107 See note 106. September 22, 2004, Gabriel Scheer, Sustainable Street Design: An Analysis of Best Practices news/092204nn9.html (accessed March 9, 2005).As Seen Within the Seattle Context, (Seattle: University of Washington, 134 Alexandra Steed, Naturalized Streetscapes: A Case Study of Crown2004). Street, Vancouver, Greenways—City of Vancouver.109 City of Toronto, Water Services, Toronto’s Water Pollution Solution— 135 Personal communication with Otto Kauffmann, Engineering ProjectGoing for the Flow, Coordinator, City of Vancouver Streets Division, April 2005.wwfmmp/index.htm (accessed April 26, 2005). 136 American dollars converted from Canadian equivalent based on110 Environment Canada, Remedial Action Plans (RAPs): Toronto and April 25, 2005, exchange rate.Region Area of Concern, Rap Status, (accessed May 18, 2005). 137 See note 10, Chapter 4.111 Environment Canada, Remedial Action Plans (RAPs): Toronto and 138 See note 11, Chapter 4.Region Area of Concern, General Information, 139 Personal communication with Joanne Griffin, City of Vancouverwater/raps/toronto/intro_e.html (accessed May 18, 2005). Streets Design Branch, June 2005.112 City of Toronto, Wet Weather Flow Management Policy, August 2003. 140 American dollars converted from Canadian equivalent based on113 See note 112. June 23, 2005, exchange rate.114 See note 109. 141 See note 135.115 City of Toronto, Water Services. Water Services—Community Program 142 American dollars converted from Canadian equivalent based onfor Stormwater Management, November 22, 2005, exchange (accessed April 26, 2005). 143 Personal communication with David Yurkovich, Greenways116 City of Toronto Department of Works and Emergency Services, Landscape Designer, City of Vancouver Greenways Branch, April 2005.Stormwater Pollution: Tips on How You Can Improve Water Quality, June 144 Kim Davis, Green Roof Inventory: Preface Report Greater Vancouver2000. Regional District, The Greater Vancouver Regional District Policy and117 City of Toronto, Wet Weather Flow Management Master Plan: Stream Planning Department, December 12, 2002.Restoration and End-of-Pipe Project Summary (2003–2027). 145 Chris Johnston, et al., Vancouver Public Library Green Roof Monitoring118 City of Toronto, Restoration Projects, Project, Public Works and Government Services Canada, April 30, 2004.don/restoration.htm (accessed April 26, 2005). 146 The Hastings Park Conservancy, The Sanctuary, http://www.vcn.bc119 Scott Peck, “Green Roofs for Healthy Cities” (Presentation given at .ca/greenhp/Sanctuary.html (accessed March 28, 2005).Climate Air Connections Workshop at Clean Air Foundation), April 2003. 147 The City of Vancouver, Broad City Initiatives, (accessed March 9, 2005). 46
  • 53. Natural Resources Defense Council Rooftops to Rivers148 Project for Public Spaces, Hastings Park, (accessed March 28, 2005).149 Kerr Wood Leidal Associates Ltd., Project Profiles—Stanley Park, _profiles/projects/stanleypark.htm(accessed March 29, 2005).150 The Stanley Park Ecological Society, Frequently Asked Questions - LostLagoon, (accessedApril 25, 2005).151 See note 9, Chapter 5.152 Barbara Deutsch, et al., Re-Greening Washington, DC: A Green RoofVision Based On Storm Water and Air Quality Benefits, Casey TreeEndowment Fund and Limno-Tech, Inc., August 24, 2005.153 See note 12, Chapter 2.154 District of Columbia Water and Sewer Authority, Combined SewerSystem Long Term Control Plan—Final Report, June 2002.155 U.S. Fish and Wildlife Service, Evaluating the Health of the TidalPotomac River Watershed—Tumor Surveys in Brown Bullhead Catfish, May2000, July 11, 2005).156 Personal communication with Neil Weinstein, Executive Director,Low Impact Development Center, July 2005.157 See note 152.158 See note 154. 47