Spring 2014
Green
Infrastructure:
Sustainable Solutions in 11 Cities
across the United States
Table of Contents
Introduction ... 2
New York City ... 7
Los Angeles ... 11 Chicago... 13 Houston ... 17 Philadelphia ... 21 Phoenix... 24 San Antonio ... 26 Dallas... 28 San Diego ... 31 San Jose... 34 Washington DC... 37 Conclusion ... 39 REFERENCES ... 40
Introduction
Originally, the term green infrastructure was used to describe a network of green spaces that were connected, offering multiple ecosystem services. In the last decade, green infrastructure benefits have expanded beyond stormwater management and urban runoff mitigation to include other ecosystem services. The most successful green infrastructure projects build on the foundation of traditional Best Management Practices (BMPs) and Low Impact Development (LID), but provide more than either of these design and management metrics. This report uses the following definitions for Green Infrastructure, BMPs and LID:
Green Infrastructure:
“Green infrastructure is an approach that communities can choose to maintain healthy waters, provide multiple environmental benefits and support sustainable communities.
Unlike single-purpose gray stormwater infrastructure, which uses pipes to dispose of rainwater, green infrastructure uses vegetation and soil to manage rainwater where it falls. By weaving natural processes into the built environment, green infrastructure provides not only stormwater management, but also flood mitigation, air quality management, and much more.” 1
-Environmental Protection Agency Best Management Practices:
“BMPs are defined […] as ‘schedules of activities, prohibitions of practices, maintenance
procedures, and structural and/or managerial practices, that when used singly or in combination, prevent or reduce the release of pollutants to waters."2
- Municipal Research and Services Center Low Impact Development:
“LID is an approach to land development (or re-development) that works with nature to manage stormwater as close to its source as possible. LID employs principles such as preserving and recreating natural landscape features, minimizing effective imperviousness to create functional and appealing site drainage that treat stormwater as a resource rather than a waste product.”3
- Environmental Protection Agency
One of the primary motivations for green infrastructure in the US is to reduce stormwater runoff which may contribute to combined sewer overflow events (CSOs). Overflow occurs in cities with Combined Sewer Systems where sanitary sewage water, stormwater and urban runoff water are collected in the same pipe network. If the capacity of a treatment plant cannot handle the amount of water collected, excess sewer water is routed directly to rivers, bays and oceans. Seven of the 11 cities assessed in this report continue to exhibit environmental degradation due to urban and
This report assesses and summarizes green infrastructure practices in 11 major cities in the United States (see (Table 1) for a summary). Green infrastructure programs are assessed then ranked based on city and municipal activities such as sustainability plans, incentive programs, and projects that utilize green infrastructure methods to better manage stormwater and urban runoff. The efforts made by private organizations that are mentioned in this report do not affect the cities’ ranking. Assessments of urban green infrastructure include New York City, Los Angeles, Chicago, Houston, Philadelphia, Phoenix, San Antonio, San Diego, Dallas, San Jose and Washington D.C. The cities are compared based on population, area, density, and precipitation in Figures 1-4.
The following research questions will be addressed for each of the targeted cities: ● Does the city have a central approach to sustainability such as a sustainability plan? ● Does the city have a central, concrete outline and agenda for implementing green
infrastructure as a stormwater management tool?
○ If so, how effective and what measurable successes could be recorded by this green infrastructure Program?
○ How extensive was the cost-benefit analysis in developing a green infrastructure Plan? (Socio-economic-environmental benefits)
○ Is there one or multiple departments that oversee the management, implementation and tracking of green infrastructure Projects?
● If no current plan exists, is the city planning to draft a plan with green infrastructure in its agenda?
Figure 1. Population of 11 major US cities in 20124.
Figure 2. Average annual precipitation in 11 major US cities5.
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Figure 3. Land area of 11 major US cities6.
Figure 4. Population density of 11 major US cities in 2010.
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New York City
(1) City Programs: PlaNYC- A Green Greater New York (Includes Green Infrastructure Plan) (2) City Departments: Department of Environmental Protection
New York City in its long vibrant history set trends, led the country, and pushed the boundaries in many arenas. Urban green infrastructure is one of those categories. Over the last decade, under Mayor Michael Bloomberg, the city has seen major developments in rethinking management of an urban environment. As described in the Introduction, one of the management issues that city governments are forced to comply with are Federal and State laws requiring storm and wastewater treatment before the water can enter rivers and oceans. In recent years, green infrastructure has gained traction especially in New York City which has a combined sewer system. New York City receives more than 50 in/yr of precipitation, the most rainwater of any of the 10 largest cities in the US (Figure 2). With PlaNYC and the Green Infrastructure Plan, the city strives to find
environmentally friendly alternatives to expensive treatment plants and so called gray infrastructure.
First and foremost PlaNYC – A Greener Greater New York, a city wide program striving to make the largest city in the US more sustainable, sets the foundation for all sustainability initiatives in NYC including the green infrastructure plan. In its own words PlaNYC has “implemented numerous innovative initiatives, including the City’s Greener Greater Buildings Plan, Clean Heat program, climate resilience initiatives, Million Trees program, Green Infrastructure Plan, and more” and
thereby trying to build a modern, more sustainable city by 2030.7 PlaNYC’s green infrastructure plan
will be the main program investigated.
In 2010, New York City’s Department of Environmental Protection (DEP) started managing the NYC Green Infrastructure Plan, A Sustainable Strategy for Clean Waterways, whose goal they described as follows: “Reducing [Combined Sewer Overflow] CSO volume by an additional 3.8 billion gallons per year (bgy), or approximately 2 bgy more than the all-gray Strategy; Capturing rainfall from 10% of impervious surfaces in CSO areas through green infrastructure and other source controls; and providing substantial, quantifiable sustainability benefits ‒ cooling the city, reducing energy use, increasing property values, and cleaning the air ‒ that the current all gray strategy does not provide.”8
The Center for Clean Air Policy summarizes the socio-economic benefits rather well for New York’s Green Infrastructure Plan:
“The cost to implement the overall Plan is $1.5 billion less than grey, with green stormwater capture alone saving $1billion at a cost per gallon of about $.15 less. Sustainability benefits over the 20 year life of the project range from $139 - $418 million depending on measures implemented. The plan estimates that ‘every fully vegetated acre of green infrastructure would provide total annual benefits of $8,522
in reduced energy demand, $166 in reduced CO2 emissions, $1,044 in improved air
quality, and $4,725 in increased property value.’” 9
The Green Infrastructure Plan is projected to reduce CSO volume from 30 billion gallons per year to 17.9 bgy. Strategies in the plan include green roofs, permeable pavement, engineered wetlands, street trees, and swales. The estimated cost of a green CSO control program is $1.5 billion in public funds, compared to $3.9 billion needed for grey infrastructure. In addition to better performance at a lower cost, the green infrastructure plan is expected to produce greater benefits over time (Figure 5). The benefits of green infrastructure extend beyond controlling CSO, which an all grey strategy provides, by supporting the city, residents and environment in a multifaceted manner.
Figure 5. Predicted benefits from the green and grey infrastructure CSO management strategies.
The Green Infrastructure plan has achieved multiple successes. In 2011 and 2012, the DEP
constructed dozens of right-of-way bioswales and green streets in addition to multiple other projects that are in the planning and developmental stages. To increase transparency and promote the work, the NYC DEP created a “Green Infrastructure Map” available on their website that displays current
sites and projects that are being implemented.10
First Green Infrastructure Success Story: Bluebelt system Staten Island
The rapid development that occurred on Staten Island after 1964 when the Verrazano Bridge was completed, resulted in a large quantity of stormwater runoff as the land area covered by impervious pavement increased. The Bluebelt system offered a solution. The Staten Island Bluebelt program consists of an extensively constructed and planned stormwater management system (Figure 6). It originally became the topic of discussion in the 1970’s with planning beginning in the late 1980’s and land acquisition in the early 1990’s. At the time it was one of the first projects built to control the amount and quality of stormwater runoff and its success has led to its expansion in Staten Island
over the last decades. In 2010, plans included “about 90 BMPs in South Richmond - of which 50 are
Figure 6. The Staten Island Bluebelt Drainage Basins in New York City
The Bluebelt system uses strategically placed wetlands within a watershed to temporarily store and filter 350,000 gallons of stormwater during a storm event. Soil placement and layering, vegetation, and rocks reduce the speed of the runoff providing more time for sediment, chemicals, and other toxins to percolate into the wetland. Slower and less stormwater runoff from these areas reduces the load on the single sewer plant in Staten Island, giving it more time to treat and discharge water. Since the water that does not reach the treatment plant has already been naturally filtered through percolation, higher quality water will be discharged into the streams, rivers and the Atlantic. This system results in cleaner runoff, reduces the amount of water flowing into the sewer system at a given time, and helps to protect downstream property from flood damage.
Not only did the program win several engineering awards, it has saved millions of dollars in
alternative sewer treatment systems. More specifically, its reputation among stakeholders is valued for both its environmental and economic benefits. By “naturally draining over 14,000 acres and
saving over $80 million in conventional sewer costs”12 it became clear that the Bluebelt system
should be expanded to other areas.
Dana Gumb, who has worked on the project since 1988, explained that one of the major obstacles in the planning stage was for the city to acquire the land to plan, construct and develop the project. Often large scale projects involve many parties such as land owners, public or private entities, and other stakeholders causing delays in development due to complicated negotiations. Fortunately, the city government of Staten Island owns land surrounding the Bluebelt system and will continue to acquire land to expand the success of the wetland system.
“Perhaps the best testament to the success of the Bluebelt has been its stellar performance during major storms and hurricanes. Hurricane Ivan, which dropped 2.3 inches (5.8cm) of rainfall over a 24-hour period, passed quietly through the region on September 17-18, 2004. Tropical Storm Tammy and Subtropical Depression 22, which combined to produce 6.4 inches (16cm) of rainfall over a 24-hour period, went by unnoticed on October 8-9, 2005. Areas that were once flooded even by minor
Other Bluebelt models have surfaced, since the success of the Staten Island system. An NYC GI project in the Bronx Botanical Garden has four catch basins with the capacity to hold 5,770 gallons stormwater/minute and a wetland water quality basin that filters and cleans the water discharged from the basins. A conservative estimate is that the Bronx Botanical Garden Bluebelt system treats
8.4 million gallons of stormwater every year and thereby reduces costly CSO events.14 Currently,
New York City is planning to build constructed wetlands in and around Shoelace Park to protect the Bronx River.
A major challenge for NYC is its combined stormwater and sewage system. It is estimated that 27 billion gallons of water passes through 6,600 miles of sanitary, storm, and combined sewer pipes, and is released into adjacent rivers without treatment. Fourteen water pollution control plants distributed among the five NYC boroughs process 1.5 billion gallons of wastewater each day. On average, a CSO event occurs once every week, and up to 70 times per year at some treatment facilities. Surrounding water ways rarely have the chance to recover. NYC recognizes this threat to
health and the environment and thus pursues the best solutions.15
In March of 2013, the Department of Environmental Conservation and DEP announced an agreement to invest “$2.4 Billion in Green Infrastructure and $1.4 Billion in gray infrastructure to Target the City’s Most Impaired Waterbodies over the next 18 years.” This will result in a total savings of $1.4 billion from gray infrastructure substitution projects and an additional $2 billion in
deferred costs.16 The estimated savings are viewed favorably by stakeholders resulting in the
potential for wide acceptance of green infrastructure programs in NYC.
Los Angeles
Los Angeles’ comparatively later development allowed engineers, city government and planners to design a more sustainable water infrastructure. With 3.9 million people in an area of roughly 470 square miles and “only” about 12 inches of precipitation per year, one could ask why stormwater management and green infrastructure should be pursued in Los Angeles at all.
The Federal Regulations of the National Pollutant Discharge Elimination System (NPDES) under the Clean Water Act requires the mitigation of stormwater runoff and pollution in nearby waters. These regulations include strict pollutant concentration maximums for effluent to open waters. A regulatory body monitors this and charges monetary penalties for rule violations. Explicit Low Impact Development (LID) requirements have spread among municipalities as well, however only apply locally. All major metropolitan areas in California are required to incorporate LID in
stormwater permits and statewide incentives help to promote their development.17
Locally, the city has derived a few key regulatory programs that support the regional development of LID and BMP’s. The Standard Urban Stormwater Mitigation Plan focuses on reducing overall water pollution from runoff and many BMPs and LID plans were developed to adhere to program requirements.
The Green Streets LA program promotes the development of LID’s and strives to expand the use of LID’s for stormwater control and recharging groundwater. Several projects have been implemented since 2008. With political incentives in place, Los Angeles shows strong interest in pursuing green solutions to stormwater runoff.
The Rio de Los Angeles park project exemplifies a combination of public space and stormwater management. While it serves as a place of recreation and natural relief for residents, it also mitigates stormwater runoff. The Rio de Los Angeles park project uses constructed repurposed
wetlands as a natural filtration system to reduce pollution.18
Another project that is similar to the Rio de Los Angeles State Park project is located in the South Los Angeles Wetlands Park, a re-purposed bus yard that serves the community as a recreational and educational space while cleaning LA’s water. After initial filtration from the park and the runoff from the streets, the stormwater runs into the system of wetlands, “where bacteria naturally cleans up the remaining pollutants. The cleaner water is sent on its way to the Los Angeles River where it
makes its way to the ocean.”19 With a capacity to process and handle 680,000 gallons of
stormwater per day, this project excels in mitigating the problems associated with pollution from stormwater.
These two park projects exemplify how Los Angeles addressed local issues, however the city would
benefit from a central approach to green infrastructure. In April of 2009 a feasibility report20 shared
showed great benefits for LA’s stormwater management, water demand, groundwater recharge, and others. Furthermore, the report cites a study that says “nearly 40% of LA County’s needs for cleaning polluted runoff could be met by implementing low impact development projects on existing public lands”. The city can use public land to develop green infrastructure without requiring a long tedious acquisition processes. The report continues on to list social and economic reasons to pursue LID and says it “would result in the savings of 74,600–152,500 acre-feet of imported water per year by 2030”. Thus, the city could become more sustainable by reducing imported water demand and dependence while realizing monetary savings from both the reduced imported water dependency, and also from energy savings by having to pump less water. Eighty-seven percent of LA’s water is sourced from the LA Aqueduct originating in Northern California; the remaining 13% comes from local groundwater. The infrastructure is aging and expensive to maintain and operate, thus giving city managers added incentive to invest in LID’s that recharge local groundwater and
decrease reliance on purchased water.20
A majority of projects cited in this study require less capital cost and save money over the project’s useful life than conventional water management initiatives. Los Angeles can evaluate the economic feasibility of low impact developments with a comprehensive, central approach to green
infrastructure through comparison of green infrastructure projects in other southern Californian communities, such as Irvine, that implement LID ordinances and requirements.
California is familiar with the problems associated with drought and dry lands. Dwindling water resources and recurring, longer lasting droughts have large implications for a metropolitan city such as LA. Green Infrastructure, not only consists of water filtration, bioswales or constructed wetlands, but includes rainwater harvesting. In the end, runoff will still be reduced and water quality improved, but the issue of drought can be addressed as well. Residential rain barrels and cisterns offer one solution to recycling and reusing water. At least 30% of all water in LA is used outdoors. By recycling and reusing rainwater, that percentage can be reduced one barrel and cistern at a time with each household contributing to reducing overall water use and runoff. The Sanitation Districts of Los Angeles County have successfully implemented programs that promote the recycling and re-use of reclaimed water. The county has a total of 10 water reclamation facilities that treat water,
“most of which essentially meets drinking water standards”.21 The water is currently used to irrigate
lawns in public open spaces. In the future, Green Infrastructure can be combined with this program to save even more money and energy.
Los Angeles County, according to the California Department of Finance forecasts, can expect
another 1.7 million people by 2060.22 More people require more water and in turn create more
wastewater and runoff. City managers must harness the economic, social and political tools at hand to prepare for that kind of growth. The existing projects show the achievements within the
community, however, for long term, reliable success and a positive image, Los Angeles should strive towards a comprehensive sustainability plan.
Chicago
(1) City Programs: Sustainable Chicago 2015 Plan; Chicago Green Roof Grant Program (2) City Departments: Department of Environment; Department of Planning and Development;
Department of Water Management; Department of Transportation; Department of Streets and Sanitation;
(3) Metropolitan Area: Metropolitan Water Reclamation District of Greater Chicago Cities such as Chicago, covered with impervious surfaces, face potentially exacerbated
consequences due to climate change. “The frequency of heavy precipitation events (or proportion of total rainfall from heavy falls) will very likely increase over most areas during the 21st century, with
consequences to the risk of rain-generated floods.”23 Not only cities that are located near coastal
waters or rivers will experience the vast effects of climate change. As the IPCC states above, storms in general as well as floods will most likely increase. In the beginning of the 21st century Chicago encountered massive floods and CSO events. The Center for Neighborhood Technology quotes that Chicago’s 500-year storm event on September 13, 2008 caused 11 billion gallons of
combined sewer water to flow into Lake Michigan.24 That is over a third of what NYC averages in
CSO in one year. This storm event size is rare in Chicago, however those of its kind may become more frequent in this century according to the IPCC. Specifically, 6-9 in. of rain fell in the course of 24 hours. That equates to 34-50 gallons per square yard in one day and almost 25% of yearly precipitation in Chicago (36.7 in/year). Designing a treatment system to process this quantity of rainfall may not be economically justifiable, however there are other more reasonable methods for mitigating and reducing the volume of CSO.
Since the 1970s Chicago addressed stormwater management through engineering and gray infrastructure methods. The city government and predominantly the municipality responsible for water management (Metropolitan Water Reclamation District of Greater Chicago) tackles this issue. To-date they have built 109 miles of deep tunnels to capture and delay sewage treatment, seven treatment plants and 23 pumping stations in the greater Chicago area. With an area of 228 square miles, Chicago has a lot of ground to cover to avoid CSO events. Maintenance of sewer pipes and related structures alone costs approximately $50 million every year. In general, the city and the MWRD shows strong commitment to “hard built” infrastructure solutions with little focus on Green
Infrastructure for stormwater management purposes.25
In fall 2012, Chicago released its Sustainable Chicago 2015 plan. Sustainable Chicago 2015 is an initiative by the city to target seven key areas with 24 specific goals for the city and make Chicago a more robust, resilient and sustainable city by 2015. While the program does facilitate coordination between departments and project assignments, its short time horizon does not establish a long-term sustainability plan for the city. Green infrastructure is not addressed as a specific topic in this
plan, though multiple goals are tied to green infrastructure and best management practices.26 By
signing Sustainable Chicago 2015 into law, Chicago recognizes the importance and value of pursuing green non-conventional management solutions through a more centralized approach.
One must look at the Metropolitan Water Reclamation District (MWRD) of greater Chicago for the history of the city’s stormwater management. Ten years ago the MWRD constructed a green infrastructure project on its own property. The Native Prairie Landscaping project was initially constructed “to reduce landscape maintenance costs for the District” by planting native grasses and vegetation, though the District recognized additional environmental and infrastructure benefits. Since then the MWRD constructed several other Native Prairie Landscaping projects and are planning to have one at each of their seven treatment facilities.
The District continued to pursue green infrastructure solutions by distributing 1,000 rain barrels to residential combined sewer areas. With one barrel carrying around 55 gallons, which sums up to a total of 55,000 gallons, this tool can assist in retaining a large amount from entering the combined sewer system. Overall the MWRD “estimates that $909,132 or 22.2% of its 2007 Stormwater Fund
expenditures”27 financed alternative green solutions. The expenditures included costs for specific
projects such as “Buffalo Creek Wetland Design”, but mostly plan for watershed management, stormwater management, or pervious pavement design. Plans, designs, analysis and ordinances were the funding priority areas instead of construction or development, which raises the question: how much green infrastructure projects will the MWRD actually pursue?
When it comes to city government or specific programs that do not focus on the benefits of
stormwater management, however, Chicago presents itself as a leader in Green Infrastructure. For example, the city’s commitment towards building green roofs is among the most ambitious in the nation. The Green Roof on City Hall, constructed in 2001, ignited movements such as Chicago Green Roofs and the Green Roof Grant program. The city realized the benefits of energy savings through green roofs and only parenthetically notes the water cleaning and water retaining qualities. Green roofs perform many benefits for cities but in terms of stormwater runoff Chicago does not include green roofs in their management plan. Nonetheless, green roofs do play a role in
stormwater management and Chicago can be considered a leader in this field. The Chicago Green Roof organization mapped out every green roof constructed in the city and made it publicly
Figure 7. Map of green roof locations throughout Chicago, provided by the Chicago Green Roof Organization28
Projects such as the Green Alley program illustrates one of Chicago’s more water focused interests in green infrastructure solutions. With its pilot project the Department of Transportation tackled the issue of flooding and stormwater runoff in certain persistent flood areas (Figure 8). The previously impervious surface showed chronic signs of flooding, but when replaced with permeable pavers and surfaces this alley now reduces runoff by allowing water to infiltrate to the subsurface.
Figure 8. Before and After images of the pilot project for the Green Alley program.29
One theme that becomes noticeable in Chicago’s GI efforts is the lack of central governmental or municipal approach, plan, or strategy. The Civic Federation, a government nonpartisan research organization, considers Chicago’s green infrastructure initiative as “diffuse with many different
departments pursuing [...] environmental agenda independently.”30 The city’s website promotes
outreach and education about green programs, although the information is dispersed among the different departments.
This list includes several departments and a description of their LID, BMP and green infrastructure efforts:31
Department of Environment:
Most of the DOE’s efforts go into enforcing regulations and permits and enhancing energy and conservation policies. In 2006, the office had a budget of $30.8 million with 87 employees. In 2008 the DOE passed an ordinance regarding stormwater that insured expenditures go to developing vegetated swales, infiltration trenches, detention basins, sediment, oil and grease traps,
raingardens, and Education and outreach on CSO/Stormwater.
Department of Planning and Development:
Green roofs are the main focal point of the DPD. With grant programs, promotions, technical assistance, education and financial support for building green roofs, the department strives to develop much of the city’s rooftop space into green space. With a budget of $41.9 million and 177 employees in 2006, the DPD was able to make great strides in developing green roofs in Chicago.
Department of Water Management:
The DWM provides the distribution of potable water and removal of wastewater in coordination with Metropolitan Water Reclamation District. Much of the department’s interests are in green
infrastructure solutions, however, green infrastructure projects can be inhibited by the bureaucratic nature of capital expense projects in Chicago. In 2006, the department had a budget $684 million and over 2.5 thousand employees. Research studies and green infrastructure issues take up many labor hours for the water department as well as coordinating projects with other branches of the government.
Department of Transportation:
Responsible for the transportation network in Chicago, the DOT handles the city’s streets. It
operates the Green Alley program, one of the most prolific green infrastructure programs in Chicago, to reduce urban and stormwater runoff and keep alleys clean. Chicago has 1,900 miles of alleyway, the nation’s longest, and with it large amounts of impervious surfaces that present an opportunity for green infrastructure. In addition to the Green Alley program, the DOT applies permeable pavers and pervious surfaces on their streets and sidewalks allowing rain to infiltrate through the pavement, as well as constructing bioswales, streetscapes and infiltration pipes. Their budget in 2006 was $260 million with 826 employees.
Department of Streets and Sanitation:
The Bureau of Forestry under the DSS is responsible for planting trees on residential and commercial streets. These trees are not specifically planted for stormwater control measures, however, even though unintended, they are beneficial and therefore fall under the green infrastructure category.
Houston
(1) City Programs: ReBuild Houston, Bayou Greenway 2020, Harrison County Flood Control District’s Capital Improvement Plan
(2) Private Initiatives: The Bayou Preservation Organization, Land/Water Sustainability Forum (3) City Departments: Public Works - Green Building Resources Center
Houston is the largest city by size and population in Texas, and is the fourth most populated city in the US. Located in southeastern Texas next to Trinity Bay, Houston lies adjacent to the Gulf of Mexico. With a total area of approximately 600 square miles and a population of 2.1 million, Houston has the lowest population density of the cities assessed in this study (285 sq. miles/ 1 million people compared to NYC: 37 sq. miles/ 1 million people). Texas, a state with a majority of arid land and little precipitation has comparatively large amounts of rainfall along its coast. In Houston the average yearly rainfall is 49.8 inches, much of it falling in storms and intense rainfall events throughout the year (Figure 9).
Figure 9. Average monthly precipitation in Houston, TX.
Flooding is a relatively frequent occurrence compared to other cities with high precipitation. Houston requires heavy load infrastructure to handle the amount of water that they receive every year. To illustrate the impact of floods on Houston one can look at the flood insurance losses for the city. From January 1, 1978 through September 30, 2001 Houston has suffered $641,722,736 in insurance losses due to floods. This is over twice the amount of flood damage for the entire state of New York. With an expanded view of Houston’s surrounding area in Harris County, the insurance costs increase to over 1 billion dollars over the same time period. Furthermore, in 2001, 22 people
died due to floods in Houston alone.32 The need for a robust and resilient infrastructure is clear.
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The existing infrastructure in Houston is insufficient for mitigating flood and stormwater issues. An independent study from 2012 by the American Society of civil Engineers (ASCE) rated Houston’s
Flood control and drainage infrastructure with a C-.33 The program ReBuild Houston, part of the
Capital Improvement Plan of greater Houston focuses solely on the drainage system. The ASCE study summarizes ReBuild Houston as follows:
“The ReBuild Houston program is aimed at providing $125 million annually toward improvements of local street and drainage systems. The City has identified that over $5 billion is needed to improve these systems. Assuming that the current rate of $125 million in annual
funding would be combined with additional grants and federal funding to an estimated $200 million, it would take approximately 25 years to
address the identified current needs.”34
ReBuild Houston’s goals are illustrated in the portfolio of infrastructure improvements the city has undertaken and aims to develop. In 2012, ReBuild Houston’s first year, the program completed dozens of projects. Most of these projects were paving and drainage improvements, curbs, gutters and sidewalk enhancements. None of the listed projects included green infrastructure criteria. In their own words, ReBuild Houston’s success will be measured by how much they can “reduce street
flooding, improve mobility and reduce structural flooding”.35 The funds are provided through four
channels: Drainage Utility Fee, Developer Impact Fee, Ad Valorem Taxes, and Third-Party Funds. Both the utility fee and impact fee were recent additions to assist and expedite the ReBuild Houston program and better manage the city’s flood problem. There is no explicit mention of green
infrastructure’s role in meeting their goals.
The most important existing green infrastructure projects in Houston are the multiple bayou’s that direct water into the Galveston Bay. However, these bayous have existed since before the city was founded and cannot handle the water capacity and stress from the impervious area of Houston. The city intends to enhance the bayous through the Bayou Greenway 2020 initiative that will create park space and recreational areas around the major bayous. There are ten major bayous in Houston and the Harris County area: Brays, Buffalo, Clear, Cypress, Greens, Halls, Hunting, Sims, Spring, White
Bayou36, that primarily function as stormwater management areas rather than natural or recreational
space where effective green infrastructure sites could be developed. The Bayou Preservation Organization describes the development as follows:
“Since the 1950s many of the natural streams of Harris County have been converted into single-purpose storm sewers. Many streams were "channelized" (sides dug out and uniformly sloped) and lined with concrete to increase the flow of water through them. Trees and
habitats were destroyed to "improve" our naturally occurring drainage systems. Concrete bayous were constructed.”37
reduce flooding but to enhance quality of life and sustainability. Retention basins along the bayous exemplify an expensive management option compared to constructed wetlands, bioretention basins and bioswales that can reduce the runoff at its source and clean the water simultaneously.
Houston’s Stormwater Management Program (www.swmp.org) works alongside the ReBuild
Houston Program and yet green infrastructure does not appear in their project descriptions. Best Management Practices in Houston’s cleanwaterways.org guidance manual merely urge residential, industrial and commercial owners to properly dispose of waste, fertilizers, and other toxins to prevent polluted water runoff. While such handbooks exist for the residents of Houston, no governmental effort aims to implement green infrastructure.
Houston and Harris County work together on many issues and their respective jurisdictions overlap. In the picture below you can see Harris County outlined in red and the city of Houston highlighted in blue.
The Harris County Flood Control District (hcfcd.org) started a five-year plan called the Capital Improvement Plan (CIP). The costs for the existing CIP that focuses on flood control and drainage
“is estimated at more than $975 million.”38 The CIP description includes projects such as “channel
modifications (modifying of existing streams, bayous or tributaries), new channel construction, excavation of large stormwater detention basins” with no intent of sustainable, alternative green infrastructure solutions. Steven Stelzer, the program director from the green building resource
center, (http://www.codegreenhouston.org/) says, when asked about Houston’s green infrastructure,
“Houston does not have a central initiative or program that the city oversees in terms of green infrastructure”.
The Green Building Resources Center, which exists within the Department of Public Works and Engineering, offers citizen tips, insights, education, and displays of green building solutions. While this center offers valuable educational resources, the city does not have laws, ordinances, or incentives in place to promote green infrastructure development.
The Land/Water Sustainability Forum of Houston exemplifies another education and outreach effort to the public. From low impact development design competitions to landscape architecture
presentations, this forum highlights the benefits of green infrastructure, LID and BMPs, and promotes practices that protect the water and environment. In contrast to the Green Building Resource Center the forum is a non-governmental entity with minimal leverage to implement sustainable initiatives in Houston.
Water management with all its intricacies must play a role in Houston’s sustainable planning and initiatives. Due to its frequent storm events and high annual precipitation rates an all gray
stormwater infrastructure does not provide a viable and financially sustainable long term foundation for its residents and environment. Incorporating the ideas and suggestions of organizations such as the Houston Sustainability forum and Green Building Resource Center into its city budget and strategy would be a formidable start.
Philadelphia
(1) City Programs: Green works Philadelphia; Green City, Clean Waters (2) City Departments: Philadelphia Water Department
Philadelphia was an early leader in the urban green infrastructure field. While New York has created its own GI Plan at this point, Philadelphia has produced several annual reports on the success of their GI Plan to date. Greenworks Philadelphia aims to turn Philadelphia into “the
greenest city in America”39 and includes and extensive list of GI measures. This group works from
the Local Action Plan that “outlines a series of steps that the City of Philadelphia government should take to reduce greenhouse gas emissions by 10 percent by 2010, the Greenworks
Philadelphia plan now expands on reducing greenhouse gases since 2009 into the areas of Energy, Environment, Equity, Economy and Engagement.” Stormwater management and green
infrastructure are categorized in the plan under equity. The Philadelphia Water Department (PWD) manages most green infrastructure projects under their program called Green City, Clean Waters. This 25-year, $2 billion, program began in 2011 and aims to mitigate stormwater issues
predominantly through green infrastructure.
Since 2011, Green City, Clean Waters has constructed 102.4 acres of new pervious surfaces. By 2015 a total of 450 acres of new green pervious surfaces are planned. That will amount to ~20 million square feet of green infrastructure that the city plans to have constructed by
2015.40 This ambitious goal illustrates the value that the government sees in green infrastructure.
Yearly progress updates help the public see where public funds go and how that money improves the city and its residents’ lives. For example, the update from 2011-2012 summarizing the
program’s green infrastructure achievements included three infiltration trenches with 14 designed and planned, and 6 completed rain gardens with 10 designed for the future. Green City, Clean Waters promotes additional stormwater management tools including downspout planters, green roofs, porous paving, rain barrels, stormwater basins, stormwater bumpouts, stormwater planters,
stormwater tree trenches, stormwater treatment wetlands and swales.41
One stormwater treatment wetland was constructed in 2005 before Philadelphia’s sustainability plans were written into law. This wetland, the Stormwater Wetland at Saylor Grove, supports the
sewershed that receives 70 million gallons of urban stormwater runoff42. Its discharge flows to the
Wissahickon Creek, the major source of Philadelphia’s drinking water. Filtering and reducing urban and stormwater runoff is critical for preserving this drinking water source. When constructed
correctly, treatment wetlands perform excellently and are proven to filter runoff, detain large
amounts of stormwater, improve water quality, provide habitat for wildlife, and space for recreation.
The PWD started the Stormwater Management Incentives Program in 2011 with the help of the Philadelphia Industrial Development Corporation. This program offers credit incentives “to owners of impervious commercial properties who build and maintain green stormwater management projects”. During the first year 45 people applied, but only eight projects were awarded grants and credits. Private development in Philadelphia has shown to provide the most green infrastructure
development. Of the total constructed green impervious acres, 79% come from private
development.43
Additional project funding comes from charging stormwater fees. Instead of a payment structure based on the amount of water runoff, the city restructured this program to collect fees based on area of impervious surfaces. In other words, non-residential customers are being assessed on a “ratio of ‘Impervious Area to Gross Area’ on the property”. Owners of parking lots which were not previously billed for stormwater runoff under the past program are now charged a similar rate as commercial customers. The city expects to receive approximately $1-1.5 billion dollars over the next 25 years because of this new program. This increase in revenue will help the Green City,
Clean Water program meet its 25 year goal.44
An economic analysis by the Center for Clean Air Policy in 2011 found that reductions in CSO and complying with federal Total Daily Maximum Load (TDML) regulations saved the city approximately $170 million. Furthermore, “the green infrastructure option compared favorably in terms of net present value, resulting in $2.8 billion in benefits compared to only $120 million for the gray
infrastructure option–more than a twenty-fold difference”.45 To illustrate the achievements of the
PWD, the city tracked and mapped all projects across the city to make information easy to understand and accessible to the public (Figure 10).
Figure 10. Locations of green infrastructure projects in Philadelphia. Projects include: swales, green roofs,
Phoenix
The city of Phoenix experienced a population increase over the last 60 years. Much of this development was due to technical advancements that have made it possible for people to live comfortably in extremely hot and arid regions. The residents of Phoenix consume a lot of electricity, mainly to power air conditioners. In an article by author and conservationist William deBuys from March 2013, deBuys describes Phoenix as the least sustainable city, and illustrates its vulnerability to power supply. “If, in summer, the grid there fails on a large scale and for a significant period of time, the fallout will make the consequences of Superstorm Sandy look mild.[...] Phoenix is an air-conditioned city. If the power goes out, people fry.”47 The city’s reliance on air conditioning will only become greater as the urban heat island effect continues to raise the city’s average temperature. As deBuys phrases it, “Studies indicate that Phoenix’s urban-heat-island effect may boost nighttime temperatures by as much as 10°F.”48
The city’s urban heat island effect can be mitigated by green infrastructure solutions such as increased
vegetation and less heat-storing pavement. The predicted impacts of green infrastructure in Phoenix should be assessed by both its stormwater management benefits as well as urban heat reduction.
The most advertised GI project in Phoenix is the Tres Rios Constructed Wetland (Figure 11). The constructed wetland improves the quality of water originating from an adjacent wastewater treatment plant through natural nitrogen and ammonia removal. This naturally treated water can replenish the local aquifer or flow to downstream users. Ron Elkins from Phoenix’ Water Services Department spoke highly of this project:
“The applicability to other arid areas are great. Obviously most wetland systems exist in water rich environments, but the idea of arid environment constructed wetlands makes much more sense. [...] After the water is cleaned it can be recycled for other uses and be used by wildlife during the process. As far as ground water supply there is the obvious correlation of infiltration and groundwater levels. The system is engineered to leak a small amount to protect ground water quality while still providing a contribution. The undefined relation is the water that does not have to be pumped out of the ground to support the habitats created by the wetlands, the established river channel that the system now provides for and the water
In addition to managing stormwater and reducing flood risks, the constructed wetlands provide benefits such as “ground water recharge; habitat restoration and development; public outreach and education; area-wide vector management; water reuse and availability; carbon footprint offset.”50
Figure 11. Phoenix: Tres Rios Wetland project map.
Beyond the Tres Rios project, the “City of Phoenix Code Review to Promote Green Infrastructure – Case Study” estimates the feasibility of Green Infrastructure, and evaluates what the city has done to promote green infrastructure solutions. City codes, plans, and policies of Phoenix include several existing green
infrastructure initiatives. Among them are “requirements for using drought tolerant plants, progressive stormwater management standards for new development, including the requirement to retain the stormwater runoff from a 100-year, 2-hour duration storm, a stormwater policy that stresses the establishment of natural corridors for multi-use flood control, trails, recreation, and habitat, linking required open space to stormwater management, building code that effectively allows rainwater harvest, and plumbing code that allows
graywater use.”51
Green infrastructure, mostly referred to as LID in a storm water control report in 2012, is incorporated into the city’s regulations for development and construction permits. To reduce pollutant runoff the city uses pervious pavements “for use in the vehicle parking areas and onsite sidewalks”. Additionally, the runoff continued to be “retained on-site by use of shallow landscaped bio-swale areas and a small shallow depression (less than one foot of depth). Through appropriate site selection and use of other LID techniques, the total site runoff to the city’s rights-of-way was decreased from the existing conditions.”52
San Antonio
(1) City Programs: SA2020 (Nonprofit - Public/Private Partnership)
(2) City Departments: Office of Sustainability; San Antonio Water System Department; Department of Public Works; Parks and Recreation Department
(3) Additional Departments: San Antonio River Authority (jurisdiction covers three counties) The city of San Antonio lies in a more arid region in Texas than Houston, and only receives the equivalent combined rainfall of Los Angeles, San Diego and Phoenix per year (Figure 2). Located roughly 140 miles off the Gulf Coast, San Antonio experiences tropical storms with intense
precipitation. The average annual precipitation can vary greatly, ranging between 10 to 50 in/yr.53
The Office of Sustainability in San Antonio focuses on buildings, communities, the environment,
jobs and education, media and outreach, and transportation.54 SA2020 is their comprehensive plan
for improving the sustainability of the city by 2020. In 2012, SA2020 was registered as a nonprofit organization to allow its citizens to work with the government in a community based approach to achieve its goals. The organization focuses on a range of subjects such as culture, community safety, downtown development, environment, economic competitiveness, with 11 indicators to evaluate progress. Neither SA2020 nor the Office of Sustainability explicitly includes Green Infrastructure or stormwater management as a goal or objective. Furthermore, city involvement is minimal for SA2020 because its financial support comes from private rather than public funding.
The San Antonio Water System Department operates an extensive water recycling program that
reuses treated water for irrigation, golf courses, commercial and industrial customers.55 The
Department of Public works also addresses stormwater management issues to minimize runoff from construction and development areas. Contractors and developers have to abide by the regulation
by minimizing stormwater runoff and mitigating its negative effects.56 Neither the Water System
Department nor the Department of Public Works suggests green infrastructure in the city’s short or long term plans as a solution to stormwater management.
The San Antonio River Authority published a technical guidance manual for the city on Low Impact Development. This manual “aids owners, designers, and caretakers in analyzing, planning,
designing, constructing, maintaining, and monitoring LID projects from start to finish.”57 While this
manual effectively helps developers use LID, the city does not require or enforce its standards. This manual, nonetheless, paves the way for more LID projects. The Unified Development Code of San Antonio supports the use of LID and green infrastructure tools; however, this adds review time for developers and lacks a review checklist to simplify the process. The San Antonio River Authority
increase stormwater infiltration rates, and reduce the urban heat island effect. The city also offers tax rebates for energy reductions resulting from commercial and residential customers planting trees on their property. The city recognizes the environmental benefits of planting trees, especially since the city’s tree population has decreased over the last 30 years. Surrounding suburban forests
declined by 22% and medium densely tree canopy decreased by 43% since 1985.60 This loss in
canopy cover has impacted stormwater management as the American Forest Organization discovered:
“Tree loss in the Greater San Antonio Area between 1985 and 2001 resulted in an estimated increase of 73 million cubic feet of stormwater flow during a peak storm event (based on a 2-year, 24-hour storm event). Using a cost estimate of $2/cubic foot to build stormwater systems, this vegetation loss is equivalent in value to a one-time savings of $146 million.”
While the City recognizes the value of tree canopy, emphasis is on energy reduction while stormwater management is simply considered an additional benefit.
San Antonio has existing government and non-profit programs to develop and implement a green infrastructure plan. As part of its development and environment initiatives, the Office of
Sustainability could integrate green infrastructure as a stormwater, flood control, energy, air/water quality, and property value management tool, ultimately saving costs for developers and the city.
Dallas
(1) City Programs: Stormwater Management Plan, ForwardDallas!
Dallas is located in northeast Texas, and is surrounded by lakes such as Lake Ray Hubbard, Mountain Creek Lake, and Lewisville Lake that provide water to over 6 million residents in the greater Dallas metropolitan area. Dallas extends over 300 square miles and receives an average rainfall of over 35 in/yr. The City of Dallas and the Trinity Watershed Department developed a Stormwater Management Plan released in April 2012.
Table 2. Key drainage system metrics for Dallas, TX61
Drainage systems managed by the city Data
Inlets 67,000
Miles of Storm Sewers 1,800
Pressure Sewers 7
Street Pump Stations 9
Miles of Levees 33
Inline Stormwater Interceptors 100
Retention/Detention Ponds & Lakes 200
Drainage outfalls 11,000
Miles of Creeks and Channels 180
Table 2 represents the storm and sewer water infrastructure that Dallas manages within five counties. The stormwater department carries many responsibilities for a storm and sewer system that covers 385 square miles. Dallas’s Stormwater Management Plan includes green infrastructure projects such as retention ponds and lakes, but the diversity of green infrastructure projects is limited with no mention of bio-swales, right-of-way detention areas, vegetated roadside garden, or pervious pavements.
makers have voiced their interests in designing a plan for Dallas’ future. The plan “has been developed by the people of Dallas, who spoke with a strong voice about what they value in their
community and what they want for its future”62
Six key initiatives were identified in the ForwardDallas! plan: (1) enhance the economy, (2) make quality housing more accessible, (3) create strong and healthy neighborhoods, (4) enhance transportation systems, (5) ensure environmental sustainability, and (6) encourage new development patterns. The environmental aspects of the plan focus on air and water quality, including protection of floodplains and riparian areas.63 The plan lists the following goals in their environmental sustainability initiative: To “promote alternative storm water management techniques such as grassy swales, biofilters, eco-roofs, green streets, pervious pavement and other more natural methods”.
Despite the progressive language used in the report, there are no quantitative goals or benchmarks in the document. The Urban Design document within FowardDallas! includes similar initiatives without listing any quantitative goals or timelines that would allow for measuring successes or
failures of the plan.64 The monitoring component of ForwardDallas! provides basic background on
the quantitative assessment as it states “once a specific action has been taken, such as establishing an action plan for a certain area, performance monitoring will assess whether
improvements are taking place. In order for performance monitoring to work, the City must establish
benchmarks on what each activity aims to achieve”.65
The city designed visualizations, maps and possible city programs to enhance green infrastructure. The plan for improving the Trinity River Corridor includes expanding tree canopy, meadows,
wetlands, trails, and levees along the river to increase resiliency and water infiltration (Figure 12).
The Agrilife Research and Extension Center illustrated progress in individual and institutional work
in Dallas in a recent case study.62 On the campus of the Research and Extension Center,
undergraduate and Ph.D. students implemented several green infrastructure projects in retaining and cleaning stormwater runoff in 2011. They achieved 70% percent reductions in runoff volume, in
addition to 68% and 97%reductions in pollutants.66
Dallas recognizes the value of green infrastructure, and ForwardDallas! exemplifies a stepping stone to mitigate urban and stormwater runoff, yet measurable and traceable steps to achieve such goals are still required. Integration of the evaluation tools from the Agrilife case study could help define successful green infrastructure projects that quantify runoff volume and pollutant reduction.
San Diego
(1) City Programs: Climate Protection Action Plan; Think Blue Program (2) City Departments: Transportation Department; Storm Water Department
One might think that cities with relatively low annual precipitation, such as San Diego (~10 in/yr), have less stormwater pollution and contamination. However, There have been cases where public
beaches are closed for up to several months due to contaminated runoff.67 Similar to five other
cities in this report, San Diego does not have a combined sewer system. Its sanitary sewer system and stormwater system run separately. Stormwater collected from the streets, buildings, and gutters runs directly into the ocean and other surface water bodies untreated. Contaminants, debris, trash, and chemicals collect on impervious surfaces and increase over time during dry periods. The necessity to mitigate storm and urban runoff is apparent even in a city such as San Diego with relatively low precipitation.
San Diego has implemented several programs to reduce the negative impacts of contaminated runoff. The Climate Protection Action Plan strives to make the city more resilient and robust against the impacts of climate change. The water related sections of the plan address water consumption, wastewater treatment and reuse. While stormwater management does not play a direct role in the Climate Protection Action Plan, the city recognizes the threats of climate change and values more sustainable operations.
San Diego’s Transportation and Storm Water Department focuses primarily on urban runoff
mitigation and reducing Total Maximum Daily Loads (TMDL) of effluents that run into the bay, river and ocean. Through their Think Blue program the department educates and engages the public by attending community events and meetings. Think Blue’s Public Information Officer, Lana Findlay, explained further that they “conduct workshops and presentations, sponsor events, outreach to schools, and utilize [their] website, social media and advertising (TV, Radio, newspapers) to reach
San Diegans with messages about pollution prevention.”68 Furthermore, Green Infrastructure, Low
Impact Development and Best Management Practices also play a part in their outreach and education. Findlay spoke about the first successfully constructed green street on Mt Abernathy, which will be followed by other projects. Think Blue informs developers and contractors of the best methods to manage runoff. Think Blue illustrate the benefits of LID/ BMPs through display events, and Findlay hopes, “the display will have take-away cards describing 9 LID BMPs in detail and will offer a physical and digital map of locations within the city where developers/contractors/architects can see real life examples of these structures after they have been built.”
As part of a larger pilot project for Think Blue, this effective stormwater runoff mitigation project was constructed on the corner of Logan Avenue and San Pasqual Street in San Diego (Figure 13).
Figure 13. Street corner bioretential basin project in San Diego, CA.
As Figure 13 illustrates, the green infrastructure tools utilized in this project include swales, planters, catch basins and an inlet to the Chollas Creek. Rerouting the runoff from the roads into the basin reduces the amount of accumulated pollutants on impervious surfaces.
With effective planning, implementation, and monitoring, these pilot projects will pave the way for additional GI developments. Another bioretential basin pilot project yielded a reduction in pollutants of 86%-87%(Table 3).
Table 3. Table of anticipated load reductions from a bioretention basin at 43rd Street and Logan Avenue, San Diego, CA.
Overall, San Diego recognizes the inherent value in green infrastructure projects, and with the help of Think Blue, the city is expanding its storm and urban runoff programs in an environmental and sustainable fashion. Another example of a pilot project is an infiltration project close to a beach
Figure 14. Kellogg Park parking lot with green infrastructure vegetated separators, San Diego, CA. The planning
document shows rows of parking space with vegetated separators and outlining used to detain, slow and retain a majority of the runoff. This is just one of many examples of how San Diego incorporates Green Infrastructure in their city planning.
69
San Jose
Located on the southern end of the San Francisco Bay, San Jose is home to many of the most innovative, entrepreneurial companies in the United States. With the expansion of the technology industry, San Jose has grown to be the tenth largest city in the US. In 2007, San Jose adopted a 15-year sustainability plan called Green Vision. While green infrastructure is not explicitly listed as one of its ten main goals, tree canopy or green building space, for example, can be considered as contributors to stormwater control. Overall, San Jose receives just a few more inches of rain per year than Los Angeles. Low annual precipitation might be a reason why water quality and storm water runoff is not listed as one of Green Vision’s top 10 goals. Figure 15 illustrates Green Vision’s ten goals and the city’s progress since 2007.
Figure 15. Green Vision agenda items and progress data for San Jose, CA.70
Figure 15 lists Green Vision’s goals and the corresponding progress for each goal. San Jose’s
strategy in measuring and assessing development allow managers to make business cases, track successes and failures, and manage more efficiently.
The EPA conducted a green infrastructure case study on several cities including San Jose and identified several interesting developments. San Jose approaches storm water from a project development and construction perspective. Contractors in San Jose must meet several stormwater criteria such as source and treatment control measures to receive a construction permit. The EPA identified that “developers are encouraged to minimize impervious surface to reduce the generation of stormwater runoff, and to treat any runoff generated with vegetative swales, biofilters or other landscape-based infiltration features”.71
treat runoff on site may be designated ‘water quality benefit projects,’ and are not required to contribute to regional or off-site treatment”72. Developers have become increasingly creative in designing their projects to have less than 10,000 square feet of impervious surfaces, which is the benchmark that the city set to be exempt from Urban Runoff Management laws. The success can be measured by the fact that “planning staff generally review over 300 plans per year, and around 90 percent of these projects are able to reduce their total imperviousness below the 10,000 square foot threshold”.
The 2012-2013 Stormwater Annual Report names a few green street pilot projects, one of which “will replace three blocks of deteriorated asphalt and bare soil with ‘green’ concrete and a band of permeable pavers draining directly to underground infiltration trenches and wells.”73 A second pilot
project “will install bioretention rain gardens along a one-half mile stretch.” To address water quality problems specifically, including discharge of toxic pollutants, the Environmental Services
Department highlights the benefits of vegetation in parks and gardens. Specifically, nitrogen and other pesticide toxins are targeted in the plan and the city “tested a landscape maintenance work plan for creating a model pesticide-free park.” While not directly related to stormwater volume control, reduction of pesticides and nitrogen in parks reduces contaminant loading in runoff, which is a component of stormwater management and exemplifies progressive thinking by the city. Much of San Jose’s stormwater management tactic lies in reusing and recycling water. The system in charge of recycling water covers three cities (Milpitas, Santa Clara and San Jose) and consists of 130 miles of distribution pipelines and recycles roughly 10.6 million gallons a day.74 Green Vision
includes a goal of increasing recycling water users (Figure 16) and delivering more recycled water to the customers (Figure 17).75
Figure 17. Average daily recycled water use (2007-2012) and target for 2022 in San Jose, CA.
Figures 16 and 17 highlight the ambitious goals of city planners. Such metrics allow managers to
track progress of long term goals. The city actively works with industry, commerce and residents to prevent waste water from going down stormwater drains. Separating waste water and stormwater allows for proper treatment and recycling of non-hazardous, reusable water.
In addition to LID requirements and incentives for developers and construction, rain water harvesting becomes an increasingly relevant tool for San Jose in reducing pollutant runoff. The Stormwater Handbook for San Jose includes application requirements for rainwater harvesting project proposals. Developers can choose rainwater harvesting as an LID tool in their strategy.76
Washington DC
The United States’ capitol, home to federal policy makers, recently moved from its moderate stance on sustainability and green infrastructure to an ambitious frontrunner in creating a greener city. In 2011 the mayor announced the Sustainable DC plan and officially signed the document into law in 2013. The plan focuses on the built environment, energy, food, nature, transportation, waste and water.
Washington DC discharges 2-3 billion gallons during CSO events into the Anacostia River per year. To help contextualize this information, we compare three cities with relatively similar precipitation averages (Figures 18 and 19). Total volume of CSO is considered with respect to city area and population.
Figure 18. Combined sewer overflow per sq. mile in Washington D.C., New York, and Philadelphia.
Figure 19. CSO volume per capita in Washington D.C., New York, and Philadelphia.
- 20,000 40,000 60,000 80,000 100,000 120,000 140,000
Washington D.C. New York Philadelphia
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0 2000 4000 6000 8000 10000 12000Washington D.C. New York Philadelphia
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The Sustainable DC plan focuses explicitly on stormwater runoff and water quality issues, and quantifies specific goals (Table 4). The first two goals in the water category of the Sustainable DC plan are to make “100% of District waterways fishable and swimmable, and to use 75% of the
landscape to capture rainwater for filtration or reuse”77 by 2032. These goals are more forward
looking and ambitious than any other city with combined sewer systems assessed in this report. The third goal in the document is to decrease total water use by 40%, decreasing demands for potable water and increasing rainwater reuse.
Table 4. Key water related goals in the Sustainable DC Plan for Washington DC.78
Goal 1 Improve the quality of waterways to standards suitable for fishing and swimming
1.1 Field test innovative technologies to improve river water quality. 1.2 Restrict the use of cosmetic pesticides and chemical fertilizers. 1.3 Restrict the use of harmful salts on roads in winter
1.4 Study the feasibility of implementing nutrient and water quality trading programs.
Goal 2 Relieve pressure on stormwater infrastructure and reduce long-‐term flood risk.
2.1 Install 2 million new square feet of green roofs. Medium DDOE Community
2.2 Increase the use of green infrastructure along public rights of way. Short DDOT DDOE, DC Water 2.3 Double the number of homes participating in the RiverSmart Homes program. Medium DDOE 2.4 Build 25 miles of green alleys. Long DDOT DDOE, PEPCO
2.5 Establish pervious surface minimums for targeted zoning districts.
Goal 3 Reduce demands for potable water and increase rainwater reuse
3.1 Update water-‐efficiency standards in District building codes. Short DCRA DDOE
3.2 Revise building codes to allow the use of alternative water systems. Short DCRA DGS, DDOE 3.3 Expand use of neighborhood-‐scale water collection networks. Long DDOE OP
3.4 Develop incentives for water-‐efficiency measures in landscaping and building design. Long DDOE 3.5 Expand the use of water monitoring technologies.
Table 4 summarizes the water related goals and initiatives Washington DC currently plans to implement. One trend is clear: very few goals have concrete quantitative measures or benchmarks. In the table above only two measures offer traceable metrics: “Build 25 miles of green alleys” and
