In the aftermath of Hurricane Harvey, the Environmental Protection Agency reported that 13 of the 41 federal Superfund sites in Texas had flooded. The Texas Commission on Environmental Quality lists 26 federal and state Superfund sites in Harris County. Houston is the county seat.

View the PDF version of this map for more detail and a key.

Source: The Place Database, www.lincolninst.edu/research-data/data/place-database

Late last August, Hurricane Harvey swept through Texas, causing widespread flooding and destruction when it stalled over the Houston metropolitan region, dumping over 50 inches of rain in four days. Harvey paralyzed Houston, the nation’s fourth-largest city and a global center for the oil industry, and it tested the resilience of a state that’s home to nearly one in twelve U.S. workers. As Houston recovers and faces the next hurricane season, preparing for inevitable and potentially more devastating storms is highly stressful for urban planners, public officials, business leaders, and others who live and work there. Having been slammed with three 500-year floods in the past three years, the region is reconsidering its “build and let build” attitude. Harvey has occasioned a rethink—though not a complete redo—regarding urban planning and development.

Nicknamed the “Bayou City,” Houston is naturally flood-prone. But critics say the region’s longtime approach to urban planning (read: the lack of it) has resulted in zone-free development, low-density urban sprawl, and weak regulations that have led to or exacerbated destructive flooding. Many are calling for resilience planning that takes a regionwide, long-term, and greener approach to land planning, urban development, and storm water management.

Houston’s city and county officials are pivoting to stricter regulations on building new homes in floodplains, and considering a wide range of flood mitigation strategies, infrastructure needs, and development changes. These include creating new flood barrier and detention facilities, rehabilitating urban drainage systems, buying out more homes in flood-prone areas, and creating green infrastructure. An important test of resilience-building will be how well the region can communicate and collaborate on these strategies.

“Harvey was a wake-up call that it might be time to revisit the sins of the past,” said Houston Director of Planning and Development Patrick Walsh, who presented a summary of Harvey’s impacts at the Lincoln Institute’s 2017 Big City Planning Directors Institute last October. Walsh has been involved in several aspects of post-Harvey planning. “There’s a broad consensus from the community and from developers and builders that we need to do better, that we’re all in this together. We need a resilient city.” Houston has recovered reasonably well in the short term, said the Houston native, “but many people are still suffering.” A new way of operating may be needed, he added, “if we want to continue to attract talented people and businesses to the city.”

(Not So) Equal Opportunity Disaster

Houston has a long history of flooding from tropical storms. Hurricanes in the 1920s and 1930s caused catastrophic floods that killed thousands. Tropical Storm Allison triggered mass flooding and caused 20 Texas deaths in 2001. Harvey came on the heels of the Memorial Day Flood of 2015 and the Tax Day Flood of April 2016. But Harvey was exponentially bigger, causing flooding in about one-third of the Houston metro region, including highways, waste-water treatment plants, and City Hall in downtown Houston. Half of the homes and businesses that were flooded by Harvey had not flooded previously, while many others flooded for the third time in three years. Harvey caused 68 deaths and $125 billion in damages in Texas, according to the National Hurricane Center’s official report, which noted that it was the most significant tropical cyclone rainfall event in U.S. history, both in scope and peak rainfall amounts, since reliable rainfall records began in the 1880s. In the Houston area, Harvey damaged an estimated 300,000 housing units and displaced more than 1 million people, forcing some 42,000 of them to seek emergency shelter. The storm left 200 million cubic yards of debris.

With climate change, rising ocean temperatures have fueled more frequent and more intense storms and higher sea levels, increasing the risk of flooding. Harvey could have caused an even greater catastrophe. A storm surge from the Gulf of Mexico could have destroyed oil refineries and sent toxic floodwaters up the Houston Ship Channel to the Houston region. That threat remains, and many say Houston cannot rely on past data to predict future storms.

Harvey slammed the region’s economy and quality of life. Before the storm—spurred by jobs in oil and gas, tech, healthcare, and other industries, as well as relatively cheap and plentiful housing—Houston was considered an affordable region. Its median July 2017 home price of $230,000 compared to a national median of $293,400, according to Redfin. Housing supply declined and costs jumped in the months following Harvey as residents competed to resettle in neighborhoods that weren’t flooded. Roughly 80 percent of Harris County homeowners lacked flood insurance; many weren’t located in areas designated as flood-prone. Prospects for renovating or rebuilding damaged homes, and the availability and cost of flood insurance, remain uncertain. Recipients of post-Harvey federal disaster assistance will have to purchase flood insurance, the New York Times reported.

While homes in the region’s high-, middle-, and low-income neighborhoods alike were affected, many regional leaders note the impacts on middle- and lower-income households have been much greater, considering these households have fewer resources to rebound from flood damages, lost wages, lost jobs, and the lost fabric of community. National media reported on problems faced by renters in poorer neighborhoods near petrochemical plants and other industrial areas, including high levels of toxins in the floodwater and air, and lack of resources for storm preparedness, response, and recovery. Many renters could not pay for proper home clean-up or find alternative housing.

As of early December, the budget-strapped Federal Emergency Management Agency (FEMA), facing clean-ups from multiple climate-related disasters, had promised $160 billion in post-Harvey aid for Houston, in addition to funds for individual recovery assistance and debris pickup. The federal funds are only a fraction of what’s needed to recover and plan for resilience. The Houston Chronicle noted the state legislature won’t reconvene until 2019, but lawmakers will be asked to consider a range of proposals, such as increasing local governments’ ability to bar development in certain areas, changing the operational guidelines of reservoirs, and mandating disclosure of flood risk for new home buyers or renters. Meanwhile, officials in Houston’s Harris County are considering a bond referendum to finance more than $1 billion in flood control projects.

Magnified Flood Risks

Houston is often criticized for its lack of zoning: It’s the only major U.S. city without a zoning code to help determine land-use planning and development rules. While urban planning alone can’t prevent a disaster like Harvey, critics have said that zoning, along with careful land-use planning and stricter development regulations, could have prevented much of the destruction (figure 1).

Planning and Development Director Walsh maintains that zoning would not have made the city less flood-prone. “It’s time that we dispel the myth of zoning,” he said. “If we were a zoned city, we would have been a zoned, flooded city with Harvey. Any zoned city that is flat like ours would have flooded.” He said the city’s “tremendous amount” of development regulation such as setbacks, parking, and landscape requirements, plus a market-driven approach, determine how and where development occurs. “We look a lot like a zoned city. We have commercial development along major thoroughfares and neighborhoods tucked away on smaller streets,” he said.

According to Walsh, other factors contributed to Harvey’s impact, including the storm’s extreme rainfall, the region’s clay soils, which don’t absorb water well, its aging and inadequate storm water infrastructure, and a “significant amount of low-density sprawl” in the surrounding county.

Walsh noted that Houston drains from west to east and that intensive growth on the western periphery has increased the volume of runoff flowing through the city. “Altering this growth pattern will be difficult, but we should be considering options like protecting the Katy Prairie,” he said, referring to the shrinking remnant of the vast prairie and wetlands west of Houston.

About 20 miles west of downtown, thousands of homes that flooded for the first time had been developed decades ago inside the “dry” basins of the Addicks and Barker reservoirs. The U.S. Army Corps constructed the basins in the 1940s to control the flow of water along Buffalo Bayou and prevent downtown flooding. Because FEMA maps didn’t place these basins in the 100-year floodplain, mortgage companies did not require flood insurance, and prospective home buyers had not been informed of the risks. Concerned that the reservoirs would fail during Harvey, the Corps allowed a controlled release of water from the dams into the bayou, inundating downstream areas, including downtown.

Unchecked development has heightened flood risks regionwide, according to hydrologists, environmental engineers, and federal officials interviewed in 2016 by the Texas Tribune and ProPublica. At an elevation of about 50 feet above sea level, the region is drained by 22 watersheds in which storm water flows west to east in a network of bayous and drainage channels that empty into the Houston Ship Channel. Once a great expanse of prairie, wetlands, and woods that were better able to absorb rainwater, much of the area is now covered with low-density development.

A city of 2.2 million people, Houston spans 627 square miles. It lies within 1,777-square-mile Harris County, which has nearly 4.6 million residents, according to 2016 U.S. Census estimates. The vast metro region has a population of 6.8 million people and, at 9,000 square miles, is equivalent in size to New Jersey. Since 2000, over 80 percent of Harris County’s nearly 1 million new residents have moved into unincorporated areas, connected by thousands of square miles of paved streets, parking lots, and over 360,000 new buildings, according to the Houston Chronicle. Development has increased storm water runoff, and during Harvey, the record amount of rainfall caused storm water, mixed with toxic chemicals and sewage, to rise to new heights and spread out, inundating areas previously not considered vulnerable to flooding.

“Cities that have a strong planning culture, including general plans and a tool kit of policies they use as part of everyday practice—with disaster plans, natural hazard mitigation plans, and zoning that reflects risk—tend to do better,” said Laurie Johnson, a Bay Area planning consultant who specializes in catastrophe risk modeling, and coauthor of After Great Disasters, published by the Lincoln Institute. Johnson, lead author of a recovery plan for New Orleans after Hurricane Katrina, said that one of the biggest tests for Houston is whether the city and county can work together effectively.

Resilience Efforts

In October 2017, Harris County officials released a 15-point plan calling for strategies such as a regional flood control organization to coordinate water management across county lines, and tougher regulations on development in flood-prone areas. The plan also proposed buying out all homes that are located in the 100-year floodplain or that have flooded repeatedly, an expansion of an existing county buyout program that could cost billions.

The City of Houston has begun to define its own strategies. “We’re now focusing on recovery and looking at long-term resilience,” said Stephen Costello, a former city council member and an engineer with 40 years of storm water management experience who was appointed the city’s chief resilience officer in 2016 by Houston Mayor Sylvester Turner. Costello said Houston does not have a resiliency plan per se, and that his role is “to open the discussion, and hopefully the regulatory issues.” He organized and led the city’s redevelopment and drainage task force, which issued a report in February addressing rules on detention for redevelopment, placement of fill dirt in floodplains, and protection of the city’s rights of way that obstruct drainage flow.

In September 2017, Mayor Turner appointed former Shell Oil Co. Chairman and President Marvin Odum as Houston’s chief recovery officer. Odum led Shell’s business recovery after Hurricane Katrina. He is charged with expediting disaster recovery and preparing the city for the next record-breaking storm. The resilience and recovery officers report to the mayor, who brings policy recommendations to the 16-member elected city council for a vote.

The city and county collaborate through a storm water management joint task force and with the Harris County Flood Control District (HCFCD), a nonregulatory special district that develops storm water management plans and builds and maintains flood control infrastructure. The county’s five elected officials determine regulations for unincorporated areas. Each of the county’s 34 municipalities has its own criteria for drainage systems, including storm water detention storage. HCFCD, among others, has asked for a “big-picture regional planning effort,” said Rob Lazaro, communications officer. Costello said he doesn’t favor a regional flood mitigation authority. “Rather than creating an overlapping entity, we need intergovernmental agreements.”

Houston is considering building a coastal barrier of dunes and gates to provide storm-surge protection for the region’s vulnerable oil refineries and shipping channel. Construction of the system could cost $10 billion. Harris County has supported the concept, which was also included in a request for FEMA funding.

Development Regulations

David Hightower, executive vice president of Midway Companies, a Houston-based developer, is a member of the city’s redevelopment and drainage task force. He said solutions may “require some out-of-the-box thinking, which is a challenge when you’re dealing with bureaucrats managing over 600 square miles.” Developers would consider “reasonable, equitable, fairly applied” rules, but they object when people blame development such as strip malls for flooding, “when factors like aging and inadequate drainage infrastructure” are really to blame, Hightower asserted.

Hightower, also a member of a Harris County flood mitigation committee, said 2009 county drainage regulations proved effective. The county analyzed where and how Harvey flooded homes in its unincorporated areas, he said, and found that only 467 built after 2009 were flooded.

“It’s the areas that are much older, like Meyerland, developed in the 1960s and located mostly within the city limits, that got hit really hard,” said Hightower. In Meyerland, an upscale enclave of 2,000 homes located west of downtown Houston along Brays Bayou, some homes have flooded three years in a row. Many homeowners say these older homes have flooded because of newer upstream development, and they want buyouts.

Planning consultant Johnson said risk modeling can show scenarios that link development with flooding risk. “You can show if you put a house here, that impervious surface will affect the system in a certain way.” Three years of 500-year storms in Houston “shows that the past is no longer a good indicator of the future,” she said. “What is lacking is a common understanding of the future risk, and that’s the challenge right now with a changing climate. As modelers, we have to add in the range of possibilities, the uncertainty.”

Houston is using climate modeling to predict future flooding impacts, according to Walsh. Post-Harvey, Harris County is requiring that all new buildings on unincorporated land be raised at least 24 inches above the flood plain. The first finished floor of new construction must be at least as high as the 500-year flood level. New houses in the floodplain must be built on piers and cannot use fill dirt to elevate construction. The regulations received wide support from the Greater Houston Builders Association, Houston Real Estate Council, American Council of Engineering Companies of Houston, Houston Apartment Association, and the Houston chapter of the American Institute of Architects.

“These regulations apply in 100-year, 500-year, and outside of 500-year floodplains,” said Christof Speiler, vice president and director of planning for Houston’s Huitt-Zollars architecture and urban planning firm and project manager for the Greater Houston Flood Mitigation Consortium. “These are very fundamental changes that have a very real impact on new development.”

The regulations apply only in unincorporated areas of the county, however, and Houston and other municipalities make their own regulations, Speiler noted. It is unlikley that new regulations will stop homes from flooding in older developed areas, however, because “a very large portion of the city is legacy building stock, which preceded any flood regulations at all.”

Walsh agrees that many homes were built in places where they never should have been, such as along the bayous. Four out of five structures in the city’s official floodplain areas were built before stricter regulations were adopted in 1981, he said. “For decades, we have allowed development in the floodplain, but we’ve had to build it higher.” Current city regulations require new or rebuilt homes to be raised one foot above the 100-year FEMA floodplain elevation; as a result, in some neighborhoods, ground-level homes that were flooded by Harvey sit side-by-side with elevated homes that were not.

In January, Mayor Turner proposed new development regulations that would require all new buildings to be raised two feet above the projected flood level, noting that Houston could not call for more state and federal flood and resilience funding “without showing that we are moving urgently at the local level to find solutions for ourselves.”

Floodplain and Detention Mitigation

Detention is Houston’s main method of flood control, but lack of available land limits the city’s ability to build large detention infrastructure that could handle Harvey-like flooding. HCFCD manages about 15,700 acres of storm water reservoirs across a 1.1 million-acre area. In the past year, HCFCD invested over $100 million in capital improvement projects to repair detention basins and widen and deepen channels along the county’s major bayous. The state plans to pay for a third reservoir to better protect areas west of Houston and to avoid the kinds of releases from Addicks and Barker dams that swamped Houston during Harvey. A systemwide upgrade to protect the region fully from a 100-year storm would require an estimated 52,000 additional detention acres, but the cost of acquiring that land exceeds HCFCD’s annual budget several times over.

Mayor Turner in January proposed new detention rules based on the recommendations of the redevelopment and detention task force.Under current measures, only new development is required to manage storm water runoff from rooftops, parking lots, and other impervious surfaces by means of detention. The task force advised closing this loophole, so that a developer intending to build a skyscraper on a parking lot would now have to provide detention to support effective drainage. Another new rule would require those redeveloping lots under 15,000 square feet to pay a fee in lieu of providing detention. Proposed changes also would provide detention credit for low-impact development options like green swales—typically planted, shallow basins designed to absorb and filter runoff.

Much of the city’s detention and drainage infrastructure dates from the 1940s and ’50s. A January 2017 report from Houston’s Storm Water Maintenance Branch said certain areas developed before 1985 were prone to flooding because of “inadequate and undersized infrastructure.” The city spends over $250 million per year on street and drainage infrastructure, and its public works department estimated it would cost $650 million annually to rebuild and maintain decaying storm water infrastructure to reduce flood threats along the city’s bayous, remove properties from the floodplain, replace storm sewer and outfall pipes, regrade ditches, and accomplish other upgrades.

The city faces other big decisions. Harvey flooded 18 of the city’s 39 waste water treatment plants, eight of which were completely inundated, said Costello. Does the city retrofit and design protection for inundated plants, or does it relocate them to other sites? Does it consolidate the waste water treatment system at an estimated cost of $10 billion?

New Mapping Needed

Walsh said the city adopted more stringent floodplain mitigation regulations after FEMA reissued maps for Harris County in 2007. Homes built after 2007 are generally elevated and protected from floods. In neighborhoods that were flooded by Harvey, many homes that were not elevated had their first floor flooded. New maps would help regulate floodplain development and facilitate other resilience efforts, he said.

FEMA maps floodplains and flood levels by modeling how water spills out of creeks, bayous, and ditches during storms and by projecting where and how high the water would rise. In Harris County, a “100-year event” equates to between 12 and 14 inches of rainfall within 24 hours, and a “500-year event” produces between 17 and 20 inches of rainfall within 24 hours. Initial post-Harvey National Oceanic and Atmospheric Administration estimates for Houston increased the 100-year-event level to 18 inches of rainfall within a 24-hour period. Data show that Harvey was at least a 500-year event across the county and in some areas rose above a 1,000-year storm level.

Costello noted, however, that remapping might come too late, at too high a cost, and with too little effect. “Even if we were to decide to remap, it would take a couple years for regulations to change,” he said.

Buyouts

A post-Harvey report from Rice University’s Baker Institute of Public Policy, recommended a home buyout and removal program, noting that many homes had flooded three or more times since Tropical Storm Allison.

Although buyouts involve an initial public investment and remove properties from tax rolls, they mitigate flood-risk and reduce the cost of repeated damage to property and infrastructure while bolstering communities’ resilience (Freudenberg et al. 2016).

Since 1985, the HCFCD’s voluntary buyout program has purchased more than 3,000 properties; over 1,060 acres have been restored as natural floodplain. By November 2017, the county had received over 3,000 requests for buyouts related just to Harvey, and in February HCFCD notified the state it would request $180 million for home buyouts. Countywide, over 100,000 homes and other buildings currently sit within 100-year floodplains along 2,500 miles of waterways, said HCFCD.

Advocates say more buyouts would have a host of resiliency benefits: They would relocate people out of harm’s way and eliminate future flood damages and health and safety risks, reduce repetitive subsidized flood insurance payments and federal disaster assistance, and allow for restoration of the floodplain to its natural function for storm water storage and release.

On the other hand, a larger scale buyout program could cost billions and have other downsides. “In a lot of very established subdivisions, people like their homes and schools, and you’d damage the fabric of the community,” said Walsh. “How aggressive should a buyout program be? Do you take the first row of houses backing up from the bayou? Do you take the first three rows? We have limited resources. It’s a difficult policy question.”

Green Infrastructure

A regional planning strategy focused on natural infrastructure like wetlands would provide “shock protection” from climate-related floods and store and slowly release floodwaters, said Forster Ndubisi, professor of landscape architecture and urban planning at Texas A&M, senior fellow with its Hazard Reduction Recovery Center, and contributor to Lincoln Institute’s Nature and Cities. The city and county could provide flood protection and amenities like parks and trails by buying and removing homes in certain neighborhoods and redeveloping bayou riparian zones with detention ponds and native vegetation, he said. “It’s a proactive plan, and it’s so much cheaper” than engineered solutions.

The Houston region has already begun to create detention basins and bayous that double as parks. On the Sims Bayou, HCFCD and the Army Corps built two regional storm water detention basins and planted trees and shrubs along the channel banks. “Sims was the only bayou that didn’t overflow its banks during Harvey,” noted HCFCD’s Lazaro. In a $480 million project with the Corps, HCFCD is building four detention ponds and widening and deepening a 21-mile stretch of the Bray’s Bayou channel, which they will plant with native vegetation. The Houston Parks Board and the city’s Parks and Recreation Department, collaborating with HCFCD, are developing the Bayou Greenways 2020 project, a 150-mile greenways trail system that provides drainage, transportation, and recreation along eight bayous. A voter-approved bond referendum is funding $100 million of the $220 million project.

In downtown Houston, a 2.3-mile stretch of Buffalo Bayou Park—part of a $58 million public-private project led by the Buffalo Bayou Partnership, the city, and HCFCD—included restoration of the banks with reinforced infrastructure and a riparian landscape, walking trails, boat launches, and picnic areas. During Harvey, when water from the Addicks and Barker dams was released into the bayou, the flood level reached as high as 25 vertical feet, said Scott McCready, senior project designer and principal of SWA Group in Houston. The deluge left 8-foot piles of sand, but compared to engineered bayou channels, he said, the park worked as intended, detaining and slowly releasing floodwaters.

Houston region officials may also use golf courses as storm water detention basins. The metro area has more than 200 golf courses, which are generally easier and cheaper to redevelop for flood control purposes than areas with construction. Clear Lake City, a master-planned community 23 miles southeast of downtown Houston, had a history of flooding, and in 2011 the city’s water authority acquired a former golf course for detention purposes. A nonprofit organization is now developing a detention and open-space park, Exploration Green, with contoured basins, wetland preserves, and miles of trails that can survive flooding. It passed its first trial during Harvey by saving 150 homes from flooding. When completed, it will manage up to one-half-billion gallons of storm water and protect up to 3,000 homes, according to the Texas Tribune.

Focus and Accelerate

“There is a larger conversation that needs to happen,” said Speiler. “What is resiliency for the region?” He said many local efforts “seem to be the right things, but we just haven’t done enough of them.” Some changes may be required to retrofit infrastructure for older developed sections of Houston and protect natural habitat upstream. But generally, he said, “it isn’t so much that we need to change, but rather that we need to focus and accelerate what we’re doing.”

Many say Houston is not likely to enact a zoning code as a resilience measure, nor is a prohibition or even a moratorium on development in floodplains likely. But Walsh said Houston is taking a more thoughtful approach. He said city and county officials are considering a resilience plan and making decisions with resilience in mind. City council, for example, is looking more carefully at infrastructure and development-related decisions they used to approve routinely. “They’ve shown they’re concerned about development in flood-prone areas,” he said, “even something like a MUD [municipal utility district].”

Ultimately, Walsh said, Houston’s long-term concern is “keeping the focus on resiliency—that’s the political challenge when the skies are blue.”

Kathleen McCormick, principal of Fountainhead Communications in Boulder, Colorado, writes frequently about healthy, sustainable, and resilient communities.

Photograph: Maribel Amador/SWA

References

Blake, Eric S. and David A. Zelinsky. 2017. “National Hurricane Center Tropical Cyclone Report, Hurricane Harvey.” (AL092017). August 17–September 1. National Hurricane Center.

City of Houston. 2018. “Final Report Redevelopment and Drainage Task Force.” February 6. http://www.houstontx.gov/council/g/Final-Report-Redev-Drainage.pdf.

Freudenberg, Robert, Ellis Calvin, Laura Tolkoff, and Dare Brawley. 2016. Buy-In for Buyouts: The Case for Managed Retreat from Flood Zones. Policy Focus Report. Cambridge, MA: Lincoln Institute of Land Policy. 

Ndubisi, Forster. 2016. “Adaptation and Regeneration: A Pathway to New Urban Places.” In Nature and Cities: The Ecological Imperative in Urban Design and Planning, ed. Frederick R. Steiner, George F. Thompson, and Armando Carbonell, 191–211. Cambridge, MA: Lincoln Institute of Land Policy.

A 2012 United States Forest Service Study of urban tree cover estimated that American cities were losing around four million trees per year. Worldwide, agriculture, logging, and other factors eliminate 18.7 million acres of forest annually, according to the World Wildlife Fund. Yet the cost of that loss is hard to quantify. It’s widely recognized that plants absorb carbon dioxide, helping to mitigate the effects of climate change, but city planners could benefit from a more precise, data-driven assessment of the urban canopy’s value to guide how trees and other vegetation can most sensibly figure in the design and planning of the contemporary city.

After all, that’s how we evaluate and install gray infrastructure, counting every light pole and parking lot to help us think about how these elements work in a city’s design. Historically, we haven’t been as thoughtful or demanding about quantifying, and thus managing, green infrastructure, according to David Nowak, a senior scientist with the U.S. Forest Service.

As a rule, cities compile and track the details of the built infrastructure, but not trees. This makes it harder to plan for, or even debate, the various potential impacts of maintaining, increasing, or reducing urban vegetation.

But that has been changing. Nowak leads a pioneering effort in the form of a Forest Service project called i-Tree, a suite of Web tools drawing in part on geographic information system (GIS) data. I-Tree combines satellite imagery and other data to help citizens, researchers, and officials understand urban canopies and other green infrastructure elements, often in economic terms.

For example, an i-Tree analysis of Austin, Texas, found that trees save the city about $19 million a year in residential energy use, $11.6 million in carbon capture, and almost $3 million in pollution removal. The city’s arboreal infrastructure produces oxygen and consumes carbon dioxide, for instance, adding up to a reduction in carbon emissions that i-Tree values at $5 million annually. Other tree payoffs—some quantified, others not—include absorbing ultraviolet radiation, helping absorb rainwater, and reducing noise pollution.

In another i-Tree analysis, conducted in 2017, researchers in the United States and Italy concluded that, worldwide, cities with populations over 10 million realize median annual savings of $505 million from reduced air pollution, mitigated “heat island” effects, and other benefits derived from their urban canopies.

This type of analysis can help cities deploy green resources for maximum impact and understand the tradeoffs involved in many planning decisions. Clearing trees to make way for a parking lot entails a loss, not just the gain associated with increased parking, Nowak noted.

In the past, trees were more likely a concern for the parks or forestry department. Increasingly, they’re central to cities’ responses to climate change. “I can tell you definitively that cities and towns across the nation are very interested in figuring out, whether or not you can talk about climate change politically, ‘What exactly are we going to do about it today?’,” said Jim Levitt, associate director of land conservation programs at the Lincoln Institute, and director of conservation innovation at the Harvard Forest. That’s true from New England to Miami to Newport News, Virginia, and Phoenix, he added, even if the specific reasons vary, whether flood issues, heat island effects, or others.

Recent arboreal infrastructure-related technology responds directly to this city-level interest. In late 2016, MIT’s Senseable City Lab, in collaboration with the World Economic Forum, launched a tool called Treepedia and has since published analyses of tree coverage in 27 cities around the world. In an interesting twist, it draws not on the satellite data behind many GIS projects, but on imagery culled from Google Street View. It offers a different skew on tree data, since, for example, it underrepresents large urban parks. But this is by design. The tool’s creators believe that detailing the “street greenery” citizens actually experience can inform the planning process. The lab will continue to add cities and has a backlog of requests from municipalities, academics, and others, according to Carlo Ratti, director of the MIT Senseable City Lab and founder of the design firm Carlo Ratti Associati.

“Cities are trying to acquire better information and understand the current state of the urban canopy,” Ratti said. “Most of them do not have the resources to manually survey the entire city. Treepedia data can give them a solid baseline” and focus efforts where they may be needed most. “Others, like planners and designers, find it useful as a proxy for measuring the perception of green space and trees by citizens,” he said, because it captures a kind of shared perspective “from the ground.” The lab will soon release an open-source version of its software to let cities, nongovernmental organizations, and community groups compile their own data. The hope is that NGOs and local groups will use Treepedia “as a tool to both determine where planting is needed and lobby their local governments with evidence-based campaigns,” Ratti explained.

This is consistent with a broader interest among citizens and planners in green city initiatives, including high-profile projects from New York to Atlanta and beyond. Nowak, of the i-Tree program, said that its tools helped guide the organizers of Million Trees NYC, a public-private initiative that increased New York’s aggregate urban forest by an estimated 20 percent. The London i-Tree Eco Project, according to its 2015 report, used i-Tree to quantify “the structure of the urban forest (the physical attributes such as tree density, tree health, leaf area, and biomass),” with a specific eye toward capturing its value “in monetary terms.” Carbon sequestration savings logged in at £4.79 million (roughly $6.75 million) annually, according to the report. “Our hope is to provide numbers that are locally derived, to help people make informed decisions—whether it’s pro or against trees,” Nowak said.

One i-Tree Web application, Landscape, is intended for planners in particular. Users can explore tree canopy, cross-matched with basic demographic information down to the census-block level, offering data related to pollution mitigation, temperature impacts, and other factors. For example, users can easily identify areas with high population density but low tree cover. The i-Tree project is adding data on tree species over the next year and is seeking feedback to modify the tool in ways that make most sense for planning, according to Nowak.

The broad idea is the same one that has shaped i-Tree from the start—a data-driven approach to thinking about green infrastructure. “We want to help answer the question: If I can plant only one tree or make one change to the city’s green landscape, where should I do it?” Nowak said.

Rob Walker (robwalker.net) is a columnist for the Sunday Business section of the New York Times.

Image credit: U.S. Forest Service

Paradójicamente, China surge como un líder global innovador en iniciativas ecológicas, cuando acaba de superar a Estados Unidos como fuente principal de emisiones de dióxido de carbono en todo el mundo (Global Carbon Atlas, 2016). La agencia oficial de noticias Xinhua destaca: “Luego de la llegada del esmog y los suelos contaminados gracias a varias décadas de expansión veloz, China se aleja invariablemente de la obsesión con el PIB y se acerca una filosofía de crecimiento equilibrado que enfatiza más el medio ambiente” (Xiang, 2017).

China fue el país que creó más energía solar en 2016. En enero de 2017, el gobierno anunció planes para invertir RMB 2,39 billones (US$ 361.000 millones) en generación de energías renovables para 2020, según la Administración Nacional de Energía. En septiembre, el gobierno también prometió prohibir la venta de autos a combustible y diésel, pero no especificó la fecha (Bradsher, 2017). Además, para lograr lo prometido en el Acuerdo climático de París, en noviembre de 2017 lanzará el mercado de “derechos de emisión” de carbón más grande del mundo, cuyo objetivo será la generación de energía por carbón y otros cinco sectores industriales que emiten carbono (Fialka, 2016; Zhu, 2017).

Una de las iniciativas ecológicas terrestres son las “ciudades esponja”, diseñadas para gestionar la filtración de agua de tormentas y evitar las inundaciones urbanas; otra, son los trabajos de conservación para proteger la calidad del agua y preservar el hábitat de la vida silvestre. El Centro de desarrollo urbano y políticas de suelo de la Universidad de Pekín y el Instituto Lincoln (PLC) colabora con el programa de The Nature Conservancy China (TNC China): ofrece asistencia técnica para un proyecto piloto de ciudad esponja en Shenzhen y para explorar mecanismos de financiación para conservaciones innovadoras en el país.

Ambos organismos se complementan en lo que respecta a la experiencia: TNC China realizó muchos trabajos preliminares para llevar las ciencias y las tecnologías a la práctica. Con el aporte de una base internacional de conocimientos por parte del Instituto Lincoln, el PLC se puede concentrar en la estrategia de conservación de China, las políticas y las finanzas. “El Instituto Lincoln realizó muchas investigaciones sobre la conservación del suelo en Estados Unidos y otros lugares del mundo, y los conocimientos internacionales obtenidos de estos trabajos ayuda a China a afrontar sus enormes desafíos en materia de conservación”, dice Zhi Liu, director del PLC y del programa de Lincoln en China.

“Durante algunos años, buscamos una forma de involucrarnos con la conservación del suelo de China. El trabajo en conjunto con TNC China comienza con el desarrollo de las ciudades esponja o, en un sentido más amplio, con la conservación en las ciudades; para nosotros, es un punto de acceso perfecto. Como una de las contrapartes en el proyecto piloto de Shenzhen, nos concentramos en los marcos estratégicos e institucionales, y en las finanzas a largo plazo. Esperamos que el trabajo de Shenzhen ayude también a establecer una base de investigación para formular políticas a nivel nacional”, explica Liu.

Ciudades esponja

El crecimiento urbano sin precedentes que presenta China cobró un precio alto en los paisajes. En 1960, el país no poseía áreas metropolitanas con más de diez millones de personas. Hoy tiene 15. En 50 años la población urbana se sextuplicó: en 1966 eran 131 millones de residentes, o el 17,9 por ciento de la población total, y en 2016 eran 781 millones, o el 56,7 por ciento (Banco Mundial, 2017). Para 2030, se espera que mil millones de personas o el 70 por ciento de la población total del país vivan en ciudades (Myers, 2016). Como resultado, proliferaron los caminos construidos y los sitios de construcción; a su vez, estos generaron una gran expansión de superficies impermeables que impiden que el agua de las tormentas llegue a la tierra para rellenar las fuentes de agua subterráneas y mitigar la amenaza de inundaciones importantes. En los últimos años hubo tormentas cada vez más fuertes y otros tipos de agua superficial que corría sobre las calles de las ciudades de China; estas presentaron un peligro de muerte para los residentes urbanos, como la inundación de 2012 en Beijing que mató a 79 personas y causó daños por RMB 11.640 millones (US$ 1.760 millones), según la agencia de noticias Xinhua.

Este evento de tormenta y otras inundaciones recientes incitaron al gobierno chino a anunciar un programa nacional que desarrollará una serie de “ciudades esponja”. Shenzhen, en el delta del río Perla, y otras 29 ciudades, desde Wuhan, en el centro, hasta Baotou, en Mongolia Interior (Leach, 2016), recibieron instrucciones e incentivos para desarrollar infraestructura ecológica, como jardines de biofiltración, tecnologías de pavimentación permeable y jardines de lluvia, para que el suelo pueda absorber el agua de las tormentas. El gobierno evaluará los resultados de los proyectos piloto con la intención de replicar a nivel nacional las prácticas que resultaron efectivas.

Según la definición del gobierno, una ciudad alcanzará su estado de “esponja” cuando el suelo llegue a absorber un 70 por ciento de la lluvia, lo que reducirá las inundaciones y la carga de los sistemas de drenaje de construcción tradicional. El objetivo es que el 20 por ciento de las zonas urbanas construidas en las ciudades piloto lleguen a la categoría de esponja en cinco años.

TNC China es la contraparte esencial y asesor técnico en el proyecto de ciudad esponja de Shenzhen. TNC invitó al PLC y otras instituciones a unirse al trabajo y ofreció conocimientos en políticas, estrategias y finanzas. El proyecto piloto de demostración de Shenzhen incluye cuatro componentes: subproyectos piloto de demostración para plantas industriales, edificios de oficinas, escuelas, barrios urbanos, etc.; divulgación y mejoras de los experimentos anteriores; una campaña de capacitación y promoción, y estudios sobre mecanismos de estrategia, políticas, y financiación.

Liu indica: “Nuestro trabajo sobre la estrategia, políticas y finanzas de la ciudad esponja se está desarrollando. Hemos estudiado en profundidad experiencias internacionales relevantes en Estados Unidos, Alemania, Países Bajos, Singapur y otros países. Los subproyectos de la demostración piloto de Shenzhen nos dan una idea muy clara sobre cuáles son las tecnologías más viables, además de los beneficios y los costos”.

El desafío más importante es cómo crear mecanismos financieros a largo plazo para desarrollar la ciudad esponja. Dicha infraestructura es costosa, se estima en más de RMB 100 millones (US$ 15,08 millones) por kilómetro cuadrado de área urbana construida. Por naturaleza, es un bien común. El problema es quién lo pagará. Hoy, el proyecto de ciudad esponja de Shenzhen se financia con subsidios del gobierno central, el presupuesto municipal y las empresas que se ofrecen como voluntarias para construir la infraestructura necesaria, como jardines y techos de lluvia en sus propios edificios. Pero los recursos financieros disponibles están muy lejos de ser suficientes para alcanzar el objetivo.

Liu explica: “Estamos investigando las experiencias de otros países en lo que respecta a financiar la gestión de tormentas. Por ejemplo, la ciudad de Filadelfia impone tarifas de agua de tormenta según la superficie impermeable de una parcela. Además, la ciudad ofrece varios programas que ayudan a los clientes no residenciales a reducir las tarifas de agua de tormenta mediante proyectos ecológicos que reducen la cantidad de superficie impermeable en su propiedad. En el contexto de China, creemos que las soluciones financieras a largo plazo requerirán estudios prudentes sobre reformas de políticas fiscales a nivel local”.

Santuarios naturales y reservas de fideicomiso territorial

TNC China también realiza actividades de conservación de recursos más allá de las ciudades. En los últimos años adaptó el modelo de fideicomiso territorial de Estados Unidos a las condiciones locales para proteger los territorios, el hábitat con biodiversidad y servicios de ecosistemas, desde purificación de aire y agua hasta mitigación de inundaciones y sequías. “Hemos estado probando este modelo localizado de fideicomiso territorial como una forma de expandir la capacidad de la sociedad de proteger y gestionar de forma sustentable las tierras y las aguas más importantes del país, y al mismo tiempo ofrecer soluciones de subsistencia ecológica en las comunidades locales y crear un mecanismo para financiar la gestión de reservas a largo plazo mediante aportes privados. Creemos que este modelo nuevo podría convertirse en un suplemento importante para el sistema actual de áreas protegidas”, dice el Dr. Jin Tong, director de ciencias en TNC China. El PLC construye sobre la base de esta experiencia exitosa y aprovecha el acceso a los conocimientos internacionales mediante la Red Internacional de Conservación del Suelo (ILCN, por su sigla en inglés), un proyecto del Instituto Lincoln, con el objetivo de explorar más sobre la financiación de la conservación del suelo en China.

Los fideicomisos territoriales son una innovación de Estados Unidos. Dado que son organizaciones benéficas, utilizan el poder del sector privado y el de organizaciones sin fines de lucro para conservar las tierras mediante la adquisición completa y la posesión del título o el derecho de propiedad; la adquisición de usufructos conservacionales, conocida como restricciones o servidumbres de conservación; o como representantes o gestores de tierras protegidas que pertenecen a terceros. De hecho, para fines de 2015 en Estados Unidos había unas 23 millones de hectáreas protegidas por fideicomisos territoriales locales, regionales y nacionales, según el Censo de fideicomisos territoriales de 2015, compilado por Land Trust Alliance junto con el Instituto Lincoln de Políticas de Suelo. Se cree que Estados Unidos es el líder global en conservación territorial privada y pública; sin embargo, no hay cifras totales que comparen países de todo el mundo en lo que respecta a la conservación territorial privada y cívica. Las tierras conservadas por ONG y otros actores cívicos y privados se suman a las 3.200 millones de hectáreas protegidas principalmente por gobiernos de todo el mundo (UNDP-WCMC, 2014).

El primer fideicomiso territorial regional del mundo fue establecido en Massachusetts en 1891. Hoy, ese grupo se conoce como The Trustees of Reservations y sigue protegiendo propiedades de belleza excepcional e importancia natural e histórica de Massachusetts mediante derechos de propiedad y usufructos conservacionales. Desde ese comienzo pequeño, hoy hay más de 1.000 organizaciones de fideicomiso territorial esparcidas por todo Estados Unidos. Existen en todos los estados de la unión y siguen mejorando el ritmo, la calidad y la permanencia de los territorios protegidos en todo el país, lo que genera varios beneficios públicos. Este trabajo se beneficia mucho de los créditos impositivos federales estadounidenses para usufructos conservacionales en fideicomisos territoriales.

La práctica de conservación territorial por parte de individuos privados y organizaciones cívicas también se esparció en todo el mundo. Según indica una encuesta realizada por el ILCN, existen grupos privados y cívicos de conservación territorial en más de 130 países y territorios de América del Norte y del Sur, Europa, África, Asia y Oceanía (ILCN, 2017). Si bien el contexto legal y los incentivos económicos para la conservación territorial en los sectores privado y cívico difieren entre los distintos países, la motivación para proteger y administrar la tierra con cuidado para el bien de las generaciones presentes y futuras es una constante en todo el mundo.

Hoy, en su nueva forma, los fideicomisos territoriales pueden tener el potencial de ayudar a moldear de otra manera el modo en que China encara la creación y la gestión de las áreas protegidas. Más del 15 por ciento del territorio chino fue designado área protegida, y hay más de 2.700 reservas naturales con el nivel más alto de protección legal. Sin embargo, todavía hay desafíos importantes que arredran a la red china de territorios protegidos. Muchas áreas protegidas carecen de los recursos financieros, los mecanismos de aplicación y gobernación y el personal gerencial necesarios. Para poder fortalecer y expandir la red de áreas protegidas existente, TNC China y sus contrapartes trabajan para desarrollar analogías a los fideicomisos territoriales que funcionen en el contexto de China.

En 2008, entró en vigor una política china que permite que los individuos y organizaciones privadas asuman derechos de administración sobre territorios forestados de propiedad colectiva; gracias a ella, se abrió la puerta para comenzar las conversaciones sobre fideicomisos territoriales. En 2011, TNC China empezó a trabajar en conjunto con el gobierno local del condado de Pingwu, en la provincia de Sichuan, para estudiar la fundación de la primera reserva de fideicomiso territorial del condado. De acuerdo con la naturaleza local de este movimiento, en ese momento TNC China catalizó el nacimiento de una nueva entidad local, la Fundación de Conservación de la Naturaleza Sichuan (SNCF), que luego cambió el nombre a Fundación Paradise. En 2013, la SNCF firmó el primer contrato de conservación del país, que le permite administrar la parcela durante los próximos 50 años.

Enseguida, el gobierno local, TNC China y la fundación declararon al territorio como reserva natural a nivel del condado, lo llamaron Reserva Laohegou de fideicomiso territorial y así lograron conservar unas 11.000 hectáreas de hábitat importante para los pandas gigantes. La ubicación estratégica de la reserva conecta áreas protegidas existentes para especies en peligro de extinción, como el panda gigante y el mono de hocico chato de Sichuan; así, se estableció un gran corredor de conservación. El corredor interconectado crea de forma efectiva un amplio territorio dentro del cual se pueden aplicar rigurosas normativas contra la caza furtiva. De modo similar, los arroyos locales que corren en libertad dentro del corredor se pueden proteger para que no se desvíen y se utilicen para energía hidráulica.

Además, la reserva es importante desde el punto de vista de las investigaciones. Los científicos realizaron un inventario de referencia de la vida silvestre y colocaron decenas de cámaras-trampa para aprender más sobre la gran cantidad de especies importantes del lugar. Estas cámaras ya filmaron un hecho poco frecuente: un panda gigante comiendo los restos de un takín (un antílope-cabra de las montañas y las mesetas asiáticas), lo que refuerza el descubrimiento relativamente nuevo de que los pandas son omnívoros y de vez en cuando comen carne.

Para las tareas cotidianas de administración de la reserva, la fundación financió la creación de una entidad local, el Centro de conservación de la naturaleza Laohegou, que a su vez contrató residentes cercanos para que administren y ejecuten los planes de trabajo de administración, aplicación y monitoreo ecológico.

Hay otras entidades que apoyan y administran la reserva y están poniendo en práctica mecanismos piloto que aumentarán los ingresos de las comunidades cercanas a las reservas y financiarán su administración. Por ejemplo, fuera de la reserva Laohegou, la Fundación Paradise estableció un sistema mediante el cual venden los productos agrícolas ecológicos e hidromiel de la comunidad a mercados de lujo. Los ingresos de estas ventas aumentan la renta de la comunidad y reducen la presión de los residentes locales que quieren cazar y buscar comida dentro de la reserva. Además, la Fundación Paradise y otras exploran el potencial del ecoturismo limitado dentro de las reservas y una colecta de fondos en línea para proyectos individuales. Por último, los gerentes del proyecto también ven con optimismo que el sector de caridad, que está creciendo en China, se interesará en estas actividades y las apoyará. Queda por determinar si estas técnicas generarán ganancias repartidas entre las comunidades cercanas a la reserva u ofrecerán la financiación constante y a largo plazo que se necesita para las actividades de administración.

El objetivo de la conservación es crear diez reservas de fideicomiso territorial en China para 2020 junto con contrapartes; cada una de las reservas debería adoptar un modelo un poco diferente para demostrar la flexibilidad del enfoque; por ejemplo, alquilar un terreno y convertirlo en una reserva, como en la provincia de Sichuan, o encargarse de las responsabilidades de administración de una reserva existente. Más allá de Laohegou, TNC y sus contrapartes también exploran otros modelos para demostrar la flexibilidad del enfoque, como sociedades civiles que se encargan de las responsabilidades de administración de una reserva existente. Hasta el día de hoy se crearon cuatro reservas de fideicomiso territorial en todo el país, entre ellas Laohegou, en conjunto con varias entidades locales. El interés sigue creciendo.

La Fundación Paradise y TNC China tomaron prestada la idea de Land Trust Alliance, de Estados Unidos, se unieron a otras 11 ONG medioambientales nacionales e internacionales, y en 2017 lanzaron la Alianza cívica de conservación territorial de China, que pretende catalizar el “movimiento de fideicomisos territoriales en China” mediante una plataforma de comunicación, financiación, estándares, políticas y construcción de capacidades. La visión a largo plazo de la Alianza es proteger de forma colaborativa el uno por ciento del suelo de China mediante individuos y organismos cívicos y privados. 

“Pronto, TNC cumplirá veinte años en China”, indica Jin Tong. “Hemos completado muchos trabajos de campo que utilizan nuestro enfoque científico y la experiencia internacional para encontrar soluciones viables a los desafíos medioambientales más urgentes del país, como el proyecto piloto de ciudades esponja y las reservas de fideicomiso territorial. Junto con el PLC, podemos amplificar el éxito de los proyectos de demostración para producir impactos a mayor escala y crear condiciones propensas para lanzar cambios sistemáticos en las estrategias de conservación, las políticas y las finanzas mediante la investigación”.  

James N. Levitt es gerente de los programas de conservación territorial en el Instituto Lincoln de Políticas de Suelo y director del Programa sobre innovaciones de conservación en el bosque de Harvard, de la Universidad de Harvard. Emily Myron es gerente de proyecto en la Red Internacional de Conservación del Suelo del Instituto Lincoln.

Fotografía: Oktay Ortakcioglu

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