Exactly two years after Hurricane Harvey blew through Houston, Texas, the state government approved a “Rainy Day Fund” earmarked for flood prevention projects and resilient infrastructure. The $1.7 billion fund will be available to local governments and communities through disaster mitigation grants and loans, which can be used to leverage additional federal funding for an even bigger investment. The bill was signed by Governor Greg Abbot on June 13, and flood experts are hopeful that some of the money will be channeled to nature-based solutions known as green infrastructure.
Houston’s history of floods
Houston is a low-lying, coastal city in Texas that has faced an ongoing battle with sea level rise and flooding. In August 2017, Hurricane Harvey touched ground as a Category Four hurricane, killing 68 people and causing over $125 billion in damages. At least 154,000 homes flooded throughout Harris County, which includes the city of Houston. The devastation caused by the hurricane — considered the second most expensive tropical cyclone in U.S. history — made it clear that conventional and outdated approaches to flood management were not enough.
For years, coastal residents have demanded less intrusive and more naturally beautiful solutions to controlling water (rather than industrial-looking levees and dams), but politicians, engineers and decision-makers are finally catching on. According to Laura Huffman, Texas state director for The Nature Conservancy, politicians are “recognizing that green infrastructure can scale just like gray infrastructure,” meaning it can be used to protect entire cities.
Although the majority of funding will go to so-called “gray infrastructure” like levees, pipes, drainage channels and retention basins, the bill explicitly states that it will help fund the “construction and implementation of nonstructural projects, including projects that use nature-based features to protect, mitigate or reduce flood risk.”
Huffman said, “We could do things as small as ‘pocket prairies’ in a neighborhood — which could be restoring a vacant lot, a parking lot, a front yard — and that actually can do a lot for helping to manage the ‘flashy’ parts of flash floods. And you can scale that strategy out to a city and a regional level.”
Why gray infrastructure isn’t good enough
Directly after Hurricane Harvey, Harris County residents voted to spend $2.5 billion on gray flood mitigation infrastructure. Indeed, for the last century, this type of infrastructure has been the norm. Throughout the 1900s, engineers indiscriminately used concrete to ensure that water traveled away from cities as fast as possible. They even went so far as to pave riverbeds, which engineers now recognize cuts rivers off from their natural floodplains and can have disastrous effects.
The U.S. Army Corp of Engineers has a current project proposal under review that will build a $31 billion barrier in Texas to protect communities from coastal flooding. The so-called coastal spine mimics gray infrastructure built in Louisiana after Hurricane Katrina. This time around, Texas has the opportunity to get it right by learning from the mistakes in New Orleans of which there were many.
If it’s broke, fix it
The flood mitigation infrastructure in Louisiana took 13 years to install. With the unprecedented and unexpected increase in flooding, natural disasters and sea level rise, the original structure no longer provides the protection it planned for back in 2006. In fact, experts estimate that it will only provide its intended level of protection until 2023, after which sea level rise and land subsidence will be more than it can handle.
When the U.S. Army Corps of Engineers publicized its plan for a similar structure in Texas, the feedback was clear — coastal residents wanted to explore green infrastructure solutions.
“I didn’t really care for that barrier wall running down the middle of the peninsula,” said Margaret Lindlow, a resident of the nearby Bolivar peninsula. “I know something has to be done, and if we have to put some kind of barrier there, then I think it should be at the beach.”
In response to the public feedback, the Army Corps of Engineers is now exploring the restoration and installation of sand dunes, which will provide the necessary mitigation impact with a more discrete and natural strategy.
Unlike engineered solutions, green infrastructure is more resilient to water stress, because it mimics nature’s flexibility by absorbing and adapting rather than breaking.
Why green is better when it comes to infrastructure
Green infrastructure is an approach to water management that utilizes and mimics natural water flow rather than trying to fight it. According to Tony Wong, founder and CEO of the Cooperative Research Centre for Water Sensitive Cities, green infrastructure “mimics the functions of forests and wetlands and open spaces to serve and cleanse our cities.”
Instead of slicing into forests to create catchment bins, green infrastructure experts advocate for restoring green areas and utilizing vegetation to not only reduce flooding and stabilize the land but also to filter and cleanse stormwater.
The Houston Parks Board predicts that wetlands and native grasslands in its Bayou Greenways project will filter 2 billion gallons of runoff annually and save the state government $1.3 million in treatment costs.
Such features act as “the kidneys of our city that filter the stormwater that carries all the urban pollution every time it rains,” Wong said.
Green infrastructure is increasingly recognized in cities around the country and around the world. In the aftermath of Hurricane Sandy, New York City also ramped up its green infrastructure by building rain gardens that help reduce the amount of contaminated stormwater reaching the ocean during extreme rainfall.
Moving out of harm’s way
One of the best ways to ensure houses aren’t flooded is by making sure there are no houses within the flood areas. Around the country, states and homeowners participate in buy-back programs, where the government purchases homes within a flood zone with the specific purpose of bulldozing the house and typically setting up beneficial green space, such as sand dunes or wetlands.
But according to FEMA regulations, buy-outs must be voluntary by the homeowner, which means that flood officials have to work hard to convince families to want to leave their homes. The offer of money helps, but natural disasters are unfortunately the best way to convince families to move.
Even before Harvey hit, Harris County had the largest buy-out program in the U.S., but it exploded after the storm. Since 2017, 4,000 homeowners volunteered their vulnerable homes for the buy-outs, but only 1,100 were approved. Of those, 450 are currently processing and only 322 homes have successfully been purchased. Between the inefficiency of the system and the unpredictable nature in which houses are volunteered and subsequently demolished, the buy-out programs create a fragmented, checkerboard effect for green space planners.
Disjointed vacant lots are not ideal for creating integrated and large-scale green infrastructure, but it is better than nothing and begins to move people to safer places while opening vulnerable land for innovative solutions.