"Behold the birds of the air, for they neither sow, nor do they reap, nor gather into barns: and your heavenly Father feedeth them. Are not you of much more value than they? And which of you by taking thought, can add to his stature by one cubit? And for raiment why are you solicitous? Consider the lilies of the field, how they grow: they labour not, neither do they spin. But I say to you, that not even Solomon in all his glory was arrayed as one of these." Matthew 6:26-29
I am disappointed to say that it the Army Corps of Engineers back at it again. In response to the catastrophic flooding caused by the almost 50 inches of rain (!!!) that Hurricane Harvey dumped on the Houston area over four days in late August of 2017, the agency has put out an interim report outlining their proposal to mitigate future mass flooding scenarios in the Buffalo Bayou watershed. Buffalo Bayou is the principal river in the Greater Houston region. It's headwaters are located 53 miles west of the Gulf Coast in Katy and it stretches eastwards through the city of Houston eventually ending up in the Houston Ship Channel.
The proposal that emerged from this two year long process, with many cost-benefit analyses made and millions of dollars in taxpayer money spent, are sadly the same old hard-engineering approaches to "handling" flooding that we are so used to hearing about in this town. They propose to either widen, deepen, channelize, or some combination of all of these, Buffalo Bayou, which has thus far avoided the worse of that tragic fate, and to create a third, massive reservoir on what remains of our tragically degraded Katy Prairie.
This report is emblematic of the ecologically-devastating urban development pattern that has made Houston a byword for concrete hellscape in the American psyche. Houston is a car-centric city. Everyone is expected to own and maintain their steel horse to participate in society, as it is often not possible to do everyday things like pick up groceries, eat at restaurants, or get to school without one. Walkers and bikers are not welcome. Overpasses and underpasses, highways and stroades, manicured park spaces and degraded waterways - Houston is the quintessential, post-modern American city (alongside Phoenix and Los Angeles perhaps).
This isn't to say that we aren't improving. Initiatives like the Bayou Greenways Initiative Initiative, the Memorial Park Land Bridge and Prairie Project and the Houston Bike Plan show that an environmental consciousness has developed in this flat, swampy city best known for being the oil and gas capital of the world. Much of the marshes, prairies, and swamps that the city sits on have been torn up to plop down McMansions and strip malls alongside endless miles of concrete parking lots. Nature has for too long been an unwanted outsider in this place, yet still manages to thrive in the interstitial places that we haven't bothered to colonize.
The types of brutal flood control projects discussed in the report, undertaken mostly from early 20th century through the 1960s here in Houston (and apparently even being considered today!), fail to decrease flood risk and control the expansion of floodplains compared with natural waterways. The theory behind these projects is as follows: Straightening, modifying, and concretizing the path of the bayous directs rapidly accumulating surface runoff from rainstorms into the Addicks and Barker reservoirs, both of which are in pretty poor shape. This in turn nominally limits the opportunity for rain water to uncontrollably pool up and flood properties. Engineers then time the release of waters from these reservoirs to minimize downstream flooding impacts.
I have one response to this approach to environmental engineering. What happens when the baseline conditions, things like climate (i.e. anthropogenic climate change), hydrology (i.e. more impermeable surfaces due to suburban development) etc., we design these projects to control for change? The projects become out of date as soon as their created. The largest floods on record are only the ones we have seen and written down, there was a previous "largest" flood before every new one on record. Continuing an artificial infrastructure based approach to mitigating flooding in the future needs to account for these dynamics, a very hard thing that leads us to building more and more "fixes" over time. This is a losing proposition.
Houston is situated in one of the most ecologically diverse settings of any major city in the United States. The city sits at the intersection of the Piney Woods, Texas Prairies, and Gulf Coastal Marshes ecoregions, among many others. The most remarkable natural features in the area are the numerous, slow-moving, tidally-influenced streams that have given the city the nickname of "The Bayou City". And yet we have thrown away this natural inheritance by dramatically altering the course and shape of these 22 bayous and their associated watersheds which make this region so unique.
Bayous cut across and serve as crucial pathways between the marshes, forests, swamps and prairies that make this part of Texas a wildlife wonderland. These ecosystems harbor a diverse array of animals, including crawfish and shrimp, catfish and bass, frogs and toads, salamanders and newts, alligators and snakes, turtles and tortoises, herons and spoonbills - among untold others, not to mention all of the flora that thrive in these ecoregions. These bayous are God's gift to our part of the world, but we have not recognized them as such. Even our parks that lie alongside the bayous do not take full advantage of the natural bounty that could thrive there, as we lay down easily erodible grass, drop concrete pathways, and cultivate manicured trees in lieu of letting a proper ecology emerge.
In light of the wonders of these waterways, and the failings of the previous flood mitigation paradigm, I would like to put forward a radical proposal to any and all who will hear my plea: Rewild our bayous! It is clear from the history of human attempts to engineer streams for human gain that it is ultimately a hopeless endeavor. Houston is a fairly young city, it was only founded in 1837, and its outrageous growth rate has made it the fourth most populous and eighth most geographically expansive city in the United States. If we think about Houston one hundred or three hundred years in the future, it is clear that sinking every more amounts of money into short term, environmentally-devastating "solutions" to our growth-inflicted flooding issues is unsustainable.
Instead of continuing to wage an unwinnable war with our environment, why not let nature deal with hydrology as it has done throughout Earth history? Removing the concrete restraints on the meandering of our bayous, buying out the properties that encroach far too close on them, and leveraging our will to dynamically shape urban geography in accord with changing environmental conditions would allow the land to mitigate our flood issue for us. Natural waterways slow floodwaters by using them to erode and shape the landscape. We need to accept low-grade floods to dampen the impact of the catastrophic ones. Regenerating prairies, marshes, and swamps at key sites along the course of our bayous would serve the purpose of additional dams by extending the residence time of water and thus limiting flooding. Instead of channelized bayous and engineered dams, why not rewilded bayous and regenerated prairies?
Rewilding our bayous would also help address the catastrophic issue of nutrient pollution and topsoil pollution that is destroying this country even more rapidly than climate change is. Agricultural runoff from our Texas-sized, monoculture expanses of cotton, corn, rice, and wheat is laced with egregious amounts of nitrogen and phosphorus fertilizer that poison streams and create toxic environments that aquatic organism struggle to live in. These nutrients, along with heavy metals, petrochemical byproducts (from our large number of refineries!), herbicides, pesticides and whatever else we end up dumping in the watershed, radically alter the baseline conditions that life is used to.
Anyone who has seen the sediment and litter choked flow of our bayous, and who has maybe even tried to fish in them, knows that they are not healthy. Indeed, human disruption is not limited to the terrestrial waters we directly pollute. All of this water ultimately makes its way into the Gulf of Mexico and where it can promote deadly algae blooms which literally choke out life in the sea by creating marine "dead zones". Rewilding bayous and regenerating prairies, marshes, and swamps allow a complex blend of plants, bacteria, fungi etc. to emerge and do what they evolved to do - purify streams by removing many environmental pollutants by using them as energy sources while also limiting erosion and sediment runoff, as trees hold the bayou banks together in a far more dynamic way than any engineered method could.
The case for rewilding our bayous is also a human one. The green spaces that we have in the city are concentrated in places only really accessible by car, as is the case with Memorial Park, which limits who gets to have even a taste of the natural beauty of this city. Parks and greenery are unevenly distributed, with wealthier areas of town having more trees, nature parks, and walking/biking paths relative to poorer ones. Being in nature is an integral part of the human experience, as many of us have recognized in the time of coronavirus, and for many Houstonians it is simply not possible to be do so. The great thing is that our bayous do not discriminate! They flow through every part of this place so that rewilding our waterways would bring nature within reach of all citizens.
Houston is widely thought to be extremely ugly. You know what would make this place beautiful? An regenerated network of bayous that binds all parts of this city together. Why can't Houston become a hotspot for ecotourism in Texas? Houston is a dynamic, creative city in fields ranging from energy to biotech, we should use this same energy a create a new path for urban environmental regeneration. Our willingness to re-create our cityscape every few years, by destroying then creating new infrastructure, makes Houston the perfect place to innovate on old models of urban conservation. The strangeness of Houston's car-centric geographic expansion means that a qualitatively different kind of urbanist philosophy is needed for this city to thrive in the 21st century. Our city could serve as a vision of a solarpunk future that inspires, rather than depresses, lovers of nature.
Here is my vision of a rewilded Houston: Concrete banks that constrain the natural course of bayous are removed. Egregiously placed buildings engineering projects are designed to protect are bought out. The natural dynamics of the bayous will be allowed to drive the evolution of the landscape. Natural channels slow water velocities as it reshapes the landscape. Setbacks emptied of buildings provide a riparian buffer that delay urban runoff and serve as excess flood water storage. I see a network of pocket ecoregions that make this city so vibrant - swamps, marshes, prairies, bottomlands, forests - acting as storm water storage, purifiers and protection against erosion while connecting the rich diversity of flora and fauna spread throughout Houston, creating a novel kind of ecotourism in our increasingly urbanized world. Some of the stream-side spaces newly freed of concrete could host an extremely productive two-story, tree crop agriculture. Mulberry, oak, persimmon, and pecan trees alongside underlying native grass pasture below provide an extremely low-maintenance, perennial food source for a thriving hog industry. I see a hunter, fisher, and birder's paradise emerging deep in the heart of our city, with naturally filtered waters playing host native fish and alligator populations while rewilded, shoreside ecosystems provide home for a range of game like pheasants and woodcock, rabbits and white-tailed deer - setting the stage for an urban wildlife industry revival. I see reintroduced beavers adding additional complexity to the flow of the bayous through their destruction of trees and creation of dams, natural dams, providing untold numbers of emergent microhabitats stimulating the return of species never recognized to live in this place before. I see Houston serving as a beacon for what other cities can do to right their environmental wrongs, by recognizing the antifragility of the biosphere around us and living within it to the benefit of both man and nature.
Rewilding Houston's bayous is an ecological, moral, and practical imperative that would provide a positive vision of the future for generations of Houstonians to work towards, and could make this city a living symbol of how man and nature can thrive together, as we did in the past. Let's do it!