With each issue, Trib+Water brings you an interview with experts on water-related issues. Here is this week's subject:
Sam Brody is a professor in the Department of Marine Sciences at the Texas A&M University at Galveston. He also serves as Director of the Center for Texas Beaches and Shores at the university. Brody's research focuses on coastal environmental planning and natural hazards mitigation. Trib+Water spoke with Brody in 2015, and you can read that Q&A here.
Editor's note: This interview has been edited for length and clarity.
Trib+Water: Can you give me an assessment of Texas and tell me which areas of the state are more vulnerable to flooding?
Sam Brody: First, overall Texas has more deaths and injuries from flooding than any other state in the country, so much so that it has twice as many casualties than the next highest state on the list. So we as a state are an outlier for impact on property and lives from flooding, even if you look at it on a per capita basis.
Texas, as a whole, is afflicted by flooding from the sky and flooding from the sea. In the Houston, Galveston area and Corpus Christi area, there are threats from storm surges associated with hurricanes and tropical storms. Inland areas, as far west as the Guadalupe, are vulnerable to flash floods from heavy downpours. In some areas, there's a thin line along the coast that goes right through Houston where populations are impacted by both kinds of flooding at the same time, and that's where we see the most vulnerability, the most exposure to flood risks and the most deaths and property damage caused from floods.
Trib+Water: Is it primarily natural considerations then that affect whether a particular area floods or can things like manmade infrastructure contribute as well?
Brody: Right, so we look at a difference between flooding and flood loss. Flooding is a natural process. The bayous and rivers and coastlines have flooded long before humans arrived. Flood damage and flood disasters is a human derived phenomenon. It's a human problem, particularly around the built environment. All of our research shows that putting pavement, people, structures into these flood-prone areas is going to exacerbate the losses – both human lives and property.
So it's a bad thing, but it's also an opportunity to think about the way we're constructing the built human environment and doing a better job at building and living in these areas in a way that doesn't cause us to lose our homes and our lives.
Trib+Water: Could you be more specific about what humans can do as far as that construction goes to make that a happy medium between natural flooding and preventing damage?
Brody: So there's not one magic solution. These are complex, regional, long-term problems. But there are four areas, we'll call them dimensions, of flood risk reduction. Each dimension has its own set of strategies and together, synergistically, is how we can really start comprehensively avoiding these impacts.
The first dimension is resistance. So that is usually structural interventions to prevent floodwaters from reaching our property. So those are dams; they're dykes, they're floodwalls, they're channels – that's the first. The second dimension is avoidance, and that's where we literally need to pull away from these flood-prone areas to avoid the floodwaters. A vertical avoidance, elevating structures above the base flood level of inundation or it could be a horizontal avoidance where we're peeling back our development from these areas, so that involves buffers and setbacks. It involves targeting development away from the flood-prone areas and encouraging it in the least flood-prone areas.
The third dimension is what I call acceptance. Those are strategies where we're going to encourage flooding to occur in retention ponds, detention ponds, natural and constructed wetlands, parklands. We're accepting those floodwaters almost as a release valve to more populated areas. And then finally, the fourth dimension, which is often overlooked, is awareness. Education, understanding the risk and what communities, households, residents can do both collectively and individually to protect their property and their lives.
The average person doesn't understand the risks when they acquire property, when they move into this area. There's all kinds of low-hanging fruit strategies we could employ to make people more aware, and in the long run we're going to reduce the adverse impacts.
So resistance, avoidance, acceptance and awareness working together synergistically over watersheds and long periods of times – that's the answer. So let me come up with an example.
We're going to create a thousand-foot buffer for development along a bayou. And in that buffer, we're going to protect the wetlands, we're going to create parks and recreational opportunities for residents. We're going to take those rights to develop and we're going to transfer them to a higher ground in an urban core so that we're going to increase development.
We're just displacing it from vulnerable areas to populous areas. And visitors to that park are going to see signs and interpretive materials on why flooding occurs and how to avoid it. So I just combined three or four different strategies across almost all those dimensions.
Trib+Water: Are those the sort of things that should be implemented then at a local level or is this something the statewide governing bodies need to be involved in or even federal entities?
Brody: That's a great question. I think it's going to be a collaborative effort across multiple scales. Really, we need strong state leadership and commitment to reduce the adverse impacts of floods. Ultimately, the adoption and implementation of specific strategies is going to occur at a community level.
But one thing you didn't mention is the household level, the individual level. One of the unsung heroes of flood mitigation is drainage maintenance. You can have the best drains in the world, the biggest channels, but if they're clogged with debris and furniture and leaves, they're not going to work in a time of heavy rainfall.
And I drive around these neighborhoods and their street drains are clogged. That's really the responsibility of homeowners associations and individual citizens to get out there with a broom and clear the drains and make sure the canals in the back of their homes don't have refrigerators and couches and other types of debris in them so they can function properly.
It's a complicated problem because it stays at the community level, it's individual, and at the federal level they're also part of the overarching equation, particularly when it comes to recovery.
Trib+Water: Last year Texas saw major flooding events with the Blanco River and Tropical Storm Bill. From what you've seen, have Texas cities learned anything from those major events? Has anything changed?
Brody: I think there are a lot of examples of very localized success. But overall, we haven't done a good job of comprehensively addressing the issue. But I'm optimistic because the new mayor of Houston has appointed an individual to look at these issues systematically, collaboratively over the long term. The Harris County Flood Control District has done wonderful work, particularly around constructing structural measures and working with communities.
I think the issue of flooding has percolated to the top of the politician's agenda so I'm optimistic that the state will begin to support these research and policy initiatives in Houston and other parts of the state. I'm in the Houston metro area, so that's where I'm focused, but it's also where most of the death and property damage is occurring because you've got this physical environment that is low-lying, clay soil-dominated, no slope, that's subject to storm surge and tidal events, flooding from those issues, and also heavy rainfall.
And then sometimes both at the same time. Houston added 90,000 people last year. Over a 15-year period, we tracked that the Houston region increased its pavement and pervious surface coverage by 25 percent. There's very little you can do to really keep up with that level of growth unless you're going to really think holistically, across boundaries long-term, and that's what we need. We need leadership to do that.
Trib+Water: So when you spoke with Trib+Water last year, you said policymakers and officials need to do a better job looking at the bigger picture when addressing these concerns. It seems you still feel that way, correct?
Brody: Absolutely. There are too many examples of short-term fixes, ad hoc approaches, re-plumbing our drainage system. We need something bigger that looks across watersheds; programs that are willing to put resources up-front to realize long-term gains.
In other words, sometimes you need to invest early so that you can reduce impacts of the long-term. We need to think more systematically across multiple jurisdictions, across regions, and not just focus on one approach or one strategy but consider multiple strategies, hybrid approaches that work synergistically. We're really not doing that.
There are great examples of local success, but you tinker with one part of a system and there's going to be ramifications for other parts. You have to come up with a decision-making process that accounts for those imbalances where small interventions can have unintended consequences in other areas down the line.