The first half of 2019 has seen record flooding in much of the Midwest and the South. This flooding has taken a terrible toll on people and local businesses, and some communities find themselves worn down by repeated flooding. Thousands of Houston residents lived through the flooding caused by Hurricane Harvey in 2017, dried out their homes and cleaned out the mold only to be flooded again this April and May by almost non-stop torrential rains. In the Midwest, chronic flooding has tipped many family farms into bankruptcy which has caused a surge in depression and even suicide.
To help us understand what is happening and how the weather may be changing in the United States, we turn to Bryan Koon, IEM’s Vice President of International Homeland Security and Emergency Management. From 2011 to 2017, he was the director of the Florida Division of Emergency Management. He is a much sought-after expert on emergency management, having been quoted in The New York Times, The Wall Street Journal, Bloomberg News, The Hill, and Emergency Management.
Q. Are there any discernable patterns to all the flooding this year?
Koon: There has been a lot of discussion on that subject, but so far, no consensus. One of the more interesting answers comes from research done at the University of Alabama using artificial intelligence. The researchers analyzed relatively rare floods in the United States using a machine-learning algorithm to place the floods into groups based on atmospheric patterns that happen at the same time. They found four main causes. The first is large air masses containing tropical moisture coming from south to north. The next is hurricanes and superstorms, then low-pressure systems, and finally melting snow. According to that analysis, these are the primary patterns associated with extreme floods. Different parts of the country are more vulnerable to different factors. For example, hurricanes and superstorms mostly occur along the Gulf Coast and Eastern Seaboard. Snowmelt is most prominent in the mountainous areas of the West, and slow-moving low-pressure systems can occur anywhere, but they hit the major rivers of the Midwest especially hard this year.
Q. Which areas and which kind of communities are at greatest risk?
Koon: The risk is very broadly distributed around the country. People in coastal communities along the Gulf and Eastern Seaboard threatened by hurricanes or superstorms can be impacted very suddenly with a hurricane spinning up to a Category 5 at the last moment. Just look at how fast and unexpectedly powerful Hurricane Michael was in the Florida Panhandle in 2018. And the danger is not just on the coast. In North Carolina, Hurricane Florence caused massive flooding many miles inland because a ridge of high pressure over eastern North America stalled Florence’s forward motion for several days in 2018. So, there it sat dumping rain for days on end, inundating cities such as Fayetteville, Smithfield, Lumberton, Durham, and Chapel Hill and major rivers such as the Neuse, the Eno, the Cape Fear, and the Lumber.
Q. Why has this spring been so bad for flooding in the Midwest?
Koon: Agricultural communities located near rivers in the Midwest and the South have always been vulnerable but were hit especially hard this year. There was great flood of 1927 and a terrible inundation as recently as 1993. This year, a series of slow-moving low-pressure systems dumped heavy amounts of rain on snow-covered, frozen ground. The result was record flooding that devastated already financially stretched farmers throughout the region. In fact, the Mississippi River sustained a period of uninterrupted flooding that came very close to breaking the record set by the Great Mississippi River Flood of 1927.
Q. We think of the West as being arid, but apparently not always. How does that work?
Koon: Mountainous areas of the West have an ongoing threat of flash floods. Rainwater flows down steep valley walls forcing it into gullies, creek beds, streams, and rivers in a very short time. You can be many miles away from the actual storm, not even be able to see or hear it, and suddenly face a wall of rushing, debris-filled water roaring down a canyon. That’s what happened with the Big Thompson Flood in 1976: During the evening of July 31, more than 4 inches of rain fell across a large portion of the Big Thompson basin in less than 6 hours, with more than 12 inches falling in a smaller area containing the western third of the Big Thompson Valley. Much of the canyon was devastated with a 20-foot-plus wall of water, killing 139 people.
Q. Starting with Katrina in New Orleans and extending to Sandy in the New York area and Harvey in Houston, we have seen some very dramatic urban flooding. What is being done about that?
Koon: Many cities are located in low-lying areas, overbuilt with too much impervious surface, and do not have enough parks, forests, and other forms of open land to absorb rainwater. Take Houston, for example. Large areas were under more than 12 inches of water when Hurricane Harvey went inland, weakened, and stalled over the city. Two feet of rain fell in the first 24 hours. At its peak on September 1, 2017, one-third of Houston was underwater. Flooding forced 39,000 people out of their homes and into shelters. Severe flooding returned to Houston in this spring as a series of slow-moving low-pressure areas dumped up to 10 inches at a time on the city. City planners have had to accept flooding as a chronic condition in Houston and have some ambitious building plans to address it.
Q. What kind of plans?
Koon: The U.S. Army Corps of Engineers and the Texas General Land Office have proposed a $31 billion project to protect the Houston and Galveston area from future hurricanes. It’s called the Coastal Spine and would include surge gates that will close Galveston Bay during storm-surge events but otherwise remain open, miles of sand-covered dunes with hardened cores stretching along the coast line on either side of the Bay, and a raised coastal highway that will be higher than any likely storm surge. In all, the Coastal Spine would be 71 miles long. It was designed by a Texas A&M engineering professor based on the successful Delta Works project built by the Dutch in 1959, but if approved and funded, it won’t be finished until 2035 at the earliest.
Q. That sounds like a very expensive, civil works centered solution. Are there any softer, more conservation-oriented approaches under consideration?
Koon: The Galveston Bay Park Plan, designed by Rice University’s Severe Storm Prediction, Education & Evacuation from Disasters Center, would create a 25-foot-high wall up the middle of Galveston Bay as a series of islands, extending from Houston Point down the ship channel to Texas City. Its appeal is that it would be multi-purpose, creating 10,000 acres of public land that would be open for recreational use. It can include camping, fishing, a marina, and an event space. It could be completed as early as 2027 and cost far less, between $3 billion and $5 billion. All the parties concerned in choosing between these two approaches are going to have to weigh the many different pros and cons that come with each and involve the affected public in the final decision.
Q. A lot of other cities besides Houston are experiencing severe flooding. What are some of their approaches?
Koon: New York; Miami; Tampa; New Orleans; Wilmington, North Carolina; and Atlantic City, New Jersey, are all flooding regularly and are poised for worse due to global sea-level rise. New York has some of the most expensive real estate in the world and is investing in what it calls the “Big U,” a 10-mile-long barrier consisting of earth berms, walls, and gates ringing lower Manhattan. It will provide park space and natural features that will help restore habitat and buffer against the kind of storm surge that flooded the city during Superstorm Sandy. The project will take several years to build and hundreds of millions of dollars. New York has also used FEMA Hazard Mitigation Grant Program money to buy out entire low-lying neighborhoods in Staten Island.
Miami Beach is especially vulnerable because it is entirely flat and built on porous ground that is slowly sinking back to the seabed. Also, Miami Beach is surrounded by seas rising three times the pace of the global average. So far, the region has invested $200 million to raise the height of roads in particularly vulnerable neighborhoods. But that’s just a start. In coming years, Miami is going to have to invest heavily in restoring natural features such as mangrove forests, reefs, and wetlands. Levees and gates won’t work because the water rises through the porous limestone that underlies the city. As the century progresses, Miami may be transformed into a smaller version of itself and pioneer new technologies for coping such as platform houses and floating structures. After all, necessity is the mother of invention.
Q. Exactly what is the role of the National Flood Insurance Program in all of this?
Koon: The National Flood Insurance Program was created by Congress in 1968. Before that, homeowners, renters, and business owners had to rely entirely on the private market, which, by itself, was unable to profitably provide flood insurance. NFIP coverage does not require a Presidential Disaster Declaration, and it restores homes to pre-flooding conditions. The NFIP operates through the private insurance market. It has an arrangement with private insurance companies by which those companies sell and service federally supported flood insurance policies.
Q. Who can participate?
Koon: To participate in the program, the home or business must be located in a participating community. These are communities that agree to adopt and enforce floodplain-management ordinances to reduce future flood damage. There are now more than 20,000 participating communities across the United States. Those most in need of flood insurance are homeowners, renters, and business owners who live in what FEMA calls Special Flood Hazard Areas, or SFHAs. This is FEMA’s designation of land areas that are at high risk for flooding, known as high-risk floodplains. In high-risk areas, there is at least a 1 in 4 chance of flooding during a 30-year mortgage. Over time, the program has had to deal with properties in areas that flood repeatedly, in some cases more than 30 times, so funding their restoration stops making sense. Finally, the program is $24 billion in debt.
Q. So now what?
Koon: That’s something Congress has been dealing with for years now. One idea is to increase insurance program premiums to more closely match the actual flood risk of individual properties. That would make it seem less like a government subsidy to people who own homes on or near the water. Another idea is to give homeowners a break on their flood insurance premiums as long as they agree in advance to a buyout that would turn their property into green space if their homes are substantially damaged by a flood. It’s expensive, but it would be a one-time expense and create belts of porous land that offer protection from future storms. Ultimately, the NFIP will be meaningfully reformed. The cost of going on like this is too high, and the exhaustion and frustration of those affected by repeated flooding is too great.
Q. What do we know about the future of flooding?
Koon: Scientists are trying to figure that out. Based on some estimates, we can probably expect between 4 and 8 inches of sea level rise by 2050 and between 1 and 7 feet by 2100. And of course, when sea levels go up, flooding gets worse. Add the storm surge that comes with a hurricane on top of that, and you’ve got quite a challenge. And it’s not just global sea rise that causes problems. Studies show that there has been a 71 percent increase in the amount of precipitation in the heaviest rainstorms and snowstorms in the Northeast United States between 1958 and 2012.
My best guess is that, while all these trends will continue, we are going to become smarter as a society and learn how to adapt. We’re going to learn to build smarter in some places by elevating homes and storm-proofing them. We’re going to retreat and rebuild elsewhere in other places. We’re going to build more resilient infrastructure such as high-capacity drainage systems, water-pervious pavement, and green streetscaping using bio swales and rain gardens and turn chronically flooded parts of cities into urban marshes. As we speak, China is building 16 of what it calls “sponge cities,” which will employ all these green technologies. The future is limited only by our own imaginations and ingenuity. And I’m heartened to see a lot of very bright young people pursuing this in their college and graduate studies.