Laura Bliss is CityLab’s west coast bureau chief, covering transportation and technology. She also authors MapLab, a biweekly newsletter about maps (subscribe here). Her work has appeared in the New York Times, The Atlantic, Los Angeles magazine, and beyond.
Better planning, stricter construction standards, and expanded insurance can help cities prepare for the next “1,000-year rain.” But they won’t be enough.
With an estimated 40,000 homes damaged, 30,000 people rescued, and 11 known dead, the Louisiana floods are a natural disaster of astonishing scale—the worst since Hurricane Sandy, according to the Red Cross. More than 25 inches of rain fell in some parts of the greater Baton Rouge area over three days this past weekend, delivered by an unusual slow-moving low-pressure storm system that “carried enough precipitation to rival a hurricane,” according to the New York Times. The National Weather Service officially declared it a “1,000-year rain”—meaning that the chance of such dramatic precipitation occurring in a given year was less than .1 percent. Yet as many scientists point out, freak storms like these are increasingly the norm as the atmosphere warms up.
Which raises the question: What could Louisiana’s hard-hit communities have done better to survive such an extraordinary event?
Provide better real-time information
As record-high crests along the Amite and Comite Rivers unfurled throughout the greater Baton Rouge area, many roads and highways quickly became impassable, cutting off access to several communities. For example, roads leading into the city of Central went completely underwater, leaving the area virtually isolated. To escape, residents had to scramble to synthesize closure information from local police departments’ social media accounts, the state department of transportation’s website, and parish-by-parish flood zone maps.
More accessible real-time information that gathers and maps road closures and water levels would help people evacuate faster, safer, and more confidently, says Craig Colten, a geography scholar at Louisiana State University focused on coastal resilience and the history of flood planning.
“There needs to be one authoritative regional source”—perhaps the website of the state's emergency management agency—“that people can rely on,” he says.
Stop building in flood zones
A lot of the places that suffered the worst flooding this week were, perhaps not surprisingly, in Special Flood Hazard Areas, which is how FEMA designates communities that have a one-percent annual chance of flooding. One of them was Centurion Estates, a subdivision east of O’Neal Lane and south of Florida Boulevard, which saw rainfall up to the rooftops. Many of the homes in Centurion were built before 1978, the year FEMA created its first Flood Insurance Rate Maps, giving citizens and planners a much fuller picture of their flood risk (and insurance requirements) than before. But plenty more homes were built within the last 15 to 20 years, an indication that community planning has not emphasized flood safety.
An even more striking example can be found in Magnolia Farms, a brand-new subdivision where “sale pending” signs are still dangling in front yards. Flood waters rose to the windows of many of its new homes. Magnolia Farms is located in Denham Springs, another SFHA. “There’s a lot of emphasis on development at the local level, because there’s interest in increasing the tax base,” says Colten. “Development spawns more development, and safety gets pushed to the background.”
Better land-use planning that points construction to less flood-prone areas would likely save Louisiana money and lives in the long run. Why isn’t this obvious in a low-lying state that receives an average 62 inches of precipitation every year? Many Louisiana communities lack the resources to undertake and enforce serious flood planning. And even those that don’t may suffer from a psychological gap, says Colten. “We’re not able to sustain a sense of urgency between these tragic events,” he says. “I don’t know that these floods will help us overcome this.”
Keep building flood protection
Also connected to a lack of urgency between major floods: It’s been hard to sustain momentum and funding for major flood protection projects.
The unfinished Comite Flood Diversion Canal, for example, has been in the works since 2000 (though discussion about it dates back to a major flood in 1983). Located north of the confluence of the Comite and Amite Rivers on the eastern side of Baton Rouge, the $211 million canal is designed to ease flooding along the Amite—whose banks rose to record heights this week—by funneling the water to the Mississippi. Some officials said that had the canal been completed before this week’s storm, more homes could have been saved. But while plans have been drawn and land has been purchased, the canal remains un-dug.
Officials variously blame a slow-moving Army Corps of Engineers, local government’s less-than-aggressive funding search, and the state’s lack of financial assistance. "What is so frustrating about this is ... you spend billions of dollars after a disaster instead of millions of dollars before," Louisiana congressman Garret Graves told the Advocate on Tuesday.
Raise the floors
Meanwhile, Louisiana has been comparatively lax in waterproofing its construction regulations. East Baton Rouge and Livingston parishes do have freeboard standards, which are essentially minimum height requirements above FEMA-designated flood levels that new construction must meet. But their one-foot standards might not be high enough, and they’re among the few places across the state that have any such stipulation at all. By comparison, “twice as many communities in Illinois have adopted more stringent construction standards than in Louisiana,” says Rob Moore, a senior water policy analyst with the Natural Resource Defense Council. “By that measure Louisiana is far less proactive at making itself less vulnerable, despite its experience with hurricanes, floods on its rivers, and the recognized problems of sea level rise.”
Expand the National Flood Insurance Program
A vast number of homeowners rebuilding after this week’s floods —which caused an estimated $1.5 billion worth of damage—will do so without the benefit of flood insurance. After all, some of the communities that flooded this week were outside of SFHAs. For these areas, property owners aren’t mandated to a buy a policy through the National Flood Insurance Program, and as a result, many forgo it. This is a big problem nationwide—FEMA estimates that “between 66 percent and 80 percent of flood losses occur outside of SFHAs.” And it’s a really big problem in flood-prone Louisiana, where, even with one of the highest numbers of active NFIP policies in the U.S., only 20 percent of homes are insured, according to the Times-Picayune.
That’s why it might be worth listening to experts who have called for expanding the mandatory territory covered by the National Flood Insurance Program by, say, including folks who live in 500-year flood zones (i.e., where the chance of annual flooding is 0.2 percent). This would in turn expand the pool of payments, lower premiums for everyone, and offer more people a safety net in the event of disaster.
But how much can you actually plan for?
Clearly, Louisiana communities can do more to batten down for storms. And plenty have made important strides. For example, the badly damaged parishes of East Baton Rouge, Ascension, and Livingston all participate in FEMA’s Community Rating System program, which subsidizes flood insurance rates in exchange for community-wide flood resiliency measures (such as freeboard standards). At the state level, Louisiana plans to invest close to $750 million to restore its coastline in 2017 alone.
But perhaps the most important point is this: All the diversion canals, freeboard standards, and flood insurance policies in the world would not have entirely saved Baton Rouge from the damaging effects of 25 inches of rain in three days. It’s a stunning amount, anomalous by every measure. “This was above and beyond anything that I think you could really could prepare for,” says Melissa Daigle, a resiliency specialist with Louisiana Sea Grant Law & Policy Program, who lives a few minutes away from (and a few feet above) some of the worst-flooded areas in the city.
This week’s disaster is the sort of event that causes some climate experts to question the federal approach to flood risk assessment, which only includes historical data and doesn’t take into account current conditions or projected changes. The probability of encountering what were once extreme events is higher than it once was. And the storms of the future may be far outside the realm of the best predictions, says Brian McInerney, a hydrologist with the National Weather Service. They force scientists to re-evaluate what’s considered a large event.
”It gives you a sense of anxiety that all of your science is not adequate to deal with what may be coming,” he says. “When I go to work and sit in front of all of these radar screens, there is a little voice in back of my head that says: ‘It might be different than what you’re seeing here.’”