But the climate is not changing fast enough to explain the dramatic spikes in disaster costs; all seven of the billion-dollar floods in American history have made landfall in the 21st century, and Harvey will be the eighth. Experts believe the main culprit is the explosive growth of low-lying riverine and coastal development, which has had the double effect of increasing floods (by replacing prairies and other natural sponges that hold water with pavement that deflects water) while moving more property into the path of those floods. An investigation last year by ProPublica and the Texas Tribune found that the Houston area’s impervious surfaces increased by 25 percent from 1996 to 2011, as thousands of new homes were built around its bayous. Houston is renowned for its anything-goes zoning rules, but the feds have also promoted those trends by providing extremely cheap insurance in high-risk areas.
Created in 1968, the national flood program was actually supposed to help prevent risky development. Its complex rules required new construction within designated 100-year floodplains to meet higher floodproofing standards, and “substantially damaged” properties that received claims worth half their value to be relocated or elevated. But most of the program’s 100-year flood maps are woefully obsolete, relocation almost never happens, and Uncle Sam has continued to cut multiple checks for repetitive losses. A recent Pew Foundation study found that the Higher Ground problems have not been solved; about 1 percent of insured properties have sustained repetitive losses, accounting for more than 25 percent of the nation’s flood claims. One $69,000 home in Mississippi flooded 34 times in 32 years, producing $663,000 in payouts. The government routinely dishes out more in claims than it takes in through premiums, and the program has gradually drifted deeper and deeper into debt.
That is from a superb Politico piece by Michael Grunwald.