Gulf states reexamine building in flood plains

A South Carolina developer has been producing glossy ads to tout its $1 billion project along the Congaree River: 4,600 acres earmarked for development in an area prone to seasonal flooding.

"This is a flood plain," says the ad, showing manicured developments in other parts of the country protected by basins and levees, suggesting what can be safely done.

But at a recent City Council meeting in Columbia, S.C., opponents of the Congaree project pointed to the lives lost and damage done in Houston by tropical storm Allison - and lawmakers are taking notice.

"This will be a real test of whether Columbia will become a flood-plain city," says Bob Wislinski, spokesman for a local task force studying the development.

The debate echoing amid the palmetto of South Carolina is one being repeated with varying intensity across the country.

After every sudden surge of the Mississippi or some other river, residents look at their vulnerability to floodwaters and weigh options to keep basements from turning into boathouses. Many cities in the Midwest, in particular, have taken aggressive steps in recent years to limit development in flood-plain areas - and even pay people to move out.

Now a similar debate is erupting across parts of the South in the wake of the $2 billion in damage done by Allison.

Underlying the civic questioning is a growing realization of how much damage - and loss of life - floods can cause. While attention often focuses on the devastation produced by hurricane winds and storm surges along the coast - and it can be significant - flooding is the real killer.

A recent study by the Tropical Prediction Center in Miami found that almost 60 percent of the people who perished in tropical cyclones (which includes hurricanes and severe storms) in the US since 1970 did so by drowning. Many of them were in inland counties, says Ed Rappaport, author of the study.

Intense rainfall is not directly related to the winds of cyclones. Some of the greatest rain accumulations occur from weaker storms that drift slowly or stall over an area. In fact, six of the 10 deadliest storms in the past 30 years occurred early in the hurricane season when air currents were too weak to steer a weather system out of an area. That's what happened with tropical storm Allison. It dropped over three feet of rain in Houston in three days, killing 22 people and forcing thousands into shelters.

The concern about flooding is especially relevant in the Gulf states, where severe weather and population growth is creating new risks. Engineers have been trying to control the water in southern cities for years with an elaborate maze of canals, drainage basins, and levees. But more black top and black skies - the South gets nearly 60 percent of all the rainfall in the US - is raising pointed questions about whether cities can simply build their way out of problems.

"With this increase in population in such an active weather arena, the potential for risk grows...," says Bill Proenza, director of the National Weather Service's southern headquarters in Fort Worth, Texas.

In many southern cities, the funding for dikes and other projects to harness the landscape continues unabated. Earlier this month, the Harris County Flood Control District (which includes Houston) increased its projects budget to $589 million for the next five years. And $537 million has been set aside for projects in southern Louisiana, including lower-than-sea-level New Orleans.

This bayou city, ringed by levees, is especially susceptible to flooding because of its proximity to the Gulf of Mexico and the Mississippi River. Recent studies show that the coast of Louisiana is sinking at a rate of 1 inch per year. In 100 years, land that's 70 miles from the coast now will be underwater, says Roy Dokka, a geologist at Louisiana State University in Baton Rouge.

His findings suggest that today's levees won't be able to withstand tomorrow's big storms. "Every place in the US is subject to flooding within a flood plain," he says. "But should we, as a society, invoke special conditions to live on them? The costs are high."

(c) Copyright 2001. The Christian Science Monitor