We have all seen the pictures of Galveston under water because of Hurricane Ike; The last time this happened six thousand people died. Instead of moving to higher ground, they moved higher ground to Galveston. Back in May, landscape website Pruned posted on Cornelia Dean's Against the Tide: The Battle for America's Beaches:
"Rather than retreating from the shifting sands to points higher elsewhere, the city instead decided to fence itself off from future disasters with a seawall; raised everything inside — houses, churches, offices, trees, gardens — by as much as 17 feet; and then flooded the revealed negative stratum with silt.
It was a "plan that even in an era of engineering daring stood out for its size, cost, and audacity."
(Engineers and surveyors marked the telephone poles to show how high owners needed to raise their houses. In each picture, the is pointing to the same white line)
Even churches got cranked up.
"The lifting operation was one of sheer brawn. Laborers ran beams under the buildings and mounted them on screwjacks that burly men turned by hand. In this way, 2,156 buildings were laboriously hoisted, a quarter of an inch at a turn, until they reached the requisite height and new foundations could be built beneath them. Meanwhile, children climbed rickety catwalks to reach their schools; housewives hung their laundry from lines strung fifteen feet above the ground.
Even substantial structures took to the air. At St. Patrick's Church, a three-hundred ton brick structure, services continued as it rose to the grunts of laborers manning two hundred screwjacks beneath it."
They then pumped fill out of the harbour to raise the ground level to the new, supposedly safer levels.
"Day and night, dredges moved back and forth between Galveston Harbor and this canal, dredging up fill from the harbor bottom and spewing it out on either side of the canal in a slurry of water and sand."
Galveston never really recovered it's role as "the center of commerce for the entire Southwest."- that is why Houston took over as the main port. It is a good model for what might well happen as waters rise again (and what is probably happening in New Orleans)- no matter how much money you throw at the problem and how many walls you build to keep the water out, people tend to learn from their experiences and move to higher ground. ::Pruned