It also brought to light the way our concerns about economics can compromise people's safety when we attempt to control Nature.
Over one million people in the Gulf area were affected by "the storm," as residents call it, including just about everyone in New Orleans. Ninety percent of this 485,000-person city evacuated as 125,000 homes were severely damaged and 250,000 homes were summarily destroyed.
"The 150 mph winds from the east funneled water into the man-made navigation canals and the Category 5 surge strength made the levees breach starting with the 17th Street Canal of the Industrial Canal," said Richard Campanella, associate director of Tulane University's Center for Bioenvironmental Research and a research professor with Tulane's Department of Earth and Environmental Science. "Sixteen feet of water poured into an area that was four feet below sea level. That caused a flood of 20 feet in St. Bernard Parish and the Lower 9th Ward. This area had been developed after Hurricane Betsy [of 1965]."
They both spoke at the annual conference of the American Planning Association (APA) recently, which focused on the effects of Katrina and the recovery effort.
"Topography does matter," said Campanella, who pointed out that sea level increased by four inches during the 20th century and predicted that in another 100 years they will rise another 41 inches, mostly due to climate change. (The U.S. Global Change Research Program reports that by 2100 global sea level is projected to rise 19 inches along most of the U.S. coastline.)
The "Big Muddy"
The Mississippi River remains a key influence on life in the Crescent City. It stretches 2,320 miles from Lake Itasca, Minnesota, to the Gulf of Mexico, just 95 river miles south of New Orleans. The "Big Muddy" is the largest river system in North America and it includes all or parts of 31 states from the Rocky Mountains in the west to the Appalachian Mountains in the east to the U.S.-Canadian border in the north.
Every spring for thousand of years, the river's banks have overflowed as million of tons of sand, silt and clay sediments settled and nourished wetlands and formed the delta coastline of southern Louisiana. Traditionally, the river and its distributaries were able to compensate for subsidence with fresh sediment spread in floods and decayed vegetation that turned into soil. That all changed when Congress decided it could tame the river.
Before cities were built, native peoples merely moved their stuff to higher and dryer ground when the floods came, and they continued with their lives, according to John McPhee in his book, The Control of Nature. In the nineteenth century, Congress funded the building of levees to hold back the floodwaters and several drainage projects in the wetlands as means of preventing disease and encouraging economic development. While this strategy has reaped hefty rewards for the farmers and industrialists who took advantage of the river's navigational assets, it reveals the folly of the unremitting determination to control Nature with the Army Corps of Engineers at the helm.
The Mississippi River has served as a major navigation route for Native Americans, explorers, and modern commerce. In 1718 the French built a fort on the high ground of a portage route through Lake Pontchartrain and up the St. John Bayou. This fort would become the town of New Orleans. Even back then its soil was soft, the water table high, and the area prone to storms and floods. Nevertheless, the fort provided a strategic position for viewing ships about to enter the mouth of the Mississippi River. It also saved 100 extra miles of travel from the port cities of Biloxi and Mobile, which were both founded in 1682. A few months after the fort was built, tragedy struck and like a harbinger of bad things to come, the settlement flooded.
A series of geopolitical events in the late 18th century also greatly impacted New Orleans, said Campanella. The slave insurrection in Haiti in 1791, the cotton boom of 1793 and the granulation of sugar in 1795 made the city a major port. President Thomas Jefferson recognized the strategic and economic importance of the city at the mouth of the Mississippi River and bought it from Napoleon in 1803. He got half a billion more acres of land (863,072 square miles) stretching across the Great Plains on a good deal known as the Louisiana Purchase.
Campanella said that land in 19th century New Orleans was far more resilient than it is today because the whole area was at or above sea level and buffered by healthier wetlands. The first levees were built in 1828, that's when the trouble started: the river refused to be confined and every once in a while it lashed out with a terrible flood.
In 1850 Congress wanted higher and stronger levees so it passed the Swamp and Overflow Land Act to give states bordering the Mississippi acres of land that they could then sell to help finance levee construction. Much of this land was a swamp, so farmers and plantation owners drained them and then demanded more flood protection.