The price of protection
The battle to save New Orleans from hurricanes begins in Louisiana delta
HOPEDALE, La. -- Raymond Krennerich and his neighbors have the misfortune of living on the delta of land that separates New Orleans from the Gulf of Mexico.
Once, that land helped protect the city from the sea.
But over the last century, roads were built to reach new homes. Canals were dug to provide shipping shortcuts and spur economic development. Levees were constructed to protect inland residents from Mississippi River floodwaters.
That work eroded natural barriers and made New Orleans -- and Krennerich's tiny community -- much more vulnerable to the storm surges brought by Hurricanes Katrina and Rita this summer.
To prevent a similar catastrophe from happening again, government officials say they need to weave nature back into the landscape -- perhaps undoing some of the man-made projects, perhaps adding more. And politicians may need to tell some people and businesses they can't rebuild.
''We can't put the natural system completely back, but we can slow the rate of decay . . . stop the bleeding," said Rex Caffey, an associate professor at Louisiana State University's Sea Grant Program, a federal university-based ocean research and education program. ''But it is going to be fraught with a lot of challenges."
It's not yet clear what those measures would mean for Krennerich, whose house was washed out to sea on Aug. 29.
''This is the only place I've ever known," said Krennerich, a shrimp fisherman, who has lived his entire life in the house.
St. Bernard Parish once shielded New Orleans from storm surges. Part of an ancient delta built by Mississippi River sediments, its miles of cypress forest and freshwater marshes absorbed and slowed the force of storm waters from the Gulf of Mexico. Freshwater floods from the Mississippi periodically washed over the region, depositing new sediments to replenish sinking land.
Then, about 40 years ago, a shipping channel was built a mile behind Krennerich's house as a shortcut to New Orleans. After a few years, cypress trees near its banks began to die from seawater that leaked from the canal. Slowly, the saltwater seeped through to a cow pasture closer to his house, turning it into a gooey marsh.
''It got so bad in that pasture. . . you had to put hip boots on those cattle," said Krennerich, 42, in a drawl born of a lifetime in the bayou.
By last year, he needed the rubber boots for his own yard when the tides were particularly high.
All around him, similar problems were developing, some so subtle that no one noticed.
Streets and man-made canals had created barriers, preventing salty stormwater -- which kill the fragile marsh plants -- from flowing back out to sea after storms. Enormous levees, built to protect St. Bernard's 67,000 residents from Mississippi River floods, blocked sediment from reaching and replenishing the marsh's soil. With less soil, water levels rose and fewer plants thrived. Slowly, square miles of marsh were turned into open water.
Then, when the giant storm surge rushed up from the Gulf of Mexico during Katrina, there was far less marsh grass to slow it down. And, the shipping channel behind Krennerich's house funneled the water toward New Orleans, where it overwhelmed the city's flood protection system and left neighborhoods in ruins.
Now, local leaders are struggling to figure out what to do.
If they do nothing, scientists predict that future hurricanes will eat away more of the coast, ultimately endangering more people and businesses. Federal officials estimate that as much as 39 square miles of marsh in southern St. Bernard and an adjoining parish were lost during Katrina.
''We're losing the protection system so fast," said Virginia Burkett, chief of the Forest Ecology Branch at the National Wetlands Research Center of the US Geological Survey.
It is possible to create more protections, rather than tear down existing infrastructure, Louisiana State University and USGS scientists said.
Existing levees would have to be built up to protect heavily populated areas, and redesigned to allow sediment to reach the sinking land. New levees would have to be built along some canals to prevent saltwater from seeping in. Vast numbers of cypress trees and marsh grass would need to be planted.
But history shows that previous efforts haven't worked as well as planned to slow the loss of coastal land: 20 to 25 square miles disappear annually, the equivalent of one football field every 38 minutes. Wetland restoration programs were under-funded. In part to save oyster beds, two key floodgates have been operated at only 10 percent to 15 percent of capacity in recent years.
And something will have to be done to the Mississippi River Gulf Outlet shipping channel -- whose acronym, MRGO, led locals to call it ''Mr. Go"
Hopedale, with only one road and too small to be included on most maps, was destined to be slowly swallowed by the sea, but scientists say the channel dramatically hastened its demise, by injecting saltwater into the marsh. Scientists have also warned for years that the channel would push floodwaters into New Orleans.
Now, scientists and residents are renewing longstanding cries for the channel to be plugged. An Army Corps of Engineers official said no decision has yet been made to close it.
Even more controversial: Some scientists are suggesting that some area homes and businesses may need to be bulldozed so the marsh's balance could be restored. Or at least, they say, government shouldn't help rebuild them.
''So maybe you say you live there on your own risk," said Don Davis, research professor at Louisiana State University, who has long studied coastal issues. ''If you want to live in a coastal area, this is the result."
Krennerich has a problem with that kind of talk. Why should he be punished, he says, when the problem is not his legally built house -- but a government-built channel that contributed to the destruction of his home. Maybe Katrina was going to take his house anyway, but Mr. Go helped.
''This isn't our fault," Krennerich said. ''Before Mr. Go, we had these beautiful cypress and live oak trees. It's all gone now. I'm going to rebuild, but Mr. Go has to go. I'm not going to live anywhere else."
Beth Daley can be reached by email at bdaley@globe.com. 