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The Corps and industry also tore up the marsh by dredging
hundreds of miles of channels so pipelines could be laid. Even
bigger navigation channels were dug, and wave erosion from ships
turned those cuts into gashes that allow hurricane-induced surges to
race into the city. Similar practices are in play at many of the
world's deltas, which could well benefit from plans such as those
now being considered in Louisiana.
Too Late to Be Saved?
The 1998 plan for protecting the
Mississippi Delta region, titled Coast 2050, and a modified scheme
in 2003 known as the Louisiana Coastal Area plan (LCA), called for
gates to be inserted into the river levees. The gates would open at
certain times of the year to allow freshwater and sediment to wash
down into the wetlands, gradually restoring them. But "a growing
number of people are recognizing that Katrina and Rita changed the
landscape enough that they may have made Coast 2050 and LCA
obsolete," laments Len Bahr, a leader in the Louisiana Governor's
Office of Coastal Activities for 15 years and an architect of Coast
2050. |
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| Furthermore, because the storm surge entered New
Orleans from Lake Pontchartrain to the north and navigation channels
to the east, "those plans would not have stopped Katrina," observes
Hassan S. Mashriqui, an assistant research professor at L.S.U.'s
Hurricane Center who has enhanced the university's 1998 surge
models. He says the models show that gates across certain channels
into the city would also have been needed to divert the surge.
Those gates would have done nothing for the rest of southeastern
Louisiana, however. Scientific American therefore asked a
wide range of experts to present solutions for the region. Three
strategies emerged: a tight ring around the New Orleans metropolitan
area alone; a comprehensive, 440-mile levee system that would snake
from the Mississippi border halfway to Texas but lie only partway to
the shoreline, leaving the coast for lost; and an outer shield
around the region's perimeter, such as the one in the Netherlands,
which would spare every locale. The ring and comprehensive plans
would inevitably leave some people "outside the wall." All three
plans include gates of some kind that are not now in place.
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| Although each approach has its proponents, the
parties agree on one thing: critics who say it is foolish to rebuild
in such a vulnerable place are missing the big picture. In addition
to being a cultural center, "the Gulf Coast is the economic engine
that drives the country," Bahr declares. "We can't possibly abandon
it." The delta produces one fifth of the country's oil, one quarter
of its natural gas, and one third of its seafood. Trillions of
dollars of goods and crops flow through the ports there. These
activities require extensive infrastructure and tens of thousands of
employees who cannot live in temporary trailers or in homes two
hours away.
A New Path
Before any plan is implemented, designers
should understand fully why the existing levees failed, so
weaknesses can be avoided in the future. Four teams are
investigating the levee and canal wall collapses in New
Orleans--from the American Society of Civil Engineers, the Corps,
the state of Louisiana and the National Science Foundation.
In October, Secretary of Defense Donald Rumsfeld announced that
the National Academy of Sciences would review all the reports to
ultimately determine why flood walls crumbled [see Working
Knowledge, on page 92]. Rumsfeld said the academy would finish
by June 2006. Yet hurricane season officially begins June 1, and
Richard Wagonaar, a U.S. Army colonel and commander of the Corps'
New Orleans district, says his goal is to restore all federal levees
to their pre-Katrina level of protection (able to withstand Category
3 hurricanes) by that date. President Bush had asked Congress to
appropriate $1.6 billion to repair levee damage from Katrina and in
December requested another $1.5 billion to improve city levees at
Category 3 levels. |
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Winner Takes All 
FEATURE
ARTICLES 
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