Levies and wetlands

[nebula]

Sorry to start a new topic on this - but with so many threads going on, I didn't know where best to post these articles.

But I thought they put a different perspective on the problems.

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Article 1

(highlighted portions are mine)

Storm surge the fatal blow for New Orleans Levees fail to hold back water

By Peggy Mihelich

CNN

Wednesday, September 7, 2005; Posted: 11:16 a.m. EDT (15:16 GMT)

(CNN) -- Hurricane storm surges have resulted in limited flooding of the city of New Orleans before. But Hurricane Katrina's winds pushed in a devastating surge of water from the Gulf of Mexico that overwhelmed the city's system of levees built to hold back the surrounding Mississippi River and Lake Pontchartrain.

(SNIP)

"Katrina was a very large storm, high energy, high intensity coming across the gulf," said Elizabeth English, an associate professor at Louisiana State University's Hurricane Center.

"When the wind speed began to go down the storm surge did not dissipate. ... There was essentially a lot more momentum in the water than there was in the wind," said English.

As Katrina moved over land Monday the water it brought surged into Lake Pontchartrain. (Watch the video of water filling the city -- 1:52)

A day later, the straining levees could not hold back the additional water and they broke in three places -- along the Industrial Canal, the 17th Street Canal, and the London Street Canal -- allowing water to pour into the city. (Map: See where the levees' broke)

The lake, which normally is 1 foot above sea level, peaked at 8.6 feet above sea level, said English.

As of Thursday afternoon the water had dropped to 2.5 feet above sea level.

"This is what we've been saying has been going to happen for years," Walter Maestri, emergency management director in neighboring Jefferson Parish, said Monday. (Watch the video report on plugging the holes -- 3:53)

The widespread damage to the city has much to do with its topography, or "lay of the land," English said.

New Orleans sits mostly below sea level on swampland on the east bank of the Mississippi River and south of Lake Pontchartrain.

"A lack of coastal irregularities," such as substantial barrier islands or hills, and the Gulf of Mexico's flat bottom make southern Louisiana "ideal for wave damage," according to the National Weather Service Web site.

"Storm vulnerability is made worse by ongoing wetland loss and barrier island erosion," according to the U.S. Geological Survey Web site.

To prevent flooding, a system of pumps, canals and levees was put in place by the Army Corps of Engineers.

Construction of levees along the river and lake over the centuries has led to a rise in the water levels, according to the National Weather Service. Each increase of the level of water puts more pressure on the levees.

The levee system is quite extensive, but had been built only to withstand a Category 3 hurricane, English said. (See video of why the levee's breech was devastating -- 1:53)

"It's not that people are willfully saying we're only going to build it to a Category 3 [rating], and that's where we'll stop. It's just that's as far as the levee system had developed," English said.

"You can't strengthen every part of it in exactly the same way at the same time. And, like a chain, it suffers from the weakest link."

"It certainly couldn't have been a surprise to the Army Corps of Engineers. They knew how risky this whole levee system has been and is," "New Orleans Times-Picayune" reporter John McQuaid told CNN on Friday.

McQuaid, who wrote a five-part, award-winning series on the vulnerability of the levee system, says "there was sort of a cross-your-fingers mentality." (Read: "Times-Picayune" Special Report: Washing away)

"Something like this depends on a storm hitting at a very precise angle, at a very precise strength, which is relatively unlikely. It's hard if you're in Congress or the Corps of Engineers to make an argument to say 'Look, we need billions of dollars to fix this problem' when you can't exactly quantify -- whether it's going to happen next year or in 100 years," McQauid said.

(SNIP)

Katrina is not the first massive storm to test the Lake Pontchartrain Basin levees.

In the wake of the hurricane of 1947 (the current naming system did not begin until 1953), levees were built along the south shore of the lake to protect Orleans and Jefferson Parishes, according to the USGS.

Officials raised existing levees in response to the flooding caused by Hurricane Betsy in 1965. Hurricane Georges in 1998 showed the vulnerability of the city and efforts were made the following year to improve the levee system, according to the USGS.

Full article: Click here

[nebula]

Article 2

Scientists want help to save Louisiana wetlands

Expert: Eroding coast an environmental time bomb

Monday, September 5, 2005; Posted: 10:03 a.m. EDT (14:03 GMT)

BATON ROUGE, Louisiana (AP) -- Windell Curole is wryly understated when he talks about how Hurricane Katrina has brought to light an environmental time bomb that he has talked about for years: the eating away of Louisiana's coast.

Now, Curole and his fellow scientists and environmentalists hope the federal government will use the rebuilding of New Orleans as an opportunity to also save the state's rapidly disappearing wetlands.

"For years and years I had hoped that the facts would get the country to intellectually understand what could happen," said Curole, a hurricane expert and coastal restoration advocate. "I think we've got their attention."

Since the 1930s, according to scientists, Louisiana has lost about 1,900 square miles of marsh and swamp, and stands to see another 700 square miles slip away by 2050 if drastic measures aren't taken.

Much of the marsh already gone was south of New Orleans, moving the city closer and closer to the Gulf of Mexico and consequently closer to hurricane storm surge. (Full story)

Scientists blame both man and nature for erosion of the Mississippi River's delta: oil speculators, massive clear cutting of coastal forests, oil drilling, buildup of the coast and construction of levees on the Mississippi combined with a rise in sea levels and the sinking of land caused by shifting geologic faults.

Louisiana officials began trying to stem the loss only in the last 15 years, and now wants Washington to not only help upgrade its flood protection system but also help restore its coastline. Until now, restoring the coast and improving the levees and floodgates were mostly seen as two projects.

The money could be given to the state and the U.S. Army Corps of Engineers on top of $10.5 billion in disaster aid for New Orleans that was approved by Congress on Friday.

What advocates fear is that the federal government will spend billions of dollars on bringing New Orleans back without going further.

"This can't just be a cleanup, it has to be a turning point," said Mark Davis of the Coalition to Restore Coastal Louisiana, a lobbying group. "If we build it back like it was, then we'll be living in a fool's paradise."

For the full article: Click here

[Keith]

I read both articles, Neb, thanks for posting them. I'm all for leaving the area to the marshlands.

Trying to rebuild an entire city and it's surrounding areas is far more expensive than anyone has the money for at this time. At the very least, if New Orleans must be rebuilt, it doesn't have to be done soon. Rebuilding an entire city that's half underwater is not high on the economic priority list.

The money for rebuilding should be used first, around the edges of the damaged areas and then work inward. Rebuild the areas in Mississippi and Alabama and the outer areas that Katrina damaged first.

As for New Orleans: To the wonderful, decent people who lived and lost there, you are in my prayers and I'm very sorry for your loss. May God comfort and guide you in rebuilding your new lives.

To the sin and wickedness that devoured New Orleans: Bye!

"God's provisions are strategically located along the path of your obedience." C. Elijah Bonner