Out of the Mouths of Corps Managers...

For anyone who wonders why New Orleanians worry about what the Corps of Engineers is doing in the "rebuilding" of the levee-floodwall system -- now renamed the Hurricane and Storm Damage Risk Reduction System -- AP's Cain Burdeau gets the money quote of the year:

"On the East Bank, they had a complete system that failed. On the West Bank, we didn't have a complete system to fail," said Jerry Spohrer, a levee manager on the West Bank.

 

Yeah, you're right.

 

Follow Harry Shearer on Twitter: www.twitter.com/letwits

Comments

[tca]

The National Weather Service Weather Forecast Office says:

"COASTAL HAZARD MESSAGE NATIONAL WEATHER SERVICE NEW ORLEANS LA 353 PM CST SAT NOV 7 2009 ...A COASTAL FLOOD WATCH REMAINS IN EFFECT THROUGH TUESDAY MORNING... [...] THIS PATTERN SHOULD RESULT IN THE INUNDATION OF COASTAL AREAS OUTSIDE OF THE HURRICANE LEVEE PROTECTION SYSTEMS. TROPICAL STORM IDA [...] WILL BE MOVING INTO THE SOUTHERN GULF OF MEXICO [...] LATE SUNDAY. THIS WILL [...] PUSH MORE WATER TOWARDS SHORE MONDAY INTO TUESDAY MORNING. [...] THIS EVENT HAS THE POTENTIAL TO PRODUCE SIGNIFICANT COASTAL FLOODING IMPACTS FOR SEVERAL DAYS. [...] RESIDENTS AND INTERESTS ALONG THE COAST ARE URGED TO MAKE PREPARATIONS FOR MODERATE TO SIGNIFICANT INUNDATION THAT MAY LAST FOR 2 TO 3 DAYS AS TIDES RISE AS HIGH AS 3 TO 4 FEET AND POSSIBLY 5 FEET ABOVE NORMAL AT TIMES THROUGH TUESDAY MORNING...ESPECIALLY ALONG EAST FACING SHORES IN ST BERNARD AND PLAQUE MINES PARISH...AND ALONG HANCOCK COUNTY."

Two things that confuse me are storm surge and flooding. Surge requires a hurricane. Flooding does not. Storm walls are primarily meant to protect against surge. Levees are primarily meant to protect against flooding. Have I got that right?

Hurricane Katrina dumped 9 inches of rain in 6 hours in addition to the storm surge. October was a rainy month in Louisiana. I'm wondering if I should worry about heavy rainfall in New Orleans.

[Bienville]

Floodwalls and levees serve the same purpose. When the water rises, they have to be higher than the water and strong enough to hold the water back. Floodwalls offer advantages over levees in an urban situation.

Floodwalls require a lot less land. For every foot of levee rise, the levee base must widen by 6-10 feet or more. The wider the base of the levee, the greater its strength and stability. Floodwalls are made of concrete and steel and can rise vertically and require very little additional width, or footprint, for additional height. In situations where urbanization are established at the very edge of the levee, either the urbanization must retreat or the additional height is acheieved by building floodwalls at the tops of the levees.

Floodwalls also allow gates for penetrations like highways and railroads. The gates are anchored in pile-supported concrete foundations. They are hinged or on rollers. When the storm apporaches, workers close the gates. Raising a highway to go over a floodwall means rebuilding the road for several hundred feet for each foot of floodwall rise. A railroad must be rebuilt for several thousand feet for each foot of rise. Everyone familiar with the Huey P. Long bridge knows that railroads require much more length to achieve vertical rise than highways. The gates are almost equally effective for far less cost.

Obviously, both levees and floodwalls must be designed and built properly or they are worse than useless.

[Bienville]

Storm surge is the high water level brought ashore by a storm. The low pressure of the storm's eye will raise a broad dome of water surface many feet above the normal level of the ocean. The lower the storm's barometric pressure, the higher the surge it brings. This dome will travel with the storm and can persist for many hours or days after the storm weakens or makes landfall. The storm's winds will add to the height of the surge and if the storm arrives at high tide, the surge will be that much higher.

Flooding is the water spreading across the land. Its causes can be storm surges in coastal areas, rivers and streams overtopping their banks, accumulations of rainfall, or combinations of those.

In August 2005, poorly designed Federal levees around New Orleans failed at far below their design elevations and let the water in. The breaches had to be sealed before the low areas could be pumped dry. That took weeks.

There is an extensive system of storm drains, canals and pumps in the urbanized part of metropolitan New Orleans. Over the years the system has been progressively improved and it can handle very intense rainfaills pretty much city-wide with little more than inconvenience, but there are exceptions.

The River has not flooded New Orleans in over 100 years. Not even the flood of 1927 entered the City, and it had rained almost nonstop for about a year all across the central United States.

[tca]

Bienville, thanks for bothering to explain to me the purpose of floodwalls and levees.

A NASA website post of September 23, 2009 is titled "Flooding Rains in U.S. Southeast Like Those of a Tropical Storm."

The Associated Press ran an article titled "Georgia: September Floods Analyzed" that was published in the New York Times on November 5, 2009. In the article a senior official at the U.S. Geological Survey "said the annual chance of flooding in some of the affected areas was so minuscule that the geological survey could not accurately calculate the probability." Despite this fact it was "near the top of the worst floods in the United States in the past 100 years."

[Bienville]

The Corps learned in 1927 that a "levees-only" policy was not the way to protect the people of the Mississippi River valley. When that first line of defense was breached, all was lost. They have since constructed a system of reserviors and floodways to complement the levees. Various structures along the River will divert high River flows and relieve stress from the levees. The system has worked much better as a result.

The Corps plainly hasn't learned that a "levees-only" policy will not work for hurricane flood protection. They continue to build levees as a first and only line of defense. When that levee fails next - as it must, because the Corps is "baking-in" (with respect to Harry Shearer) the same flaws as the last levees that failed - widespread flooding will again ensue. The Corps is doing the same thing that failed before and is expecting a different result next time. What do you call that?

The President or Congress must order a 8/29 comission to investigate the failed policies and execution of the Corps and create a new system that is more answerable for its failure than the Corps has been. Join Levees.org and sign the petition.

[JoAnn Livanos]

I am astonished about the ire that is directed at New Orleans and her citizens instead of a miserably incompetent and failed federal project that New Orleans has no control over but by which she was catastrophically affected.

[RepugsOut08]

I'm 55 years old. I thought I'd pretty much seen it all.
Yet, I've spent the last year watching the Democratic party and it's leader, in total control of the government, wasting every opportunity to give this country back to the people it has always claimed to represent.
I've watched working class folks and the poor, marching on Washington DC in SUPPORT of health insurance companies!
Nothing astonishes me anymore.

[doctorj2u]

Yeah, but the Westbank will fail when a storm comes in from a different direction because that is what this country does - build subpar infrastructure. It is the best infrastructure lobbyists can buy. Protection of the citizens? LOL! Give me a break!

[GreatNews27]

NOLA is just a memory. In 5 years the gulf will have reclaimed most of it.

[Harry Shearer - Huffpost Blogger]

"Reclaimed" assumes it was ever part of the Gulf before. It wasn't. But I'm sure, with your depth of ecological wisdom, you know that.

[Harry Shearer - Huffpost Blogger]

By the way, your home town sucks, too.

[GeorgeKaplan]

This may be your hope or your wish, but back on planet earth its not going to happen. Too bad you feel that way...

[RepugsOut08]

New Orleans, the reason for Jefferson's historic "Louisianna Purchase."
New Orleans, the birthplace of America's ONLY cultural contribution to the world, Jazz.and Blues.
New Orleans will be here, still being enjoyed, loved and respected, long after you and your children's children have been long forgotten.

[alumcreek]

Nice assessment of gross incompetence.

[HoppinHill]

Folks in SE Louisiana are not the only people in America who live near the water. 55% of the nation's population (156 million people) live in counties protected by levees.

http://levees.org/2009/09/30/new-data-sheds-light-on-georgia-flooding/

Further, 39 of 50 of the nation's largest cities lie partly on a floodplain.

http://www.nced.umn.edu/files/NCED_web_site_documents/Education/educator_resources/k12_resources/activities/floodplainactivity.pdf

[skatoolaki]

Wow....