Duh Concrete Solution

Some things you just think would be obvious, but I guess not:

(Seattle Times) "My recommendation would be to build the levees of something other than earthen materials that would not be so subject to erosion, like concrete."

So spoke Richard Weggel, a civil engineer at Drexel University in Philadelphia. Mr Weggel is supposedly an expert in coastal engineering issues. Either I too am an expert, or the concept is so bleeding obvious that if you want to dam a body of water, and failure is not an option, you don't rely on a mound of dirt to do it!

I've found myself considering another structure that was built over 20 years ago to protect a major city. The stated rationale is certainly of relevance to the after-effects of hurricane Katrina (I've adjusted the wording to see if you can figure out which city this refers to):

A severe flood ... could paralyse the central part of the [transportation system], cause damage to fresh water and sewer systems and disrupt power, gas, telephone and vital data services.

Thousands of homes, shops, factories, businesses and buildings would be affected. It could take months to get [the city] functioning again.

The financial cost of a major flood could be enormous, possibly topping [$55 billion], without counting the cost in human suffering and potential loss of life.

The structure is the Thames Barrier, and it protects London, England from North Sea tidal surges. It was completed in 1982 at a cost of £1 billion. Half a million tons of concrete were used. Sure, this dam system works differently than something that would protect New Orleans from Lake Pontchartrain and the Mississippi river, but the fact is money was spent on a real solution, rather than wishful thinking that the inevitable failure of an earthen wall wouldn't occur, even while everybody expected it would.

Take this story from July 2000 that USA Today has reprinted:

[Joseph Suhayda, director of the Louisiana Water Resources Research Institute at Louisiana State University in Baton Rouge] says the 15-foot levee will protect the city from a minimum hurricane of Category 1 or 2 intensity and at best a fast-moving Category 3 hurricane on the Saffir-Simpson hurricane intensity scale.

"A slow-moving Category 3 or any Category 4 or 5 hurricane passing within 20 or 30 miles of New Orleans would be devastating," Suhayda says.

The storm surge — water pushed into a mound by hurricane winds — would pour over the Pontchartrain levee and flood the city. A severe hurricane could push floodwaters inside the New Orleans bowl as high as 20-30 feet, covering most homes and the first three or four stories of buildings in the city, he says. "This brings a great risk of casualties."

In this type of scenario the metro area could be submerged for more than 10 weeks, says Walter S. Maestri, Director of Emergency Management for Jefferson Parish, which encompasses more than half of the city. In those 10 weeks, residents would need drinking water, food and a dry place to live.

Besides the major problems flooding would bring, there is also concern about a potentially explosive and deadly problem. Suhayda says flooding of the whole city could easily mix industrial and household chemicals into a toxic and volatile mix. Coupled with an estimated 100,000 tons of sediment, a cleanup could take several months. In the worst case scenario, the mix of toxic chemicals could make some areas of the city uninhabitable. "It could take several years for the city to recover fully, economically, from a strong hurricane," says Suhayda.

Nope, none of this is a surprise.

Of course that doesn't make it any less shocking.

The question is, how do we make sure a real concrete solution is what the Army Corps of Engineers comes up with. Where else do we have a looming disaster that we've been neglecting for too long simply hoping it will never happen?

I can think of at least a couple in my neck of the woods, but that's a topic for another day.