Tidal Interchange Structures? Will they work against surge while simultaneously protecting the wetlands?

It's an engineering problem. Can you build a structure that can penetrate a protection levee, remain open most of the time and close reliably when extreme weather threatens? Typically you approach this type of problem with prototypes and use time to perfect the engineering. Time is not on our side so the probability is that we'll build a system at enormous expense out of unproven prototypes and learn as we go.

Corps officials could name only one project in the New Orleans area where such a structure exists: a section of the eastern New Orleans levee enclosing about 13,000 acres of the Bayou Sauvage National Wildlife Refuge.

Constructed in the 1980s, the levee has four "flap gates" built into it to allow water movement. But refuge managers complain the gates are overly labor intensive and require frequent maintenance.

"They don't function like they were intended to function," said refuge lead biologist James Harris. "Most of the flap gates that control water are gone, they've rusted off. It makes management that much more difficult for us, because now we're constantly opening and closing the gates."

Matthew Brown at the TP 1/2007

Does the Corp know how many leaks are necessary to protect the wetlands. The Morganza to the Gulf project proposes one culvert every two miles. Is that enough to protect the environment or does it just protect the construction budget? Is there adequate money for maintenence? Skepticism is natural given the results we've seen from new engineering products of this organization.

Engineering is important. It takes time and effort to get it right. Too often sponsors don't understand this problem and want to mass produce a product before the work is done. Congress is a particulary difficult sponsor.