In this US Army Corps of Engineers response [PDF] “to speculation and concern about temporary pumps,” the USACE provides a history of the levees. Some of it can be read as “We told you so”:
In 1965, when the Lake Pontchartrain and Vicinity Hurricane Protection Project was originally authorized, it did not require flood protection improvements along the 17th Street, London Avenue or Orleans Avenue Canals. The reason for this was that the proposed barriers at the Rigolets and Chef Passes were intended to keep the design storm surge out of Lake Pontchartrain.Implication: If the barriers at the passes had been built, the floodwalls at the outfall canals would have held.
Why weren’t the barriers at the passes built? According to the USACE, the environmentalists shut them down:
In response to the 1977 injunction (due to a lawsuit by Save Our Wetlands) challenging the Corps’ Environmental Impact Statement, the Lake Pontchartrain and Vicinity Hurricane Protection Project was re-evaluated. The 1985 Reevaluation Report by the Corps eliminated the Rigolets and Chef Barriers from the project and, instead, recommended higher levees along the southern lakeshore of Lake Pontchartrain.And the outfall canal levees were then deemed inadequate, leading to the inadequate construction of floodwalls on the 17th Street Canal and London Avenue Canal.
This version of the history of the levees is accurate, but (surprise, surprise) inadequate. It leaves out an interesting detail that the Government Accountability Office included [PDF]in its history:
In fact, Corps staff believe that flooding would have been worse if the original proposed design had been built because the storm surge would likely have gone over the top of the barrier and floodgates, flooded Lake Pontchartain, and gone over the original lower levees planned for the lakefront area as part of the barrier plan.More official UASCE history [PDF]:
In the mid to late 1980s, the Corps of Engineers recommended the construction of storm surge gates at the London Avenue and Orleans Avenue outfall canals to block the design storm surge from entering the canals.The gates, of course, are being built now, along with gates at the 17th Street Canal.
Continuing the history lesson:
Ultimately, for the 17th Street Canal, the Corps agreed to and recommended construction of the locally preferred plan which consisted of floodwalls instead of a structure at the mouth of the canal. The Corps agreement was based on the fact that the estimated cost for each alternative was almost equal.Implication: Politicians forced the USACE to build floodwalls on the London Avenue and Orleans Avenue Canals instead of what they wanted to do, build gates, which they are now building.
The cost for the gated structures at London Avenue and Orleans Avenue outfall canals was far less expensive than the locally preferred floodwalls. Therefore, the Corps maintained that the additional costs for construction of those floodwalls would have to be paid by the local sponsor. The local sponsor, the Orleans Levee District, did not want to pay those additional costs.
Finally, Congress passed the Energy and Water Development Appropriations Act (EWDAA) of 1992 that directed the Corps of Engineers to construct floodwalls along London Avenue and Orleans Avenue outfall canals, the locally-preferred plan.
My opinion: the USACE public relations strategy is “We didn’t build a defective levee system. We were forced by local interests to build a levee system we didn’t want to build, which ultimately failed. We are now building the levee system we had originally planned to build. We hate to say it; but, we told you so.”
Of course, my opinion doesn't get written into the history books.