Unfinished 1965 Project Left Gaps

As investigators scrutinized the city’s levees after Hurricane Katrina, they were astounded by what they had discovered along the Orleans Canal: lengthy gaps in the concrete flood walls designed to protect the central city.

For hundreds of feet near the canal’s endpoint, the levees on both sides were built 9 feet lower than on the rest of the 3-mile-long canal, allowing water from Lake Pontchartrain to pour into the city during the storm surge.

“It made no sense to us to line miles of canals with levees and then leave a gap like that,” said Raymond Seed, a UC Berkeley engineering professor who is heading a National Science Foundation investigation. “It basically failed before the storm began.”

Although much of the flooding in New Orleans resulted from engineering failures, the gaps in the Orleans Canal and elsewhere were caused by something more mundane: funding shortages and poor planning.

The city’s hurricane protection system was authorized by Congress in 1965, but it was only 90% completed when Katrina struck, and the unfinished work created many weak links in the system.

There were dozens of low points in the levee system that contributed to the flooding, according to National Science Foundation and Army investigators.

Bridges that crossed several levees were lower than the levee walls in several areas, said Paul Mlakar, who is leading the field investigation for the Army Corps of Engineers. Flood water poured through gaps on the London Avenue bridges.

Massive gaps also exist on another waterway, the Inner Harbor Navigation Canal, known locally as the Industrial Canal. At least three major breaches on the canal were to blame for devastating flooding in the Lower 9th Ward and parts of adjacent St. Bernard Parish.

Even before the canals breached, the levee system’s complex patchwork of construction, uneven heights and gaps allowed water to pour into the Lower 9th Ward. On one section of the Industrial Canal, a railroad bridge that passes through openings in the walls was supposed to be sandbagged in the event of a hurricane. The sandbags were either never readied for Katrina or they washed away, Seed said.

The gaps on the Orleans Canal ensured that it could never fill up during Katrina, relieving pressure on the storm walls. Indeed, the gaps were left to prevent storm surges from pressing against the walls of a century-old pumping station, which could not bear the pressure.

Completing the levee would have also required reinforcing the pump station walls, and the entire project was budgeted at $10 million. The Bush administration elected not to fund the project in each of the last three fiscal years.

“We’ve been trying to get money the last few years, but the money just dried up,” said Stevan Spencer, chief engineer of the Orleans Levee District. “We pushed for it and the corps pushed for it, but the administration wouldn’t appropriate it.”

Now, the corps’ $3.1-billion repair effort would complete the 1965 program.