From CNN’s Marsha Walton

NEW ORLEANS (CNN) — The weaknesses remaining in Louisiana’s levee system could leave the state open to a worse disaster than 2005’s Hurricane Katrina if Hurricane Gustav continues on its present course, a leading researcher said Sunday.

With Gustav forecast to strike the northern Gulf Coast as a major hurricane, Louisiana State University Professor Ivor van Heerden said state and federal officials could have done a lot more to repair damaged levees and restore the coastal wetlands and barrier islands that can blunt the impact of a hurricane.

“If the models are correct, Gustav will destroy what Katrina and Rita did not,” van Heerden said. “This is going to be flooding of a much larger area than Katrina.”

As deputy director of LSU’s Hurricane Center, van Heerden warned of the catastrophic consequences a major hurricane would have on New Orleans long before Katrina struck three years ago. On the eve of its landfall, he told CNN that New Orleans faced “our equivalent of the Asian tsunami.” And after the storm flooded more than three-quarters of the city and killed more than 1,800 people in Mississippi and Louisiana, the engineering professor led an investigation into how the levees failed and why.

Sunday, he said authorities could have done more to assess the weak links in the levee system from New Orleans to Morgan City, about 85 miles southwest of the city. He said some of the levees damaged by Katrina remain heaps of bare soil, and that the coastal cypress swamps and barrier islands — which act as speed bumps with an approaching storm — continue to disappear rapidly.

“If the existing barrier islands were a little higher and wider, it could knock two to three feet off the storm surge,” he said. “It would have been about a $200 million project. It could have been finished by now.”

Coastal authorities in Louisiana did complete some restoration projects, van Heerden said. But he said bureaucratic snags, ranging from a limit on what companies could dredge in the Gulf to the cutting and selling of cypress trees for garden mulch, kept many others from being started.

“For 14 years we’ve been trying to get the state to start a more large scale effort to rebuild the barrier islands,” he said.

Even before it hits, Gustav is likely to disrupt the oil and natural gas industries in the Gulf of Mexico, sending the price of gasoline through the roofand delivering “a huge economic blow” internationally, he said.  But he said the human toll would be greater.

“Who is going to suffer?” he asked. “Not the decision-makers. It is the poor Louisianans.”