Hurricane Isaac's surge was no surprise to St. Charles Parish managers

A boat moves down Bayou Des Allemands Friday afternoon (John Snell)
A boat moves down Bayou Des Allemands Friday afternoon (John Snell)

Hahnville, La. -- Hurricane Isaac will go down in history for its surprising punch, a Category 1 storm packing a 14-foot surge.

While Isaac caught many people off guard, its effects came as no surprise to Scott Whelchel.  On Sunday, August 26, with Isaac still a tropical storm, the St. Charles Parish Emergency Preparedness Director grew more alarmed as he looked at computer surge models.

One of the models for Sea, Lake, and Overland Surges, or SLOSH, showed 15 feet of water piling into the west bank of St. Charles.

"In my mind, it was a large storm, had a very wide wind field," Whelchel said. "It was going to bring some surge."

Whelchel points out that while the National Hurricane Center has made great strides predicting the paths of storms, forecasters have "made no progress predicting intensity for the last 50 years."

The prudent thing, Whelchel decided, was to take the "worst case scenario and go one category higher."  He convinced his boss, St. Charles Parish President V.J. St. Pierre, to order a mandatory evacuation for both banks of the river.

Even though no other parish was evacuating anyplace other than the most exposed areas, St. Pierre said "it was really a no-brainier."  Still, he concedes some of the reaction was disbelief.

"Some of the [chemical] plants called and said, 'What are you doing?' Some of the people called and said, 'What are you doing? This is not going to be a very big storm.'"

As it turned out, Isaac took a different track, piling water into other areas.

On the east bank of St. Charles, the community of Montz-- outside the hurricane protection system-- took on water.

Although the SLOSH models generally provided warnings for areas that were hardest hit, they understated the surge on the east bank of Plaquemines Parish by a foot or so.

In some ways, St. Charles Parish is a victim of its own preparation, or luck.  On the west bank, the parish estimates $10.5 billion worth of property goes virtually unprotected.

In Washington, where money was already tight, parish leaders are told the priority must be on areas that have already suffered catastrophic flooding.

"How do you tell a guy, a senator or a congressman in Arizona what your problem is over here? They can't visualize that," St. Pierre said.

The parish is working to raise nine miles of levees to 100-year protection with $20 million in state and local funding.  However, extending the levee would cost another $130 million while still leaving a gap at Bayou Des Allemands.

St. Pierre and his aides argue the chemical and fertilizer plants in the parish play a vital role in the nation's economy.  Parish leaders say one plant ranks as the world's leading producer of glyphosate, a major herbicide in U.S. agricultural production.

While the plants hugging the river are on relatively higher ground -- nine feet of elevation -- Public Works Director Sam Scholle says their workforces would still be impacted by flooding.

"When the plants come back and try to reopen, their people have no place to live."

Some of the SLOSH models for major hurricanes predict water would be lapping at the Mississippi River levee.