Oil spill gets freshwater diversion running wide open


Associated Press

Posted on May 24, 2010 at 8:08 AM

Updated Tuesday, May 25 at 1:08 PM

For the first time since the state began its Mississippi River freshwater diversion program, projects are running at full or near full capacity.

"The main reason is to battle the effect of the oil on our wetlands," Chuck Villarubia said. "This is totally new territory for all of us."

Villarubia headed the first venture, the Caernarvon Freshwater Diversion in St. Bernard Parish, nearly 10 years ago. Seven others, the newest at Bayou Lamoque in Plaquemines Parish, have come on line since 2003.

Villarubia said the projects' target is to reintroduce freshwater into wetlands that were freshwater areas before the Mississippi River's levees were raised to their current heights during the past 80 years.

"The water in these areas was turning saltier and saltier ... and the projects were designed to return a more historically natural regime to these areas," Villarubia said.

He said any success combating the oil in the state's wetlands will not be known immediately, but flow rates are usually not strong enough to offset tidal movement.

"How much it will help is anybody's guess," he said. "Nature moves a lot more water than we can, but the flushing that comes from the projects, and the extraneous material from the river that's deposited in the areas helps ... with productivity in the food chain during period when the diversions are running."

Project outlines show light sediment deposits and increased freshwater enhances plant growth, plant diversity and wetlands stabilization.

The Caernarvon Project had another effect: The canals and downflow areas in the Delacroix marshes became a freshwater fisherman's heaven.

The state's Inland Fisheries Section stocked Florida-strain largemouth bass. Bass weighing more than eight pounds were common until Hurricane Katrina in 2005. Sac-a-lait and bluegill also thrived.

"It definitely expanded the freshwater fishery in the Delacroix area," state fisheries biologist Tim Morrison said. "And what we found out at Caernarvon helped us to anticipate what would happen at Davis Pond (diversion)."

Davis Pond, the northernmost completed project, is pumping at capacity for the first time since it was put on line nearly three years ago. It feeds freshwater into the upper reaches of the Barataria estuary that wends south toward Barataria and Caminada bays.

The largest north-area lakes are Cataouatche and Salvador, and it's Cataouatche that's attracted bass anglers' attention across the country.

During the past three years, as many as 30 bass weighing more than 10 pounds have come from this once brackish-water lake.

"Prior to starting up the (Davis Pond) diversion, we stocked Florida bass there," Morrison said. "We have crews there now and other diversion areas to find out the current effects as we go through this process. There might be some consequences, maybe expanding some aquatic vegetation."

Morrison said the staff understands bass fishermen like expansive grass beds, but added that it causes navigation problems: "And too much turbidity (muddy water) could remove some of the vegetation and that's not good either," Morrison said.

Another state biologist, Larry Reynolds, the state's Waterfowl Study leader, said he prays daily for anything that will help the marshes near the mouth of the Mississippi River, areas that are home to a million or more overwinter migratory waterfowl annually.

He said his worst fears were realized when oil was found in the interior areas of the Pass a Loutre Wildlife Management Area and the Delta National Refuge, expanses of marshes rich in the history of North American waterfowl lore.

"We are debating what the impacts will be to waterfowl when their habitat gets oiled," Reynolds said. "We're hoping the freshwater diversions will be preventative mechanisms, but we're not sure how much they can help.

"We've never seen this flow from the diversions before, so we might get help (with waterfowl habitat) in other wetlands," Reynolds said. "It's interesting that it took an emergency like this to give us the political will to flow these projects at the rates they were designed to flow."

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