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Davis Pond Freshwater Diversion Project

Stemming the Tide: The Mississippi River Delta and
the Davis Pond Freshwater Diversion Project

 

FOR IMMEDIATE RELEASE

Contact: John Hall, Jim Addison or Julie Morgan, 504-862-2201

March 26, 2002

Attached: Map of Davis Pond project area.

Water flows through Davis Pond

World’s largest freshwater diversion project opened

NEW ORLEANS – Water flowed through massive metal gates for the first time today as a (2 p.m.) ceremony was held to dedicate the Davis Pond Freshwater Diversion project, 23 miles up the Mississippi River from New Orleans.

The $119.6 million project, the world’s largest freshwater diversion project, will reintroduce fresh water, nutrients and sediment to the salt-threatened Barataria estuary, which stretches south to the Gulf of Mexico.

Gov. Mike Foster said Davis Pond is “one of the most important projects in the fight against the loss of our coast. It is located in the middle of the area that’s experiencing some of the highest rates of land loss in our state.

"The Caernarvon Freshwater Diversion Project shows that these projects do a lot more than reduce salinity - they actually build new marsh. This project should build marsh where we need it most, and is an example of the type of projects we want to focus on as a priority in our nation's conservation agenda," Foster said.

The key feature is a reinforced-concrete diversion structure, built into the mainline Mississippi River levee, with four 14- by 14-foot gates. It will divert up to 10,650 cubic feet per second to help restore vanishing wetlands that stretch to the Gulf of Mexico.

Davis Pond is the second major freshwater diversion project built by a partnership of the U.S. Army Corps of Engineers and the Louisiana Department of Natural Resources. The Caernarvon project, opened in 1991, is 15 miles downriver from New Orleans and has the capacity to divert up 8,000 cubic feet per second.

U.S. Rep. Billy Tauzin of Louisiana said: “Louisiana’s coastal wetlands – from fisheries and recreation to the oil and gas industry – have an economic impact of over $8 billion a year on our state. And yet many of those wetland areas over the years have disappeared before our eyes.

“Today we’re cutting not just another ribbon, we’re celebrating the rebirth of one of America’s most treasured resources,” Tauzin said.

Water will flow through a two-mile outflow channel to spread into a ponding area that covers most of the project’s 10,084 acres. A far greater area will benefit. The project is expected to preserve 33,000 acres of marsh and benefit 777,000 acres of marshes and bays, the latter being equal to Rhode Island’s land area.

Lt. Gen. Robert Flowers, the chief of engineers, introduced the Corps of Engineers’ seven Environmental Operating Principles. Davis Pond is a good example, Flowers said, of how the new principles make clear the Corps’ commitment to balancing human need, economic growth and the environment, he said.

"In projects from coast to coast, the Corps already does much that is embodied in these principles. They make clear the connection between water resources, protection of environmental health and the security of our country," Flowers said.

By improving marsh conditions, Davis Pond is expected to provide average annual benefits of $15 million a year for fish and wildlife, including $300,000 for recreation. The Barataria estuary is important in making Louisiana’s wetlands one of America’s most prolific producers of oysters, shrimp, crab and fish, as well as major habitat for migratory waterfowl, fur-bearing animals and alligators.

As an additional benefit, the restoration of the Barataria wetlands will help to protect homes and jobs from the destructive force of hurricanes. By absorbing energy, wetlands reduce hurricane storm surges as compared with the open water created by wetland loss. It takes one to three miles of wetlands to reduce a hurricane surge by one foot.

Oysters will thrive on salt-fresh mix created by the diversion. However, the process will push the location of these benefits closer to the sea, while the nearer oyster beds must be relocated or die. A great deal of effort, including up to $7.5 million of project cost, went into oyster relocation, and three lease areas remain to be relocated. It is expected that this job will be accomplished in several weeks and large-scale diversion can commence.

Davis Pond will be operated by the Public Works Department of St. Charles Parish under the direction of the Louisiana Department of Natural Resources. Diversion rates will be based on salinity levels in the Barataria estuary and recommendations made by the Davis Pond Advisory Committee.

The 19-member advisory committee has representatives from: DNR; the Corps; U.S. Environmental Protection Agency; National Marine Fisheries Service; U.S. Fish and Wildlife Service; U.S. Natural Resources Conservation Service; Louisiana Department of Environmental Quality; Louisiana Department of Wildlife and Fisheries; Louisiana Department of Health and Hospitals; Barataria-Terrebonne National Estuary Program; St. Charles, Jefferson, Lafourche and Plaquemines parishes; landowners; shrimpers (2); oyster fishermen and recreational fishermen.

"While Davis Pond's capacity is almost as large as the annual flow of the Pontomac River, which averages 11,900 cubic feet per second, the project's diversions will have minimal effects on water levels in the Mississippi River and the Barataria estuary," said Jack Fredine, the Corps' project manager since before construction began in 1997.

Most of the diversion is expected to occur during the river’s high-water season in the first half of the year. But the structure will be closed when storms and tides are expected to increase stages by more than 1.5 feet in Lakes Cataouatche and Salvador.

At maximum flow, Davis Pond would add three inches of water to Lake Cataouatche, one inch to Lake Salvador and none at all to Lake des Allemands. For the Mississippi River, diversion at the maximum rate would have removed only 14 cubic feet per thousand cubic feet from Monday’s flow of 759,000 cubic feet per second past the Davis Pond structure.

In addition to the diversion structure and oyster relocations, the Davis Pond project includes levees along the outflow channel and east and west of the 9,300-acre ponding area, a pumping station for levee-intercepted storm water, a rock weir on the ponding area’s border with Lake Cataouatche to the south and the relocation of six lanes of highway and five sets of railroad tracks.

Costs of the Davis Pond and Caernarvon freshwater diversion projects were shared 75 percent federal and 25 percent state. Construction has not been scheduled for a third federally authorized project, the Bonnet Carr Freshwater Diversion Project, which would be built at the Bonnet Carr Spillway, a Corps flood-control project on the Mississippi’s east bank 33 river miles above New Orleans.

The Barataria estuary lies immediately south of the New Orleans area and parishes immediately upriver. It is bordered on the east by the Mississippi River below New Orleans and on the west by Bayou Lafourche, an ancient course of the Mississippi.

Web brochure. http://www.mvn.usace.army.mil/pao/bro/FreshwaterDiversion.pdf

Davis Pond Project Overview

Davis Pond Freshwater Diversion Structure (at the USACE)

Davis Pond Freshwater Diversion Construction (at the USACE)

 

For more information contact:

Chuck Villarubia - biologist 225-342-0932
Thomas Bernard - engineer 504-280-4071