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Davis Pond Freshwater Diversions

Location

The Davis Pond Feature is located in St. Charles Parish on the west bank of the Mississippi River near Mile 118 Above Head of Passes. It is approximately 15 miles upstream of New Orleans, Louisiana. The project consists of a gated, four barrel, 14' x 14' reinforced concrete culvert with corresponding inflow and outflow channels, approximately 19 miles of guide levees, 1.8 miles of Rock wier, a 570 cfs pumping station and a Ponding Area. The project area is 10,084 acres; 9,311 of these acres are in the Ponding Area.

Purpose
The project will divert fresh water, with its accompanying nutrients and sediments, from the Mississippi River into the Barataria Basin - - reducing saltwater intrusion and establishing favorable salinity conditions in the area, thus combating land loss. These diversions will also increase commercial and recreational fish and wildlife productivity, and enhance vegetated growth for a healthier estuarine ecosystem in the Barataria Basin. The shallow embayments support oyster and crab production and shrimp and food fish reproduction, while the marsh areas produce food for fur-bearing animals and migratory waterfowl. Approximately 33,000 acres (133.5 km2)of wetlands will be preserved and 777,000 acres (3,145 km2) of marshes and bays will be benefited during the 50-year life of project. Fresh water diversions will occur under regulated conditions developed by monitoring basin salinities, and the fish and wildlife resources. The project area is 10,084 acres; 9,311 of these acres (3,768 ha) are in the ponding area. Estimated annual benefits: $14,997,000 for commercial fish and wildlife, plus $298,000 for recreation, or $15,295,000.


Status

Project Diversions began in July of 2002 and have continued since then. The extremely fresh conditions that have been experienced over the past three years have diluted the measurable progress of the project. Results are most effective and visible when above-average salinity conditions are present in the Barataria Basin, and the project's freshwater diversions bring the salinities back down to the optimum level.


Benefit to the Community & Project Features

Mississippi Delta Region studies were suspended in 1973 at the request of local interests who were restudying freshwater needs in the area. The project remained inactive until January 1982, when the State of Louisiana became interested in implementing the Caernarvon Freshwater Diversion structure. A Post-Authorization Change (PAC) report was approved in June 1987, authorizing relocating the Myrtle Grove site to the present Davis Pond site. The PAC increased the benefited marsh area and maximized the total benefits. Davis Pond Design Memorandum studies began in FY 1988, were submitted to higher authority in August 1991, and approved by the Assistant Secretary of the Army (Civil Works) in September 1992. The Davis Pond Project Cooperation Agreement between the Corps and the Louisiana Department of Natural Resources was signed on April 17, 1993. Construction began in Nov. 1996, and was substantially complete in Feb. 2002.


Authority

The project was authorized by the Flood Control Act of 1928, (PL 70-391) and the Flood Control Act of 1965, (PL 89-298). The project was further amended by the Water Resources Development Acts (WDRA) of 1986 (PL 99-622), and of 1996 (PL 104-303).


Scope

Deterioration of the marshes surrounding New Orleans is caused by several factors including subsidence, erosion, and saltwater intrusion. Introduction of fresh water, nutrients and sediments from the Mississippi River via the Davis Pond diversion structure will serve to reduce this degenerating trend in the Barataria Basin.