Assessing the Influence of the Davis Pond Freshwater Diversion on Water-Quality in Waterways and Marshes of Barataria Preserve

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In 2002, the Davis Pond Freshwater Diversion began diverting up to 10,000 cfs of Mississippi River water into the waters surrounding the Barataria Preserve of the Jean Lafitte National Historical Park and Preserve. Previously, precipitation, local surface-water runoff, and occasional marine intrusion largely determined quality of surface and marsh porewaters at the Preserve. The new influx of river water will change the quality of the Preserve waterways and marsh porewaters in as yet undetermined ways. The floating marshes of the Preserve may be particularly sensitive to water-quality shifts because of their highly organic substrate, derived almost exclusively from root production. Porewater constituents, including nutrients and salinity, directly affect the health and vigor of the plant community, and the ability of the plant community to build a healthy, fibric substrate. 

Assessing the Influence of the Davis Pond Freshwater Diversion on Water-Quality in Waterways and Marshes of Barataria Preserve

In 2002, the Davis Pond Freshwater Diversion began diverting up to 10,000 cfs of Mississippi River water into the waters surrounding the Barataria Preserve of the Jean Lafitte National Historical Park and Preserve. Previously, precipitation, local surface-water runoff, and occasional marine intrusion largely determined quality of surface and marsh porewaters at the Preserve. The new influx of river water will change the quality of the Preserve waterways and marsh porewaters in as yet undetermined ways. The floating marshes of the Preserve may be particularly sensitive to water-quality shifts because of their highly organic substrate, derived almost exclusively from root production. Porewater constituents, including nutrients and salinity, directly affect the health and vigor of the plant community, and the ability of the plant community to build a healthy, fibric substrate. The proposed project will sample porewater and surface waters to determine where river water has infiltrated the Preserve, and whether constituents, sampled 10 years earlier, are changing from the pre-diversion baseline. Porewaters of the six distinct marsh communities at the Preserve will be sampled for the parameters that are most likely to be affected by the influx of river water and that also could affect plant production. The marsh peat substrate for each community will be analyzed for decomposition. Water in the canals and bayous within the Preserve also will be sampled. This study is funded through the USGS-National Park Service Partnership Program. The work is cooperatively funded by the Louisiana Department of Transportation and Development and the U.S. Geological Survey.