Using Controlled River Diversions for Restoration
River diversions have been built along the Mississippi River in Louisiana to help replace some of the lost function of periodic pulses of fresh water, historically delivered during periods of high water, into the coastal wetlands. River diversions are water control structures that allow controlled flows from the Mississippi River into various basins of the delta. The Davis Pond diversion, with a 300 cubic meter per second discharge, upstream from New Orleans, releases fresh river water into the Barataria Basin which strongly influences salinities and sediment loads into the Jean Lafitte NHPP Barataria Preserve. Abundant fresh water and nutrient input into the preserve results in a robust growth response from submerged aquatic vegetation (SAV).
Local and state governments provide funding for these expensive structures. Public agreement is essential as changes to the hydrology and the ecosystem will impact users, though most see this as an improvement.
Not everyone agrees that freshwater inputs are good. Commercial fishermen worry that their fishing grounds may change and they will have to travel farther, and use more fuel, to find the same species they currently catch. Excessive water and sediment inputs can also change the floating and submerged plant communities in ways not desired. Periodic monitoring is essential to be sure the diversions are managed and operated in an optimal manner.