River diversions are only one part of the integrated plan for coastal restoration and flood protection in the state, but they are an essential part, Jerome Zeringue told the Baton Rouge Press Club on Monday.
The state Coastal Protection and Restoration Authority chairman, Zeringue explained that within the 2012 state master plan for restoration and protection, projections have the state getting to a net gain, instead of loss, of coastal wetlands in about 20 years.
That effort will include work to use dredged material to build instant wetland areas, but also will depend on diversions of sediment and water from the Mississippi and possibly Atchafalaya rivers to help sustain those wetlands and build new land.
“Diversions, as we say, are the gift that keeps on giving,” Zeringue said.
Diversions, he said, aren’t new and have been used for various reasons since the 1930s. The difference for the three diversions the state is now moving forward with is the focus will be on maximizing the amount of sediment that can be delivered to adjacent wetlands.
Some people want multiple small diversions, he said, but that would result in the same amount of fresh water being put into the marshes but without the ability to deliver sediment as well.
“We’ll never get back the land form of what we had in the 1930s,” he said.
However, it is possible, even with the reduced sediment loads in the Mississippi River, to develop a stabilized coastal land size.
The diversion project that is moving forward the fastest is the Mid-Barataria diversion in the area of Myrtle Grove in Plaquemines Parish. The state expects to have the design done in about two years with a capacity of 75,000 cubic feet per second, Zeringue said.
Although fisheries have been a concern, with some people saying a large diversion like the one planned for Myrtle Grove will destroy fisheries, Zeringue said that hasn’t been the case for other diversions in the state.
There will be shifts in where fisheries will occur, but there are shifts going on now as the state continues to lose wetlands, he said.