Diversions May Be Less Effective Than Previously Thought

An LSU study finds Mississippi River diversions can actually do more harm than good for wetland restoration. The study looked at Caernarvon, St. Phillips, and Davis Pond diversions and found land loss, instead of creating or maintaining land. Coastal Sciences Professor Gene Turner says that runs contrary to the prevailing opinion on how to restore the coast.

“They indicate that things may not go exactly as we wanted because they are still presented as being diversions that will help.”

Caernarvon opened in 1991, Davis Pond in 2002, and St. Phillips was a natural diversion that occurred in 1973.

Turner says that may be because of the significant side effects of introducing so much freshwater to the brackish systems.

“You can have sand and sediment build up right where the diversions are made but further away the water level and nutrients are high and those can have a negative effect on a wider area.”

The study raises concerns about five billion dollars worth of planned diversion projects the state is seeking to initiate. Turner says more study needs to be done before opening the flood gates.

“It’s a cautionary note that we need to reduce the uncertainty of the models before we commit to them because it is going to be very hard to stop them once they begin.”

The study was conducted by studying satellite imagery before and after the diversions opened.