The Coast of Yesterday is Not the Coast of Tomorrow – No Matter What We Do

This report is a coastal Louisiana game-changer.A couple of LSU researchers have weighed in on the ability of the Mississippi River to sustain our coastal wetlands, and the math isn’t good. Due to increased sea level rise, decreased sediment in the river, and our ever-subsiding coast, the Mississippi River estuarine wetlands aren’t long for this earth. 2100 or so. By that time, Louisiana’s coast will lose another 4-5,000 square miles, an area about the size of Connecticut.Of course this report doesn’t look at the beneficial use of dredged material, or pipeline sediment delivery, but my gut is that there’s not enough dredge spoil in the Corps entire navigation maintenance operation to make up the difference. This fantastic Times-Picayune article reports that Louisiana officials put the number of dredged tons available for use for marsh building at 60 million tons per year, while the LSU researchers put the historic amount of sediment in the river at 400-500 million tons, with the current river holding about 200 million tons. Seems like we haven’t gotten to where we need to be, even capturing everything in the river, and everything the Corps dredges.What this report very graphically shows is that the coast of tomorrow is not the coast of yesterday. That’s been said a number of times, by a number of experts, but this is the first time it’s really been shoved in our faces.We’ve got to get serious about picking critical areas and sustaining them with sediment delivery backed up with sediment diversions from the river. The authors say something similar when questioned by the Times-Picayune in this article, pointing to a couple important, big river diversions – possibly at Caernarvon and Bayou Lafourche.The dirty secret of coastal restoration is that everyone in Louisiana knows it’s important and supports it, yet when asked what needs to be done, very few people (state and local politicians, engineers, biologists, fishermen, etc.) will say remotely similar things. Understandably, everyone wants the coast that they know. Unfortunately, this report shows that’s impossible. It also makes it clear that if we don’t quickly make some important decisions, we won’t be left with any coast at all.Aaron Viles is GRN’s campaign director

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