In this graphic from the restoration authority, the land that will
be lost to erosion if the plan isn’t undertaken is shown in red.
Six years after Hurricane Katrina devastated New Orleans and the Louisiana coast, the state’s Coastal Protection and Restoration Authority has finally released a draft of a plan to try to keep it from happening again. How? By restoring the wetlands along the Mississippi River Delta, which we have more or less systematically destroyed but used to act as buffers between storm surge waves and inland cities.
Previous plans had relied on mainly on building levees and seawalls, so it’s striking that this plan, which would unroll over the course of 50 years at a cost of $50 billion, focuses on wetland restoration, writes Mark Fischetti, who has been covering this issue for Scientific American for years. Here’s how it would work:
Along the outer edge of the torn-up coast, furthest from New Orleans, former barrier islands that have been worn to thin wisps of land would be broadened with sandy sediment, mostly dredged from the ocean bottom and conveyed through pipelines. Natural ridges of land along the coast would be strengthened in similar fashion. Together, the islands and ridges would form a dotted line around southeastern Louisiana that can cut down storm surges. They would not all connect, so wind-driven water could still find its way through, but the many segments would break up the incoming wavefront into chaotic eddies flowing in conflicting directions that would at least partially cancel out one another.
The plan is already drawing ire from fishermen, who say that current restoration projects haven’t had much effect, and that all this shuttling of sand and water will interfere with their livelihoods.
Read more at Scientific American.
Images courtesy of the Coastal Protection and Restoration Authority
Build a wall of sand: That was Louisiana Governor Bobby Jindal’s answer to protecting the state’s delicate marshlands when it became clear that BP wasn’t going to stop its gushing oil leak anytime soon. But now the federal government has put the kibosh on Louisiana’s construction, saying that the project to save one ecologically sensitive area will ruin another.
Scientists raised several objections to the state’s first proposal last month to build a long line of sand berms on 10 May. One key concern was that taking sand from in front of the Chandeleur Islands would make them more vulnerable to erosion. The state agreed to change its approach by taking sand from a site further away and then pumping it through pipes to build the berms [ScienceNOW].
However, that didn’t happen. Louisiana officials said they couldn’t get the pipes built in time, and asked the feds to let them dredge near Chandeleur at least until the other site was ready. OK, the Interior Department said—you’ve got a week. That week has lapsed, but Louisiana is still requesting more time to dredge near Chandeleur, promising to return the sand once the berm project has done its job.