Aboard tall-mast ship, Dutch scientist's pep talk lauds Louisiana coastal initiative

Mar 30, 2017

Aboard a tall-masted sailing ship in the Mississippi River in New Orleans, The Water Institute of the Gulf celebrated its fifth anniversary as a think tank with a discussion by Louisiana and Dutch scientists about the future of coastal restoration. The conversation came Wednesday (March 29) as the Louisiana Legislature prepares to vote on the 2017 update of of the state's master plan for coastal restoration and protection, which Water Institute scientists helped develop.

The Baton Rouge-based institute has served as a research arm of Louisiana's Coastal Protection and Restoration Authority since its inception in 2010. Its work has included leading a complex modeling program that is being used to design the proposed Mid-Barataria sediment diversion, which would be located near Myrtle Grove on the west bank of Plaquemines Parish.

It's been assisted by Deltares, a much larger water think tank based in the Netherlands, in developing a suite of complex models used to predict the flow of sediment and water and nutrients through the diversion into open water and wetlands in Barataria Bay. Those models also predict the diversion's effects on wetland plant growth and the availability of key fishery species, including oysters and shrimp.

Justin Ehrenwerth, the institute's new executive director, told those gathered aboard the Stad Amsterdam, berthed near the Aquarium of the Americas, that he thinks 2017 master plan update, including the Mid-Barataria diversion, will be instrumental in reducing the effects of dramatic wetlands loss on the safety of coastal communities.

"We've got the plan -- It is a science-based plan. It is a rigorous plan -- and now our challenge is to move forward," Ehrenwerth said. He discounted concerns raised by Army Corps of Engineers officials that federal permits will delay construction of the diversion until 2022, rather than the 2020 start proposed by state officials.

"We are going to turn it on sooner, and it will be at 75,000 (cubic feet per second) one of the largest -- we could call it a river, but it won't be -- one of the largest water bodies in terms of that movement (of water and sediment) in North America," Ehrenwerth said. "We've done the modeling. We have done the science. We know that this will work."

A Deltares scientist who flew to New Orleans to participate in the anniversary event said the state's focus on large-scale solutions to its erosion problems will help it assist other countries such as Indonesia facing similar coastal erosion problems caused by climate change, sea level rise and subsidence, such as Indonesia. The problem, said Bregje van Wesenbeeck, was recognizing the potential of small-scale changes when added together.

"You look at the acre of marsh in your backyard and what it can do for you, and it may seem kind of irrelevant. An acre of marsh may reduce the size of waves and surge just a tiny bit, or may reduce the crest height on your levee by only a half-meter," she said.

"But if you zoom out and look at the Mississippi River delta as a system, look at your barrier islands, your salt marshes behind it, your brackish marsh, and then your freshwater marsh bordering the Mississippi, which spills over its banks, feeding that marsh with sediment and nutrients -- then your marsh starts playing a whole different role. You realize this system determines the stability, the prosperity, of your whole coastline, and that it may make the difference between keeping a city like New Orleans safe. Or not, if that system is down."

Equally important to recognize, van Wesenbeeck said, is that Louisiana's initiative is brand new. "Nobody has yet managed a coastal system on a delta scale," she said. "That means you need to go beyond the traditional measures of restoration. It's not about planting little tufts of marsh grasses here and there anymore. It's about big-time engineering measures. It's about a big-time diversion. It's about big sand nourishment projects to keep your barrier islands stable."

And, she said, it's about adaptive management, using the modeling tools that The Water Institute and Deltares have been creating to monitor how the restoration program is working. "And if it doesn't work the way you expected, you feed that data back into the model and adapt," she said.

Also at the event was Henne Schuwer, Netherlands' ambassador to the United States. He helped bring the Stad Amsterdam to New Orleans. Schuwer pointed out that his country has had a consular presence in New Orleans since 1815, and its government -- and Deltares -- were quick to provide assistance after Hurricane Katrina in 2005.

"You have a long history with a number of European countries in this city -- France, Spain, et cetera -- but you have a future with us," he said. "We are your future when you celebrate in 2018, reminisce about your past 300 years. We want to be there because we will be there for you for your next 300 years."

Schuwer said Netherlands' late Queen Juliana, speaking to the U.S. Congress years ago, talked about the ocean that separates -- and connects the two countries. "In modern terms, it would be: We have a choice between a wall and a bridge, and I can tell you we definitely would choose the bridge, and we very much hope the United States will also choose the bridge, because I think that in the present situation where we are these days, the bridge is very important," he said. "Our relationship is very important."