Sediment Diversions

Helping Communities Participate in the NEPA Scoping Process

Helping Communities Participate in the NEPA Scoping Process

In mid-July, I traveled to Louisiana with fellow ELI Gulf Team member Teresa Chan to host three workshops with the Restore the Mississippi River Delta coalition. Held in three different parishes, these workshops were intended to help the community meaningfully participate in the “scoping” process for the Mid-Barataria Sediment Diversion by providing some background on the project, explaining what scoping is, and discussing how the public can participate. Nearly 60 people attended the workshops, where there were lots of lively discussions!  Mid-Barataria Sediment Diversion …

Let’s Get Muddy: How A Mixture of Mud and Sand Can Help Revive Louisiana’s Wetlands

With the recent unanimous passage of the 2017 Coastal Master Plan, the State of Louisiana is working hard to advance priority restoration projects, including numerous sediment diversions. These project types have been called a “cornerstone” of our efforts to restore and protect Louisiana’s coastal wetlands. As such, it’s important to understand the valuable resource they help capture and deliver to our wetlands: sediment. This is a fancy word for the sands, silts, clays and muds that flow through the Mississippi …

Can We Build Stable Land in the Mississippi River Delta with River Sediments?

Does partially diverting the flow of the Mississippi River help build land, or can it contribute to wetland erosion? It’s a question that has plagued Louisiana scientists for over a decade. This controversy developed in the years after Hurricane Katrina, when scientists noticed that there were large areas of wetland loss near the Caernarvon Freshwater Diversion. Some looked at this situation and thought that the problem was that freshwater marshes, which are a major type of wetlands created by river …

Project Synergies: Getting the Most Bang for our Buck from Coastal Restoration

Coastal restoration is not cheap. Most projects cost on the order of millions, sometimes billions, to plan, design and construct. Such high stakes call for solutions that provide the greatest benefit over the long term. But how do you select projects that provide the most bang for the buck? Part of the answer lies in project synergies and complementary projects. What are synergies? Synergies are the interactions between projects that happen based on project scale, location and timing of construction …

Your Voice is Needed for #OurCoast: Attend Upcoming Mid-Barataria Scoping Meetings

As the State of Louisiana and the U.S. Army Corps of Engineers (Corps) move forward with the permitting process for the Mid-Barataria Sediment Diversion – one of the most important restoration projects in the Coastal Master Plan – your voice and support are needed! The Mid-Barataria Sediment Diversion would reconnect the river with nearby wetlands and deliver sediment to build and maintain tens of thousands of acres in this crucial area. To get this project constructed, the Corps must follow …

The History of the Mid-Barataria Sediment Diversion

As an individual working and studying in the interior United States, I have always been passionate about the assessment and quality of rivers, from the Snake River in Wyoming to the Schuylkill in Pennsylvania. Using the geography of interior waterways, I have worked as an environmental educator and taught students about watersheds and the importance of healthy water resources considering the growing demands of agriculture, industry and urban centers. And yet, there has been no river more powerful than the …

How Will Sediment Diversions Impact Fisheries?

Prior to its leveeing and control structures, the Mississippi switched course roughly every 600 to 1,000 years, finding a more efficient route to the Gulf of Mexico as it filled with sediment. Over the course of its history, the Mississippi has had 6 Holocene delta complexes, including the most recent Atchafalaya. Each delta complex experiences stages of compaction, subsidence, and building. This delta switching, combined with the high sediment load (7th highest in the world), has resulted in the current …

Getting Down to Basics: The Environmental Impact Statement Process for the Mid-Barataria Sediment Diversion

As CPRA advances the Mid-Barataria Sediment Diversion and other priority projects toward construction, Restore the Mississippi River Delta staff experts will aim to give you updates on key steps of the process. The Mid-Barataria Sediment Diversion aims to be “the first controlled sediment diversion reconnecting the Mississippi river with its delta,” Louisiana’s Coastal Protection and Restoration Authority (CPRA) indicated in a recent press release, and, recently, there have been some important developments toward that end. In March, CPRA announced that …

How Will a Sediment Diversion Affect the Coastal Environment? The Answer Lies in the Operations.

Sediment diversions have long been proposed as an essential component in every major restoration plan in coastal Louisiana. Sediment diversions are man-made structures built directly into the Mississippi River levee system with gates that can be opened and closed to allow sediment, fresh water and nutrients to nourish and revive the dying wetlands. In the “Answering 10 Fundamental Questions about the Mississippi River Delta” report, scientists clearly demonstrated that sediment diversions are the most effective tool to build and sustain …

Will Diversions Introduce Nutrients That Harm Wetland Vegetation?

Within the scientific community, and among the general public, there is controversy over the effects that nutrients, introduced through sediment diversions, will have on wetland vegetation. The speculation is that increased nutrients, especially nitrate, will result in decreased root growth. With increased nutrient availability, plant roots will no longer have to “search” for nutrients, resulting in decreased growth. This results in fewer roots to hold and trap soil and organic matter, creating weaker wetlands. In addition, the increase in nutrients …

Diversions, Old Vegetation and New Vegetation

By Jenneke Visser, University of Louisiana at Lafayette, & Andy Nyman, Louisiana State University This is part five of the series “Building Land in Coastal Louisiana: Expert Recommendations for Operating a Successful Sediment Diversion that Balances Ecosystem and Community Needs.” See previous parts on the Sediment Diversion Operations Expert Working Group, Hydrodynamics of a sediment diversion, Geology of land building using sediment diversions, and Building land while balancing historic and cultural effects. In the last 50 years, coastal Louisiana has …

Reconnecting the Delta: How Increased Mud Supply Can Improve Sediment Diversions

Jordan Davis, Mississippi River Delta Restoration Science Intern, Environmental Defense Fund Rising sea level and anthropogenic sediment loss is a combination affecting sustainability of deltaic ecosystems. Around the world, major deltas have been experiencing a 44% decline in sediment supply since the 1950s due to construction of dams and reservoirs, including the Mississippi River Delta. A recent journal article, published in Estuarine, Coastal and Shelf Science, examined the role of fine-grained sediments in deltaic restoration. The authors found that the …

Beyond the Basin: Reflections on my Upstream Upbringing

By Christina Rouse, Mississippi River Delta Restoration Projects Intern, Environmental Defense Fund Clang. A knot of rusted chains pulls shut the driveway gate, bringing it closed with a final smack against a worn fencepost. Just like that, my Sunday afternoon visit to our family farm in Clarksville, Missouri ends. After a quick trip home to Saint Louis, it’s time to catch a flight to Washington, D.C. for my internship. On top of a hill, our farmhouse is safe from flooding; …

The Geology of Land Building Using Mississippi River Sediment Diversions

This is part three of the series “Building Land in Coastal Louisiana: Expert Recommendations for Operating a Successful Sediment Diversion that Balances Ecosystem and Community Needs.” View parts one and two. Successfully operating a sediment diversion in Louisiana requires that we understand how water and sediment naturally flow in places where the river enters the coast. The basic physical processes are relatively simple. When a sediment-rich river, like the Mississippi, enters an open bay, the flow spreads out and sediments …

Exploring the Hydrodynamics of a Sediment Diversion at Mid-Barataria

This is part two of the series “Building Land in Coastal Louisiana: Expert Recommendations for Operating a Successful Sediment Diversion that Balances Ecosystem and Community Needs.” See part one here. Historically, the Mississippi River has periodically overtopped its natural levee and flooded the adjacent wetlands with sediment-laden water. This natural process has been interrupted by the construction of flood control levees, and the available sediment has been reduced by the construction of upriver reservoirs. The proposed introduction of diversions from …