Joint fed-state river study to support future projects

By Susan Buchanan
Contributing Writer

At a public meeting Wednesday, the U.S. Army Corps of Engineers and Louisiana’s Coastal Protection and Restoration Authority updated residents on a joint Louisiana Coas­tal Area study called the Mississippi River Hydrodynamic and Delta Management Study that’s intended to underpin future projects. Funding for the study, which got under way in 2011 and predates the state’s $50 billion Coastal Master Plan ap­proved last year, is $25.4 million to be split between the feds and the state.

The MRHDM study was conceived more than ten years ago and authorized for the Louisiana Coastal Area under the federal Water Resources Development Act of 2007. The study area runs from Vicksburg, Miss., to the Old River Control Structure-located in a central Louisiana branch of the Mississippi River—to the Gulf of Mexico but doesn’t include the Atchafalaya River, Carol Parsons Richards, hydrodynamic manager at CRPA said. She spoke Wednesday evening at the Lindy C. Boggs International Conference Center at University of New Orleans, following technical sessions on the study that afternoon.

Richards said the MRHDM study’s goal is to use the Missis­si­p-pi’s fresh water, sediment and nutrients to restore the coastal ecosystem, while also managing the river in a balanced way. The two-part study is focused on river hydrodynamics on the one hand and management of the delta and basins on the other. Over thirty federal, state, academic and private scientists and engineers are engaged in the MRHDM. The hydrodynamic study is further along than the delta study, Richards said.

“Modeling and data from these two studies will be applicable in future projects,” Chuck Perrodin, CPRA spokesman, said outside of the meeting last week. “In this area of research, for now, we’re devoting our efforts to gain the best science and knowledge to maximize our effectiveness as we seek to utilize the Mississippi River—the greatest resource that nature has provided us,” he said. So far, no coastal restoration or flood-control projects have been funded using study money. The study is building a foundation of knowledge that the state can rely on in the future, he said.

Richards said the objectives of the study’s hydrodynamic portion include developing tools for the Lower Mississippi River so that researchers and project managers can understand existing conditions, evaluate the consequences of taking no action, and can assess cumulative impacts of restoration projects. Under the hydrodynamic portion, a final report analyzing geomorphic or natural features is expected in December. Data collection and analysis will continue into 2014. Production runs or results from the study’s one-dimensional, hydrodynamic model—estimating variations in sediment delivery and deposition along the river—are expected in December 2013 and early 2014.

No-action simulations from the study’s multi-dimensional hydrodynamic models are expected in December, following runs from those multi-models starting in early 2014, Richards said. Multi-dimensional modeling simulates water and sediment transport processes on the lower Mississippi, including salinity and temperatures.

The goals of the second study on delta management are to evaluate features that would increase the deposit of Mississippi River sediments in shallow coastal areas, restoring deltaic growth, Richards said. The intent there is to revive as many acres of wetlands as possible and to maintain habitats and diversity, she said.

In the two-part study, the hydrodynamic segment is expected to cost about $10.97 million, Perrodin said last week. As of Sept. 30, CPRA had spent roughly $2.8 million so far in funds and in-kind services on the hydrodynamic portion in an unaudited figure, he said, with expenses continuing. CPRA staffers have done some preparatory work for the delta management study but man hours in that phase have been minimal so far.

The Army Corps to date has spent $3.9 million on MRHDM study tasks, according to Cherie Price, the Corps’ plan formulator for the study. For more information on the two-pronged MRHDM study and its components, visit lca.gov on the web.

In a separate but related development, the U.S. House of Repre­sentatives last Wednesday passed the Water Resources Reform and Development Act or WRRDA. In March, the Senate approved its version. The House bill provides authority for the Army Corps to use Louisiana’s 2012 Coastal Master Plan rather than the Com­prehensive Plan authorized under WRDA 2007, and directs the Corps to focus on high-priority, ecosystem projects identified in the Coastal Master Plan. But last week’s House WRRDA bill doesn’t include the Morganza to the Gulf project, a proposed system of levees and gates to protect Terre­bonne and Lafourche parishes.

The House WRRDA bill creates a program to cut red tape and expedite Army Corps projects by delegating more management to state and local governments. Last year, the state told the Army Corps that it wanted to suspend work on some Louisiana Coastal Area projects because of the Corps’ costly feasibility studies and a lack of congruity in a number of LCA projects with the Coastal Master Plan.

This article originally published in the October 28, 2013 print edition of The Louisiana Weekly newspaper.