Archive for Diversions


Diversions Expert Panel engages scientific community for second public meeting

May 1, 2014 | Posted by Delta Dispatches in 2012 Coastal Master Plan, Diversions, Meetings/Events, Mid-Barataria Sediment Diversion, Restoration Projects, Science

By Erin Greeson (National Audubon Society) and Alisha Renfro (National Wildlife Federation)

While there is no question that large-scale action is urgently needed to add address Louisiana’s land loss crisis, some questions surround the scientific solutions necessary to address this challenge. As the state of Louisiana advances its Coastal Master Plan and the comprehensive set of restoration projects within it, experts have opened discussion to scientists and interested members of the public to provide information, share science and encourage dialogue.

This week in New Orleans, the Expert Panel on Diversion Planning and Implementation had their second meeting, which offered an opportunity to reconvene for updates and discussion on sediment diversions – one of the key tools in Louisiana’s coastal restoration toolbox. In addition to addressing environmental concerns, the panel addressed social and economic questions about river diversions and the communities they will impact.

Sediment-starved-sediment-wasted-CPRA

At the start of the meeting, Mr. King Milling, Chair of the Governor’s Advisory Commission on Coastal Protection, Restoration and Conservation, delivered a powerful reminder of Louisiana’s disappearing coast:

“Demise of this delta would be an environmental impact of international proportions: disaster for economy, culture, communities – all the things we do and live for in the delta. If we don’t proceed urgently, we will lose the delta. Nothing will stop this damage if we don’t proceed in an orderly fashion with large-scale, comprehensive solutions. This is not a time for debate. Our role is to address the issue of remarkable deterioration, and the state’s diversion committee will be addressing issues and conflicts. Its position is to focus on the larger picture of how we can preserve as much as we can, and how can we create a system that will protect as much as we can.”

2012-Master-Plan-Coastwide1

The first day of the meeting was open to the public, and the agenda reflected many of the areas of focus that require follow-up from the panel’s first meeting. Presentations from the Army Corps of Engineers, The Water Institute of the Gulf and Biedenharn Group focused on the Hydrodynamic Study, which is collecting data in the river and using models to represent conditions in the river as it is today, predicting what the river will be like in the future without diversion projects and how the construction and operation of diversion projects change the river compared to the future without the diversions. They also briefly discussed the Mississippi River Delta Management Study, expected to begin soon, which will focus on the basin-side effects of diversions and evaluate combinations of diversion projects that maximize the number of acres of wetlands built or sustained over time.

Presentations from David Lindquist from the state’s Coastal Protection and Restoration Authority (CPRA) summarized the current state of knowledge on fisheries and wildlife response to existing freshwater diversions. Craig Colten, Ph.D. from the Water Institute of the Gulf highlighted the importance of considering the influences of restoration projects on communities.

A presentation from Micaela Coner and Bob Beduhn narrowed the discussion down to the engineering and design considerations of a single project – the Mid-Barataria Diversion. Ms. Coner, CPRA, discussed the Mid-Barataria sediment diversion project within the context of the 109 Coastal Master Plan projects. Speaking to the plan’s theme of reconnecting the river with its estuaries, she described sediment diversions as the best opportunity to build, maintain and sustain land.

Dr. Robert Twilley, Louisiana State University

Dr. Robert Twilley

Dr. Robert Twilley, Louisiana State University, described how the river once built natural resource wealth: “Natural resource economies and the flooding of the river once coexisted. The wealth of fisheries, and the wealth of the river building wetlands, once coexisted. Today, there’s a conflict. Historically, the river built land during big flood events. Nature had this figured out. We’re forcing a conflict. There is a resolution to this.”

During the closing portion of the meeting, attendees had opportunities to provide comments to the Expert Panel. Mississippi River Delta Restoration Coalition leaders were among the conversation.

David Muth

David Muth, NWF

David Muth of the National Wildlife Federation urged the panel to consider the historical context of the river in addressing site-specific questions about diversions: “We have glimpses from historical record about how productive this system once was. But for the past 300 years, we have been choking off that system.”

John Lopez of the Lake Pontchartrain Basin Foundation described the coastal land loss crisis in powerful terms and underscored for a sense of urgency: “This house is on fire. Lives are at risk. We have a great scientific challenge, but we don’t have time to delay.”

More background on the Expert Panel:

During its first meeting in January, the Expert Panel was asked to focus on the topics of uncertainty – underlying natural variability and limitations in knowledge – they perceived surrounding the design and operation of major freshwater and sediment diversions. A report summarizing their findings and recommendations from that first meeting was released in February.

In this report the panel focused on identifying six areas that should be answered or considered as sediment diversions move further from idea into planning, engineering and design:

  1. Data collection is important for understanding the system as it is today and for evaluating performance of individual diversion projects.
  2. A controlled sediment diversion does not currently exist, but some information needed to understand the time scales and extent of land building that could be expected from a controlled sediment diversion can be gleaned from natural crevasses.
  3. The response of plant, fish and wildlife communities to the operation of sediment diversions should be incorporated into modeling of different scenarios, both capacity and operation, of a diversion.
  4. The potential social and economic influences of a diversion project need to be considered to minimize any potential negative impacts that can be foreseen.
  5. Planning and design of diversion projects need to be explored under present day and possible future conditions (e.g. sea level rise, changes in precipitation) to maximize project success in the very near and long-term future.
  6. Communications between planners and stakeholders to discuss the realities and limitations of any predictions is essential for project success.
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Mississippi River carries enough sand to build new land for at least 600 years, new study suggests

April 28, 2014 | Posted by Delta Dispatches in Diversions, Reports, Restoration Projects, Science

By Alisha A. Renfro, Ph.D., National Wildlife Federation

As spring weather warms the Midwest, snow melts and drains from 31 states into the Mississippi River. In south Louisiana, the mighty Mississippi River is nearing its peak flow of nearly 900,000 cubic feet of water per second. Rolling down the river with the water is mud and sand, which are essential to building wetlands in the disappearing Mississippi River Delta.

Mississippi River Basin modified from nps.gov

Every hour in Louisiana, a football field of land becomes open water. This land loss crisis is caused in part by levees built for flood protection and navigation which severed the connection between the delta and the river, almost completely halting the land-building processes that once created this iconic landscape.

Sediment diversions are large-scale restoration projects that move sand and mud from the river through the levees into nearby wetlands during high river flows – such as this year’s spring high water flow – to restart the land-building process and help sustain existing wetlands. One important question to understand the full land-building potential of these projects is: Is the Mississippi River a long-term, sustainable source of mud and sand?

A recent Nature Geoscience paper by Jeffrey Nittrouer, Ph.D. of River University and Enrica Viparelli, Ph.D. of the University of South Carolina, “Sand as a stable and sustainable resource for nourishing the Mississippi River delta,” suggests that while the amount of mud carried by the Mississippi River has decreased since the 1970s, the sand it carries has remained steady and may do so for the next 600 years.

The Missouri River is an important source of sediment to the Mississippi, historically supplying about one-half of the total sediment moving down the Mississippi River. However, dams built in the 1950s along the Missouri have been hypothesized as the cause of the large reduction in the amount of total sediment (mud plus sand) that makes its way down to the Mississippi.

In this study, Nittrouer and Viparelli look at changes in the mud and sand carried by the river over a year since the 1970s and found that while the amount of mud that makes it to Tarbert Landing, Miss. (306 miles above the Bird’s Foot delta) has decreased over time, the amount of sand has been consistent. They point out that the likely source of sand is material that is being eroded out of the river channel.

Nittrouer and Enrica applied a model to simulate the response of a sudden reduction in sediment supply that likely occurred with dam construction along the Missouri River in the 1950s. The model indicates that erosion of sand in the river channel between Cairo, Ill. and Vicksburg, Miss. keeps the amount of sand available at Tarbert Landing, Miss. steady for the next 600 years.  

Sand and mud are both needed to restore the Mississippi River Delta. Sand, which is 20 percent of the sediment carried by the river, is essential for building new platforms that can support marsh vegetation. Mud, which makes up the other 80 percent, is necessary for maintaining and increasing the resiliency of existing marsh to sea level rise and storm events.

This study suggests that there is a steady supply of sand to the lowermost part of the Mississippi River that can be put to work by constructing and using sediment diversions to mimic nature to build new land, help sustain existing wetlands and begin the restoration of the Mississippi River Delta. This is positive news for large-scale coastal restoration efforts. 

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Rebuilding coastal Louisiana, using the natural power of the mighty Mississippi

February 12, 2014 | Posted by Delta Dispatches in 2011 Mississippi River Flood, 2012 Coastal Master Plan, Birds, Diversions, Mardi Gras Pass, Restoration Projects, Science

This was originally posted by Environmental Defense Fund on EDF Voices.

By Estelle Robichaux, Restoration Project Analyst, Environmental Defense Fund

Soon after my flyover of the Mississippi River Delta, I joined Dr. John Lopez of the Lake Pontchartrain Basin Foundation (LPBF) on a boat ride down the Bohemia Spillway to Mardi Gras Pass. As we sped down the spillway canal, beautiful swamp lilies and purple morning glories popped out against a backdrop of lush, green plants. Once we reached our destination, we saw an incredible number of birds: Laughing Gulls, Snowy Egrets, Great Blue and Tricolored Herons – just to name a few. This, along with an increase in the number of river otters and beavers observed, is a good indicator that there are healthy fish populations in the area.

mardigraspass

Thirty-five miles southeast of New Orleans, Mardi Gras Pass is the Mississippi River’s newest and naturally evolving “distributary,” a channel of water that flows away from the main branch of the river. This new distributary began forming during the spring flood of 2011, when the water level of the Mississippi River was so high that it flowed over the natural levee in this area. When the floodwaters receded, Dr. Lopez and his team of scientists noticed two breaches in the embankment. These breaches continued to widen and deepen and soon, right around Mardi Gras Day 2012, the breach was complete. The Mississippi River was once again connected to the surrounding wetlands, allowing freshwater and land-building sediment back into the area.

Losing Louisiana

Louisiana has lost 25% of its coastal land area since 1930 and continues to lose land at an alarming rate – one football field every hour, on average. Man-made levees along the Mississippi River cut off many small distributaries, like Mardi Gras Pass, from the wetlands in the floodplain of the river and have contributed to this massive wetland loss. Our team here at EDF works with partner organizations, including the Lake Pontchartrain Basin Foundation, as part of the Mississippi River Delta Restoration Coalition, which has a vision of reconnecting the Mississippi River to its delta to help protect people, wildlife and jobs in coastal Louisiana.

To address the complex, yet urgent need for coastal restoration in Louisiana, the state legislature unanimously passed the 2012 Coastal Master Plan. This plan is a long-term, science-based restoration program that includes nearly 250 restoration projects such as barrier island restoration, marsh creation, establishment of oyster barrier reefs and sediment diversions that will help rebuild Louisiana’s disappearing coast.

Restoring our coast, restoring my hope

One of the principal guidelines for restoration under the Coastal Master Plan is to address the root causes of land loss by using the natural power of the Mississippi River to build land at a large scale. Sediment diversions, a central component of the plan, embody this principle because they are designed to mimic the natural stages of the river and carry sediment to the areas of coastal Louisiana that need it most. By operating diversions at times of high water flow (like during a flood), large amounts of sediment can be diverted. It will then settle out in the wetlands and shallow bays, eventually building land mass in vulnerable coastal areas.

In a way, Mardi Gras Pass is a naturally occurring ‘pilot project’ of a sediment diversion. Knowledge gained from studying this area can tell us about the land-building properties, as well as the short-term effects, of sediment diversions. To learn more about this, LPBF scientists are studying how the reintroduction of freshwater and sediment to the spillway area is changing the wetlands and affecting wildlife populations.

Swift currents and downed trees along the edge of the flooded forest can make navigating Mardi Gras Pass somewhat treacherous, but we, in a trusty 14’ skiff, maneuvered through the channel and onto the Mississippi River for a brief but thrilling cruise.

This is what it means for the river to be connected to its floodplain, I thought as we emerged out onto the open water, this is what this ecosystem is supposed to be like.

Although I grew up only a few miles from it, this was the third time in my life I had been out on the Mississippi River and the first time it was in a boat small enough that I could reach down and touch its muddy waters. As our tiny boat circled out in that mighty river, despite the heat and the midday sun, I had goose bumps.

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Expert panel discusses diversions as a coastal restoration tool

January 17, 2014 | Posted by Delta Dispatches in 2012 Coastal Master Plan, Army Corps of Engineers, Diversions, Meetings/Events, Restoration Projects, Science

By Alisha A. Renfro, Ph.D., National Wildlife Federation

Last week in Baton Rouge, The Water Institute of the Gulf hosted the inaugural meeting of the Expert Panel on Diversion Planning and Implementation. The panel – comprised of 12 experts in natural and social sciences, engineering and economics – was selected from more than 60 nominees from across the country. Panel members are all from outside Louisiana, in order to foster critical and constructive review of work being led by Louisiana-based experts. Under the direction of The Water Institute of the Gulf and meeting up to three times a year, this independent panel will provide technical review, input and guidance as the state moves forward and refines its plans for diverting fresh water and sediment from the Mississippi and Atchafalaya Rivers to build, maintain and sustain coastal wetlands. For this first meeting, the panel was asked to consider the most suitable approaches to addressing current or perceived uncertainties in the planning and design of sediment diversions.

The first day of this meeting was open to the public and included a series of presentations outlining the urgent need for restoration in coastal Louisiana as well as various perspectives on sediment diversions. Kyle Graham, Deputy Executive Director of the Coastal Protection and Restoration Authority (CPRA), summarized Louisiana’s 2012 Coastal Master Plan. In his presentation, Graham pointed out that there was no single restoration project type that can address the state’s land-loss crisis in one fell swoop, but that a suite of restoration projects are needed, including barrier island restoration, marsh creation, oyster barrier reefs, shoreline protection, hydrologic restoration and sediment diversions. Barrier island restoration and marsh creation can mechanically create land in strategic locations, but sediment diversions convey sediment to not only build new land but also to maintain existing wetlands that would otherwise be lost.

2012-Master-Plan-Coastwide1

Brigadier General Duke DeLuca, Commander of the U.S Army Corps of Engineers’ Mississippi Valley Division, presented the Corps’ perspective on sediment diversions. DeLuca discussed some of the questions that the Corps would like to see answered as sediment diversions move from plan to implementation. Many of these outstanding questions should be directly addressed through the Mississippi River Hydrodynamic and Delta Management Study, a joint project being conducted by the State of Louisiana and the Corps. The study will use historic and field data, along with models, to do an assessment of large-scale restoration features to address sustainability of the Mississippi River Delta.

Additional presenters included Jim Tripp from Environmental Defense Fund, Michael Massimi from the Barataria-Terrebonne National Estuary Program, Dr. Ehab Mesehle from The Water Institute of the Gulf and Dr. Alaa Ali from South Florida Water Management District.

In a late afternoon panel, Mark Wingate and Martin Mayer of the Corps’ New Orleans District, John Ettinger of the Environmental Protection Agency and Ronnie Paille of U.S. Fish and Wildlife Service, discussed their federal agencies’ views on diversions. Afterwards, the public was given the opportunity to voice their thoughts and concerns about coastal restoration directly to the panel.

The following day, panel members met in private to discuss the uncertainties discussed and the science that needs to be done to address these uncertainties. A report on that meeting will be given at a CPRA meeting in the coming months.

Bold solutions are needed to halt the rate of catastrophic land loss in coastal Louisiana. Every year, communities throughout the coast inch closer to disaster, becoming more and more exposed to the destructive forces of storm events. Infrastructure, which is vitally important to the economy of Louisiana and the nation, becomes more vulnerable, and important habitat for wildlife, fish and birds vanishes.

Limited by money and sediment resources, there is no one type of restoration project that is a cure-all solution. A suite of restoration projects that strengthen and sustain the landscape is necessary. Sediment diversions use the natural power of the river to build new land and help maintain the existing wetlands. To do nothing or to only implement the least challenging types of restoration projects would doom the resource-rich Louisiana coast.

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National Fish and Wildlife Foundation Announces Nearly $68 Million for Louisiana Restoration Projects

November 14, 2013 | Posted by Ryan Rastegar in 2012 Coastal Master Plan, Media Resources, Mid-Barataria Sediment Diversion, Restoration Projects

FOR IMMEDIATE RELEASE

Contact:
Erin Greeson, National Audubon Society, 503.913.8978, egreeson@audubon.org
Emily Guidry Schatzel, National Wildlife Federation, 225.253.9781, schatzele@nwf.org
Elizabeth Skree, Environmental Defense Fund, 202.553.2543, eskree@edf.org

National Fish and Wildlife Foundation Announces Nearly $68 Million for Louisiana Restoration Projects

$40.4 million dedicated to Mid-Barataria Diversion, a critical project to comprehensive coastal restoration

(New Orleans, LA – November 14, 2013) Today, leading national and local conservation and restoration organizations – Environmental Defense Fund, National Audubon Society, National Wildlife Federation, Coalition to Restore Coastal Louisiana and the Lake Pontchartrain Basin Foundation – released the following joint statement:

“We applaud the National Fish and Wildlife Foundation (NFWF), in partnership with Louisiana’s Coastal Protection and Restoration Authority, for dedicating $67.9 million to seven key barrier island and river diversion projects, including $40.4 million for the Mid-Barataria Diversion project. The Barataria Basin has one of the highest rates of land loss in the world, and this large-scale wetland restoration project is crucial to reversing that trend.

“The mid-sized Mid-Barataria sediment diversion is a key component of Louisiana’s 2012 Comprehensive Master Plan for a Sustainable Coast. The master plan is a blueprint for restoring the Mississippi River Delta and Louisiana’s coast and contains a suite of coastal restoration and protection projects. Our organizations support the full suite of restoration projects in that plan, of which the Mid-Barataria Diversion is a critical piece.

“Restoration of Louisiana’s disappearing wetlands is important not only to Louisiana but to the entire nation. Louisiana’s wetlands and waters provide one-third of the nation’s seafood, are a stopover point for migratory birds traveling the Mississippi Flyway and provide critical wildlife habitat. Projects like the Mid-Barataria Diversion can help revive Louisiana’s coastal wetlands – part of America’s largest delta – to a productive, functioning state, which provides important ecological and economic opportunities for people and wildlife. We look forward to continued work with both the National Fish and Wildlife Foundation and the State of Louisiana to implement the Mid-Barataria sediment diversion on its current timeline of being ready for construction in 2015.”

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Recap of Wednesday's Mississippi River Hydrodynamic and Delta Management Study Technical Meeting

October 25, 2013 | Posted by Delta Dispatches in Army Corps of Engineers, Diversions, Meetings/Events, Restoration Projects, Science

By Alisha Renfro, Coastal Scientist, National Wildlife Federation

The Mississippi River is one of the most managed river systems in the world. However, that management has focused on navigation and flood control needs to the detriment of the economically and ecologically important coastal Louisiana landscape. This week, the U.S. Army Corps of Engineers and Louisiana’s Coastal Protection and Restoration Authority (CPRA) hosted a public meeting in New Orleans to present information and preliminary results of their joint effort on the Mississippi River Hydrodynamic and Delta Management Study. This large-scale, long-term study is developing tools to evaluate different combinations of restoration projects in an effort to address the long-term sustainability of the Mississippi River and its delta while balancing the needs of navigation, flood protection and restoration.

The scope of the study extends from Vicksburg, Miss. south to the Bird’s Foot delta. The study is actually comprised of two coupled, but somewhat distinct, efforts. The hydrodynamic portion of the study will focus on characterizing the dynamics in the river and developing models that can be used to evaluate river-side changes due to proposed freshwater and sediment diversion projects. It will also inform location and design of these projects to maximize their effectiveness and minimize the potential for shoaling in the river’s navigation channel. The delta management part of the study will focus on the basin-side benefits and changes caused by these restoration projects. The delta management portion of the study has not yet begun. Currently, the state of Louisiana and the Army Corps are working to define the depth and breadth of that part of the study.

The afternoon session of the meeting focused on detailed technical presentations on the study. The different tasks of the Mississippi River Hydrodynamic and Delta Management Study include a geomorphic assessment, data collection and an extensive modeling effort. The geomorphic assessment focuses on compiling historical river data, dredging records and satellite imagery to document the historical trends in the river. The data collection effort will compile existing data and conduct field work to fill in gaps in understanding of the water and sediment dynamics that currently exist in the river. The historical data and present data will be integrated into the modeling work to inform the models and to ensure that the models capture the dynamics of the river system. The modeling effort includes a suite of models that each has different strengths and weaknesses. These models will be used to forecast the large-scale, long-term and shorter-term regional changes expected in the river in both a future without river diversions and a future that includes different combinations of diversion projects.

The presentations from the technical meeting indicate that this collaborative state of Louisiana and Army Corps effort has moved forward significantly since it began. The geomorphic assessment has been completed and a final report on its results is expected by the end of this year. The data collection effort is ongoing, having captured the low discharge of the river last year and the higher flow discharge from this past spring. Many of the preliminary model simulations have begun, and the preliminary results presented at this meeting emphasized the dynamic nature of the Mississippi River system, where water discharge, sediment transport and deposition can not only vary greatly from year to year, but also from week to week. The preliminary results also point to the importance of appropriate size, location and operation of sediment diversions in order to maximize sediment conveyance into adjacent wetlands and to reduce potential riverside impacts.

The Mississippi River has been a key feature in the growth and development of the U.S. However, for more than 80 years, the management of the river has focused on balancing the needs of navigation and flood control. A shift away from that management scheme towards one that balances navigation, flood control and restoration is absolutely critical for the survival of the delta ecosystem and, ultimately, the communities and navigation industry that depend on the Mississippi River Delta. The Hydrodynamic and Delta Management study is poised to be the effort that changes the way we think about management of the river and how we build a more sustainable, holistic system for our future.

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Conservation Groups Respond to Mid-Barataria Sediment Diversion Environmental Impact Statement Launch

October 8, 2013 | Posted by Elizabeth Van Cleve in Media Resources, Mid-Barataria Sediment Diversion

FOR IMMEDIATE RELEASE

CONTACTS: Erin Greeson, National Audubon Society, 503.913.8978, egreeson@audubon.org
Emily Guidry Schatzel, National Wildlife Federation, 225.253.9781, schatzele@nwf.org
Elizabeth Skree, Environmental Defense Fund, 202.553.2543, eskree@edf.org

Conservation Groups Respond to Mid-Barataria Sediment Diversion Environmental Impact Statement Launch

Corps’ intention to conduct EIS seen as crucial step forward

(New Orleans, LA – October 8, 2013) Today, a coalition of leading national and local conservation and restoration organizations – Environmental Defense Fund, National Audubon Society, National Wildlife Federation, Coalition to Restore Coastal Louisiana and the Lake Pontchartrain Basin Foundation– released the following joint statement:

"The U.S. Army Corps of Engineers announced in last Friday’s Federal Register their intention to conduct an Environmental Impact Statement on the Mid-Barataria Sediment Diversion. The Mid-Barataria Sediment Diversion will be the first major controlled sediment diversion reconnecting the Mississippi River with its delta. It is a cornerstone of the state’s master plan for sustaining our coast.

"The Mississippi River Delta Restoration Campaign believes that launching the Environmental Impact Statement is an important step forward for the project. Given the urgency of restoring and sustaining our coast, a thorough and rigorous Draft Environmental Impact Statement should be completed by fall of 2014, with final review and permits issued by spring of 2015. We look forward to collaborating with the Corps and its state and federal partners to achieve this exciting and crucial 2015 construction goal. Our coast can’t wait. It's time to get together and get it done.”

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The Restore the Mississippi River Delta coalition is working to protect people, wildlife and jobs by reconnecting the river with its wetlands. As our region faces the crisis of threatening land loss, we offer science-based solutions through a comprehensive approach to restoration. Comprised of conservation, policy, science and outreach experts from Environmental Defense Fund, National Audubon Society, National Wildlife Federation, Coalition to Restore Coastal Louisiana and Lake Pontchartrain Basin Foundation, we are located in Houma, New Orleans and Baton Rouge, Louisiana; Washington, D.C.; and around the United States. See more at www.mississippiriverdelta.org.

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Conservation Groups Issue Statement on New Timeline for Mid-Barataria Sediment Diversion

September 20, 2013 | Posted by Elizabeth Van Cleve in Media Resources, Mid-Barataria Sediment Diversion

FOR IMMEDIATE RELEASE
CONTACTS: Erin Greeson, National Audubon Society, 503.913.8978, egreeson@audubon.org
Emily Guidry Schatzel, National Wildlife Federation, 225.253.9781, schatzele@nwf.org
Elizabeth Skree, Environmental Defense Fund, 202.553.2543, eskree@edf.org

Conservation Groups Issue Statement on New Timeline for Mid-Barataria Sediment Diversion

 (New Orleans, LA – September 20, 2013) Today, leading national and local conservation and restoration organizations Environmental Defense Fund, National Audubon Society, National Wildlife Federation, Coalition to Restore Coastal Louisiana and the Lake Pontchartrain Basin Foundation released the following joint statement:

“The Mississippi River Delta Restoration Campaign commends the Louisiana Coastal Protection and Restoration Authority (CPRA) for adopting an ambitious timeline for the Mid-Barataria Sediment Diversion. Announced at the Authority's monthly meeting in New Orleans on September 18, the state plans to complete environmental review, engineering and design documents, and permit applications and submit them to the U.S. Army Corps of Engineers by Spring 2015. Construction could begin later that year.

“The Mid-Barataria Sediment Diversion is the first major controlled sediment diversion reconnecting the Mississippi River with its delta. It is a cornerstone of the state’s master plan for sustaining our coast. CPRA’s timeline matches the urgency of our coastal land loss crisis. Funding from BP oil spill settlements makes this schedule altogether feasible.

“We know that the Army Corps of Engineers and the other federal resource agencies consider this project to be a national ecosystem restoration priority and will do everything possible to work with the State to make this schedule a reality. We look forward to collaborating with the State and its federal partners to achieve this exciting and crucial 2015 construction goal. Our coast can’t wait. It's time to get together and get it done.”

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Study demonstrates importance of sediment diversions for building land in the Mississippi River Delta

March 27, 2013 | Posted by Delta Dispatches in 2012 Coastal Master Plan, Diversions, Restoration Projects, Science

By Alisha A. Renfro, Ph.D., Staff Scientist, National Wildlife Federation

Last week, an independent scientific panel comprised of prominent scientists from throughout the U.S. released a report, “Mississippi River Freshwater Diversions in Southern Louisiana: Effects of Wetland Vegetation, Soils, and Elevation,” which examines some of the ecological effects of freshwater river diversions. The panel concluded that there is little evidence suggesting that the existing freshwater diversions in Louisiana have appreciably reversed the rate of land loss in the region, and that to reverse the land loss trend, significant inputs of sediment are needed. While most of the existing diversions in Louisiana were built to move fresh water only, many of the diversions included in Louisiana’s 2012 Coastal Master Plan focus on sediment capture and conveyance into coastal wetlands.

Freshwater diversions affect basins by reducing salinities. Extensive dredging of canals throughout the Mississippi River Delta’s wetlands has allowed for salt water from the gulf to intrude into wetlands adapted to lower salinity conditions, resulting in large areas of these wetlands dying and being converted to open water. Wetland vegetation is affected directly by the salinity of the water in wetland soil. High salt concentrations in the soil can affect vegetation by reducing the overall rate of photosynthesis, decreasing nutrient uptake and stunting growth rates. Consequently, the introduction of fresh water into wetland communities damaged by saltwater intrusion is vital in any restoration effort.

Freshwater diversions also increase the amount of nutrients introduced into the receiving basin. While increases in nutrient availability to wetland vegetation would presumably stimulate growth, scientific information collected in Louisiana marsh communities have exhibited varying results depending on plant species, nutrient concentrations and the abundance of different types of nutrients. Increasing the amount of nutrients may also alter the composition of the plant community, as some species of plants have a competitive advantage when it comes to nutrient uptake and growth.

Locations of sediment diversion projects included in Louisians's 2012 Coastal Master Plan. The brown stippled areas show the diversion impact areas. Credit: CPRA

River diversions can also have an influence on wetland elevation. In order for wetlands to persist over time, processes that increase the surface elevation of the wetlands must be equal to factors that increase the threat of submergence (e.g. sea level rise, storms). Diversions have the potential to promote an increase in the elevation of a wetland by adding mineral sediment to the surface and stimulating plant growth both above and below ground. However, the surface elevation of a wetland could decrease as nutrients become less scarce, as the abundance of vegetation roots decline and as an increase in the breakdown of belowground organic material by bacteria takes place. More scientific studies are needed to enhance our understanding of the relationship between marsh response and river input in order to better predict the net effect that sediment and freshwater diversions may have on different marsh types.

This scientific panel found that any freshwater diversion that does not transport a substantial sediment load is unlikely to reverse the current trend of wetland loss in Louisiana. The 2012 Coastal Master Plan recognizes and addresses this reality by focusing on large-scale diversions that would be capable of transporting significant amounts of river sediment into the nearby wetlands. In addition to shifting the focus of diversions from fresh water to sediment, the panel determined that a formal adaptive management scheme is needed for existing and planned diversions where the goals of the project are clear, the pre-diversion conditions of the affected area are well characterized, monitoring in the outfall area is done to measure the progress of the project in relation to its goals and a process exists to adjust the operation of the structure to increase the likelihood those goals are reached.

Related resources:

 

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Mardi Gras Pass: Compromise will be key

March 4, 2013 | Posted by Elizabeth Van Cleve in Diversions, Mardi Gras Pass, Science, Videos

By Emily Guidry Schatzel, Communications Manager, National Wildlife Federation

Recent news reports suggest that the potential for compromise exists in the case of Mardi Gras Pass, the newest known distributary of the Mississippi River. The pass was discovered in 2012 when the river cut a channel through its bank in the Bohemia Spillway, a stretch without levees, giving an exciting and rare view at how a natural delta system operates.

While the pass promises ecological prosperity for the delta, the newly enlarged channel washed out the private road that one local oil company uses to access its facilities. The company has since applied for a permit to rebuild that road. Coastal restoration advocates believe that the current plan to rebuild will effectively close the Mardi Gras Pass and will eliminate encouraging ecological benefits that scientists from the Lake Pontchartrain Basin Foundation have been monitoring since the channel’s development.

FOX 8 WVUE New Orleans News, Weather, Sports

This video further explains the debate over keeping the pass open, and alternatives for compromise. The key takeaway? Whether it be construction of a bridge, or another reasonable alternative that gives the oil company access while allowing Mother Nature to literally “run its course,” this is clearly an issue that requires the full attention of key decision-makers so that the best long-term solution is achieved.

As Dr. John Lopez, executive director of the Lake Pontchartrain Basin Foundation — the organization that discovered the pass in 2012 — said, “It’s the kind of thing that most scientists sit in their offices there, dreaming how it might happen. Here, you can actually see it.” Keeping Mardi Gras Pass open is important — it’s a chance for the river to reconnect with its wetlands, which is exactly what the river is designed to do.

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