Archive for Reports
By Whit Remer, Policy Analyst, Environmental Defense Fund
The Gulf Coast Ecosystem Restoration Council recently released "The Path Forward to Restoring the Gulf Coast: A Proposed Comprehensive Plan." The RESTORE Act, signed into law in July, required the newly created Restoration Council to publish a Proposed Plan within six months of the legislation becoming law. Only six pages in length, the Path Forward provides a general framework for the Restoration Council to follow while developing their more robust Initial Comprehensive Plan, due out in July 2013. Moving forward, it is important that the Restoration Council create a Comprehensive Plan concentrated on restoring Gulf Coast ecosystems, which are the backbone of a healthy and thriving gulf economy.
Following the 2010 gulf oil disaster, Congress passed the RESTORE Act to ensure robust restoration of the Gulf Coast. Through the RESTORE Act, Congress developed a framework for federal and state officials to undertake comprehensive restoration. Congress provided money for restoration by ensuring at least 30 percent of funds under the RESTORE Act are dedicated to ecosystem projects. To oversee much of the restoration, the RESTORE Act establishes a highly experienced body of federal and state stakeholders, known at the Gulf Coast Ecosystem Restoration Council. Finally, the law requires the Restoration Council to develop a scientifically-based Comprehensive Plan to guide ecosystem restoration projects to implementation. The “Path Forward” document is a first step to building a plan for ecosystem restoration.
As expected, and required by law, the Path Forward builds on the work and recommendations of the Gulf Coast Ecosystem Restoration Task Force, which was led by the Environmental Protection Agency. The Task Force strategy had four overarching goals: habitat restoration, restore water quality, replenish marine resources and enhance community resilience. The newly released Path Forward adds a fifth goal of revitalizing the gulf economy. Moving forward, it is important for the Restoration Council to ensure that funds dedicated to the Comprehensive Plan are used solely for ecosystem restoration projects. After all, numerous studies have shown that ecosystem restoration supports economic restoration, including healthy tourism and fishing industries. New jobs created by the ecosystem restoration projects help protect existing infrastructure, rebuild critical wetlands, and create a new export industry focused on coastal and delta restoration.
We are excited about the Restoration Council’s commitment to long-term recovery in the gulf. In the Path Forward, the Restoration Council has reaffirmed their plans to invest in “specific actions, projects, and programs that can be carried out in the near-term to help ensure on-the-ground results to restore the overall health of the ecosystem.” By incorporating the best available science and adapting the Comprehensive Plan over time to incorporate new science, the plan can advance innovative ecosystem restoration solutions, like freshwater sediment diversions.
We look forward to the next draft of the Comprehensive Plan due out sometime before July.No Comments
By Alisha A. Renfro, Ph.D., Staff Scientist, National Wildlife Federation
This year, drought conditions throughout most of the country have left the Mississippi River flowing at a near all-time low. This is a stark comparison to 2011, when heavy rains and a large snowmelt in the spring sent record levels of water and sediment flowing down the river. At the Old River Control Structure north of Baton Rouge, the flow of the river is split, with 70 percent continuing down the Mississippi to the Bird’s Foot delta, and the remaining 30 percent flowing down the Atchafalaya River. During the 2011 flood, the flood protection levees and the opening of the Morganza and Bonnet Carré spillways successfully shunted water safely past the high population centers in the region. However, this event was a missed opportunity to capitalize on the influx of fresh water and sediment and to reconnect the river with sediment-starved wetlands of Louisiana.
In a recent study published in Nature Geoscience, research led by Federico Falcini, Ph.D. examined the link between the historic 2011 river flood and sediment accumulation in nearby wetlands. Their analysis suggested that the natural dynamics of the coastal system coupled with man-made alterations to the river system influenced the amount of sediment deposited in the wetlands. This work shows that under river flood conditions, diverting the flow of the river into shallow basins adjacent to the river could contribute significantly to sediment deposition in the wetlands and therefore contribute to wetland growth.
In the study, the sediment plumes of the Mississippi and Atchafalaya Rivers were tracked using satellite imagery from the 2011 flood event to understand where the sediment went once it exited these rivers. The Mississippi’s sediment plume exited the river in focused jets of sediment-laden water due to the confinement of much of the river’s flow between artificial levees. This plume moved past the coastal current and into the deeper waters of the Gulf of Mexico, limiting the amount of sediment that could be deposited in the near-shore area and adjacent wetlands. In contrast, the Atchafalaya’s sediment plume exited the river and moved along a broad, near-shore area, mixing with waters from the Gulf of Mexico and creating conditions that were likely to favor sediment deposition.
A comparison of sediment accumulation during the 2011 flood in nearby marshes shows a trend that corresponds to the difference in behavior of the two river plumes. Sediment accumulation was highest at marsh sites near the Atchafalaya River, which supports the idea that its sediment plume spreading out over a large area in relatively shallow water, promoting increased sedimentation in the region. Sediment accumulation in wetlands near the mouth of the Mississippi River was substantial, but significantly lower than near the Atchafalaya. While the Mississippi River carried a larger sediment load during the 2011 flood event, much of the sediment was lost to the deeper waters of the gulf.
Louisiana’s 2012 Coastal Master Plan identifies several sediment diversions that are key to restoring the important coastal Louisiana landscape. The success of these diversions will depend on a variety of factors, including location and operation. However, this new research confirms that fine sediments introduced into shallow water can substantially contribute to sediment accumulation in wetlands. In order to restore the rapidly deteriorating wetlands of coastal Louisiana, it is critical to reintroduce the sediment that once built this productive region.2 Comments
By Alisha Renfro, Ph.D., Staff Scientist, National Wildlife Federation
In the aftermath of the BP oil disaster, President Obama created the Gulf Coast Ecosystem Restoration Task Force through an executive order in October 2010. The mission of this Environmental Protection Agency-led group was to develop a long-term, holistic and science-based ecosystem restoration plan for the Gulf Coast.
Included in this effort was the Science Coordination Team which involved more than 70 scientists from federal and state agencies who provided scientific input for the development of the strategy document. While the final Gulf of Mexico Regional Ecosystem Restoration Strategy was released in December 2011, the Science Coordination Team realized there was also a need to develop a science program to ensure that both focused and ecosystem-wide science would be available to implement and maintain the Gulf Coast restoration projects. The science team produced a report in April 2012 titled “Gulf of Mexico Ecosystem Science Assessment and Needs,” which identified current conditions in the gulf and specified actions that need to be taken to meet the goals set for a healthier ecosystem.
The qualifiers for the recovery of the Gulf of Mexico ecosystem are:
- Coastal wetland and barrier shoreline habitats are healthy and resilient.
- Fisheries are healthy, diverse, and sustainable.
- Coastal communities are adaptable and resilient.
- A more sustainable storm buffer exists.
- Inland habitats, watersheds, and offshore waters are healthy and well managed.
The coastal habitats of the Gulf of Mexico are some of the most productive ecosystems on earth. However, there has been an overall decline in health of these ecosystems as wetlands have been lost, barrier islands have eroded, and water and sediment quality has declined, which has increased stressors on commercially-important species and other organisms. As miles of the Gulf Coast’s protective wetlands and shorelines have been lost due to natural disasters and other events, including the BP oil spill and several hurricanes, the vulnerability of the people who call the region home has increased.
To address these changes, the science team recommended a variety of actions, including identifying historic changes in land use and shoreline changes; determining the sediment, water and nutrient resources needed to support sustainable habitats; and increasing the understanding of the relationships between different types of gulf habitats. Additionally, long-term, continuous scientific data, analysis, and interpretation were identified as critical for informing the design, construction, and operation of restoration projects. They were also considered key in developing modeling tools, methods, and protocols for undertaking ecosystem-level restoration planning and assessing restoration success.
Increasing the health of the surrounding ecosystem will also help improve the resiliency of coastal communities. To directly address risk reduction for communities, the science team suggested holding workshops and training opportunities to bring together local community planners, emergency managers and building code officials to learn about the surrounding environment and how to build more resilient coastal communities.
In September 2012, the duties and responsibilities of the Task Force were transitioned to the Gulf Coast Ecosystem Restoration Council. That month, President Obama issued an Executive Order recognizing the importance of the Gulf Coast as a national treasure and acknowledging the successful completion of the Task Force and its strategy document. The Executive Order transferred the Task Force’s duties to the new Restoration Council. The Council, established by the RESTORE Act, will build on the work of the Task Force, identifying projects and programs that would help restore and protect natural resources and ecosystems of the Gulf Coast with funding from the RESTORE Act’s Gulf Coast Restoration Trust Fund. With a strategy and source of funding in place, recovery and restoration of the Gulf Coast, including the Mississippi River Delta, moves one step closer to becoming a reality.No Comments
Sportsmen and women want fines from 2010 gulf oil disaster used to restore critical coastal ecosystems.
This was originally posted on VanishingParadise.org.
A new national poll released yesterday shows that hunters and anglers prioritize protecting the gulf ecosystem and using fines paid by BP and other parties responsible for the 2010 Gulf oil disaster to be used for gulf restoration. The poll conducted by Chesapeake Beach Consulting shows threats to America’s conservation heritage are priority issues for sportsmen and women, on par with gun rights.
An overwhelming 81 percent of sportsmen polled strongly believe BP should be held accountable and fined the maximum amount allowed for the 2010 gulf oil disaster.
The poll’s results further support the RESTORE Act, an important piece of bipartisan, bicameral legislation passed earlier this year that dedicates 80 percent of the Clean Water Act fines collected from BP and other responsible parties to restoring the Gulf Coast.
“America’s sportsmen and women understand the importance the entire Gulf Coast has for our nation’s hunting and fishing heritage,” said Land Tawney, National Wildlife Federation’s senior manager for sportsmen leadership. “From the 10 million migratory waterfowl that use the marshes around the Mississippi River Delta for wintering grounds to the extremely important fisheries of the gulf, this is a region that matters to the entire nation.”
The gulf ecosystem suffered from rapid decline before the oil spill, which only exacerbated existing land loss issues, especially around the Mississippi River Delta. Although much of the visible oil is gone, some of the tar balls and tar mats stirred up by last month’s Hurricane Isaac were identified as remnants from the 2010 gulf spill. The region remains in jeopardy as food supplies and habitats are still recovering from the impacts of oil — and may face impacts from the spill for decades.
“Restoring the gulf is crucial to the safekeeping of our American conservation traditions,” Tawney continued. “This poll ultimately validates what so many individuals, organizations and businesses have been calling for since the summer of 2010 — that the gulf’s fish and wildlife habitats must be made whole and preserved for our future generations’ use and enjoyment.”
This national public opinion poll conducted among 800 self-identified hunters and anglers was conducted by Chesapeake Beach Consulting from August 27 through September 1, 2012 for the National Wildlife Federation. The sample for this survey was randomly drawn from a list of self-identified hunters and anglers. To qualify, a respondent must have indicated they were a hunter, an angler or both, as well as a registered voter. All interviews were conducted by telephone, including 15 percent of the interviews by cell phone. The margin of error for this study is plus or minus 3.2 percent at the 95 percent confidence level.No Comments
By Shannon Hood, Environmental Defense Fund
On October 9 and 10, the Mississippi River Delta Science and Engineering Special Team (SEST) will host its first conference, titled “Answering Fundamental Questions about Mississippi River Delta Restoration.”
The SEST was convened over two years ago and is comprised of leading engineers, economists and scientists from around the country with specialties ranging from river engineering to coastal ecology to sociology. This team brings a new approach to Mississippi River Delta restoration, in that they recognize its multifaceted nature and have brought together specialists to approach the most salient issues from a wide range of viewpoints. The conference is a further discussion of the group’s previously released report and a precursor to their forthcoming book.
On Oct. 9, the experts will discuss topics including the usefulness of river diversions to build land, the amount of available sediment in the Mississippi River, navigation and flood control issues, the region’s economic contributions, climate change impacts, the effects of nutrients on wetlands and the effects of restoration on communities and fisheries. On Oct. 10, the SEST group will convene for an interactive panel discussion of policy implications. View the full agenda here.
Louisiana’s Mississippi River Delta region is home to vibrant communities, rich habitats and is a hub for international commerce. For all to thrive in the future, a restoration plan must consider the full array of interests encompassed here within the context of rising seas. A dynamic issue requires dynamic thinking, and that is what this team has provided.
SEST members include:
For more information or to register for the conference, please click here.No Comments
Contact: Elizabeth Skree, 202-553-2543, firstname.lastname@example.org
Geosynthetics Industry Poised to Grow as Gulf Coast Restoration Ramps Up
RESTORE Act will increase environmental restoration, spur economic growth
(Washington, D.C.—July 26, 2012) What are geosynthetics and why are they central to the creation of jobs and expansion of coastal restoration projects? A new Duke University study, “GEOSYNTHETICS: Coastal Management Applications in the Gulf of Mexico,” details how the emerging geosynthetics industry can create jobs benefitting nearly 200 employee locations in 36 states, including more than 72 in the five gulf states and 24 in Louisiana. Duke has also created an online interactive map showing firm-level data and firm locations by state and value chain segment.
Geosynthetics are plastic materials manufactured into fabrics or sheets of various sizes, strengths and textures that are used in engineering projects. Some geosynthetic products include sand-filled geotextile tubes used as containment dikes for restoration projects, as well as marine mattresses – large, rectangular geogrid pouches filled with rocks that are used to support structures and control erosion. Increased investment in coastal restoration, as expected through the recently approved RESTORE Act, will stimulate more local projects and job sites using these innovative construction materials, which will in turn stimulate job creation and the economy.
The report, funded by Environmental Defense Fund and The Walton Family Foundation, is a study of 84 firms involved in the geosynthetics supply chain. The report finds that increased investment in coastal restoration will provide quadruple economic returns and create new opportunities for the growing geosynthetics industry.
Seventy-three percent of firms sampled in the study are considered small businesses according to the U.S. Small Business Administration guidelines on number of employees, and nearly half the firms have fewer than 100 employees. In addition to qualifying as small businesses, almost a quarter of geosynthetics manufacturing firms cited were established in just the last 10 years.
“The geosynthetics industry has been heavily involved in coastal restoration projects throughout Louisiana and the gulf states. As more projects are launched in response to RESTORE Act passage, our member companies are poised to grow our business and local staff to meet increased demand,” said Laurie Honningford, managing director for the International Association of Geosynthetics Installers (IAGI).
“As restoration projects ramp up all along the Gulf Coast and Mississippi River Delta as a result of the RESTORE Act, so will the coastal engineering and construction profession and the geosynthetics industry on which it relies,” said Jackie Prince Roberts, director of sustainable technologies for Environmental Defense Fund. “Geosynthetics – geotextiles and other manmade, polymer-based materials used in environmental restoration, flood prevention and erosion control projects – are an emerging industry and projected to grow at an annual rate of 6.8 percent through 2015. Long-term investment in coastal management will not only benefit the environment, but it will also spur economic growth all along the geosynthetics supply chain by both protecting current jobs – like Gulf Coast fishing, tourism and shipping – and creating new jobs. It’s an economic and environmental win-win.”
The study’s release is timely because earlier this month, the U.S. Congress passed and the President signed into law the RESTORE Act as part of the Surface Transportation Extension Act. This historic legislation will direct 80 percent of the Clean Water Act penalties paid by BP and others responsible for the 2010 gulf oil disaster to the Gulf Coast states to use for restoration. It is the single largest investment in environmental restoration ever made by the U.S. Congress.
“Our geotextile products are incorporated into a welded-wire system which provides a low-cost solution to a wide range of coastal restoration and protection challenges, from oyster reef construction to flood protection,” said Stephanie Victory, president of HESCO Bastion Environmental Inc. “We have completed projects all over the world. Some of the most recent range from emergency flood responses in Thailand to building HESCO Delta® Unit oyster reefs just north of Gulf Shores, Ala. We are thrilled that the RESTORE Act passage will create more opportunities for jobs and coastal restoration efforts back home in Louisiana and across the gulf region.”
“The geosynthetics industry is growing and evolving rapidly as it finds more applications for its product,” says the report. “Coastal management programs across the Gulf Coast states are growing as well, developing plans worth billions of dollars for ecosystem restoration, flood prevention, and erosion control. With geosynthetics playing an increasing role in coastal management, this convergence of events presents an opportunity for geosynthetics manufacturers to diversify and grow, and for coastal engineering to evolve and improve.”
The study also serves as a follow-up to two previous Duke University studies, “RESTORING THE GULF COAST: New Markets for Established Firms” and “RESTORING GULF OYSTER REEFS: Opportunities for Innovation.” The former, released in December, determined that using Clean Water Act penalties from the 2010 gulf oil spill could create jobs that would benefit at least 140 businesses with nearly 400 employee locations in 37 states, including more than 260 locations in the Gulf Coast. The latter, released in June, identified 130 firms nationwide involved with oyster reef restoration and poised to grow with passage of the RESTORE Act.
For more information on how investing in environmental restoration provides quadruple economic returns, please visit www.MississippiRiverDelta.org/economics.
Environmental Defense Fund (edf.org), a leading national nonprofit organization, creates transformational solutions to the most serious environmental problems. EDF links science, economics, law and innovative private-sector partnerships. Connect with us at Twitter.com/EDF_Louisiana and on Facebook.No Comments
FOR IMMEDIATE RELEASE
Elizabeth Skree, Environmental Defense Fund, 202.553.2543, email@example.com
Emily Guidry Schatzel, National Wildlife Federation, 225.253.9781, firstname.lastname@example.org
Kevin Chandler, National Audubon Society, 202.596.0960, email@example.com
Heather Layman, The Nature Conservancy, 703.475.1733, firstname.lastname@example.org
David Willett, Ocean Conservancy, 202.351.0465, email@example.com
Mary Babic, Oxfam America, 617.517.9475, firstname.lastname@example.org
GROUPS COMMEND CONGRESS ON RESTORE ACT
Legislation restoring Gulf Coast ecosystems and economy included in transportation bill
(Washington, D.C. – June 28, 2012) Local and national conservation groups have issued the following joint statement in response to the Senate and House inclusion of the RESTORE Act in the Surface Transportation Extension Act. Consistent with recent findings from two independent commissions, the RESTORE Act dedicates 80 percent of the Clean Water Act fines from BP and other parties responsible for the 2010 Gulf oil spill to restoring the Gulf Coast environment and economy.
“We applaud the transportation bill conferees and the Gulf Coast Senators and Representatives for making Gulf Coast restoration a priority by including the RESTORE Act in their final bill,” said Environmental Defense Fund, National Audubon Society, National Wildlife Federation, The Nature Conservancy, Ocean Conservancy and Oxfam America. “The RESTORE Act will help revitalize the entire region by ensuring the bulk of the fines collected from those responsible for the spill are directed back to the area that suffered so much harm.”
“Funding from the RESTORE Act will help the ailing Gulf Coast as well as the entire nation. Our economy depends on a healthy Gulf – it is where roughly 40 percent of America’s domestically caught seafood is produced, and billions of dollars in goods flow in and out of its ports every year. It is also home to some of the nation’s most at-risk wetlands, socially vulnerable communities and richest natural resources. This legislation will not only restore ecosystems and communities, it will also help create jobs and boost our economy.”
“We look forward to seeing the RESTORE Act cross the finish line in Congress and working with the states and Administration to ensure that every dollar is used to help restore the Gulf and increase the resiliency of its ecosystems and communities. Passage of the RESTORE Act would be an affirmation by the nation that the Gulf of Mexico is a valuable economic and ecological resource that benefits all Americans.”
Getting back to nature: New study looks at the past, present and future of the Mississippi River DeltaJune 4, 2012 | Posted by Delta Dispatches in Diversions, Reports, Restoration Projects, Science
By Alisha A. Renfro, Ph.D, Coastal Scientist, National Wildlife Federation
The Mississippi River has played an important role in the history, physical and economic growth of the United States. However, the Mississippi River and the delta region it built didn’t always look the way they do today. In an article by Michael Blum, Ph.D. and Harry Roberts, Ph.D. titled “The Mississippi Delta Region: Past, Present, and Future” published in The Annual Review of Earth and Planetary Sciences (vol. 40), researchers assemble the extensive scientific information that has been reported about the development of the Mississippi River Delta region, the state of the area today and what this means for the future of coastal Louisiana. This study will help scientists plan a sustainable future for the delta.
The modern landscape of the Mississippi River Delta region began to form around 7,000-8,000 years ago. As the river meandered back and forth across the delta plain, it deposited sediments that had been collected from throughout the river’s 31-state drainage basin. Five delta headlands were built as the river changed its course every 1,000-1,500 years across what is now coastal Louisiana. Once the river changes locations and is no longer actively building and maintaining a particular delta lobe, natural processes begin reworking the area, causing marsh to retreat landward and the sandy seaward extent of the lobe becomes a barrier-island arc. It was these processes that formed the Louisiana bayous and barrier islands that we know of today.
The modern day Bird’s Foot delta, also known as the Plaquemines/Balize delta, began forming just over 1,000 years ago. About 500 years ago, the Atchafalaya River, which branches off of the Mississippi River south of the Old River Control Structure, formed the Atchafalaya and Wax Lake deltas, which emerged in the 1970s. Today, active delta building is limited in the Mississippi River Delta to only the mouth of the Atchafalaya River and Wax Lake Outlet as well as a few controlled and uncontrolled diversions an along the Mississippi River. Without more land building opportunities, the delta will collapse.
Modifications along the river system, such as levees and dams, along with sea level rise and higher rates of land sinking have drastically changed conditions along the Mississippi River system that once built and maintained the delta region. Today, rather than migrating back and forth across the deltaic plain, the river is locked in place by an extensive levee system. Even if the river could still migrate, dams and reservoirs in the upper drainage basin states have reduced the amount of sediment carried by the river by half since the 1950s. In addition, sea level rise coupled with land sinking due to compaction of muddy river sediment and fluid withdrawal associated with the gas and oil industry has accelerated land loss in the abandoned delta headlands.
The changes in the river, sea level and sediment supply mean that the future delta landscape will not resemble that of the past. Restoring the delta-building processes of the river will require us to rethink how we manage the resources of the Mississippi River and re-imagine what the future coastline could look like. River diversions that reconnect the sediment and water resources in the Mississippi River to the marsh landscape that surrounds it is a crucial step toward restoring the delta-building and land-sustaining processes of the region.2 Comments
Managing the Mississippi River for ecosystem restoration, navigation and flood protection: A win-win-winMay 16, 2012 | Posted by Delta Dispatches in Diversions, Louisiana Coastal Area (LCA), Reports, Restoration Projects, Science
By Alisha A. Renfro, Ph.D., Coastal Scientist, National Wildlife Federation
The Mississippi River is one of the largest rivers in the world, carrying water, nutrients and sediment across America’s heartland, through Louisiana and into the Gulf of Mexico. The Mississippi River Hydrodynamic and Delta Management Study is a Louisiana Coastal Area project that has recently been initiated by the U.S. Army Corps of Engineers and Louisiana’s Coastal Protection and Restoration Authority. The purpose of this 5-year, large-scale study is to assess the resources of the lower Mississippi River and evaluate restoration efforts that could increase the long-term sustainability of the delta. To take serious steps toward using the river for coastal restoration, the management of the Mississippi River must be re-envisioned to regard navigation, flood protection and ecosystem restoration as equally important services provided by the river.
The hydrodynamic part of this study will focus on compiling previous scientific research and collecting new information about river discharge, water flow, changes in the river bottom and sediment availability. The information collected will be used to inform models that replicate the current conditions of the Mississippi River from the Old River Control Structure north of Baton Rouge down to the Bird’s Foot Delta. The delta management part of this study will use the newly-developed models to assess the benefits and effects of different proposed restoration projects on the river and the nearby basins.
This study is important because it provides us with an opportunity to reevaluate how we manage the Mississippi River. Currently, the river is being managed exclusively for navigation interests, which has directly contributed to Louisiana’s coastal land loss crisis over the last 80 years. However, despite this focus on navigation, increases in the cost of dredging and decreases in the Corps of Engineers’ dredging budget have threatened to diminish the depth and width of the navigation channel, reducing the cargo capacity the ships can carry and decreasing the ability of U.S.-produced exports to compete on the world market.
Integrating well-designed river diversions into the management of the river has the potential to be a win-win-win for the Mississippi River Delta: restoring the ecosystem, providing a more reliable navigation channel and bolstering the flood protection system. Sediment diversions can mimic the natural processes that once built the surrounding delta. They can also remove sediment from the river, which reduces the need and cost for dredging in the navigation channel. During flood events, river diversions can also be used as additional outlets for flood waters, reducing pressure against the flood protection levees that protect communities and important infrastructure.
The Hydrodynamic and Delta Management Study is an important tool that will improve the understanding of the current conditions of the mighty Mississippi River and the resources available for coastal restoration. It is imperative that the information from this study be used to accelerate large-scale ecosystem restoration efforts and better manage the river for the important services it provides not only to Louisiana, but to the entire nation.1 Comment
Study looks at sediment and water flow through Mississippi River, helps scientists plan effective restoration projectsMay 1, 2012 | Posted by Elizabeth Skree in Diversions, Reports, Restoration Projects, Science
By Alisha A. Renfro, Ph.D., National Wildlife Federation
The sediment and water transported by the Mississippi River built much of the ecologically-rich Mississippi River Delta and Louisiana coastline. But over the last decade, manmade modifications throughout the river basin to improve navigation and flood protection have disconnected the river from its delta. This has reduced the amount of sediment carried by the river and severed the connection between the river and the adjacent wetlands it naturally built. Sediment is a precious resource, and the ability to restore the Mississippi River Delta relies on a thorough understanding of how much sediment is moving in the river, where it is deposited and how much is lost to the Gulf of Mexico. Answering these questions will help scientists and coastal planners develop restoration projects, such as river diversions, that effectively reconnect the sediment in the river with the coastal wetlands that need it.
A recent study led by Mead Allison, Ph.D., “A water and sediment budget for the lower Mississippi-Atchafalaya River in flood years 2008-2010: Implications for sediment discharge to the oceans and coastal restoration in Louisiana” (Journal of Hydrology, Vol. 432-433), advances the understanding of resources transported through the Atchafalaya-Mississippi River system. Using data from monitoring stations, previous studies and boat-based measurements, the researchers measured and tracked the water and sediment as it moved through the Mississippi-Atchafalaya River system.
The Mississippi River discharge varied seasonally and annually during the study period (2008-2010). Averaged over the three-year study period, only 50 percent of the water measured at Baton Rouge, La. is still carried by the river by the time it reaches the Bird’s Foot Delta. Much of this loss occurs more than 30 miles below New Orleans and is due to natural and manmade breaks in the river levees. The fine mud and silt that comprise the bulk of the sediment carried by the Mississippi River followed a similar pattern as the water.
In contrast, sand, which is often considered crucial for coastal restoration, had a much different pattern. More than 50 percent of the suspended sand that was measured in the river was deposited either in the river channel or along the river bank between Tarbert Landing, Miss. and Baton Rouge, La. Down at the Bird’s Foot Delta, only around 2 percent of the suspended sand measured at Tarbert Landing, Miss. was transported through the southern passes and lost to the Gulf of Mexico The rest was either deposited in the river channel (approximately 30 percent) or transported out through the natural and manmade breaks in the river levee (approximately 15 percent).
The 2012 Louisiana Coastal Master Plan includes a suite of river diversions that are instrumental in diminishing the current rate of land loss in the region. The data from Allison’s study suggests that to use the limited amount of sand available to build land, diversions should be located above the rapidly sinking Bird’s Foot Delta and operate during rising river discharge to maximize the sediment transported through the diversion into the wetlands, while minimizing the sediment deposited in the river channel which can interfere with navigation. Strategically locating river diversions will both help rebuild land in the Mississippi River Delta as well as reduce the need to dredge the river for navigation.No Comments