Archive for Diversions
The Next 50 Years: Climate change and the Coastal Master Plan: “Hope for the best but plan for the worst”
July 19, 2012 | Posted by Delta Dispatches in 2012 Coastal Master Plan, Coastal Master Plan series, Diversions, Hurricanes, ScienceBy Dr. Doug Meffert, Executive Director, Audubon Louisiana
Louisiana’s 2012 Coastal Master Plan takes a realistic and critical examination of the effects of climate change impacts on the future of coastal Louisiana, both in terms of prioritization of restoration projects as well as risk reduction. In its “less optimistic scenario,” the master plan estimates 0.45 meters of sea level rise over the next fifty years. This is in addition to between zero and 25 millimeters per year of land subsidence, with the fragile deltaic plain having the highest rates. The resultant combination of sea level rise and subsidence predicts that relative sea level rise will be more than one meter during the next century in some areas of the Mississippi River Delta. Additionally, this scenario anticipates a 20 percent increase in storm intensity and a 2.5 percent increase in storm frequency for Category 1 hurricanes and greater. As climate change brings more severe storms and rising seas to Louisiana’s coast, it is important to incorporate these predictions into the formulation of the Coastal Master Plan.
Predicted land change over the next 50 years. Source: Coastal Protection and Restoration Authority of Louisiana (CPRA).
This “less optimistic scenario” predicts a very different and more vulnerable coast than we had in the 20th century. The master plan uses this scenario for its predictions for future flooding from a 100-year event and for prioritization of restoration projects, since what is labeled as “less optimistic” in the report could just as accurately be labeled as “increasingly likely.” This scenario is consistent with the recent assessments by the Intergovernmental Panel for Climate Change (IPCC), the findings from the Durban Climate Change Conference in November 2011, and more recently, peer-reviewed articles (Blum and Roberts, 2012; Day et al., 2012). In fact, one of the master plan’s Science and Engineering Board members, Dr. Virginia Burkett, was a coauthor of the IPCC’s 2007 report, which garnered the 2007 Nobel Peace Prize for the IPCC.
“Hope for the best but plan for the worst” is the adage adopted by the Coastal Master Plan, and I couldn’t agree more. As it is, there is not enough sediment in the Mississippi River to offset the predicted land loss from relative sea level rise and erosion if we do nothing. This means we need to act now for a future coast that supports the fisheries, birds and other ecological services upon which we depend. We need to plan for a future coast that still provides a natural storm surge buffer for our cities, towns and critical infrastructure. That future coast will just be different than what we’ve known in the past. And that future coast depends on implementing large-scale river diversions with no further delay. We finally have a realistic master plan based on the best science possible. Now, we just need to implement it.
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The Next 50 Years: Sediment diversions as a necessary restoration tool
June 19, 2012 | Posted by Delta Dispatches in 2012 Coastal Master Plan, Coastal Master Plan series, Diversions, Restoration Projects, ScienceThis is the second post in our "The Next 50 Years" Coastal Master Plan series. Check back as we continue diving into the master plan and what it means for the people and environment of the Mississippi River Delta.
By Alisha A. Renfro, Ph.D., Staff Scientist, National Wildlife Federation
Since 1932, coastal Louisiana has lost almost 1,900 square miles of land and if bold action is not taken, another 1,700 square miles could be lost by 2060. Louisiana’s 2012 Coastal Master Plan, passed last month by the state legislature, is a 50-year strategy that aims to realistically, but aggressively, use numerous restoration tools to ensure a sustainable and more resilient coast. The plan’s analysis indicates that sediment diversions, structures that allow Mississippi and Atchafalaya River water to be moved strategically into the surrounding wetlands, are critical projects for halting land loss and building a more sustainable coastline for the future of the Mississippi River Delta.
Symbol used for sediment diversions in the 2012 Coastal Master Plan. Sediment diversions use channels and/or structures to divert sediment and fresh water from the Mississippi and Atchafalaya Rivers into adjacent basins. Source: Coastal Restoration & Protection Authority (CPRA)
Ten projects identified as sediment diversions were judged as important restoration tools in the plan. Sediment diversions mimic some of the natural processes that once built the Mississippi River deltaic region. By operating these types of control structures when river discharge is high, the large amount of sediment, that is being moved along with the water, is captured and funneled into the nearby wetlands. The introduction of sediment would not only help restore areas that are today shallow open water, but it would also help prevent future wetland loss due to rising sea levels.
Sediment diversions can build new marsh by transporting sediment-laden water from the river into the nearby basin. The heavier sand sediment is deposited quickly and over time, and a marsh platform is built. Once vegetation begins to colonize the area, sediment deposition increases as silts and clays are trapped by plants, and a new marsh will emerge. Sediment diversions can also help sustain the newly-built and existing marsh as sea levels rise, by providing a source of sediment that can be deposited on the marsh surface. Ultimately, this can increase the elevation of the marsh surface, which helps prevent prolonged flooding of the marsh, even as sea levels rise. Sediment diversion critics have voiced concerns about the introduction of fresh water into these basins and have questioned whether diversions are essential to restoring Louisiana’s coast.
This map of southeastern Louisiana shows the locations of the sediment diversion projects included in the 2012 Coastal Master Plan, represented by brown circled triangles like the one in the previous image. The brown stippled areas show the diversion impact areas. Credit: CPRA
To evaluate the necessity of the sediment diversion projects in the master plan, the authors conducted an experiment to analyze the amount of land that could be built only using other types of restoration tools. The results of this experiment indicated that by removing the sediment diversion projects from the plan, total land built would be reduced by 340 to 630 square miles over the 50 years. This indicates that sediment diversion projects are crucial projects in the plan and necessary for rebuilding the Mississippi River Delta.
A similar experiment was conducted to address questions about using a few larger sediment diversions versus multiple smaller diversions. The multiple small diversions not only affected the benefits that people get from the land, such as oysters, as much or more than larger diversions, but the smaller diversions also built significantly less land over the next 50 years.
The restoration projects selected in the 2012 Coastal Master Plan may potentially build or sustain up to 800 square miles of land over the next 50 years – land that otherwise would be lost. While sediment diversions are not the only types of restoration project identified as critical to the future of the Louisiana coastline, scientific assessment suggests they are absolutely necessary. Other types of projects, such as barrier island restoration and marsh creation, can build land quickly, but without tapping into the sustainable power, sediment and fresh water of the river, these projects cannot be maintained over the long term.
The land loss crisis in Louisiana requires aggressive action. Louisiana’s 2012 Coastal Master Plan shows us that the path forward for building a more sustainable and resilient coastline is by reconnecting the Mississippi River to the landscape it once built.
No CommentsNRDA Trustees should consider long-term sustainability of wetland creation projects
June 13, 2012 | Posted by Delta Dispatches in BP Oil Disaster, Diversions, Natural Resource Damage Assessment (NRDA), Restoration ProjectsBy Whit Remer, Policy Analyst, Environmental Defense Fund
In late April, the Deepwater Horizon Natural Resource Damage Assessment (NRDA) Trustees finalized the first phase of projects to address Gulf Coast environmental damage caused by the 2010 oil disaster. The trustees are a group of federal and state representatives charged with overseeing environmental restoration following the oil spill. The project document, known as the Deepwater Horizon Oil Spill Phase I Early Restoration Plan and Environmental Assessment (ERP/EA), comes on the heels of the draft version released in February for public comment.
The document includes a variety of projects across the gulf, including oyster restoration, wetland creation and improvements to public amenities. Rightfully, the trustees have considered a diverse suite of restoration options, and we encourage them to continue exploring the use of sediment diversions to achieve restoration goals in the Mississippi River Delta.
One of the most promising techniques for restoring, rebuilding and stabilizing wetlands in coastal Louisiana is the use of sediment diversions along the Mississippi River. Diversions replenish wetlands adjacent to the river with the fresh water, nutrients and sediments necessary to maintain healthy ecosystem functions. The State of Louisiana recently recognized the importance of such diversions in the 2012 Coastal Master Plan, which the State Legislature unanimously passed earlier this month. The master plan outlines a 50-year, $50 billion strategy to restore Louisiana’s coast and protect communities. Diversions are a critical component to achieving the long-term and comprehensive restoration envisioned by the plan.
The final Phase I ERP/EA includes the Lake Hermitage Marsh Creation project, a small-scale sediment pipeline project in Plaquemines Parish. The project will transport fresh water and sediment from the Mississippi River through a pipeline to wetlands adjacent to the river, and is expected to create over 100 new acres of marshland at a cost of $14 million. Pipeline projects have been effective in Louisiana in the past, but they do not provide the long-term sediment flow necessary to sustain the land-building functions needed to restore the coast.
The Lake Hermitage project serves as a good starting point for restoration in the Mississippi River Delta, but to achieve long-term restoration, wetlands need a constant source of sediment and nutrients that pipeline projects do not provide. Moving forward, we recommend NRDA Trustees consider actions that will promote the lasting sustainability of Louisiana’s coast. Without such actions, we may lose a unique opportunity to undertake comprehensive restoration.
No CommentsCoastal restoration as a climate change adaptation strategy
June 12, 2012 | Posted by Delta Dispatches in Diversions, Hurricane Katrina, Hurricanes, Restoration Projects, ScienceBy Meg Sutton, Environmental Defense Fund
Global climate change has induced an increase in global mean sea level with a 3.1 mm/year average rate of increase since 1991[1]. Climate projections indicate a widespread increase of more intense precipitation events, with an associated increased risk of flooding. Similarly, climate scientists also predict an increase in hurricane wind speed and total volume.
The low lying, coastal Mississippi River Delta region is particularly vulnerable to the climate change threats of sea level rise, increased flood risk and more intense hurricanes. The area is additionally plagued by human-induced environmental degradation that has occurred over the past 200-300 years. The region has lost 1,900 square miles of land since the 1930s and is losing the wetland areas that are crucial to the region’s ecosystem function, economy and character.
Predicted land change along the Louisiana coast over the next 50 years if we do nothing more than we have done to date. Red indicates areas likely to be lost, and green indicates areas of new land. This map is based on assumptions about increases in sea level rise, subsidence, and other factors. (Estimate based on less optimistic scenario of future coastal conditions.) Map provided courtesy of the Louisiana’s Coastal Protection and Restoration Authority.
The numerous threats to the region set up a potential dilemma of competing interests. Should resources and attention be focused on immediate restoration or longer term climate change adaptation? Fortunately, no such choice has to be made. Climate change adaptation and coastal restoration do not constitute a zero sum game. Restoration of coastal Louisiana reduces the vulnerability to the major risks posed by climate change and therefore can be seen as a climate change adaptation strategy.
The global rise in mean sea level — termed eustatic sea level rise — is further complicated in the Mississippi River Delta region by subsidence (sinking land). The sum of the two is referred to as relative sea level rise. The Gulf of Mexico has one of the highest rates of subsidence in the nation due to sediment compaction and the extraction of groundwater, oil and natural gas[2]. These encroaching sea levels increase mean water levels in boundary regions, accelerate coastal erosion and alter the salinity levels of sensitive coastal habitat systems. These factors have contributed to the high rate of land loss in the region.
Restoration of the deltaic system can help stabilize shorelines and reduce the associated risks with rising sea levels. Deltas are formed by the constant inflow of sediment from rivers. However, the Mississippi River Delta has been cut off from this natural process through the construction of extensive levee systems for navigation and flood protection. Through planned sediment diversions, the natural deltaic process can be restored and help increase the resiliency of coastal areas. This will combat the effects of both eustatic sea level rise and subsidence.
The projected increase in the intensity of precipitation events due to global climate change will exacerbate flood risk in the Mississippi River Delta region. Research has shown that coastal wetlands can greatly reduce flooding and storm damage. A one-acre area of wetland can store up to one million gallons of water[3], providing a significant buffer between flood waters and populated areas. In addition, wetland vegetation acts as a natural flood barrier by reducing the speed of flood waters. Healthy wetlands therefore have the potential to reduce both the volume and speed of floodwaters that reach surrounding areas. Restoration efforts seek to improve the condition of surviving wetlands in the Mississippi River Delta region as well as strategically reestablish historical wetland areas with sediment diversions. The restoration efforts to augment total healthy wetland area in the region will simultaneously reduce flooding risk associated with climate change.
As highlighted by Hurricanes Katrina and Rita in 2005, the coastal Mississippi River Delta region is highly vulnerable to hurricanes and their associated storm surge. Climate change is predicted to increase hurricane wind speed and total precipitation, further amplifying this threat. Coastal wetlands have been shown to reduce both wave energy and wave height when storm surge passes through them[4]. These wetland regions introduce a frictional drag that reduces the intensity of waves, and restoration will therefore help protect surrounding regions from storm surge now and into the future.
The restoration of ecosystem function in the Mississippi River Delta would provide significant benefits for both the short and long-term future of this crucial economic and ecologic zone. The overlapping interests of restoration and long-term climate change adaptation serve to strengthen the case for large-scale immediate restoration of the region.
[1] IPCC, 2007: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.
[2] Needelman, B.A., S. Crooks, C.A. Shumway, J.G. Titus, R.Takacs, and J.E. Hawkes. 2012 Restore-Adapt-Mitigate: Responding to Climate Change Through Coastal Habitat Restoration. B.A. Needelman, J. Benoit, S. Bosak, and C. Lyons (eds.). Restore America’s Estuaries, Washington D.C., pp. 1-63. Published by: Restore America’s Estuaries 2012
[3] Wetlands Protecting Life and Property from Flooding. United States Environmental Protection Agency, May 2006.
[4] Shepard CC, Crain CM, Beck MW (2011). The Protective Role of Coastal Marshes: A Systematic Review and Meta-analysis. PLoS ONE 6(11): e27374. doi:10.1371/journal.pone.0027374
Getting back to nature: New study looks at the past, present and future of the Mississippi River Delta
June 4, 2012 | Posted by Delta Dispatches in Diversions, Reports, Restoration Projects, ScienceBy 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.
Coastal Louisiana's historic delta lobes.
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 CommentsManaging the Mississippi River for ecosystem restoration, navigation and flood protection: A win-win-win
May 16, 2012 | Posted by Delta Dispatches in Diversions, Louisiana Coastal Area (LCA), Reports, Restoration Projects, ScienceBy 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.
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.
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 CommentTake action: Help protect Louisiana's coast
May 15, 2012 | Posted by Elizabeth Skree in 2012 Coastal Master Plan, Army Corps of Engineers, BP Oil Disaster, Diversions, Myrtle Grove Sediment Diversion, Restoration Projects
By Elizabeth Skree, Environmental Defense Fund
The Myrtle Grove sediment diversion is a linchpin of Louisiana's groundbreaking plan to restore the coast and repair damage inflicted by the BP oil disaster. However, the State and the U.S. Army Corps of Engineers are considering permits for the construction of a massive coal export terminal right next to this critical restoration project. Allowing these permits to proceed could stop the Myrtle Grove project in its tracks.
RAM Terminal, LLC has recently applied for permission to locate a coal export facility immediately adjacent to the location of the Myrtle Grove sediment diversion. The proposed facility will likely have a significant impact on the water and sediment flow in the river — and would therefore impact the Myrtle Grove sediment diversion’s ability to restore the surrounding wetlands and marshes.
For a state that has lost nearly 2,000 square miles of wetlands and barrier islands, Myrtle Grove represents one of the best opportunities to build and sustain our coast. By harnessing the river’s water and sediment, Myrtle Grove can sustain coastal communities and ecosystems for decades to come. Allowing the RAM coal export facility to proceed without demonstrating that it will not have a negative effect on Myrtle Grove would set a dangerous precedent. As the Coastal Master Plan moves through the State Legislature, Louisiana and the Army Corps must make restoration a top priority.
The public has been invited to comment on the project, but the deadline is close of business today!
Louisiana residents: Please take action and tell the U.S. Army Corps of Engineers and State of Louisiana to demand proof that this coal export facility will not interfere with plans to restore our coast.
Action alerts:
Environmental Defense Fund: Take Action: Put Louisiana's Coast over Big Coal
National Wildlife Federation: Defend Habitat Restoration for Brown Pelicans
Since the 1930s, Louisiana has lost almost 2,000 square miles of coastal wetlands and barrier islands. Not only are these vital for species such as the brown pelican, they provide critical hurricane protections for Louisiana’s coastal residents. Louisiana's 2012 Coastal Master Plan estimates that restoration projects like the one at Myrtle Grove will create as many as 800 square miles of new healthy coastal habitats for pelicans and other wildlife over the next 50 years.
Take action and tell the State of Louisiana and U.S. Army Corps of Engineers that restoring the coast is a national priority and should not be blocked due to a new coal facility.
Study looks at sediment and water flow through Mississippi River, helps scientists plan effective restoration projects
May 1, 2012 | Posted by Elizabeth Skree in Diversions, Reports, Restoration Projects, ScienceBy 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.
Mississippi River Delta and sediment plume, 2001.
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 CommentsReport: Reengineer Mississippi River Delta To Protect Nation’s Economic, Ecological Assets
April 11, 2012 | Posted by Delta Dispatches in 2012 Coastal Master Plan, Diversions, Reports, ScienceScientists call for “immediate action” to address disintegration of delta
News Release (Baton Rouge, La.—April 11, 2012) Building a series of engineered structures called diversions along the lower Mississippi River will yield tens of billions of dollars in net annual benefits to the nation and hedge against future disasters, according to a new report co-authored by 22 prominent scientists and engineers.
The report, “Answering 10 Fundamental Questions about the Mississippi River Delta,” makes a scientific and economic case for restoring the Mississippi River Delta wetlands, which have shrunk in size by nearly 1,900 square miles since the 1930s. The report also makes the case for reengineering the aging lower Mississippi River flood-control and navigation systems, which are increasingly vulnerable to catastrophic failures.
“Our research reveals considerable consensus within and across scientific disciplines about how the Mississippi River Delta functions and what actions must be taken to ensure long-term sustainability,” the report says. “It is clear that immediate action is warranted and is essential to the future stability of our nation’s economy.”
The report projects annual losses to the United States of $41 billion dollars if the delta continues to collapse unchecked. Conversely, it estimates an annual net benefit of at least $62 billion if the delta can be maintained and expanded. The report also makes it clear that the only way to maintain delta wetlands in the long term is through the construction and operation of structures called diversions, which release water and sediment from the river into the wetlands, mimicking historical flows. The report concludes that the use of diversions will satisfy a number of interlocking demands.
The report is timely because the Louisiana legislature is currently considering the state’s 2012 Coastal Master Plan, which relies heavily on river diversions to turn the tide on the state’s ongoing land loss crisis. The plan lays out a 50-year vision for protecting and restoring the coast, including increased hurricane risk reduction for coastal communities and eventually reaching a net growth, rather than a net loss, of wetlands.
A recent telephone survey found that 67 percent of likely voters nationwide believe it is an “extremely” or “very” important priority for the federal government to take steps to restore the Mississippi River Delta and that overwhelming numbers (84 percent) believe the Mississippi River Delta and Gulf Coast affect the nation’s economy.
The Mississippi River Delta Science and Engineering Special Team, which produced the report, is a network of eminent scientists and engineers convened by the National Audubon Society, the Environmental Defense Fund and the National Wildlife Federation to provide objective and independent analysis pertaining to Mississippi River Delta restoration.
The report released this week is a precursor to scientific articles that will be published in peer-reviewed journals and a book slated for release in the coming months.
Contacts:
John Day, Mississippi River Delta Science and Engineering Special Team, 225-773-7165, johnday@lsu.edu
David J. Ringer, National Audubon Society, 601-642-7058, dringer@audubon.org
Sean Crowley, Environmental Defense Fund, 202-550-6524, scrowley@edf.org
Emily Guidry Schatzel, National Wildlife Federation, 225-253-9781, guidrye@nwf.org
Louisiana’s Coastal Master Plan moves on to state legislature for approval
March 29, 2012 | Posted by Delta Dispatches in 2012 Coastal Master Plan, Community Resiliency, Diversions, Hurricanes, Restoration ProjectsBy David Muth, National Wildlife Federation
On March 21, Louisiana’s Coastal Protection and Restoration Authority (CPRA) unanimously adopted the revised Comprehensive Master Plan for a Sustainable Coast, which lays out a 50-year restoration plan for Louisiana’s coast. The Mississippi River Delta Restoration Campaign has worked closely with the state in the development of the plan, and many of our recommendations for improving and strengthening the draft were adopted in the final version.
Map depicting sediment starved wetlands and areas of wasted sediment in southeast Louisiana. Credit: CPRA 2012 Coastal Master Plan final draft
One such recommendation made by our campaign was to create clear paths forward for implementation of the nonstructural hurricane protection program and the design of a lower Mississippi River realignment. The final version of the plan also includes revisions supported by coastal stakeholders during the public review process, including relocating marsh creation or shoreline protection projects to locations that would help buffer vulnerable coastal communities. While these revised projects were not necessarily the best projects for optimizing land creation, they were justified because of the synergies they could provide with nearby protection projects. Even with these changes, 85% of the projects in the final plan were chosen by the Planning Tool to optimize land building in the face of less optimistic sea level rise scenarios.
Proposed Mississippi River diversions. Credit: CPRA 2012 Coastal Master Plan final draft
The final Coastal Master Plan revolutionizes the way Louisiana intends to move toward a sustainable coast. It proposes to spend $3.8 billion to reintroduce 50% of the peak flow of the Mississippi River into the most sediment-starved and deteriorating parts of the delta — a key goal of our campaign. This reintroduction could build up to 300 square miles of new delta over the next 50 years in the face of moderate subsidence and sea level rise. The plan also recommends designing a new navigation system to free up most of the remaining 50% of peak river flow for a new lower river alignment that will build additional new deltaic land. It also dedicates $20 billion toward the creation of over 200 square miles of marsh through sediment pipeline delivery to areas that cannot be reached by riverine reintroduction of sediment.
Credit: CPRA 2012 Coastal Master Plan final draft
Additionally, the plan provides for increased hurricane risk reduction for every coastal resident, by building resiliency for coastal communities through nonstructural measures such as elevating buildings, strengthening infrastructure and facilitating voluntary relocation. This fundamental shift away from the old standard of total reliance on levees, floodwalls and floodgates ratifies another fundamental goal of our campaign.
The Coastal Master Plan now goes to the Louisiana Legislature for adoption during the current session, which began on Monday and continues through June 4, 2012. If adopted, we move an important step closer towards implementing the goals of our campaign. Louisiana could become a world leader among vulnerable coastal areas in learning to live with the realities of future climate change and in learning to start living with water and natural processes rather than conducting a futile fight to the death against them.
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