Archive for Diversions
Managing 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.
No CommentsTake 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.
No CommentsMardi Gras Pass: A new diversion on the Mississippi River springs to life
March 21, 2012 | Posted by Delta Dispatches in 2011 Mississippi River Flood, 2012 Coastal Master Plan, Army Corps of Engineers, Diversions, Science, VideosBy John Lopez, Ph.D., Lake Pontchartrain Basin Foundation
The Bohemia Spillway, located along the east bank of the Mississippi River two miles south of Pointe a la Hache, La., is a rare opportunity to observe the natural processes and potential benefits of the Mississippi River flow into the Louisiana wetlands. Because there is no artificial river levee to obstruct flow during high water, the river has been flowing into the adjacent wetlands for 85 years. In 2011, the Lake Pontchartrain Basin Foundation (LPBF) conducted a hydrologic study of how much water enters the spillway and where it flows during floods. It was over the course of this work that LPBF researchers made an unexpected discovery: a new channel was being cut by the flowing water from the Mississippi River.
Feb. 2012 -- Mardi Gras Pass as it reached the Mississippi River, just prior to a complete cut into the river. Credit: LPBF
As the 2011 flood waned, we began noticing this new channel, and in July, the channel made a dramatic breach into the nearby roadway. On Mardi Gras Day 2012 (Feb. 21), scientists noted that the channel had reached the bank of the Mississippi River and shortly after, a complete breach into the river occurred. With this milestone, the channel is now an extension of the Mississippi River that helps distribute the river flow through the new distributary channel.
At this time, the distributary flow through the newly-dubbed “Mardi Gras Pass” is small, estimated to be less than 1% of the river’s peak discharge (5,000 to 10,000 cubic feet per second). The channel is 30 to 40 feet wide near the river but deep enough to capture river flow continuously even under very low water. This new diversion was not manmade – it was the result of natural river forces seeking a shorter outlet to the sea.
March 2012 -- Mardi Gras Pass (Credit: LPBF)
It can be expected that Mardi Gras Pass will expand over time. The rate of enlargement is of great interest because this process has not been observed in modern times, and the concern is that the diversion may become too large. However, enlargement of the pass may be desirable, because just one mile away, the new draft Louisiana Coastal Master Plan recommends a large diversion of about 4% of the river’s peak flow (50,000 cubic feet per second). This new diversion is estimated to cost $220 million, so LPBF is encouraging the state and Army Corps of Engineers to consider Mardi Gras Pass as an alternative, since it may provide the same wetland benefits for a much smaller cost and much sooner than a constructed diversion.
March 2012 -- Mardi Gras Pass (Credit: LPBF)
Another exciting aspect of Mardi Gras Pass is the rapid emergence of the riverine ecology. When the channel was just a few weeks old, schools of fish were observed migrating up current toward the river. These pogy fish were feasting on the plant detritus being washed into the pass from the river. The influx of fish to the area attracted river otters, which have been commonly observed feeding in the pass. Additionally, beaver, heron and other critters have begun taking advantage of the bounty created by the river flow in Mardi Gras Pass.
Support for this research is provided by The McKnight Foundation, Environmental Defense Fund, The Walton Family Foundation, Surdna and The National Audubon Society. To learn more about LPBF and the Bohemia Spillway, please visit SaveOurLake.org (go to Coastal > Technical Reports > Bohemia Spillway Documentation).
Additional resources:
- Video: Bohemia Rising: Exploring the Mississippi Delta in South Louisiana, (Lake Pontchartrain Basin Foundation).
- Resiliency of the Bohemia Spillway and the Evolution of Mardi Gras Pass, Southeast Louisiana, (Lake Pontchartrain Basin Foundation).
Turbidity monitoring at Caernarvon diversion provides real-time data for effective river management
March 2, 2012 | Posted by Delta Dispatches in Diversions, ScienceBy Andy Baker, Lake Pontchartrain Basin Foundation
For two years, the Lake Pontchartrain Basin Foundation (LPBF) has been testing the turbidity of the water flowing through the Caernarvon diversion, 15 miles downriver from New Orleans. Turbidity – described as cloudiness or muddiness – is a measure of how much sediment is suspended in the water. Recently, the diversion managers at the Louisiana Office of Coastal Protection and Restoration (OCPR) used turbidity data for the first time to briefly increase flow through the diversion while sediment levels were high. This adaptive management decision resulted in approximately 4,000 m³ of extra sediment being delivered to the upper Breton Sound marsh (see graph). Though the coastal restoration impact was relatively small, it has large implications for how diversions can be managed in the future.
Since one of the purposes of diverting water from the river is to build land by depositing sediment, LPBF scientists wanted to investigate how measurements of sediment concentration could be used to manage diversions more effectively. Other research has shown that sediment levels in the Mississippi River vary greatly in time and space, with very complex dynamics. At Caernarvon, LPBF has found that high turbidity often comes in pulses that last two to six weeks, where sediment levels are 10 to 20 times higher than their lowest levels. These sediment pulses often occur at the beginning of a rise in the river level, though upstream flooding and other factors can cause spikes as well. To see data for 2010 and 2011, click on the links in the Additional Resources section below.
The recently released Comprehensive Master Plan for a Sustainable Coast calls for a system of eight diversions along the Mississippi River in Louisiana, with the long-term goal of delivering sediment to rebuild coastal wetlands. The impact and effectiveness of these diversions will largely depend on how they are operated. As more diversions are built, they will have to be managed as a system. Even at flood stage, the Mississippi River has finite resources of water, sediment and energy. Large diversions remove these resources from the river and affect conditions upstream and downstream. Knowing the concentration of sediment in the river will be a key to making scientific, system-level management choices.
As has been seen at Caernarvon, introducing large volumes of fresh water into coastal marshes has positive and negative effects. By regulating flow based in part on how much sediment the river is carrying, diversion managers can maximize land building while minimizing the negative effects of fresh water on brackish and saline marshes.
LPBF hopes that the state will eventually establish a network of turbidity monitoring stations to provide real-time data for diversion management. Until then, the modest research efforts of local nonprofits will provide data to environmental managers and public.
Additional Resources:
- Coastal Technical Resources (LPBF)
- Caernarvon Diversion Turbidity Sampling 12/2009 – 10/2010 (LPBF)
- Caernarvon Diversion Turbidity Sampling 2/2011 – 12/2011 (LPBF)
CPRA conducts successful week of public meetings on 2012 Coastal Master Plan
February 7, 2012 | Posted by Delta Dispatches in 2012 Coastal Master Plan, Community Resiliency, Diversions, Meetings/Events, Reports, Restoration ProjectsThis story was originally posted on the Coalition to Restore Coastal Louisiana's Coast Currents blog.
By Scott M. Madere, Coalition to Restore Coastal Louisiana
From Jan. 23-25, 2012, the Coastal Protection and Restoration Authority (CPRA) of Louisiana held a series of public meetings in New Orleans, Houma and Lake Charles to receive public feedback regarding the recently-released draft of the 2012 Coastal Master Plan. The public comment period, which continues until Feb. 25, is an essential part of refining the master plan before it reaches the Louisiana legislature for approval on March 26. The Coalition to Restore Coastal Louisiana (CRCL) was present at all three public meetings and listened to hundreds of Louisiana residents express their concerns about the plan’s potential to address coastal land loss. No two venues were the same, as citizens in the three meeting locales brought up topics unique to their coastal zones.
CRCL Executive Director Steven Peyronnin expresses support for CPRA's efforts in constructing the 2012 Coastal Master Plan.
New Orleans – More than 270 people attended the first CPRA public meeting, held at the University of New Orleans. Governmental representatives from Plaquemines, Jefferson and St. Bernard parishes were on hand as well as commercial fishing interests from these and other communities near New Orleans. Many of the fishers present expressed concerns regarding the master plan’s reliance on large-scale sediment diversions from the Mississippi River to rebuild marshlands on Louisiana’s southeastern coast. In their view, these sediment diversions would introduce a volume of fresh water into the coastal zones which would be unfavorable to the commercial harvest of oysters and shrimp. Sediment diversions are a key element among the many tools available in the 2012 Coastal Master Plan for coastal restoration. The use of these diversions maximize the land-building potential of the plan and reconnect the Mississippi River with its delta.
Jefferson Parish President John Young requested that flood protection plans for Lafitte, Crown Point and Barataria be implemented on faster pace than originally planned in the 2012 master plan draft. There were also a number of non-governmental organizations present including CRCL, National Audubon Society, National Wildlife Federation, Nature Conservancy of Louisiana, Gulf Restoration Network and the Lake Pontchartrain Basin Foundation which expressed support for the processes and effort involved in creating the 2012 Coastal Master Plan.
More than 250 residents turned out for the CPRA public meeting in Houma.
Houma – The Houma-Terrebonne Civic Center played host to more than 270 attendees to CPRA’s second public meeting about the 2012 Coastal Master Plan. The Houma meeting’s comments were centered primarily on requests for more restoration projects on the eastern side of Terrebonne Parish, which includes Pointe aux Chenes, Isle de Jean Charles and other communities. Residents of these areas and representatives of the United Houma Nation and other Native American groups appealed to the CPRA representatives, asking for the inclusion of their communities in plans for restoration.
The 2012 master plan does feature restoration and protection projects in Terrebonne Parish. There is enhanced levee protection for Houma and highly-populated areas in the center of the parish, restoration for Timbalier Island, Isle Dernieres and other barrier islands, and marsh restoration in the form of a sediment diversion from the Atchafalaya River in western Terrebonne Parish.
The position of residents in the eastern part of the parish is that western Terrebonne is either uninhabited or very lightly populated, and the money spent restoring the marsh there should be moved to protect communities in the east.
Restore the Mississippi River Delta Campaign Director Derek Brockbank speaks before CPRA in Lake Charles.
Lake Charles – More than 150 people braved heavy thunderstorms to attend the third and final CPRA public meeting on the master plan, and their voice was fairly united in seeking shoreline protection for Cameron Parish in the form of rock barriers.
CPRA has a number of marsh protection projects slated in the Cameron/Calcasieu area, including new proposed salinity control structures. The idea is to build the wetlands around Lake Charles and Cameron to bolster its risk reduction capacity with regard to hurricanes and floods. A long-term solution in the master plan for flood protection in Lake Charles includes a significant levee build within the next 50 years as well.
Cameron Parish residents and their supporters in Calcasieu are asking for a more direct line of defense by placing breakwater barriers on the Cameron shoreline. Cameron Parish governmental officials like Police Jury President Darryl Farque were very determined to make the point that they wish to see this kind of protection added to the plan.
Lake Charles Mayor Randy Roach also asked CPRA to not draw political differences between Calcasieu and Cameron when considering projects, as they are “one place hydrologically” in nature.
Overall, the week saw a high degree of public interest in the 2012 Coastal Master Plan, and CPRA executed three very successful consecutive days of public meetings. No opinion was turned away during these meetings, and extra time was allotted past the meeting schedule to accommodate public opinion. The public comment phase of the 2012 Coastal Master Plan is a vital step in creating the best plan possible for Louisiana and continues until Feb. 25. CRCL would like to encourage those who wish to comment on the plan to do so at CPRA’s Coastal Master Plan website: http://www.coastalmasterplan.louisiana.gov/2012-master-plan/public-comment-form/
Louisiana Coastal Master Plan public meetings start today
January 23, 2012 | Posted by Delta Dispatches in 2012 Coastal Master Plan, Community Resiliency, Diversions, Meetings/Events, Restoration Projects, ScienceBy David Muth, National Wildlife Federation
Louisiana’s Draft 2012 Coastal Master Plan, released Jan. 12, is the most ambitious ecosystem restoration plan proposed in United States history and is the first to lay out a comprehensive vision for how a coastal state will cope with land loss, subsidence, and projected sea-level rise over the next half century. With an expenditure of $1 billion per year over 50 years, split equally between protection and restoration, Louisiana could build or prevent the loss of 550-850 square miles of deltaic, estuarine and coastal marshes, swamps, and barrier islands, as well as protect coastal communities from storm surge and rising sea levels. Fifty billion dollars seems like an large sum, until you consider that the 2005 hurricanes alone coast American taxpayers $175 billion.
An unprecedented aspect of the master plan is the proposal to divert half the flow of the Mississippi River back into the delta for restoration purposes — restoring the river’s capacity to build land and re-establishing a vital natural process, not just rebuilding natural habitat. Also unprecedented is the proposal to invest almost $13 billion in measures that increase community resilience to flooding. These measures, including elevating and flood-proofing homes, protect flood-prone property and allow communities to continue to live in close connection to a wetland-based economy and culture.
However, it is also clear that some parts of Louisiana’s coast and wetlands cannot be saved in their current form — there is neither enough time nor sufficient resources to stop or reverse the physical forces that are destroying them. This will be a very difficult and painful reality for some coastal residents and communities. Hard truths will surface in the coming days and weeks as details of the technical analysis are examined, but leaders and planners have a responsibility to base their decisions firmly in reality and help people cope with anticipated changes.
Louisiana's agencies and legislators need to hear that the public supports a comprehensive science-based plan that creates new wetlands and increases hurricane protection for people living in the coastal zone while laying out achievable transition plans for coastal residents in areas that cannot be preserved.
Take the next step by attending one of three public meetings this week:
- New Orleans, Jan. 23, University of New Orleans Lindy Boggs Center (map)
- Houma, Jan. 24, Terrebonne Civic Center (map)
- Lake Charles, Jan. 25, Lake Charles Civic Center, Contraband Room (map)
Each meeting will include an open house from 1-5:30 p.m. and a public hearing from 5:30-7:30 p.m. The open house in particular offers an opportunity to learn one-on-one from the plan formulators about the specifics of the master plan.
No CommentsNew report studies river diversions as an important restoration tool
September 15, 2011 | Posted by Elizabeth Skree in Diversions, Reports, Restoration ProjectsBy Alisha Renfro, Ph.D., National Wildlife Federation
Since 1932, almost 1,900 square miles of ecologically and economically important land has been lost in coastal Louisiana. Historically, flooding from the Mississippi River built and maintained these coastal wetlands, but the construction of flood protection levees and upstream dams have cut off the connection between the river and its delta. River diversions direct water, nutrients and sediment back into the deteriorating wetlands and serve as an important restoration tool in the Mississippi River Delta.
A report prepared for the Coastal Protection and Restoration Authority of Louisiana titled "Assessment of 'Lessons Learned' from the Operations of Existing Freshwater Diversions in South Louisiana” explores almost 1,300 documents related to the subject of river diversions and their effects on soils, vegetation, wildlife and fisheries in coastal Louisiana. As an ecosystem-changing tool, river diversions have both benefits and drawbacks, and the goal of this effort was to investigate the current understanding of the diversions that are in place in order to use the best science and technology available to assist the planning, design and operation of future diversions.
The Wax Lake Delta (pictured) is proof that river diversions can build land in coastal Louisiana. (Photo credit: USGS)
The diversions currently in place in Louisiana have been implemented for a variety of reasons. The report evaluates siphons (West Point a la Hache, Violet), freshwater diversions (Caernarvon, David Pond), crevasses (Cubit’s Gap, West Bay) and floodway control structures (Bonnet Carré Spillway). The findings indicate that diversions that are modeled after natural crevasses with wide and deep channels are able to transport more sediment–particularly sand–and have been the most successful at building new land (e.g. Cubit’s Gap). Several studies also suggest that high river events–such as the one that occurred the spring of 2011–can account for much of the sediment that is deposited in the wetlands. Although mineral sediment input is important to rebuilding marshes, freshwater and nutrients also play an important role.
Freshwater and nutrient input from diversions have affected wetlands at some sites by increasing plant productivity, the abundance of freshwater and intermediate vegetation and submerged aquatic vegetation. High nutrients from the Mississippi River may also cause negative effects in the basins and wetlands by increasing phytoplankton growth, decreasing the quality of soil and the root production of vegetation. But increases in mineral sediment may help offset some of these factors.
Diversions can also influence important fishery species, and the report shows a slight increase in many of the important fishery species (e.g. crabs, white shrimp). The literature also indicated that populations of alligators, muskrats and waterfowl have increased in diversion areas.
Evaluation of the freshwater diversions currently in place indicates the importance of clear objectives, coordinated efforts and sharing of information between projects that will move towards maximizing the benefit for future projects development, design and implementation. Ecosystem-scale restoration projects such as river diversions that harness the power of the river to rebuild the delta have both benefits and drawbacks, but through increased understanding of these challenges, the most effective management decisions can be made to move towards a better future for the Mississippi River Delta.
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