Archive for Diversions
FOR IMMEDIATE RELEASE
CONTACTS: Erin Greeson, National Audubon Society, 503.913.8978, email@example.com
Emily Guidry Schatzel, National Wildlife Federation, 225.253.9781, firstname.lastname@example.org
Elizabeth Skree, Environmental Defense Fund, 202.553.2543, email@example.com
Conservation Groups Issue Statement on New Timeline for Mid-Barataria Sediment Diversion
(New Orleans, LA – September 20, 2013) Today, leading national and local conservation and restoration organizations – Environmental Defense Fund, National Audubon Society, National Wildlife Federation, Coalition to Restore Coastal Louisiana and the Lake Pontchartrain Basin Foundation – released the following joint statement:
“The Mississippi River Delta Restoration Campaign commends the Louisiana Coastal Protection and Restoration Authority (CPRA) for adopting an ambitious timeline for the Mid-Barataria Sediment Diversion. Announced at the Authority's monthly meeting in New Orleans on September 18, the state plans to complete environmental review, engineering and design documents, and permit applications and submit them to the U.S. Army Corps of Engineers by Spring 2015. Construction could begin later that year.
“The Mid-Barataria Sediment Diversion is the first major controlled sediment diversion reconnecting the Mississippi River with its delta. It is a cornerstone of the state’s master plan for sustaining our coast. CPRA’s timeline matches the urgency of our coastal land loss crisis. Funding from BP oil spill settlements makes this schedule altogether feasible.
“We know that the Army Corps of Engineers and the other federal resource agencies consider this project to be a national ecosystem restoration priority and will do everything possible to work with the State to make this schedule a reality. We look forward to collaborating with the State and its federal partners to achieve this exciting and crucial 2015 construction goal. Our coast can’t wait. It's time to get together and get it done.”
Study demonstrates importance of sediment diversions for building land in the Mississippi River DeltaMarch 27, 2013 | Posted by Delta Dispatches in 2012 Coastal Master Plan, Diversions, Restoration Projects, Science
By Alisha A. Renfro, Ph.D., Staff Scientist, National Wildlife Federation
Last week, an independent scientific panel comprised of prominent scientists from throughout the U.S. released a report, “Mississippi River Freshwater Diversions in Southern Louisiana: Effects of Wetland Vegetation, Soils, and Elevation,” which examines some of the ecological effects of freshwater river diversions. The panel concluded that there is little evidence suggesting that the existing freshwater diversions in Louisiana have appreciably reversed the rate of land loss in the region, and that to reverse the land loss trend, significant inputs of sediment are needed. While most of the existing diversions in Louisiana were built to move fresh water only, many of the diversions included in Louisiana’s 2012 Coastal Master Plan focus on sediment capture and conveyance into coastal wetlands.
Freshwater diversions affect basins by reducing salinities. Extensive dredging of canals throughout the Mississippi River Delta’s wetlands has allowed for salt water from the gulf to intrude into wetlands adapted to lower salinity conditions, resulting in large areas of these wetlands dying and being converted to open water. Wetland vegetation is affected directly by the salinity of the water in wetland soil. High salt concentrations in the soil can affect vegetation by reducing the overall rate of photosynthesis, decreasing nutrient uptake and stunting growth rates. Consequently, the introduction of fresh water into wetland communities damaged by saltwater intrusion is vital in any restoration effort.
Freshwater diversions also increase the amount of nutrients introduced into the receiving basin. While increases in nutrient availability to wetland vegetation would presumably stimulate growth, scientific information collected in Louisiana marsh communities have exhibited varying results depending on plant species, nutrient concentrations and the abundance of different types of nutrients. Increasing the amount of nutrients may also alter the composition of the plant community, as some species of plants have a competitive advantage when it comes to nutrient uptake and growth.
River diversions can also have an influence on wetland elevation. In order for wetlands to persist over time, processes that increase the surface elevation of the wetlands must be equal to factors that increase the threat of submergence (e.g. sea level rise, storms). Diversions have the potential to promote an increase in the elevation of a wetland by adding mineral sediment to the surface and stimulating plant growth both above and below ground. However, the surface elevation of a wetland could decrease as nutrients become less scarce, as the abundance of vegetation roots decline and as an increase in the breakdown of belowground organic material by bacteria takes place. More scientific studies are needed to enhance our understanding of the relationship between marsh response and river input in order to better predict the net effect that sediment and freshwater diversions may have on different marsh types.
This scientific panel found that any freshwater diversion that does not transport a substantial sediment load is unlikely to reverse the current trend of wetland loss in Louisiana. The 2012 Coastal Master Plan recognizes and addresses this reality by focusing on large-scale diversions that would be capable of transporting significant amounts of river sediment into the nearby wetlands. In addition to shifting the focus of diversions from fresh water to sediment, the panel determined that a formal adaptive management scheme is needed for existing and planned diversions where the goals of the project are clear, the pre-diversion conditions of the affected area are well characterized, monitoring in the outfall area is done to measure the progress of the project in relation to its goals and a process exists to adjust the operation of the structure to increase the likelihood those goals are reached.
- Fact sheet: "Pulsed" land-building sediment diversions
- Mississippi River Freshwater Diversions in Southern Louisiana: Effects of Wetland Vegetation, Soils, and Elevation (Technical Panel from the Workshop on Response of Louisiana Marsh Soils and Vegetation to Diversions)
By Emily Guidry Schatzel, Communications Manager, National Wildlife Federation
Recent news reports suggest that the potential for compromise exists in the case of Mardi Gras Pass, the newest known distributary of the Mississippi River. The pass was discovered in 2012 when the river cut a channel through its bank in the Bohemia Spillway, a stretch without levees, giving an exciting and rare view at how a natural delta system operates.
While the pass promises ecological prosperity for the delta, the newly enlarged channel washed out the private road that one local oil company uses to access its facilities. The company has since applied for a permit to rebuild that road. Coastal restoration advocates believe that the current plan to rebuild will effectively close the Mardi Gras Pass and will eliminate encouraging ecological benefits that scientists from the Lake Pontchartrain Basin Foundation have been monitoring since the channel’s development.
This video further explains the debate over keeping the pass open, and alternatives for compromise. The key takeaway? Whether it be construction of a bridge, or another reasonable alternative that gives the oil company access while allowing Mother Nature to literally “run its course,” this is clearly an issue that requires the full attention of key decision-makers so that the best long-term solution is achieved.
As Dr. John Lopez, executive director of the Lake Pontchartrain Basin Foundation — the organization that discovered the pass in 2012 — said, “It’s the kind of thing that most scientists sit in their offices there, dreaming how it might happen. Here, you can actually see it.” Keeping Mardi Gras Pass open is important — it’s a chance for the river to reconnect with its wetlands, which is exactly what the river is designed to do.1 Comment
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 Whit Remer, Policy Analyst, Environmental Defense Fund
Last week, the Gulf Coast Ecosystem Restoration Council held its first public meeting in Mobile, Ala. to update residents on the progress of implementing the RESTORE Act. The law, which Congress passed in June 2012, dedicates 80 percent of Clean Water Act fines from the BP oil spill back to the Gulf Coast for restoration. Those fines, expected to reach billions of dollars, will help stabilize and revive troubled ecosystems across the Gulf Coast.
The Council was created by the RESTORE Act to develop a long-term ecosystem restoration plan for the region. This plan is expected to reverse coastal land loss, create new marshland and rebuild fisheries and marine environments across the Gulf Coast. At this week’s meeting, Council members recognized that challenges lie ahead, but they are optimistic they have the resources and expertise necessary to revive the Gulf Coast.
The Restoration Council is a diverse group of federal agency and state representatives who are tasked with developing an ecosystem restoration plan to address the varying needs of complex and diverse environments stretching across five states. To develop a comprehensive and multidisciplinary plan, the Council will rely on the expertise housed in its federal member agencies and state partners, including the Department of Interior, Environmental Protection Agency, Department of Commerce, National Oceanic and Atmospheric Administration, Coast Guard, Army and Department of Agriculture. The federal agencies will be joined by the governors from each of the five gulf states.
The basis of the restoration plan has already been developed by a similar, and often overlapping in membership, group of federal and state partners known as the Gulf Coast Ecosystem Restoration Task Force. Following the 2010 BP oil disaster, President Obama commissioned the group to study the environment of the Gulf Coast and submit a holistic restoration strategy. The Task Force produced a Gulf Coast restoration strategy document in December 2011, which identified four key areas of restoration: habits restoration, water quality improvement, marine resources protection and community resiliency enhancement.
In September 2012, the President released an Executive Order which rolled the Task Force’s strategy into the planning process of the comprehensive plan being developed by the RESTORE Act’s Restoration Council. This means we can expect the Restoration Council’s comprehensive restoration plan to look similar to the Task Force’s strategy document.
Of particular importance to the Comprehensive Plan will be incorporating the Task Force’s strategy recommendation to stabilize and reverse land loss along Louisiana’s coast through the use of sediment diversions. Sediment diversions are recommended as a key Mississippi River Delta restoration tool in both the Task Force strategy and Louisiana’s 2012 Coastal Master Plan.
The Restoration Council plans to meet multiple times over the next few months to update the public on the progress of developing the comprehensive plan, which must be finished by June 2013. The Council will fund the comprehensive plan with 30 percent of the money dedicated to the Gulf Coast Restoration Trust Fund established by the RESTORE Act. That could mean billions of dollars for ecosystem restoration projects and programs identified by the plan. This is welcome news for all those who rely on the Gulf Coast for recreation, seafood, energy and their livelihoods.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 Whit Remer, Policy Analyst, Environmental Defense Fund
Just in time for the holidays, the U.S. Department of Justice (DOJ) delivered welcomed and unexpected good news for Gulf Coast restoration efforts. On November 15, DOJ announced they had reached a settlement with BP on all criminal charges related to the 2010 Deepwater Horizon oil spill. But what was expected to be a simple press conference outlining the details of the criminal plea agreement turned out to be a huge $2.4 billion win for Gulf Coast restoration.
For the last two years, the Department of Justice has been working to bring criminal and civil charges against BP for its involvement in the deadly rig explosion and nation’s largest environmental disaster. On the criminal side, DOJ claimed BP broke a number of securities violations and environmental laws. Environmental laws often contain provisions that allow the government to pursue criminal charges when the party is suspected of acting negligently during the incident. Criminal charges can carry hefty fines, require probation and may lead to the imprisonment of company officials. BP plead guilty to all criminal charges brought by DOJ and agreed to pay $4 billion in fines.
Criminal fines are separate from the civil fines the company will pay for violations under the Clean Water Act and Oil Pollution Act in a forthcoming settlement or trial. The RESTORE Act, passed by Congress in June of this year, will direct 80 percent of civil fines to Gulf Coast restoration. The RESTORE Act does not capture criminal fines, which generally flow to the U.S. Treasury, or natural resource damage money assessed under the Oil Pollution Act.
The agreement reached by DOJ and BP is unprecedented for two reasons. One, the criminal fines assessed by DOJ, and agreed to by BP, are the largest ever levied against a corporation. If the criminal fine is any indication of the seriousness to which DOJ is pursuing civil charges under the Clean Water Act, then those fines could reach the $21 billion mark that some analysts have predicted. Whatever the amount, 80 percent will be returned to the Gulf Coast for restoration under the RESTORE Act.
The second reason the agreement reached by DOJ is unprecedented is the fact that the agency allocated more than half of the fine money – $2.4 billion – for Gulf Coast environmental restoration. Neither the gulf states nor coastal restoration planners expected DOJ to unilaterally direct money to environmental restoration.
What’s even more exciting is that $1.2 billion of this money is reserved to advance sediment diversions and barrier island restoration projects in the rapidly-disappearing Mississippi River Delta. Sediment diversions reconnect the Mississippi River, which is full of vital freshwater, sediment, and nutrients, with adjacent dying wetlands that have been cut off from the river by manmade levees.
Dedicating this much money towards restoration of the Gulf Coast signals that the Administration recognizes the importance of the gulf to the nation, and perhaps more pointedly, the importance of the Mississippi River Delta to the gulf. With its recently passed 2012 Coastal Master Plan, Louisiana is well-situated to devote money from the BP oil spill to critical restoration projects in the delta. We applaud the Department of Justice for their recognition of this important issue and encourage them to pursue civil Clean Water Act and Oil Pollution Act penalties with the same vindication, so the Gulf Coast and Mississippi River Delta can be restored and revitalized.2 Comments
This was originally posted on the Coalition to Restore Coastal Louisiana's Coastal Currents blog.
The much-debated West Bay Diversion will remain open for at least the next 10 years. That’s the word from the CWPPRA Task Force, which reversed its own 2008 decision to close the sediment diversion at its meeting on Thursday, October 12, 2012.
The move keeps open one of the few land-building diversions off of the Mississippi River, allowing sediment in nearby wetlands to continue to accumulate. Researchers will also have the opportunity to continue studying the diversion, which has reportedly built more than 10 acres of land in 2011 alone.
Quoted by The Advocate’s Amy Wold on Thursday, Colonel Ed Fleming of the U.S. Army Corps of Engineers said new research suggests the diversion is providing more benefit to the surrounding wetlands than first thought. “It appears the diversion is working better than expected,” he said. “When the task force made the decision a few years ago to close this, we didn’t have all the information we have today.”
The original decision to close West Bay was based on a complicated funding scenario that concluded the diversion was not providing enough benefit to justify the expense of keeping it open.
In light of new evidence, the CWPPRA Task Force decided to allocate the money it would have spent closing the diversion to take the necessary steps to keep it open for 10 more years.
While the West Bay Diversion has been criticized over the years for flaws in its design and the expense of keeping it open, the decision to keep the diversion running is important. The 2012 Coastal Master Plan, passed by the Louisiana Legislature this summer, relies on the use of properly designed and operated sediment diversions to rebuild sections of our delta. The acres of land created by West Bay lend credence to the position that these diversions will work. The opportunity to study a working sediment diversion is valuable to researchers who have few other options for studying this restoration method in the field. If West Bay continues its recent track record of success, it will also help proponents of diversions convince policymakers, and the public, of the worthiness of sediment diversions within Louisiana’s coastal restoration strategy.No Comments
By David Muth, Louisiana State Director, National Wildlife Federation
Now that Louisiana’s 2012 Coastal Master Plan is law, it is critical that the state’s Coastal Protection and Restoration Authority (CPRA) moves the process forward as quickly as possible. While the plan lays out a series of projects for over its fifty-year timeframe, the actual sequence of projects has not yet been completely planned. The sooner CPRA can finalize this project list and timeline, the sooner vital construction and restoration can begin.
Several things are necessary for creating that list of projects. First is to carry out continued modeling to measure how projects and suites of projects will interact with one another. One example is looking at how a mid-Barataria 50,000 cubic feet per second (cfs) sediment diversion will interact with marsh creation projects in the middle Barataria Basin and with a ring levee and community resiliency measures for the nearby town of Lafitte.
Second is to work out how funding streams can be most effectively sequenced to begin building out the projects identified in the list. This is especially critical with Clean Water Act penalty funding to be distributed under the RESTORE Act and the separate Natural Resource Damage Assessment (NRDA) process. These funding sources, resulting from the BP Deepwater Horizon oil spill, could become available at almost any time over the next few years.
Third is to move quickly to implement nonstructural hurricane risk reduction measures. Nonstructural storm protection measures are those that build community resiliency by means other than “structural” methods such as levees, floodwalls and floodgates. They include raising structures and homes up out of danger, hardening infrastructure and assisting with voluntary relocation. Unfortunately, the suite of existing nonstructural programs is reactive: invoked after, but not before, a disaster. That has to be changed moving forward.
Another challenge concerns the Chenier Plain in southwest Louisiana. The key to long-term restoration in that area is to find ways to modify the hydrology of the area’s navigation system to prevent the continued influx of sea water into formerly freshwater marshes. Simple on paper, tricky in practice.
At an implementation level, two important capabilities need to be developed for the master plan to move forward. One is to demonstrate the feasibility of long-distance pipeline sediment delivery. Much of the Coastal Master Plan depends upon finding a viable way to move vast volumes of sediment many tens of miles through dredge pipes. We have a great deal of experience with relatively smaller scale projects for both marsh creation and barrier island restoration, but the master plan proposes projects that will be carried out on a much larger scale — moving material over much greater distances than ever before. While there seems to be no technical reason this cannot be done, actually doing it will be important for fine tuning the plan.
Similarly, we need to test and demonstrate a sediment diversion somewhere other than at the mouth of the Mississippi River. The very existence of southeast Louisiana proves that such diversions build land. We have extensive experience cutting artificial distributaries near the mouth of the river and letting them build land – from Cubit’s Gap and a dozen other cuts on the Mississippi below Venice to the Wax Lake Outlet on the lower Atchafalaya River. We also know that crevasses through the man-made levee system prior to 1928 moved vast quantities of sediment into the upper estuaries. But we have never deliberately designed and constructed a controlled sediment diversion, and we will learn a great deal more than modeling can tell us by actually doing it.
All told, the to-do list for Coastal Master Plan implementation seems long, but with RESTORE Act and NRDA fines on the way, we will have the funding to jumpstart restoration. Combine this funding with the proper planning and prioritization, and coastal Louisiana will take several steps closer to a more sustainable future.1 Comment
At just five months old, Mardi Gras Pass is the newest distributary of the Mississippi River — a modern addition to an ancient system. Located about 50 miles south of New Orleans on the east bank of the river, the pass was discovered by Lake Pontchartrain Basin Foundation (LPBF) staff on Mardi Gras Day 2012. The natural flow of the Mississippi River had cut a continuous channel through the river’s bank and into the Bohemia Spillway, creating a new distributary and offering a small glimpse at what a natural delta system looks like.
On August 1, Louisiana’s Governor’s Coastal Advisory Commission held their regular meeting in Davant in Plaquemines Parish. At the meeting, Dr. John Lopez, executive director and coastal sustainability program director for LPBF, presented on the status of Mardi Gras Pass to the commission. The presentation showcased how LPBF and its partners were taking every advantage to study and learn about the river’s natural ability to connect to the wetlands. In June, LPBF released a report on the dimensions of the new channel, and its staff continues to regularly monitor the pass’s progress. Both the report and Dr. Lopez’s presentation can be found at SaveOurLake.org.
Mardi Gras Pass’s flow has increased modestly since February, but the discharge is almost entirely dependent on the height of the Mississippi River water level. This summer, while the river has been exceptionally low, the flow rate has been less than 500 cubic feet per second. But when the river rises toward the end of the year, the flow could be ten times greater.
The Governor’s Commission also visited Bohemia Spillway and Mardi Gras Pass themselves. They were taken to a location where the newly-established Mardi Gras Pass has cut through a private road within the spillway, making it impassable. A local oil company has applied for a permit to repair the road, which could close off the flow from the river and block the pass. The state has expressed scientific interest in Mardi Gras Pass and recognizes it as a potential restoration opportunity. Therefore, the state has requested that the company evaluate alternatives to repairing the road which would allow the pass to still function.
The Commission also visited the actual location where Mardi Gras Pass has cut through the Mississippi River’s bank. Some Commission members had never seen the Mississippi River without an artificial river levee, and it was a moving experience to see the river in its natural condition and to see the meandering Mardi Gras Pass’s channel cutting through the river’s willow tree forested bank. Mardi Gras Pass is a real-life example of nature at work. As a natural distributary and natural diversion, Mardi Gras Pass represents a small precursor to what a more natural Mississippi River and delta could look like in a Coastal Master Plan future.
- Presentation to Governor's Commission: Status of Mardi Gras Pass, the Newest Distributary Pass of the Mississippi River within the Bohemia Spillway, Southeast Louisiana (Lake Pontchartrain Basin Foundation)