The large-scale manipulation (via dams, levees, and channelization) of the river’s natural course has served our nation well over many decades. It has allowed for more stable navigation, more suitable areas for habitation and somewhat more predictable flood risk. Yet, it has also had significant consequences, including an increasing and alarming rate of land loss in recent decades.
Land loss in the Mississippi River Delta is caused by three dominant factors:
The river is carrying three to four times less sediment than it once did.
Sea levels are rising and land is sinking.
The sediment in the river today is being sent out into the Gulf of Mexico, a by-product of channelization.
Other factors contributing to land loss include dredged canals, oil and gas extraction, roads, and other landscape changes.
2. Why do we need to act?
With much of the land of the delta less than three feet above sea level, the combination of increasing sea level rise (ten times the historic rate by some predictions) and continued land sinking (“subsidence”) threaten to submerge a large part of the delta in the next 50 to 150 years. The need to act has never been greater. We can and must choose to change the future if we want to preserve the delta.
3. Why doesn't the river naturally build land like it did historically?
Channelization of the river has forced its rich sediment to bypass the wetland landscapes it once replenished. The delta, as a whole, has ceased to grow naturally. Valuable and protective wetlands are disappearing at alarming rates, putting the economy, ecology, and cultures of the delta at risk.
4. How are you proposing to solve this problem?
When the Mississippi River flowed naturally, without human intervention (via dams, levees, and channelization), it deposited sediment across the delta, maintaining and building new land. But now we are losing land far too quickly. This plan would work to reverse this trend, leveraging the river’s own natural process. By opening new river mouths in targeted locations for certain periods of time we can replenish land more efficiently and successfully than we have to date.
This approach is purposely bold because it is the only way we can be successful in rebuilding land faster than we are losing it, protecting the most people from flooding and the loss of their homes and jobs. It will also improve transportation along the river and ensure that fishing remains sustainable.
While other solutions have mostly focused on land loss, often at the expense of others (fisheries), or without regard to possible synergies (navigation), our solution is more holistic, and sees increasing opportunities from planning for “A Delta for All.”
5. How does your approach compare to the other proposed approaches?
Our team and approach have several advantages:
We are reinventing the system because the delta region needs a solution that does more than what has been suggested to date. Subtle tweaks to the 2012 Coastal Master Plan ideas simply will not work.
Largest sustainable delta. Our approach could save significantly more of the delta. The Master Plan could harness no more than 50 percent of the delta.
Real options. We have concrete ideas to get communities started on thinking about how to transition and implement ideas.
Room for input. We have purposefully left room for public input throughout this process.
Game-changing flood protection. Our proposed idea brings immediate flood protection while other solutions would yield lower flood risk reduction over the course of 15+ years.
We aim to balance the concerns of fisheries the need to build land so that ultimately the delta becomes more sustainable for all.
More engineering rigor. We engaged in detailed engineering modeling to test options and theories to assess the feasibility of our ideas.
Integrated team. Our experts all work together throughout so our solutions are well-rounded.
Local experts on our team. Uniquely, we have counsel from the Navigation Expert Advisory Panel (NEAP), which consists of senior leaders of key local ports, both pilots associations, and the Marine Navigational Safety Association.
6. What's the difference between your approach and the 2012 Coastal Master Plan?
Our plan takes into account that the future delta will be smaller, as the river is depositing less sediment today and the sea is rising more quickly than in the past.
The new river mouths we are proposing will harness 100 percent of the river and deploy it for land building. The proposed diversions of the Master Plan would capture no more than half of the river’s land building potential.
Fully taking the river out of the channel below English Turn—or, in other words, opening new river mouths strategically located above the English Turn to build new sub-deltas— provides the potential for tremendous immediate gains in flood risk reduction and expansion of shipping. These are advantages not gained by the Master Plan diversions.
We plan to rotate sediment distribution over time in the delta’s sub-basins to ensure there is always a balance between fresh and estuarine environments, preserving the natural delta cycle and opportunities for commercial and recreational fisheries.
7. How will delta communities be affected?
Delta communities are deeply tied to water, economically, culturally, and socially. The increasing loss of protective coastal wetlands, major oil spills, and hurricanes all threaten this way of life. Our goal is to create as large a delta as possible by enabling the river to build up a delta that can be sustained in the face of sea level rise and sinking land. Our approach reduces flood risk, restores coastal wetlands, reduces uncertainty for the delta’s people, helps maintain and expand local and regional economies, and allows communities to maintain ties to the delta for generations to come.
We will lead an equitable and transparent process to empower the delta’s people with options and provide support. This means incorporating public knowledge and feedback into delta decision-making, as well as working with existing social organizations by providing policies, tools, and information they need to lead their communities to greater resilience. Transitions will not always be easy; it’s our job to provide many options and clearly communicate the best science so everyone can make informed decisions. Our approach offers tremendous opportunities to grow local economies—especially navigation, recreational fishing, ecotourism, and water management. We have many ideas about how to help local families transition over time at a gradual pace that they can plan around and we are eager to develop these ideas further with community input.
8. Will this effect oystermen and fishermen?
Building with the river maximizes land growth, but it introduces freshwater into areas that are currently estuarine and significant for commercial fisheries and oysters. Our plan acknowledges that this is a very difficult tradeoff. We must find a way to balance the needs of all residents of the delta to find a way forward.
We simply can’t afford to sustain the Delta solely through dredging, so our plan begins to identify ways to build with the river while also providing the greatest possible support for the fishing community. We seek to find an equitable balance between freshwater and estuarine areas through turning new river mouths off and on with time. This approach replicates the natural delta cycle of growth and abandonment, supporting ecological restoration to the fullest extent. Some areas of the Delta would always be estuarine with our approach; not all faucets would be turned on simultaneously. It also allows fishing communities to plan for controlled shifts. It will require near-term compromises, but far greater compromises will be needed in the long-term if we do not commit to sustaining the overall delta to the best of our ability now. Our initial proposal will need the input of many local communities, fishing and oyster communities included, to be successful. The ultimate goal is to arrive at a large, sustainable delta that supports all local communities as best it can.
9. How will you address freshwater?
Our approach only freshens some basins at any given time so there will always be a balance of fresh and estuarine basins in the delta. This staggered approach allows for those most affected—fisheries and oystermen—to plan accordingly. This approach contrasts with the master plan’s proposed diversion approach, which would potentially introduce fresh water in all basins.
10. Can't we just dredge to solve the problems without impacting fisheries and oysters?
Dredging is one means to create wetlands, but it’s more expensive and the land it builds isn’t sustainable: over time, the dredged sediment placed in an area sinks vs. managed distributaries that supply a continual re-nourishment of sediment for wetlands; several decades after dredging is used to create wetlands, it must be repeated again because the previous wetlands will also be lost.
11. What is a 'managed distributary' and is it just another name for a diversion?
Although there could appear to be some similarities between managed distributaries and diversions at first glance, they have significant differences. Like a diversion, a managed distributary focuses on building land with the river (in contrast to dredging), but the scale and benefits are widely different. Here is how:
Whereas diversions, as described in the 2012 Coastal Master Plan, would capture less than 50 percent of the river (even if they were all on at the same time), managed distributaries are much larger, capturing 100 percent of the river's total capacity across all faucets.
The diversions in the Master Plan would all be turned on at the same time, freshening all basins in the delta and thereby harming the fish and oyster communities. With managed distributaries, only some are on at any given time, ensuring there will always be some estuarine basins in the delta.
With diversions, flood protection only improves over 15 or more years as new land grows, but the bold approach of distributaries unlocks substantial benefits immediately, primarily for flood risk and navigation.
12. Does your approach improve navigation on the river?
Today, navigation and marine commerce are approaching a ceiling— the existing river isn’t deep enough for the largest vessels that will pass through the third lane of the Panama Canal, and significant barge traffic and anchorage areas make traveling on the river less safe.
With the help of a Navigation Expert Advisory Panel (NEAP), which included senior leaders of key local ports, pilots associations, and the Marine Navigational Safety Association, we have developed an approach that expands the capacity of navigation in the region and up the Mississippi River.
The greatest current need for shipping on the Mississippi River is to increase the navigable depth to 50 feet to allow larger ships to navigate the river. By placing new river mouths upstream of English Turn, dredging costs will plummet because we fully remove the sediment supply that necessitates maintenance dredging of the lower course of the Mississippi.
Additionally, by converting the Lower Mississippi River to a tidal channel without river sediment, localized expansion of the channel at strategic locations becomes feasible, allowing for development of a mega multi-modal logistics hub. Our plan also removes the need for lock structures connecting the Mississippi to the Gulf Intracoastal Waterway (GIWW), enhancing the efficiency of the GIWW shipping and avoiding significant future costs.
These improvements, along with the deeper channel, would substantially change the economic maritime impact for the State of Louisiana and ensure that the ports of southern Louisiana can keep up with other ports nationally and globally.
13. You mention a “faucet.” What does that look like?
The concept of “faucets” illustrate that there will be new water mouths along the river that can be “turned on and off.” It is early in the process and we have not yet designed them, but we envision creating infrastructure on the side of the river that acts like a gate to restrict or release river flow as needed. We could start with one or two basins, monitor and adjust the faucets over time, and design the infrastructure to be potentially expandable and movable for reuse.
14. What will this cost and who will pay for it?
It is too early to define a definite estimate since our approach still needs community input and will likely evolve. However, our proposed strategy is significantly less expensive than dredging. If we were to dredge to build just half of the land required to sustain the delta, that would cost $625M to $1.75B every year. This equates to $25-70M per km². Comparatively, our idea to build land using the river’s sediment costs $5-10M per km². In addition, we’d save more than $2 billion in replacement costs for outdated infrastructure.
Consider the following cost savings and estimated costs we have outlined so far:
15. How will the public be involved?
Until now, due to confidentiality requirements of the competition, we have had limited engagement with the public to shape our ideas, but we are excited to receive much more community input as we continue to improve upon this work.
We know big decisions like this require broad public input; that’s why our team’s work for the competition did not include a “plan.” Our team’s work consists of an approach, principles, and options, but it is not a defined “plan.” It does not specify when and where to start land building through opening new river mouths. These are significant decisions that we have left unanswered because they require public and stakeholder input. Selecting a starting point is not a question for our team to decide; it will require openness, honesty, tough conversations, tradeoffs, education, outreach, and broad public input.
To define the first stage of river mouths, we still have significant additional outreach and analysis to do, including:
Gathering significant public and stakeholder input from a diversity of sources