CPRA

Louisiana's 2023 Coastal Master Plan

Historical Land Change

  • Persistent Land Loss
  • Persistent Land Gain

A History of Change

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Louisiana's map has changed significantly over the past century, with what was land changing into open water in many areas. Between 1932 and 2015, over 2,000 square miles of coastal land has been lost. This loss is a result of many factors—the impacts of leveeing the Mississippi River and reducing sediment transport, cutting navigation and oil and gas industry canals, and climate change.

Use the year slider to see how land loss (blue) has changed the landscape since 1932.

A Continuing Crisis

As sea level rises and storms increase in intensity due to climate change, land loss will continue to be a threat to coastal Louisiana. Land change over time is uncertain to some degree, so the 2023 Coastal Master Plan considers multiple future environmental scenarios to ensure we prepare for a wide range of possibilities.

In the next few slides, we'll take a look at projections of land change over time under a lower (more moderate) and higher (more severe) scenario to understand what coastal Louisiana may look like in the future.

Land Change Without Action

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Without the implementation of the 2023 Coastal Master Plan, Louisiana would be at risk of losing approximately 1,100 square miles of land under a lower environmental scenario and 3,000 square miles under a higher environmental scenario over 50 years. The threat of significant land loss underlines the importance of taking action to address coastal challenges.

Use the year slider to view modeled land change over time. Compare the land loss maps at the same point in time under different environmental scenarios to see a range of possible future outcomes.

Flood Depth Without Action

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Land loss is not the only challenge facing coastal Louisiana. Storm surge-based flooding brings waters into coastal communities and can damage homes and business, costing tens of billions of dollars. We model a range of storm intensities, sizes, and landfall locations across the coast which provides an idea of how flooding could occur across Louisiana's coast over the next 50 years if no action is taken.

Adjust the year slider and environmental scenario to see how flood depths change over time under different scenarios. You can also view projected flood depths resulting from storm events of various intensities (measured in annual exceedance probability or AEP).

Expected Annual Damage Without Action

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Future storm surge-based flooding damages can be estimated by considering flood depths and the number and type of assets flooded in events across the coast. The cost of these damages is the Expected Annual Damage in Dollars or EADD. Another way to quantify damages is to count how many whole and partial structures are damaged from an event and sum them to determine the Expected Annual Structural Damage, or EASD.

Both damage metrics are projected over time and for different scenarios and event AEPs. Adjust the year slider and environmental scenario to see how damages may change into the future for both damage metrics.

Taking Action

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To take action toward addressing the challenges of a changing coast, a suite of 77 restoration and risk reduction projects has been selected for the 2023 Coastal Master Plan. When fully implemented, the plan will provide a myriad of benefits for coastal communities and ecosystems, including avoiding hundreds of square miles of land loss and reducing expected annual damage from storm surge-based flooding by billions of dollars.

Projects take time to design and construct, and therefore do not all appear on the landscape at the same time. Adjust the year slider to see when and where selected projects are implemented across the 50 year master plan period.

Land Change With the Master Plan

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Projects included in the 2023 Coastal Master Plan will reduce land loss in areas across the coast. Through building and/or maintaining coastal wetlands, the fully implemented master plan would avoid losing approximately 310 square miles of land under a lower environmental scenario and 230 square miles under a higher environmental scenario over 50 years. This is in addition to the benefits expected from projects in progress and those that are already on the ground.

Change the plan implementation scenario and use the year slider to compare a future without action to a future with the master plan over time and see the impact of investment in the coast.

Flood Depth With the Master Plan

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Structural risk reductions projects can reduce storm surge-based flood depths in locations across coastal Louisiana. By building a physical impediment to surge flows, these projects work to improve outcomes during surge events.

Change the plan implementation scenario and use the year slider to see the impact of investment in the coast. You can also view changes to projected flood depths resulting from storm events of various intensities (measured in annual exceedance probability or AEP).

Expected Annual Damage With the Master Plan

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As with flood depths, economic and structure damage can be reduced through the implementation of master plan projects. Reduction in both the cost (billions of dollars) and number (thousands) of structures damaged during storm events is a significant benefit of the 2023 Coastal Master Plan.

Change the plan implementation scenario to see the impact of investment in the coast. Change the damage metric and use the year slider to see how the master plan changes damage values into the future.

Time to Explore

The future coast of Louisiana is going to be experienced differently than today's coast. The 2023 Coastal Master Plan presents a vision for a future coast that can support people living, working, and playing in Louisiana into the future while adapting to the changing landscape through the implementation of the 77 restoration and risk reduction projects selected for the plan.

Use the button below to move to the Explore portion of the master plan data viewer. While exploring, you can learn more about the future coast and projects worth investing in!

Welcome to the 2023 Coastal Master Plan Data Viewer