How the Delta Was Formed

To understand the necessary solutions to stop the land loss crisis around the Mississippi River Delta, it is important to look back at how the delta was created.

The modern Mississippi River Delta formed over the last 7,000 years in a dynamic process known as the delta cycle. Each delta cycle results in a new delta lobe, created over a period of around 1,000-2,000 years as the river carries sediments from the interior of the continent and deposits them near its mouth in the warm waters of the Gulf of Mexico. When enough sediment stacks up underwater, plants begin to grow, and even more sediment and organic materials accumulate as plant communities thrive and develop.

map_delta lobes As the delta lobe continues to build, the river’s path to the Gulf becomes longer and more difficult. In response, the river finally changes course, abandoning the older lobe and cutting a shorter route to the Gulf, starting the process again.

These abandoned lobes gradually sink and erode, forming extremely productive estuaries that attract fish, waterfowl and other wildlife and leaving barrier island arcs behind to mark their former extent. New lobes form with the river’s new route, building up new land for marsh plants and trees to take hold. This constant ebb and flow creates a dynamic and ever-changing mosaic of habitats and natural resources. A natural delta exists in a state of constant change.

Today, the delta’s natural cycles of change have been ground almost to a halt by human activities, laying the groundwork for today’s ecological collapse. Learn more >>

The river’s powerful land-building force must be allowed to rebuild and restore the Mississippi River Delta. This reconnecting of the river to its delta requires a scientifically grounded package of federal and state polices and restoration projects.

Related Information:

- The Importance of Wetlands
- Wide Open Bull Reds a Testament to the Delta

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