Coastal Louisiana was shaped and built by the Mississippi River.
The River drains 40% of the continental United States, capturing water and sediment from rivers from as far north as the Canadian border, west to the Rockies, and east to the Appalachian Mountains. The Mississippi River Delta is one of a few river deltas in the United States, and is relatively young, geologically speaking, dating back 7,000 years.
Over centuries the flows of sand and silt carried by the River built the land in present-day coastal Louisiana.The land-building was the result of the natural deltaic process of the River changing course over time. As the River would lengthen, its gradient would decline, its speed would slow, and sediment would build in its bed. As those deposits accumulated, the River would seek a new path of least resistance, building new channels and over time extending the coastline further into the Gulf.
Land was also built when seasonal floods would spill over the banks of the River, replenishing wetlands with sediment and fresh water. About once every thousand years the River would shift dramatically into a new channel, and the land-building process would begin anew.
Today, the more than four million acres of wetlands created across this constantly changing landscape host some of the world’s most diverse ecosystems. Yet they also support a century’s worth of infrastructure and development that rely on the River’s current footprint—including crucial oil and gas infrastructure, and navigation channels that serve five of the nation’s fifteen busiest ports.
Economies of major cities such as New Orleans and Baton Rouge, along with navigation interests, major energy infrastructure, and fisheries are all tied to the River’s current location. Those dependencies drive engineering works that have maintained the River in its present course.