The Gulf’s watershed encompasses more than half of the land mass of the continental United States, including thirty-three major rivers. The Mississippi River and its distributaries alone provide up to 90% of the fresh water and 95% of all sediment entering the northern Gulf.

But the Mississippi River is straitjacketed by levees from the Midwest to the bottom of Louisiana’s boot toe. Sediment that once fed Louisiana’s coastal wetlands is now sent into the Gulf of Mexico. Louisiana’s wetlands and marshes are disappearing rapidly, in part because they are starved of the river’s sediment and fresh water. Without sand from the river, many barrier islands are also rapidly eroding—and offering less protection from storms. In total, Louisiana’s coastline loses an average of a football field of land every hour.