What percentage of the Mississippi River flow is allowed to enter the Atchafalaya River at the Old River Control Structure?

The percentage of the Mississippi River flow allowed to enter the Atchafalaya River at the Old River Control Structure is indeed 30%. This allocation is part of a carefully designed system of levees and structures that manages the flow of water between the two rivers to prevent excessive sedimentation in the Atchafalaya and to maintain navigational depth in the Mississippi.

The Old River Control Structure was implemented to address the natural tendency of the river system; the Atchafalaya is geologically poised to capture a significant portion of the Mississippi's flow due to its lower elevation and shorter path to the Gulf of Mexico. However, if left unchecked, this could lead to significant changes in river dynamics and potential flooding in areas along the Mississippi.

Therefore, the 30% allocation is a compromise that serves various interests, balancing ecological health and economic considerations. Understanding this flow allocation is crucial for grasping the dynamics of river management in Louisiana, as it affects sediment transport, water quality, and habitat conditions in both river systems.