This article, on the deleterious effect of dams on coastal systems, contains a major conceptual error. It states that “another important cause of the ground sinking is the waning of sediment deposition by the Mississippi River.” But over the past 100 million years, the northern Gulf Coast region has been subsiding because of excessive sediment loading produced by the Mississippi and its ancestors. Since the sediment supply is now waning, the subsiding will also begin to diminish, albeit at an extremely slow rate. It will take a long time to achieve equilibrium. What is true (and noted in the story) is that because of the decreased sediment supply, beaches, deltas, and sandbars are being starved and have been eroding for some time. However, this is very different from the statement quoted above.