Letters from the July 16, 2005, issue of Science News

Muddy, clarified

“Muddy Waters” (SN: 5/21/05, p. 328), 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.