Global distribution of estuarine dams and their sedimentological impact

Estuarine dams are dams constructed within the salt or tidal intrusion limits of estuaries for securing freshwater resources or flood control. In this work, we deal with the global distribution of estuarine dams and their sedimentological impact on estuaries. Approximately 10 percent of all estuaries we analyzed (about 2400 estuaries for which river mouth width is greater than 90 m) were affected by estuarine dams and direct human modifications are responsible for more than 1,000 km² of the observed estuarine surface area loss worldwide. Our field and numerical studies revealed that regardless of estuarine type, estuarine dams amplified the tidal range and reduced the tidal currents. The estuarine turbidity maximum moved seaward, and the suspended sediment concentration tended to decrease. While the morphologic changes depended on the estuarine type, the surficial sediment texture shifted to being muddier for all types. This work is one of the first to show the global extent of estuaries of an estuarine dam and their systematic effects on estuarine sedimentary processes.