Altered estuaries with an estuarine dame in the Anthropocene

초록

Estuaries host ecosystems with great ecological and economic value in the world but underwent many physical alterations, degrading their economic values. Amongst physical alterations such as dredging, land reclamation, and estuarine dam, the effects of an estuarine dam has not been adequately dealt in the literature. Here, the estuarine dam refers to a dam or sluice gates located in the salt intrusion. In this work, we deal with the global distribution and impact of estuaries with an estuarine dam. Approximately 10 percent of all estuaries we analyzed (about 2400 estuaries for which river mouth width 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 are loss worldwide. Further, the hydrodynamic and sedimentary impacts of estuaries due to the estuarine dam have been investigated with field and numerical studies. 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 firs to show the global extent of estuaries of an estuarine dam and their systematic effects on estuarine sedimentary processes.