The coastal transition at the mouth of a small mountainous river in Taiwan

Abstract

The Tseng‐wen River is a small mountainous river in southern Taiwan that has distinct dry and flood seasons. Several lines of evidence have revealed that the depositional system at the mouth of the river has transformed from a deltaic system to an estuarine system. The evidence includes long to short‐term shoreline changes, geomorphology of the river mouth, mixed sediment sources inside the river mouth, mixing and suspended sediment characteristics inside the river mouth, and the grain‐size distribution patterns on the river bed. Unlike the long‐term evolution of many other coastal systems, the transformation at the Tseng‐wen River mouth is largely caused by the building of a reservoir in the middle reaches of the river. The present study provides an example that coastal environments can be influenced by human activities farther inland on a time scale much faster than what would occur naturally.