Channel evolution conceptual model associated with dam removal at Chijiawan Creek

This study focused on channel responses one and a half years after dam removal in the Chijiawan Creek and proposed a channel evolution model based on analyses of hydrology, morphology, and images. Channel adjustment is highly influenced by the distance between the dam and the headcut erosion. We defined nine and six stages of the channel evolution model for the upstream and downstream reach, respectively, according to the cross sections 48 m upstream and 30 m downstream from the dam. It took a couple of minutes to reach stage B (main channel migration) and one year or so to reach stage E3 (widening and continued incision). As Chijiawan Creek has not reached the quasi-equilibrium state, stage F', we suggest that the establishment of a long-term channel evolution model is critical for in-situ monitoring.