Author(s)

Sinae Kim¹, Yuji Toda²

¹Department of Land, Water and Environment Research, Korea Institute of Civil Engineering and Building Technology, Goyang-si, Korea.
²Department of Civil Engineering, Nagoya University, Nagoya, Japan.

The long-term existence of dam structures significantly modified the river channel. In accordance with a drastic increase of low-head dams under consideration for removal in recent years, it is important to predict the effects of low-head dam removal from the modified river channel by the low-head dam construction. This study intends to investigate the long-term channel evolution process following low-head construction and removal and to find out the influential parameters (sediment diameter, river bed slope, dam height) for those channel evolution by two-dimensional numerical simulation model. Following the low-head dam construction, sediment deposition rates in upstream of the low-head dam are varied with the influential parameters. The sediment deposition rates and sandbar formation with riparian vegetation settlement on sandbars have significantly affected for channel evolution following low-head dam removal. Especially the knickpoint formation and the types of vegetation (grass type and tree type) on the sandbars are critical factors for channel evolution following low-head dam removal. Through the numerical simulation results of low-head dam construction (50 years) and low-head dam removal (50 years), it is identified that the modified river channel by low-head dam may not be easily restored to pre-dam conditions following its removal especially in river geomorphology and riparian vegetation. Consequently, this study found that the reversibility following low-head dam construction and removal depends on the sediment deposition rates in upstream of the low-head dam.

Low-Head Dam, Dam Construction, Dam Removal, Channel Evolution, Influential Parameter

Kim, S. and Toda, Y. (2018) Effects of Influential Parameters on Long-Term Channel Evolution Following Low-Head Dam Construction and Removal. Journal of Water Resource and Protection, 10, 780-793. doi: 10.4236/jwarp.2018.108044.