Geomorphological and riparian vegetation responses following a low-head dam removal: a study based on literature review

摘要

More and more low-head dam structures have deteriorated in recent years. Unlike the large dam, the geomorphological and ecological impacts of a low-head dam removal have not been quantified with insufficient monitoring data on pre- and post-removal. Therefore, this study intends to identify the low-head dam removal impacts on geomorphology and riparian vegetation based on previous studies. The characteristics of stored sediment in the impoundment play a critical role for geomorphological responses on a low-head dam removal creating a knickpoint and promoting a headcut migration. These geomorphological changes often form a new floodplain and create enough room for riparian vegetation establishment. The river geomorphology after a low-head dam removal can be a state of quasi-equilibrium within about a decade. In this state, a newly formed floodplain tends to be colonized by riparian vegetation in many low-head dam removal cases. After a decade to several decades, the riparian vegetation in the floodplain often develops to tree plants.