Study of sediment transport and deposition in the Kuma River and tidal flat for evaluation of environmental impact associated with removal of the Arase Dam

Abstract

For the assessment of the impact by dam removal at the Arase Dam in the Kuma River, Kyushu, Japan, preliminary survey focused on SS transport and sediment characteristic was conducted. The results showed that more than 2,000,000m3 of SS transported during fulltime gate open operation started in April 2010 and annual quantity of SS in 2011 was the third largest in the past 19 years. Comparing with the results of past investigation conducted in 2002, sediment in estuary and near shore zone have shifted from mud to sand. The results of constituent element concentration of sediment supported the possibility that element bringing the grain coarsening in shore zone have origin in the Kuma river.