Author(s): Akihiro Tominaga; Naoki Kojima; Tomomichi Kato
Linked Author(s): Akihiro Tominaga
Keywords: Riverside concavity; Spur dike; Recirculation eddy; Sand deposition
Abstract: The riverside concavity tends to cause recirculation eddies and resultantly deposition of suspended sediment. In this study, a spur dike located upstream of the concavity is used to control the deposition in the concavity zone. The effects of spur dike on flow structures and sand deposition were investigated experimentally. The length and height of spur dike and the location distance of the spur dike from the upstream end of the concavity zone were changed under two different discharges. The morphological shape of sand deposition is affected by the strength of recirculation eddy and the sediment discharge along the open interface of concavity. The strong velocity of recirculation eddy removes the sand from the concavity zone. The spur dike located upstream deviates the sediment toward the counter side. As a result, relatively long and middle-height spur dike set at just upstream end of the concavity is most effective for reducing sand deposition in the concavity zone.