Performance of riffle structures on the stabilization of two successive knickpoints over a sandy bed

• 作 者: Afshin Fouladi Semnan Mohammad Reza Jaefarzadeh
• 机 构: Civil Engineering Department,Ferdowsi University of Mashhad,Iran“,”Civil Engineering Department,Scho
• 出 处: 国际泥沙研究（英文版）
• 发表日期: 2020年4期
• 关键词: Control structures Cross-vane riffle Knickpoint migration Newbury rock riffle Ri

Two successive knickpoints with a 10％slope were constructed 1 m apart on a sandy bed in a rectangular flume with a longitudinal slope of 0.003. Bed erosion and knickpoint migration were studied experi-mentally for different discharges. The performance of two grade-control structures-Newbury rock riffles (NRR) and cross-vane riffles (CVR)-were studied experimentally for the stabilization of each knickpoint. Both of the structures were successful in controlling the bed erosion; however, the NRR operated rela-tively better than the CVR for they could concentrate the flow at the middle part of the channel to produce more regular contours with less local erosion and bed settlement. The experiments demon-strated that the construction of a control structure was not only effective in the stabilization of a knickpoint but also retarded the migration of its neighboring counterpart.