Transport and Mixing Characteristics of Pollutants by Continuous Point Source Discharge in the Multi-anabranch River with Three Braid Bars

The physical processes of the pollutant transport in multi-anabranch rivers are not clear at the present time compared with straight rivers and meandering rivers. A physical model of a multi-anabranch river with three braid bars was set up to explore the pollutant mixing characteristics in this paper. The multi-anabranch reach is separated into seven branches B1, B2, B3, B4, B5, B6 and B7 by three braid bars. Tracer release location was arranged at the centerline of the straight flume before branching reach. The cross-sectional concentration distributions at seven branches in the multi-anabranch river with three braid bars were measured and analyzed. The transport and mixing characteristics of pollutants in the multi-anabranch river with three braid bars were obtained. High concentration regions of branch B1 and B2 individually locate at left and right sides of braid bar M1. High concentration region of branch B3 locates at the bottom of the branch.