In the prcscncc of a fixed weir, flow and bed topography in river is not only affected by the weir but also by horizontal and cross sectional channel shape around the fixed weir.
In this paper, we studied influence of a fixed weir upon flow and bed topography. At first, the fundamental influence of fixed weirs on flow was investigated by experiments of a single straight channel and a compound meandering channel with rigid bed. Secondly, the influence of a fixed weir on flow and bed topography of compound meandering channel with movable bed through experiment was discussed. Special attention was placed on the change comparison in the flow and bed topography caused by the weir position and plane shape such as perpendicular and oblique weirs.