Abstract

The key problem of construction of a barrage in tidal estuaries is siltation in downstream area. There is an essential difference of downstream siltation between tidal barrages built in trunk stream and the mouth of its tributary, and the latter mainly depends on the location of the main channel of tidal trunk stream. The Barrage built at the mouth of the Cao’e River, a tributary of the Qiantang Estuary, is taken as an example in this paper. Siltation features and siltation rate downstream the Barrage were prognosticated by using fluvial process analyses, movable bed physical model，flume model and field sedimentation tests. Based on this, discharging the water upstream the Barrage to erode the silt downstream area is brought forward as operation rule for the Barrage. It provides the scientific foundation for the construction of the Barrage.

Keywords: Sediment siltation downstream tidal barrage; tributary barrages; tidal estuaries; movable bed physical model; field sedimentation tests.