Analysis of Sediment Deposition Downstream Tidal Sluice of Estuary

In order to fully utilize the freshwater and improve urban water environment, the feasibility studies of tidal sluice construction have been carried out in recent years. The key problem is sediment siltation at the reach downstream the gate. Based on measured data of sedimentation under existing tidal sluices of estuaries, this paper analyzes characteristics and strength of siltation downstream tidal sluices in different regions of China, and evaluates sedimentation of tidal sluices according to reduction of river cross section, reduction of discharge capacity and watercourse length downstream tidal sluices; analyzes overall sediment deposition of watercourse downstream tidal sluices, sediment deposition and sediment thickness of some river reaches. The analysis shows that the longer the watercourse downstream tidal sluices, the greater the total volume of sediment deposition; annual average sediment deposition in each kilometer is 40~186,000 m3 according to overall sedimentation of watercourse downstream tidal sluices; back-silting intensity is the largest within the first year after tidal sluice built, annual sediment thickness is about 1.1m, decreases gradually and tends to be stable. Width of watercourse downstream tidal sluices involved in this paper are among 100~250m and influence of watercourse width on sediment deposition needs to be further analyzed.