关键词: 河道演变, 数学模型, 调控方式, 三峡水库调度, 长江中下游

Abstract:

With the impact by reduction of runoff and sediment transportation from trunk stream and tributaries in upper reaches as well as water storage and sediment blocking by upstream cascade reservoirs, the series of runoff and sediment transportation as well as the evolution of watercourse in the lower reaches of the dam have changed significantly. For the research on effect of watercourse evolutionary at the downstream of the dam under different regulation modes of the Three Gorges reservoir, this article adopts methods of numerical model calculation. The result shows: different discharge would affect the erosion and deposit in a limit extent and with the accumulation of reservoir operation period, the difference among different discharge scenarios would reduce; flushing is expected in all different sections of watercourse and shrink is expected at islands and beaches, however, as time elapse, flushing would decrease, river regime would be stable and thalweg swing scope would be small; when flood peak discharge deceased by operation, evolution trend of watercourse would be stable, however, flushing would increase in most parts of channel with the phenomena of channel expansion and deepening.

Key words: channel evolution, mathematical model, the Three Gorges reservoir, regulation mode