摘要
从长期来看 ,在治理度达到 70 %条件下与治理前相比泥沙输移比减小 50 %左右 ,治理的效益是十分显著的。在治理的过程中 ,与治理前相比泥沙输移比变幅明显减小 ,但在短期内由于暴雨洪水侵蚀力大于工程设计标准而发生毁、垮坝或淤平后 ,仍可以将前期滞留的泥沙重新搬运而出现泥沙输移比大于 1的情况。在黄土高原地区治理前后流域系统次暴雨泥沙输移比均可用径流深度比来定量计算获得 。
From long term point of view, sediment delivery ratio of a drainage basin with a control degree reaching 70% can be reduced by around 50% in contrast to pre control conditions. The effect of erosion control is quite significant. In the management process, although delivery ratio drops considerably in comparison to pre control conditions, yet the previous retained sediment can still be carried, resulting in the situation of delivery ratio greater than 1 since erosive strength of rainstorm induced erosion is greater than project designed standard in a short spell following dike breach and scouring. In the loess plateau region, individual rainstorm event related delivery ratio under either pre or post control conditions in drainge system can be obtained by using runoff depth, and dynamic mechanism for changes of delivery ratio can be explained with shear force changes following fluctuations of runoff depth.
出处
《地理研究》
CSCD
北大核心
2001年第1期68-75,共8页
Geographical Research
基金
国家重点基础研究发展规划项目!(G1 9990 4 360 4 )
地理所知识创新工程领域前沿项目!(CX1 0 G- A0 0 - 0 5- 0 2 )
国家自然科学基
