黄河中游水利水保措施减沙效益分析中几个值得注意的问题

河流输沙量的变化受流域降水和下垫面影响很大。采用水文法分析水利水保措施减沙效益时应注意如下问题:降雨量是最重要的基础资料,要认真分析工程实施前后雨量站的分布、代表性及前后期降雨量的可比性;暴雨对产沙的影响很大,暴雨强度是决定产沙量多少的重要参数,选用有效降雨量、有效降雨强度能较好地反映暴雨产沙作用;用径流量预报产沙量要区别地下、地表径流的不同影响;要考虑不同地貌类型区对产沙量的影响。

Several Problems Worth Paying Attention in Analysis of the Benefit of Sediment Reduction of Water Con-servancy and Soil Conservation Measures in the Middle Yellow River

The variation of river sediment load is considerably affected by rainfall and underlying surface. When hydrologfe method is used in making analysis of the benefits of sediment reduction of soil conservation measures, the following problems should be paid attention to: Rainfall is the most Important basic data, so we should make serious analysis of the distribution of rainfall stations, representativeness and the comparison of rainfall before and after project construction. Intense rainfall has great influence on sediment yield and rainstorm intensity is an important decisive parameter of sediment load, therefore we should select effective rainfall and rainstorm intensity to betterty reflect the effects of rainstorm in sediment yield. When runoff is used to forecast sediment yield, the different affects of underground and surface water should be differentiated. The affects of different types of geomorphy on sediment yield should also be taken into consideration.