黄河中游水土保持措施的减水减沙作用研究

本文对黄河中游河口至龙门区间以及泾河、北洛河、渭河流域水土保持措施保存率、保存面积以及水土保持坡面措施和淤地坝减水减沙作用的计算方法进行了研究，并用之于实际计算。结果表明：1970年～1996年，河龙区间及泾河、北洛河、渭河流域水土保持措施年均减少径流5.456×10.8m³，年均减沙2.23810⁸t，分别占对应区间及流域多年平均来水来沙量总和的4.6%和22.9%；水土保持措施减水减沙量依时序递增；每年可为黄河下游减少淤积1.57×10⁸t，减少冲沙用水45×108m³。1970～1996年河龙区间淤地坝年均减水减沙量分别占水土保持措施年均减水减沙总量的59.3%和64.7%；河龙区间淤地坝的减水减沙作用随着时间的延续呈明显的下降趋势，具有时限性及非持续性，据此提出黄河中游地区生态保育对策。

Water and Sediment Variation and Ecological Protection Measures in the Middle Reach of the Yellow River

The paper discussed existent rate and area of soil and water conservation measures and calculation methods for reducing flood and sediment through slope measures and warping dam as well as their applications in He-Long area,Jinghe,Beiluohe,and Weihe watershed in the middle reach of the Yellow River.Research results of soil and water conservation method showed that the mean flood and sediment reduced 0.5456 billion m~3 and 0.2238 billion tons in Helong area,Jinghe,Beiluohe,Weihe watershed respectively from 1970 to 1996,which accounted for 4.6% and 22.9% of the total amount in the corresponding watershed.The reduced flood and sediment from soil and water conservation measures increased chronologically;the sediment and scouring water into the lower reach reduced 0.157 billion tons and 4.5 billion m~3 respectively.The reduced flood and sediment from warping dam accounted for 59.3% and 64.7% of the total flood and sediment reduction from soil and water conservation measures respectively.The water and sediment reduction from warping dams decreased chronologically and shown a periodic and unsustainable trend.The ecological protection policy was discussed in the middle reach of the Yellow River based on ecological construction of soil and water conservation,the relationship between engineering measures,ecological measures and cultivation measures,forest and grass measures and ecological protection.