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为了研究淤地坝对流域径流过程的影响,阐明淤地坝的减蚀机制,以淤地坝系布设完整的黄土高原丘陵沟壑区第一副区典型流域为研究对象。首先,从表观上分析水土保持措施对径流系数、输沙模数和流域滞时的影响,发现韭园沟、王茂沟、想她沟较未治理的裴家峁、李家寨、团园沟径流系数分别减少了29.43%、34.63%、16.78%,输沙模数分别减少了28.09%、67.75%、27.75%;其次,通过构建单位过流量的概念,分析淤地坝淤积对沟道过流能力的影响,淤地坝淤积降低了沟道的过流能力,淤积沟道的单位过流量降为未淤积沟道的40%;最后,借助图论理论,定义沟道汇聚节点、沟道障碍性节点(淤地坝)以及沟道特征变换点3类沟道节点,并将沟道障碍性节点依据其放水建筑物类别划分为强连通性结点、弱连通性结点、无连通性结点3个子类。对每类节点赋予权重,计算出整个王茂沟流域的权重值(0.21),经过和实测的洪峰流量拟合,发现权重值和洪峰流量之间有较好相关性。研究结果对分析淤地坝等水土保持措施对流域水文过程的影响有一定意义。
In order to study the effect of silt dam on the runoff process of the drainage basin and elucidate the mechanism of erosion reduction of the silt dam, the typical catchment of the first sub-area in the hilly and gully area of the Loess Plateau is constructed. First of all, from the perspective of the impact of soil and water conservation measures on runoff coefficient, sediment transport modulus and catchment lag, we found that Jiuyuangou and Wangmaogou are better than Peijiagou and Lijiazhai, The runoff coefficient decreased by 29.43%, 34.63% and 16.78%, respectively, and the sediment transport modulus decreased by 28.09%, 67.75% and 27.75% respectively. Secondly, by analyzing the concept of unit overflow, Overcurrent ability siltation dams reduce the overcurrent capacity of the channel, siltation channel unit over-flow reduced to 40% of the silt channel; Finally, the use of graph theory to define the channel convergence node, the ditch Barrier-type nodes (check dam), and channel feature change point, and classified the channel obstruction nodes into strong connectivity nodes and weak connectivity nodes according to the type of their drainage structures, without connectivity Sexual nodes 3 subclasses. The weight of each type of node is calculated, and the weight value (0.21) of the entire Wangmaogou basin is calculated. After fitting with the measured peak flow, it is found that there is a good correlation between weight value and peak flow. The research results have certain significance to analyze the impact of soil and water conservation measures such as silt dam on the hydrological process in the basin.