基于MIKE模型的不同淤地坝型组合情景对小流域侵蚀动力和输沙量的影响

为科学认识黄土高原淤地坝建设对小流域侵蚀动力过程的影响,通过分布式水文模型MIKE SHE和一维水动力模型MIKE 11耦合模拟了王茂沟流域的洪水过程,并计算了流域主沟不同断面的侵蚀动力参数和不同坝型组合的减沙效益。结果表明:(1)淤地坝建设在不同程度上改变了小流域沟道的侵蚀动力分布,坝系建成后沟道的侵蚀动力参数减幅最大。(2)小流域径流侵蚀功率表现为上中游剧烈变化,下游趋于稳定,且下游径流侵蚀功率明显小于上游。(3)淤地坝建设可以有效减小流域的输沙量,其中单独建设骨干、中型、小型坝相比流域未建坝时,输沙模数分别减少24.74%,47.11%,64.11%;流域坝系建成后减沙效益最明显,流域输沙量减少83.92%。研究成果可为黄土高原淤地坝减沙效益评估提供科学参考。

Effect of Different Check Dam Type Combined Scenarios on the Erosion Dynamics and Sediment Transport in Small Watershed Base on the MIKE Model

In order to scientifically understand the effect of the construction of check dam system on the erosion dynamic process in small watershed on the Loess Plateau, the storm flood process in the Wangmaogou small watershed was simulated by coupling the distributed hydrological model MIKE SHE with the one-dimensional hydrodynamic model MIKE 11, and the erosion dynamic parameters of the different sections of the main ditch as well as the sediment reduction benefits of different combination of dam types were calculated. The results showed that:(1) The erosion dynamic distribution of the gullies in the small watershed was changed by dam construction, and the erosion dynamic parameters of gullies decreased the most after the dam system was completed. (2) The runoff erosion power varied greatly in the upper and middle reaches, while tended to be stable in the lower reaches, and the runoff erosion power in the lower reaches was obviously lower than that in the upper reaches. (3) The construction of check dam could effectively reduce the sediment transport in the watershed. When the key, medium and small dams were built separately, the sediment transport modules were reduced by 24.74%, 47.11% and 64.11%, respectively, compared with those without dams in the watershed. After the completion of the dam system, the benefit of sediment reduction was the most obvious, and the sediment transport modulus was reduced by 83.92%. The research results were intended to provide scientific reference for evaluating sand reduction benefits of check dam on the Loess Plateau.