黄土区人类活动影响下的产汇流模拟研究

Study of Runoff Simulation Considering Effect of Human Activity on the Loess Plateau

日益频繁的人类活动改变了流域下垫面条件,对流域产汇流产生很大的影响。本文以黄河中游典型支流岔巴沟为研究区域.提出利用基于DEM的分布式水文模拟技术.探讨流域人类活动过程中的产汇流模拟,避免了经验公式的概化和由此引起的局限。模拟的结果证实了该方法的可行性。采用网格滞蓄的方法可以在子网格上体现人类活动引起的下垫面的变化及其对产汇流的影响,反映各个时期的产汇流条件,对降雨做出合理响应。

Human activity has great effect on runoff producing and conflux for basins and can not be neglected, especially for the day-scale hydrology modeling. Because of the special human activity on the Loess Plateau, the Yellow River's runoff has been decreasing from 1960's. Because of the complex land surface condition, the relationship of rain-off and runoff is very anomaly. Runoff is hard to be modeled by uniform experience formula. And what' s more, when the land surface condition changes, the experience formula loses its validity. Based on distributed hydrologic model, a grid-based lag-and-storage method, with consideration of the effect of human activity, is in detail shown, taking Chabagou (a typical watershed on the loess plateau) as an example. The digital terrain parameters are extracted from DEM(digital elevation model) with resolution of 950mx950m. The location of dams and reservoirs et al are distributed on the grids with their real location on the watershed in mind. The model also uses the mix-runoff-producing method, which considers the variation of runoff-producing area. The modeling results show the feasibility of this method. Model using the gird-based lag-and-storage method can consider the land change on grid-scale and reflect the condition of every periods, so it would make reasonable response to rain-off. With the effect of human activity on runoff brought into the distributed hydrologic model, the nature law of watershed and the effect of human activity on runoff can be deeply understood.