川中丘陵区小流域分布式水沙模型

Distributed hydrological and sediment transport model for central Sichuan hilly areas

以川中丘陵区的解家湾小流域为研究对象,将分布式水文模型与土壤侵蚀产沙模型嵌套,构建了解家湾分布式流域水沙模型。模型基于DEM将流域离散为"坡面+沟道"系统,利用数理方程描述流域水沙过程,坡面单元模拟了降雨、截留、蒸散发、入渗、地表径流、壤中流和地下水、侵蚀产沙过程,沟道单元模拟了汇流演算以及泥沙输移过程。在解家湾小流域的率定和验证结果表明,模型结构合理,水文模块精度良好,侵蚀产沙模块令人满意。通过对不同工况下径流过程的模拟,对径流参数的敏感性进行了检验,表明饱和导水率是模型敏感参数,植被截留影响较小,土壤前期含水量影响壤中流。

A physically-based distributed hydrological and sediment transport model was developed through a combination of distributed hydrological component and soil erosion/sediment transport component, and it was applied to the Xiejiawan watershed in the central Sichuan hilly areas. It generalizes the watershed into a system of hillslopes and river channels based on DEM, and uses mathematical equations to model the hydrological and sediment processes, such as rainfall, interception, evapotranspiration, infiltration, surface runoff, subsurface flow, groundwater, erosion and sediment transport in the hillslope module, and flow convergence and sediment transport in the river channels module. Calibration and validation using the watershed data show that the hydrological component has good accuracy and the component of soil erosion and sediment transport performs well. Sensitivity of the hydrological component has been tested. Saturated hydraulic conductivity is a sensitive parameter, vegetation interception has little influence, and antecedent soil water content affects subsurface flow.