基于降雨-径流试验的高寒草甸产流机制研究

对黄河源区高寒草甸产流机制进行研究,为河源区生态环境保护、水资源科学规划管理提供基础水文理论认知。基于野外降雨-径流试验,通过回归分析构建考虑坡度和覆被因子的暴雨和中小雨产流计算模式,精度良好,能够反映暴雨和中小雨2种降雨模式下高寒草甸产流的一般特征。试验结果表明,因草甸土-植体系蓄容能力较强,高寒草甸区地表产流主要发生在暴雨模式下,中小雨模式下的地表产流量一般很小。模式应用表明,草甸发生退化后,暴雨和中小雨入渗均有减少,暴雨模式下退化草甸比高覆草甸入渗减少约12%,中小雨模式下减少约3%。

Mechanism of Land Surface Runoff Yield in Alpine Meadow Based on Field Rainfall-Runoff Experiments

Study on the mechanism of runoff yield on land surface in the alpine meadow-dominated area is helpful for better understanding hydrological processes and rationally planning water resources and protecting ecological environment in the alpine-cold regions. On the basis of field rainfall-runoff experiments, multi-variable driven modules were established for analyzing the regime of land surface flow generation in the alpine meadow area under the influences of different terrain and land cover factors in two rainfall modes (rainstorm and medium-light rainfall). The modules, calibrated with good accuracy, reflected the general characteristics of alpine meadow runoff under the two rainfall types. Due to the large storage capacity of the soil-planting system, surface runoff in the alpine meadow mainly occurred in the rainstorm mode, whereas in the medium-light rainfall mode, the amount of surface runoff was small in general. The application of the models showed that after the degradation of the meadow, the infiltration during both rainstorm and medium-light rainfall attenuated. Rainfall infiltration in the degraded meadow in rainstorm mode dropped by about 12% compared with that in largely-covered meadow, and the infiltration in medium-light rainfall mode decreased by about 3%.