坡面泥沙输移比时空分布式的构建与分析

Study on spatial-temporal distribution of hillslope sediment delivery ratio

坡面泥沙输移比分布式的构建是计算坡面输沙分布和吸附态非点源污染负荷分布的基础。在对已构建的坡面泥沙输移比式进行分析研究的基础上,鉴于降雨形成的地表径流是坡面泥沙输移的直接推动力,对现有的"流动连通性"指标进行改进,提出了"径流连通性"指标并以此构建坡面泥沙输移比时空分布式。将泥沙输移比式与修正的通用土壤流失方程结合,形成山地流域输沙模型。以三峡库区大宁河流域为例,通过对输沙量的模拟,对比分析了所构建的坡面泥沙输移比式的合理性。基于径流连通性指标的坡面泥沙输移比时空分布式,考虑了降雨产生的坡面泥沙输移比随时间的变化,更为合理、模拟精度更佳。

Hillslope sediment delivery ratio(HSDR) distribution is the key to calculate distributions of hillslope sediment delivery and adsorbed non-point source pollution load. Based on the established formula of HSDR, and considering that the overland runoff formed by rainfall is the direct driving force of hillslope sediment delivery, the existing "flow connectivity" index is improved, and the "runoff connectivity" index is proposed. The spatial and temporal distributions of HSDR are developed. The sediment transport model is established by combining the HSDR formula with the modified general soil loss equation. Taking the Daning river basin in the Three Gorges Reservoir Region as an example, the rationality of the constructed HSDR formula is compared and analyzed by the simulation of sediment delivery amount. Results show that the HSDR based on the runoff connectivity index is more reasonable and the simulation precision is better.