应用输沙量推演流域侵蚀量的方法探讨

鉴于至今还没有一个有效获取流域侵蚀产沙量的方法,在分析悬移质泥沙与侵蚀泥沙之间的数量与粒配关系的基础上,阐述了应用输沙量推演流域侵蚀量在理论上的可能性,但却存在着难点,且主要表现在水文站数量不足与区域分布不均、流域内的生态环境复杂与区域差异大、水文站输沙量观测记录起始时间不同步、及新技术应用存在时空条件的局限性。结合与侵蚀产沙和泥沙输移比相关的定性与定量指标,提出了应用输沙量推演流域侵蚀量的方法,即"层次类剔法",来计算与评估流域侵蚀量和泥沙输移比,具体的操作过程是首先制作一幅流域地貌类型地块图,然后是逐类型、逐类型地块的侵蚀量计算和沟道流域泥沙输移比的判断,最终获取流域不同地块的侵蚀强度和流域泥沙输移比。本研究结果可为水土流失监测点的选择提供科学依据,同时对解决流域的泥沙问题也有重要的启迪作用。

Method of deducing soil erosion amount of drainage basin with sediment discharge

Owing to no effective methods to obtain soil erosion amount of drainage basin at present,the possibility of deducing soil erosion amount of drainage basin with sediment discharge of hydrological stations was analyzed according to the quantitive and grain size relationships between suspended sediment and eroded soil.This possibility is existing,but has difficulties,i.e.insufficient amount of hydrological stations and their unevenly regional distribution,regional diversity of environment in a drainage basin,different time series of sediment records of hydrological stations,and space-time restriction of new technology application.Combining with the qualitative and quantitative indexes related to soil erosion and sediment delivery ratio,a method of deducing soil erosion amount of drainage basin with sediment discharge,namely "relief-plot hierarchy analysis method",was put forward to calculate and estimate the soil erosion amount and sediment delivery ratio of drainage basin.The approach is firstly to draw a relief-plot type map of a studied drainage basin,then to calculate soil erosion amount of plots in different relief types and estimate the sediment delivery ratio of gully,and finally to get the erosion intensity of different plots and sediment delivery ratio of drainage basin.The study could provide scientific basis for choosing observation stations of soil and water loss,and has an initiative role for resolving the sediment problems in drainage basin.