风水两相作用和人类活动对无定河粗泥沙输沙量的影响

风沙活动、降雨和人类活动是干旱-湿润过渡区影响粗泥沙(d>0.05mm)入黄的几个重要因素。粗泥沙输沙量的变化取决于全沙输沙量和粗泥沙在全沙中所占的比例。基于悬移质输沙量和泥沙粒径构成、降雨量、沙尘暴日数和水土保持面积等数据,分析了粗泥沙输沙量与影响因素之间的关系,利用Arc-GIS和SPSS软件定量分析了影响无定河流域代表自然过程的风水两相作用和人类活动对粗泥沙输沙量的影响,并通过回归分析确定了不同影响因素对全沙输沙量和粗泥沙比例的贡献。结果表明,影响全沙输沙量的主要因素是降雨量和水土保持措施,而影响粗泥沙比例的是风沙活动和水土保持措施。利用二元回归分析确定了各因素的贡献比例,认为降雨量的减少和人类活动对全沙量减少的贡献相当,人类活动对粗泥沙比例降低的贡献高于风沙活动的作用。

Effects of Interactive Fluvial and Aeolian Processes Along with Human Activities on Coarse Sediment Yield in Wudinghe River Basin

Aeolian activities,precipitation and human activities are the main factors affecting the delivery of the coarse sediments(0.05 mm) from the transition zones of arid and humid areas into the Yellow River in Northern China.The variations of coarse sediment transportation are determined by the total sediment yield and the percentage of coarse sediment.Based field collected suspended sediment yield,grain size of suspended sediment,precipitation,events of sand-dust storms and areas of soil and water conservation measures,the relationship between coarse sediment yield and its influencing factors were investigated in the basin of Wudinghe River.Both total sediment yield and proportion of coarse sediment in the total yield were used to describe the dynamics of coarse sediment transportation.Effects of physical process,referred to as the interactive fluvial-aeolian process,and human activities on the generation of the coarse sediment were studied,and the relationships between the two parameters and the influencing factors were investigated using geographic information system(ArcGIS) and statistical software(SPSS 12.0).The contribution of fluvial-aeolian changes and human activities to coarse sediment ratio and the total suspended sediment yield was analyzed using multivariate regression.The results showed that total suspended sediment yield correlated closely with the amount of precipitation and the area of soil and water conservation measures.The coarse sediment ratio was linked closely with aeolian factors and the area of soil and water conservation measures.It was also found that the contribution of precipitation to total suspended sediment yield was almost equal to that of human activities,while the contribution of human activities to the reduction of coarse sediment ratio was higher than that of aeolian activities.