黄土丘陵沟壑区典型流域土地利用变化对水沙关系的影响

Effects of Land Use Change on Runoff-Sediment Relationship at Watershed in the Loess Hilly Region

以黄土丘陵沟壑区内相邻的2条支沟(桥子东沟和桥子西沟)为研究对象,基于遥感影像获得土地利用数据,利用水文站1986-2004年观测的次降雨-径流-泥沙过程资料,研究了小流域土地利用变化(主要以增加水土保持措施为主)对径流输沙的影响。结果表明:在黄土丘陵沟壑区,增加土地利用/土地覆被能够有效地减少小流域的径流量、产沙量;在次降雨量、降雨强度较小,土地利用变化不明显的情况下,两流域次降雨水沙关系差异不显著,在次降雨量、降雨强度较大和土地利用变化明显时,两流域次降雨水沙关系差异显著,坡耕地改梯田的农田水利建设可能是导致水沙变化的主要原因。

Taking Qiaozidonggou and Qiaozixigou watershed as examples in the loess hilly region,using remote sensing image to obtain land use data,based on the observed rainfall,runoff and sediment data during 1986-2004,this paper analysed the effects of land use change on runoff-sediment relationship.The results showed that in the loess hilly and gully areas,increasing land use/land cover can reduce effectively the watershed runoff and sediment yield;when rainfall and rainfall intensity were smaller,land-use change was limited and the runoff-sediment relationship had no significant differences.When the rainfall and rainfall intensity and land-use change were significant,the difference of runoff-sediment relationship was obvious.It might be the main reason for sloping land changing into terraced land.