黄土丘陵沟壑区典型流域径流输沙对土地利用/覆被变化的响应

基于动力水文过程测定技术和景观生态学测度方法，对位于黄土丘陵沟壑区第三副区的甘肃天水罗玉沟流域1986—2004年土地利用/覆被变化对流域径流输沙的影响进行了研究.结果表明：研究期间，罗玉沟流域土地利用/覆被变化对年径流输沙有显著影响，1995—2004年的输沙量比1986—1994年减少约63.0%，且随着年降水量的增多，其减沙效应明显;土地利用/覆被变化对流域径流输沙的影响具有季节性特征，相对于1986—1994年而言，研究区1995—2004年的减沙效应主要集中在5—10月，且月降水越多，后期的月均输沙量较前期减少得越多.降雨和洪峰流量频率分析表明，若具有相同频率分布的雨强，则任一重现期下罗玉沟流域1995—2004年的洪水平均含沙量小于1986—1994年.

Effects of land use/cover change on runoff sediment discharge in typical watershed in Loess gullied-hilly region of China.

By using the measurement technique of dynamic hydrological process and the estim ation method of landscape ecology, this paper studied the effects of 1986〖KG-*2 〗-〖KG-*7〗2004 land use/cover change (LUCC) on the runoff sediment discharge i n the Luoyugou watershed in Tianshui of Gansu Province in third sub-region of L oess Plateau. The results showed that the LUCC in Luoyugou watershed had signifi cant effects on the annual sediment yield. In 1995〖KG-*2〗-〖KG-*7〗2004, the s ediment discharge was reduced by approximately 630%, compared with that in 198 6〖KG-*2〗-〖KG-*7〗1994, and the reduction effect was more significant with inc reasing annual precipitation. The effects of LUCC on sediment discharge demonstr ated seasonal fluctuation characteristic. Relative to that in 1986〖KG-*2〗-〖KG -*7〗1994, the reduction effect of sediment discharge in 1995〖KG-*2〗-〖KG-*7〗 2004 was more concentrated in the period from May to October, and, the more the monthly precipitation, the more the reduction of monthly average sediment discha rge in 1995〖KG-*2〗-〖KG-*7〗2004 than in 1986〖KG-*2〗-〖KG-*7〗1994. The anal ysis on precipitation and flood peak discharge frequency indicated that under th e same frequency distribution of precipitation intensity, the average sediment c oncentration in any recurrence period in Luoyugou watershed was smaller in 1995 〖KG-*2〗-〖KG-*7〗2004 than in 1986〖KG-*2〗-〖KG-*7〗1994.