Variation Trend of Runoff in Fujiang River Catchment and Its Responses to Climate Change

Variation of runoff in the Fujiang River catchment was analyzed with Mann-Kendall method.Based on hypothetical scenarios and projections of HADCM3,responses of runoff to climate change were simulated using a simple water balance model.The results indicate that the recorded runoff in the Fujiang River catchment presented decreasing trend during 1955-2000,which mainly resulted from climate change.Although human activities across the catchment did put much effect on annual runoff amount,it altered seasonal distribution of runoff to some extent.The adopted monthly water balance model performed well for discharge simulation.The recorded and simulated discharges match well in general,except a little bit underestimation for some peak discharges.Relationship between changes in precipitation and changes in runoff under the fixed temperature change is a linear approaching.Under the same changes in precipitation,a unite change in temperature will result in an approximate change in runoff.Although projected runoffs under the different emission scenarios are different,water resources in the Fujiang River catchment will likely undergo decreasing trend,especially during the period after 2030,the decreasing range could beyond 5% as comparing to baseline in 1961-1990.