Abstract: In order to test applicability of the MIKESHE model in the Chaohe watershed,and to examine impacts of the changes on decadal runoff of the Chaohe River over the past 45 years,the MIKESHE model was applied to the research in the Chaohe watershed.After calibrating the model with a multi-site calibration procedure,hydrological impacts of changes in land use and precipitation were disentangled by running scenario simulations.Results show that the model was generally good at simulating the average runoff and the dynamic variation of the runoff in the watershed,although the modeling performance was less satisfactory in the Dage Station than in the Xiahui and Daiying Stations,with Nash-sutchliffe coefficient for the three stations being 0.56 and 0.49,0.65 and 0.69,and 0.57 and 0.68 for the calibration and validation periods,respectively.Compared with the reference period(1963 to 1979),the period from 1980 to 1989 witnessed a sharp decrease,ca 22 mm,in annual runoff in the watershed,to which changes in land use and precipitation contributed almost equally,accounting for 59% and 41%,respectively.The period from 1990 to 1999 did not see much change in annual runoff as compared with the reference period,which was owing to the hydrological impact of the change in precipitation being offset by that of the change in land use during this period.And the period from 2000 to 2008 had its annual runoff cut by 35 mm,of which 80% was attributed to the change in precipitation and 20% to that in land use.

Key words: MIKESHE model, land use change, precipitation variation, hydrological impact, Chaohe watershed