Abstract: The changes in hydrology in the Yehe catchment,an important branch of the Hutuo river,from climate fluctuation and land cover changes during 1971-2000 were analyzed.During this period,Yehe basin experienced decreases in annual precipitation and the annual temperature increased significantly,especially during the winter period from November to February in the following year.During the study period,the total change in area of each land use,including grass,forest,farmland(irrigated and non-irrigated) and others was not obvious.However in 1995,the forest and densely grass coverage dropped fast,the farmland area increased to a maximum of 29.75%.Over time,irrigation area of farmland gradually increased.For instance,irrigation area of Xiyang city was only 1 190 ha in 1990,but in 2000 it reached 3 109 ha.In the meantime,the hydrological system changed significantly.To 2000,the land coverage recovered in 1980.Annual streamflow decreased considerably and the downward trend was more significant than that of annual temperature and annual precipitation.Especially after the 1980s,the annual runoff decrease was serious and some of the upstream rivers dried up.

Key words: Climate fluctuation, Land cover change, Hydrological effect

CLC Number: 

• S162