Document Type : Research Paper
Urmia Lake is the largest lake in the country which during recent years faces a dramatic reduction in the water level. Many reasons such as climate change, continuous droughts, development of cultivation and land use changes as well as construction of dams were mentioned, but the provided reasons have less been well documented by scientific evidences. This study is an attempt to investigate the later problem with scientific point of view. In this regard, the effects land use changes on Ajichai river on Urmia Lake were investigated.In order to evaluate the land use change impacts, Landsat images of 1976, 1989, 2002 and 2008 years were considered as inputs to SWAT model and under the same input data, models were calibrated within the year of their application. All four models were run monthly for years from 1976 to 2008. Output results of four models indicated significant 51% output water volume reduction and increase actual evapotranspiration rate 13% during these years for the basin. Generally, Results from this paper showed that the land use change has effective role on reduction in the water level of the lake in three past decades.