Long-Term Changes Trend Analysis in Rainfall and Discharge in West Lake Urmia

Discharge and rainfall are important factors in climate parameters، as their prediction and the identification of their behavior is important for water resources management. To evaluate the long-term changes in climatic factors، i. e. discharge and rainfall، in west Lake Urmia، six stations have been used over a period of 30 years from 1977-2007. In this research، the trend analysis is done by the R software and nonparametric statistical methods (Mann - Kendall and seasonal Kendall test) were studied. The results showed that the rainfall has no trend in some stations and with a negative trend in the others. But، discharge is in most cases has a significant decreasing trend. According to the study area، this decreasing trend is in agreement with the global climatic changes in the northern 30◦- latitude. The results of this study can be used for water management programs in future planning.