عنوان مقاله [English]
The Karun basin is one of the most important water supply sources in the country. However, no comprehensive study has been done on rainfall and river flow in this basin. According to importance of subject, in this study the trend changing of rain and river flow of the Karun basin in 74 meteorological stations and 46 hydrometric stations in three monthly, seasonal and annual periods using non-parametric mann-kendall test. (TFPW-MK).
The results showed that the trend of more than 82 percent of the stations on annual basis are descending and. On monthly scale, the most precipitous months of the year (Day, Bahman and Esfand) have decreasing trend, and the trend of more than 99% of stations in the month of Esfand (73 stations) having a decreasing trend. On seasonal scale, 50.5% of annual rainfall in the basin occurs in the winter. In this season trend of more than 45 percent of the stations (32 stations) in the winter season are descending trend rates in significant. Due to the decreasing trend of rainfall variation in the catchment area, the river flow should be reduced, and the results of this research confirm this point. The results showed that the trend of more than 82 percent of the stations on monthly basis are descending trend and 63 percent of the stations are descending trend rates in significant.