عنوان مقاله [English]
In this paper temporal and spatial trend of water quality in the Karun basin were examined from upstream to downstream. To assess the trend of change, 16 stations with a statistical period of 37 years (1353-1390) were selected. Station scattering was considered to cover the whole basin. In order to analyze the trend, the MK test was performed and according to this test, the discharge has decreased throughout the basin, except for the southeastern part of the basin. Changes in z statistics for the quality parameters were higher at Ahwaz and Shushtar stations located below the basin and at a significant level of 1%. After analysis of the concentration of anions and cations along with the type and facies of water, it was determined that Ahwaz, Gotvand and Shushtar stations have chlorine, Sodic facies and other stations with Bicarbonate and Calcic type. The quality of drinking water in the stations has decreased from the upstream to the outlet of the Karun basin and the worst quality is related to stations in Ahwaz, Gotvand and Shushtar, which are within acceptable limits. In the Investigation of agricultural water quality, also determined Ahwaz, Gotvand and Shushtar are located in the C3S1 and other stations in the C2S1. The results show that the water quality of the Karun basin has decreased from the upstream to downstream.