Evaluation of Water Quality of Beheshtabad Watershed Rivers using Different Methods (with Emphasis on Irrigation)

Various indices are used to assess the suitability of water quality for drinking and agricultural uses. The aim of this study is to investigate the water quality of rivers in Beheshtabad watershed for irrigation purposes. Some water quality parameters were measured in 4 selected stations monthly during spring and summer 2013 and 2019 with using the standard methods. Then, SAR, RSC, SSP, KR, PI and MAR indices were calculated. According to the results, the water quality of the stations was in good condition in terms of PI with values less than 80 mg/l, was in good condition in terms of KR with values less than one and in terms of SSP with values less than 200. The water of the studied rivers was hard in terms of total hardness, sweet in terms of total dissolved solids, and had a good condition in terms of permeability index, residual sodium carbonate, soluble sodium percentage, Kelly’s Ratio, magnesium adsorption ratio indices. According to water quality indices, water quality did not change in 2019 compared to 2013. According to the Wilcox diagram, the water of these rivers were in class C2S1, suitable for agricultural use, and according to the Piper diagram were located in Bicarbonate-Magnesium-Calcium group, in the category of water with temporary hardness. In general, evaluation of water quality of these rivers showed that the water of these rivers did not have limitation in terms of agriculture and were almost acceptable and suitable for irrigation.