Effect of Geological and Geomorphological Factors on Gotvand Dam Water Quality

Abstract

This research aimed to investigate the effect of geological and geomorphological factors on the water quality of Gotvand Dam in Iran. Given the role of geomorphological parameters in water quality, the water quality indices were analyzed in the Excel and Chemistry applications. Water quality was evaluated by analyzing water samples obtained from the Statistical Data Center of Water and Power Organization of Khuzestan, and the total dissolved solids (TDS), electrical conductivity (EC), and pH of water were measured using the Mann-Kendall test. Then the effect of geomorphological factors on the physicochemical properties of the Karun River was assessed. The qualitative variables were pH, EC, and TDS in the statistical period of 2006–2021. The results of the Mann-Kendall test showed an insignificant decreasing trend in the TDS series in the Gotvand station. Meanwhile, August had a significant increasing trend in TDS, and considering the calculated Sen’s slope, this parameter increased by 35% in the last 15 years (2006–2021). Like TDS, EC had both increasing and decreasing trends of changes. On the monthly scale, pH had a significant decreasing trend, meaning that the water is acidified, which severely affects the downstream fields and reservoirs. In the Gotvand station, the trend of changes in TDS and EC increased in 11 and 12 months of the year, respectively.