Long-term assessment of water quality and soil degradation risk via hydrochemical indices of Gharasoo River, Iran

The suitability of Gharasoo River water for irrigation uses was evaluated in Kermanshah city, Iran. Long-term datasets including major cations, anions and other parameters such as electrical conductivity (EC), total dissolved solids (TDS) were analyzed. Sodium absorption ratio (SAR), magnesium ratio (MR), % sodium (%Na), residual sodium carbonate (RSC), permeability index (PI) and Ca2+/Mg2+ ratio were calculated to evaluate the suitability of Gharasoo River water for irrigation purposes. Piper trilinear diagram reveals that the water is the alkaline earth than alkaline type. Based on the SAR values plotted in the U.S. Salinity Laboratory Staff diagram, Gharasoo River water belongs to class medium-salinity hazard and low-sodium hazard (C2S1) which indicates that there is no limitation to use water for irrigation. According to FAO method, soil degradation risk was low in the study area and potential plant nutritional disorders will not be expected. Different indices showed the regional sodicity problems: the high risks for %Na, PI, Ca2+/Mg2+ and magnesium ratios for soil and clogging of irrigation systems only at one station.