Integrating GIS and irrigation water quality index approaches for identifying groundwater irrigation potential zones in Central Gujarat, India

In this study, groundwater irrigation potential zones are identified by measuring an integrated irrigation water quality index using a GIS platform in the Vishwamitri River Basin (VRB) region, Gujarat, India. Classification of different irrigation potential zones is about the collective paraphernalia of thematic maps, namely, electrical conductivity (EC), sodium adsorption ratio (SAR), Na+, Cl−, and HCO3−, which principally regulate the groundwater quality for irrigation. The EC, SAR, and chloride values are > 3000 µS/cm, > 9 meq/L, and > 10 meq/L, respectively, indicating 98.78%, 41.78%, and 84.88% of the total area, respectively, belong to groundwater both hazardous and unsuitable for irrigation. Similarly, 39.55% of the total area is unsuitable for irrigation due to its high Na+ concentration. The permeability, porosity, and infiltration risk usually appear when excessive sodium ions reduce the rate of flow of irrigation water which moves in the lower soil zones. Similarly, high bicarbonate and chloride concentrations have been denoted to hamper the development of several crops causing symptoms analogous to lime-induced chlorosis due to toxic effects of the salt. The final irrigation potential map is marked by four levels, such as “most suitable,” “moderately suitable,” “moderately unsuitable,” and “unsuitable for irrigation.” Approximately, 56.69% of the total VRB region are covered with unsuitable for irrigation purposes. In such areas, irrigation must be avoided in usual conditions, and the halophytes, namely, Khati palak (Atriplex stocksii), Lamb’s quarters (Chenopodium album), and Rudravanti (Cressa cretica) should be recommended with high soil permeability and proper drainage facilities. The soil must be highly permeable for groundwaters with high salinity and sodicity. Based on this study, policymakers and environmental managers can estimate the resource implications for drinking and irrigation.