Irrigation risk assessment of groundwater in a non-perennial river basin of South India: implication from irrigation water quality index (IWQI) and geographical information system (GIS) approaches

Groundwater is an important natural resource for irrigation purpose in the non-perennial River basin (Shanmuganadhi) of South India. The present investigation was conducted to determine the groundwater suitability for irrigation purpose, using irrigation water quality index (IWQI) with the application of GIS. A total of 61 groundwater samples collected from the present study region were chemically analyzed such as TDS, EC, pH, Ca2+, Mg2+, Na+, K+, HCO3-, Cl-, and SO42-. Groundwater quality shows slight alkalinity (7.11-7.95). The Wilcox, USSL, and Doneen's diagrams, and RSC, KR, and MHR indices indicate that maximum groundwater sampling locations fall under the unsuitable category for irrigation purpose. According to the classification of IWQI, 57% of the total groundwater samples belongs to the poor to unsuitable water quality types for irrigation. The spatial distribution of IWQI displays that 77.27% of the present study region comes under the vulnerable zones such as moderate restriction (51.99%, high restriction (23.10%), and severe restriction (2.18%) water quality for irrigation purpose. Therefore, the present study suggests the suitable treatment methods for increasing the soil permeability and thereby to improve the crop production.