Suitability of groundwater quality for irrigation in and around the main Gadilam river basin on the east coast of southern India

Abstract

The main intent of this study was to investigate the condition of groundwater quality for irrigation purposes in and around the main Gadilam river basin, the east coast of southern India. A total of fifty groundwater samples were collected and analyzed for various parameters such as electrical conductivity (EC), pH, TDS, major cations (Ca2+, Mg2+, Na+, and K+) and anions (SO42-, Cl-, HCO3-, and NO3-). Irrigation water quality parameters like the sodium absorption ratio (SAR), residual sodium carbonate (RSC), percentage sodium (%Na), magnesium hazard (MH), permeability index (PI), and Kelly ratio (KR) were computed to assess the irrigation water quality of groundwater. Furthermore, graphical representation diagrams such as USSL, Wilcox, and Doneen have been prepared for irrigation water quality. From the computation of SAR, Na%, RSC, PI, and KR values, it was found that 100% of groundwater samples were found to be suitable for irrigation purposes. Besides, USSL and Doneen diagrams show that the samples are safe for irrigation usage. The Wilcox diagram in the classification of electrical conductivity reveals that most samples fall into the good to permissible class (78%), in doubtful to unsuitable class (20%), and 2% of samples are unsuitable. Magnesium hazards of 82% of the groundwater samples are suitable for irrigation, while the remaining 18% of the samples exceeded the limit and found to be unsuitable for irrigation purposes. The study concludes that higher percentages of groundwater samples were suitable for irrigation purposes in the study area, and the concentration of magnesium influenced groundwater at a few locations.