Groundwater Quality Assessment for Sri Sathyasai Puttaparthy Region of Andhra Pradesh using Geographical Information System

The study area falls under scarce rainfall zone of Andhra Pradesh, groundwater is the major source of irrigation, two hundred and thirty one (231) groundwater samples were collected and were analyzed for water reaction, conductivity, ionic composition. The suitability was correlated based on the EC, sodium adsorption ratio (SAR), residual sodium carbonate (RSC), permeability index (PI), Kelly's ratio (KR), soluble sodium percentage, irrigation water quality index (IWQI). Inverse distance weightage interpolation method used in geographical information system to develop spatial variability maps of pH, EC, SAR, RSC and groundwater irrigation quality. The analysis of groundwater showed the pH of groundwater falls in the range of 6.8–8.4, EC 0.1–4.2 dSm⁻¹, RSC -19.4 to 8.0, SAR 0.45–8.59, KR 0.20–3.69, PI 20.32–105.63 and SSP 12.6–71.78. The irrigation water quality index (IWQI) falls in the range 14.9–192.34. As per the AICRP criteria 64.50% reported good, 20.78% marginally saline, 0.43% saline, 6.93% marginally alkaline, 7.36% alkali in quality for irrigation.