Evaluation of spatial variability and irrigation water quality of groundwater in Prakasam district of Andhra Pradesh

Astudy was conducted in the year 2021 to evaluate spatial variability and irrigation water quality of groundwater in Praksam district, Andhra Pradesh. Representative 261 samples with GPS locations were collected. The groundwater samples were analyzed for pH, EC, Ca⁺², Mg⁺², Na⁺ and K^+-; CO^-23, HCO^3-, Cl^- and SO^-2₄. The pH, electrical conductivity, SAR and RSC of groundwater ranged from 6.6-9.1, 0.5-31 (dSm^-1), 0.42-40.6 (mmol l^-1)1½2, -146 -19.4 (me l^-1). The concentration of cations viz., Ca⁺², Mg⁺², Na⁺ and K⁺ varied from 0.8-48.0, 0.4-105, 0.7-355 and 0.004-30.04 meql^-1. Anions viz.,CO^3-2, HCO^3-, Cl^- and SO^4-2 varied from 0.0-1.4,1.6-21.8,0.8-318 and 0.21-17.08 meq L^-1. Abundance of ions in ground water samples were Na⁺> Mg⁺²>Ca⁺²> K⁺ for cations and HCO₃> Cl > SO₄^-2 > CO^3- for anions. According to CSSRI classification of irrigation water, 37.16, 27.20, 2.29, 8.81, 9.19, 6.89 and 8.42 per cent samples were good, marginally saline, Saline, High SAR Saline, marginally alkaline, alkali and highly alkali, respectively. Spatial variability maps of pH, EC, SAR, RSC and quality of groundwater for Prakasamwere developed for monitoring of irrigation groundwater quality of the district.