Groundwater Quality Assessment of Nandyal district using Geographical Information System

Nandyal district was situated on west side of Nallamala of Eastern ghats range in Andhra Pradesh. The physiography of the district acts as catchment and basin for Kundu river drain a rivulet to Penna river of Andhra Pradesh. Groundwater samples of Nandyal district were analyzed for various properties viz., pH, EC, Ca⁺², Mg⁺², Na⁺ and K⁺; CO^-2₃, HCO^-₃, Cl^- and SO^-2₄. The pH, EC, SAR, RSC, Kelly’s ratio (KR), soluble sodium percentage (SSP) and permeability index (PI) in groundwater ranged from 6.5 to 8.4, 0.2 to 22.0 (dSm^-1), 0.18 to 34.1 (mmol l^-1)^½, -91.2 to 7.6 (me l^-1), 0.07 to 10.9, 6.99 to 88.45 and 32.79 to 110 respectively. The relative abundance of ions for most of the water samples were Na⁺> Ca⁺²> Mg⁺²> K⁺ for cations and HCO^-₃> Cl^-> SO^-2₄> CO^-₃ for anions. The irrigation water quality of groundwater classified as good (66.67%), marginally saline (19.75%), saline (3.29%), high SAR saline (7.41%), marginally alkali (1.65%), alkali (0.41%) and high SAR alkali (0.82%). Based on thematic maps developed using inverse distance weightage method in geographical information system, the poor quality groundwater was observed in Midtur, Nandyal, Gadivemula, Gospadu, Koilakuntla, Dornipadu, Uyyalawada, Chagalamarri,Allagadda mandals of Nandyal district.