Assessment of Natural Groundwater Recharge in the Tungabhadra River Basin of Kurnool District, Andhra Pradesh, India

Groundwater plays a critical role in sustaining human health, economic development, and ecological balance. Its effective management requires accurate estimation of recharge rates, especially in regions with limited hydrological data. This study focuses on estimating natural groundwater recharge in the Tungabhadra River basin, located in the northwestern part of Kurnool district, Andhra Pradesh, India. Using a 30-year rainfall dataset from nine rain gauge stations, recharge estimates were derived through eight empirical formulae: Radha Krishna (1974), U.S. Geological Survey Method (1962), Chaturvedi (1936), Amritsar (1973), U.P.I.R.I. (1954), Bhattacharjee (1954), Kumar and Sethapathi (2002), and Krishna Rao (1970). The results revealed significant variability in recharge estimates, with values ranging from 66.75 mm to 203.16 mm annually. The average recharge across all stations was 115.27 mm, representing 17.26% of the total annual rainfall. The analysis also highlighted moderate variability in recharge values, with the Coefficient of Variability (CV) ranging from 5.07 to 13.66. The study's findings underscore the importance of selecting appropriate empirical models based on the availability of data and the need for using multiple methods to ensure robustness and reliability in groundwater management strategies