Integrated approach for delineating potential zones to explore for groundwater in the Pageru River basin, Cuddapah District, Andhra Pradesh, India

Hydrogeomorphological, hydrogeological and geophysical investigations were carried out in the Pageru River basin of Cuddapah district, Andhra Pradesh, to delineate potential zones for future groundwater exploration. The study area is underlain by Proterozoic formations of the Indian Peninsula comprising limestones and shales as the sedimentary cover. Limestone and shale formations of the Cuddapah Super group that are later overlain by the Kurnool group (shale, limestone and quartzite) are exposed extensively. The high drainage density (2.61 km/km²) in the western region also suggests that the area is characterized by low permeable zones compared with low drainage density (1.04 km/km²) of the flood plains, which form the potential aquifers in the east. The hydro-geomorphological data are further supported from evidence of the water-table fluctuation in wells and resistivity of the saturated formations. The results indicate that the favourable, moderately favourable and poor zones characterized geomorphologically, have water-level fluctuations in the range of 0–2, 2–6 and above 6 m, respectively. The resistivities of these zones are also in the range of 1–26, 40–466, and >1,900 ohm-m. A few pumping tests have also been conducted to assess the broad range in the values of aquifer parameters. Based on these data, good to poor potential zones for obtaining groundwater have been delineated in the study area.