Hydro-Geomorphology and Hydrogeology of the Pennar River Basin, India: Implications on Basin Scale Surface and Ground Water Resource Management

The Pennar river basin covering an area about 58,479 km² has been studied to delineate the landforms, structural features, and hydro-geomorphic units, ground water level variations, fluctuations and recharge. The landforms are classified into denudational, fluvio-denudational, fluvial, aeolian and coastal categories. Hydro-geomorphologically, the deltaic plains and fluvial plains are grouped under excellent ground water potential, irrigated plains other than fluvial and deltaic plains as good ground water potential, wash plains, valley fills, piedmont plains and creep built plains as fair ground water potential, shallow and moderately weathered pediment plains as poor ground water potential and slope zones of hilly terrain as run-off zones. The Pennar Basin consists of Archean unclassified granitic terrain in the western and southern parts of the basin followed by Proterozoic formations consisting of shales, quartzites and limestone in the central parts of the basin and Quaternary and Holocene sediments in the eastern side. Hydro-geologically the ground water potential is high in the weathered, fissured, fractured and faulted zones of the basin. The ground water potential in the Archean granitic terrain is very poor. The ground water potential in Quaternary and Recent sedimentary formations is good. Thus, the study of land forms in terms of their causative agents, associated lithological and hydrogeological characteristics and categorizing them into hydro-geomorphic units helps to evaluate and manage water resources efficiently.