Simulation of Flow in Weathered-Fractured Aquifer in a Semi-Arid and Over-Exploited Region

Abstract

The granites in and around Hyderabad, India, form part of the largest of all granite bodies recorded in Peninsular India. Alcaline intrusions, aplite, pegmatite, epidote, quartz veins and dolerite dykes traverse the granite. There are three types of fracture patterns (Fig. 1) in the area, viz. (i) mineralised or weathering fractures, (ii) fractures traversed by dykes, and (iii) late-stage fractures represented by joints. The vertical fracture pattern is partly responsible for the development of the weathered zone and the horizontal fractures are the result of the weathering. Hydrogeologically, the aquifer occurs both in the weathered zone and in the underlying weathered-fractured zone. The Maheshwaram watershed of about 53 km² in the Ranga Reddy district (Fig. 2) of Andhra Pradesh, India, is underlain by granitic rocks. This watershed is a representative Southern India catchment in terms of overexploitation of its weathered hard rock aquifer, its cropping pattern, rural socio-economy, agricultural practices and semi-arid climate. The objective of this study is to develop and test well-suited modelling approaches to simulate the flow in the existing aquifer system that consist of two layers with any separating strata.