REVIEW OF HYDROGEOLOGY OF TEKEZE RIVER BASIN: IMPLICATIONS FOR RURAL AND URBAN WATER SUPPLY IN THE REGION

Abstract

This paper reviews the available published and unpublished data on the geology, hydrology and hydrogeology of the Tekeze River Basin (trb) with the aim to better conceptualize the hydrodynamics of the basin and its implications on the water resources potential for the development of rural and urban water supply system.  The work also highlights some of the knowledge gaps to fully understand the hydrogeology of the basin and proposes better scientific approach that will lead to the understanding of the movement and occurrence of groundwater in the complex river basin. The trb constitutes different rock types with ages ranging from Precambrian to Quaternary. These rocks are affected by different sets of faults, folds and lineaments with different orientations. The groundwater occurrence and flow is strongly controlled by the geomorphology, geological structures, type of rock and their hydraulic characteristics. The major aquifers in the basin are the Trap Basalts, the Antalo Limestone Formation, the Adigrat Sandstone and Quaternary sediments. An increase in permeability in shales and marls is observed due to the presence of dolerite dykes and sills. The Neoproterozoic basement rocks and associated intrusive bodies, and the Paleozoic sediments are characterised by shallow and localised aquifers. In many places the igneous intrusive bodies act as aquicludes. The major faults and associated drag folds in the basin form favourable conditions for groundwater recharge and groundwater localisation irrespective of lithology.