PLANNING WATER RESOURCE MANAGEMENT IN PISHIN-LORA BASIN OF BALOCIDSTAN USING GIS

Abstract

The recent drought (1998-2004) in water deficient province of Balochistan affected the availability of seasonal rainwater and vegetation cover. The growth rate of tubewells increased and over-abstraction of groundwater continued during the drought period, particularly in Pishin-Lora river basin which is the most populous river basin out of 13 river basins in Balochistan. As a result, acute depletion in water table was observed in this river basin. The capabilities of Geographical Information Systems (GIS) and Remote Sensing (RS) were utilized to study the impacts of recent drought on volumes of seasonal rainwater as well as the seasonal vegetation cover in the province of Balochistan. The reduction in rainwater was apparent during both summer and winter seasons of the drought period, which affected the vegetation cover negatively. In addition, a historical trend of reduction in summer and winter season vegetation cover was observed. The summer drought ended in 2005 when exceptional rainfall disrupted the persistent summer drought and the volume of rainwater increased, whereas the winter drought persisted in 2005 as well. The reduction in rainwater availability during the drought period, being responsible for reduction in groundwater recharge, exacerbated the issue of groundwater depletion, especially in Pishin-Lora river basin. The spatial analysis conducted in Pishin-Lora river basin using four parameters, surface slope, drainage network, lithology and settlements, revealed that about 50 per cent of the basin has medium to high potential for recharging groundwater. Further analysis of the potential recharge sites along with surface slope, drainage network and settlements revealed that 3 per cent area of the basin was suitable for siting delay action dams.