FINDING CAUSES OF GROUNDWATER FLUCTUATIONS IN QUETTA BASIN, PAKISTAN

Quetta Basin in Western Pakistan has frequently experienced shortage of groundwater. In recent years water availability has been compromised as indicated by a sharp decline in water table level in many locations. Dropping water level has been coupled with simultaneous rise in ground water levels in other areas of the Quetta Valley. The study of groundwater resources in this basin is an attempt to understand the causes of such water level fluctuations. Currently, there are two hypotheses explaining this water disequilibrium. The first hypothesis states that rising aerial temperatures could potentially reduce annual average snowfall and ultimately the groundwater recharge as well. The second hypothesis states that population expansion has led to an increase in groundwater usage and to dropping of water table. This work tests these two hypotheses by integration of climatological, hydrological and land-use data for the basin. Geographic Information System (GIS) software ArcGIS has been utilized to integrate and analyze relevant data sets. We are currently conducting the following investigations to address problem described above: (1) temporal changes in the temperature of the Quetta Valley are being examined in the context of global temperature change, (2) spatial and temporal variations in the amount of precipitation and snow cover are being examined in relation to observed water table fluctuations, (3) Urban expansion and land use change is being investigated using temporal satellite images and is here used as a proxy for monitoring population increase. Our preliminary results indicate that water fluctuations are apparently caused by a combination of climatologic and anthropogenic factors. Different water sources could have also contributed to this unique and problematic water level fluctuations in Quetta basin. This research provides basis for future work which will involve detailed hydrological modeling and water quality studies.