THE CONJUNCTIVE USE OF GROUNDWATER MODELING AND GEOGRAPHIC INFORMATION SYSTEM (GIS) TO STUDY THE WATER RESOURCES OF UPPER JHELUM SCARP AREA IN INDUS BASIN

A three-dimensional numerical groundwater flow model was developed in conjunction with Geographic Information System (GIS) and Remote sensing (RS) techniques for Upper Chaj Doab area of Indus basin, Pakistan. The approach has provided efficient way of analyzing and monitoring groundwater resource of the area. The GIS was used as additive tool to develop supportive data for numerical groundwater flow modeling, integration, analysis and presentation of image processing and modeling results. The thematic layers of landforms, landuse, hydrology, infrastructure and climate were developed using Geographic Information System (GIS). The RS data was used to analysis surface hydrological conditions and landcover/landuse status in order to conceptualize the recharge/discharge sources involved in groundwater system and to observe the behaviour of waterlogging and salinity in the area.A steady-state model was calibrated for 1985 hydrologic conditions when water levels in the aquifer were near equilibrium. The model was calibrated to an average residual of 0.06m and variance of 1.46m using automatic parameter method - PEST. The model was calibrated again in transient-state condition over a six-month period of wet period using steady-state heads as initial condition. Using the model, values of recharge, hydraulic conductivity and specific yield were calibrated for the aquifer.The calibrated model was used to predict future changes in piezometric heads from year 2006 to 2020. The piezometric heads indicated initially a rising trend from 1988 to 1999, then a declining trend from 1999 onward from where a breakthrough in watertable trend was observed. The groundwater development was studied under different scenarios of extreme drought and flood conditions, and variable rates of groundwater abstraction. Finally, based on the results, better strategies for groundwater planning and management have been outlined.