Informing Groundwater Policy In The Indus Basin In Pakistan Using A Physically-Based Groundwater Model

Abstract:

The rapid expansion in groundwater abstraction in the past few decades in Pakistan is credited with the huge increases in crop production bringing about significant economic gains and ensuring food security for millions. Most of the groundwater usage in Pakistan takes place in Punjab province. This exponential increase in groundwater usage is however, also responsible for the significant groundwater table decline in many parts of the province. There is an urgent need for policy measures to better manage groundwater use. A better understanding of the underground water balance is necessary to make groundwater management policies. This study develops the first physically-based groundwater model for the entire Punjab province. Using the calibrated province-wide model, we perform various simulations to evaluate groundwater dynamics in the future under different scenarios. These scenarios comprise of groundwater conservation efforts, increasing efficiency of the canal irrigation system and changing volume of precipitation. We also make a preliminary attempt to characterize the impact of transboundary groundwater abstractions in Indian Punjab on groundwater levels in Pakistan. We investigate the impact of the future scenarios on major urban centers across Punjab. Our results show that seepage from the canal supply system into the aquifer forms the biggest component of the groundwater flux, while the effect of changing precipitation is negligible. Farmers in central and north-western Punjab are projected to have the highest pumping costs in the future. Areas in southern Punjab are shown to be most vulnerable to waterlogging in the future. The results of this study can help guide policy-makers in developing a thorough groundwater management plan for Punjab.