Impact of floods on groundwater: A case study of Chaj Doab in Indus Basin of Pakistan

Groundwater is the most valuable natural resource and playing globally a vital role in agri-based economy of the nations. Uncertainty and scarcity of surface water, tremendous increase in population, and urbanization have shifted the pressure towards the groundwater. Pakistan has become 4th largest user of groundwater after India, USA and China. Groundwater has helped in increasing cropping intensity from 67% in 1947 to 150% or even more in some irrigated areas in Indus River Basin (IRB) of Pakistan at present. In Punjab province, more than one million private tubewells are extracting groundwater to meet about 40-50% crop water requirements. On the other hands, devastating floods cause huge damage to the agricultural production, physical infrastructures and human lives. Very less research has been done on the impacts of floods on aquifer recharge. To evaluate the impacts of flood 2014 on aquifer storage a quantitative analysis of groundwater levels data from about 200 piezometers has been carried in Chaj Doab (area between two rivers—Chenab and Jhelum) in Indus River Basin (IRB) of Pakistan. Results have indicated that groundwater levels in Chaj Doab are rising at an average annual rate of 0.4 ft. It has been found that during 2014 maximum area (44%) lies under depth to watertable range of 5-10 ft. It has been observed that flood 2014 recharged 1.319 MAF of water to groundwater reservoir. Over-exploitation, deterioration of quality of groundwater, secondary salinization, lack of regulatory framework, scarcity and uncertainty of surface water, lack of education and awareness among the stakeholders, gaps in monitoring and mapping of aquifer extent, lack of coordination and institutional setup have been identified as potential challenges for groundwater management in the study area. Flood water contributes significantly to aquifer recharge and the depleted aquifer can act as a storage for flood water to lessen the flood-intensity.