Assessing the potential of underground storage of flood water: A case study from Southern Punjab Region in Pakistan

An intensively irrigated area in southern part of Punjab Province, Pakistan, has been selected by the Punjab Irrigation Department (PID) to implement a Managed Aquifer Recharge (MAR) project. This project involves diverting floodwater from the Islam Headwork on Sutlej River into the abandoned Mailsi Canal. Utilizing various structures such as depressions, abandoned canals, flood channels, open fields, and deserts for MAR can reduce the flood intensity while recharging aquifer and wetlands. The study area, known for its fertile lands and serving as a food basket for the Punjab Province, is experiencing groundwater depletion at the rate of 0.30 m to 0.70 m per year, significantly increasing pumping costs. This study aims to evaluate the suitability of the sites for the MAR project and assess the storage capacity of the aquifer for floodwater retention. Historical groundwater level data from 25 observation wells across an area of 1,522 km² were analysed, with the study area divided in to 25 polygons using ArcMap10.6 software. Specific yield method was employed to assess the available storage capacity of the aquifer. Results indicate that the site is suitable for MAR and has the potential to store approximately 1.88 km³ of floodwater as of 2020, thereby reducing flood intensity and enhancing eco-hydrogeological conditions. MAR is identified as a Nature-Based Solution (NBS) for both flood mitigation and groundwater sustainability.