LAUSR

The Indus Delta is an endangered wetland on the Ramsar list due to a continued decrease of river flow toward the delta, resulting in seawater intrusion into the inland areas and deteriorating the potable patches of shallow groundwater and wetland areas. The groundwater in the lower Indus Basin is brackish, except for a few potable pockets, which are shrinking due to water extraction for drinking purposes. The gap thus occupied by saline water permanently degrades the potable groundwater. This paper correlates the potable patches with surface seepage due to either rainfall or river flows, to recommend a continuous flow of fresh water in the river system, and a revival of the ruined wetlands and lagoons. Twelve nested piezometers at various depths have been installed in the study area to monitor the groundwater quality temporally transformation. The water samples have been periodically collected to analyze physical and chemical properties for three years. The data trend indicates the rapid changes in shallow groundwater quality (up to the depth of 10 m) to the surface availability of freshwater. An area of 378 km2 was turned from saline to fresh groundwater with only two spells of rainfall. The result confirms the positive impact on groundwater quality improvement due to rainfall and water in river tributaries. Based on this analysis, it is recommended to replenish the lagoons and shallow lakes with fresh water. Canals should run continuously to constantly recharge the shallow groundwater as the only source of drinking water in the study area.