Lithological exploration for potable water lens in the Indus Delta and their connectivity with freshwater seepage and environment

Abstract

The world's seventh-largest Indus Delta is gripped to extinction due to a continuous shortage of Indus River flows. The drastic fall in the ecology and coastal habitat due to the lack of freshwater flows, and the land degradation due to seawater intrusion is a simultaneous creeping hazard. The study aims to explore the potable water lens and their possible connection with seepage from freshwater bodies (rivers/ canals) to sustain them for drinking and agriculture use of 2 million populations. The study employed the electrical resistivity survey and 10 selected points along the Indus River at depths up to 300 m to baseline the rock type and groundwater quality; and drilling of bore logs at a maximum depth of 25 m. The result confirms the availability of two sandstone layers with marginal freshwater along the river and in some pockets; however brackish water was observed along the coast in a limestone formation. It is evident from the results that surface seepage from the Indus River and non-perennial ‘Pinyari’ canal has a progressive influence on the improvement of groundwater quality and confinement of seawater intrusion. HIGHLIGHTS Investigating the potable water lens and their possible connection with seepage from freshwater bodies (rivers/canals).; Investigation of baseline rock type and groundwater quality using electrical resistivity survey.; Research proposed the construction of Sindh Barrage for a sustainable delta and ecosystem.;

Keywords

• electrical resistivity sounding
• groundwater
• indus delta
• lithology
• seawater intrusion