Mapping Of Groundwater Zones Using Vertical Electrical Sounding (VES): A Case Study of Malwah Distributary

Abstract

In the last two decades, the water requirements for agriculture sector have increased due to high food demand, changes in the cropping pattern, and the increase of evapotranspiration rate due to the climate change. The irrigation water demands are not completely fulfilled by the available surface water, which resulted an increased use of the groundwater in Pakistan. It is essential that before applying the groundwater to agriculture land, its quality should be assessed. In this study, groundwater quality and quantum have been investigated through Vertical Electrical Sounding (VES) for the command area of Malwah distributary, district Shaheed Benazirabad. Total 23 sites were selected in a grid of 3km-by-3km area for the VES survey using Terrameter up to 100-meter depth. The VES results are interpreted in terms of the resistivity and corresponding thickness of various underground zones using IX1D software. The results indicated fresh groundwater up to maximum of 50 m depth, covers 75.65 km2 i.e., 21% of the total command area of 359.94 km2. However, the freshwater is accessible up to 100 m depth near the Indus River. The study suggests that the tubewells should be installed up to 50-meter depth, where the maximum quantity of fresh groundwater is available.