Demarcation of Groundwater Quantum and Quality of Lower Indus Basin: A Case Study of Seri and Muhammad Khan Distributaries

Abstract

This paper presents an assessment of groundwater quality and quantum in the command areas of two secondary canals in lower Sindh, the southern province of Pakistan. These canals off-take from Rohri main canal of Sukkur barrage in the Indus basin system. The scarcity of canal water is due to climate change, population growth and increased water demands. The farming community uses groundwater to meet the needs and improve their livelihood. The fresh groundwater in Sindh is only 22 percent, which is available in shallow aquifers underlain by salty groundwater of marine nature. The groundwater quality was assessed using electrical resistivity survey (ERS), which portrayed groundwater zones through 1D inversion software (IX1D) and geospatial tool inverse distance weighted (IDW). Four classes (fresh, marginal fresh, marginal saline, and highly saline) have been delineated at different depths from 25 to 150 m below ground surface. The groundwater aquifers are identified, and their quantum is estimated. The ERS results were also compared with the quality of collected water samples at various depths. The ERS results have identified fresh groundwater up to 40 m depth. The marginal quality groundwater could be utilized to increase crop productivity through conjunctive use with the canal water