Groundwater investigation of district Khushab (Thal Doab) using electrical resistivity method (T-1459) (MFN 3327)

Abstract

Water is becoming scarce commodity in many countries of the Word due to rapid growth in population and industrialization. Pakistan is also facing the water shortage problem and is declared as one of water stressed countries. Surface water resources of the country are almost exploited. Further expansion will depend upon groundwater resources. Water table is declining in many parts of the country due to excessive groundwater mining. Thal Doab is one of the areas where groundwater is under stress. District Khushab (Upper Thal Doab) is facing severe shortage of water for irrigation purpose, because canal water is not available and groundwater is saline. Farmers in many parts of this district are utilizing marginal and saline water for cropping. Further development in irrigation requires careful mapping of groundwater resources. The most useful and economical geophysical method in groundwater exploration is electrical resistivity. It gives information on water quality and subsurface lithology. To investigate study area, electrical resistivity survey is conducted at regular grid of 5 x 5km by Pakistan Council of Research in Water Resources (PCRWR), Islamabad. The electrical resistivity survey is supported by well drilling at 20 x 20km regular grid. Soil and water samples are collected at vertical interval of 3 meters. Correlation of electrical models with the geology and water quality is carried out. Four water quality zones at depth of 300meters (based on electrical resistivity and well data) are mapped using GIS techniques (at six vertical horizons with interval of 50 meters). Quality of water samples are analyzed in different ways by using Aqua-Chem Software. Specific yield is estimated for future utilization of groundwater.