Abstract:
Intensive agriculture is prevalent in Punjab state. Amritsar, Jalandhar, Ludhiana and Muktsar districts of Punjab is drained by three perennial rivers Ravi, Beas and Sutlej. Most of the irrigation water met from groundwater as surface water in canals is dwindling during recent years. Early 70's and 80's shallow tube well irrigation is practiced. Recently farmers are switching over to deep well irrigation in Amritsar, Ludhiana and Jalandhar districts, which causing rapid depletion of the ground water levels — 50-60 cm/yr. In order to increase the agriculture productivity heavy dose of agriculture inputs like fertilizers and pesticides are being used, which may be causing groundwater contamination. The groundwater in Muktasr district is facing acute problems of water logging due to increasing salinity and sodicity. Integrated geophysical Surveys using the Electrical Resistivity Tomography (ERT) equipment has been carried out at 34 locations in the four districts for ascertaining thickness of unsaturated zone and water table conditions in the Amritsar, Jalandhar, Ludhiana and Muktsar districts. Interpretation of ERT images revealed that unsaturated zone thickness/dry sand is found varying from
14 to 34 m with a resistivity value of 200 to 350 Ohm-m in Amritsar, Ludhiana and Jalandhar districts. Large thickness of dry sand zones encountered near Beas River in Amritsar District represent heavy withdrawal of groundwater in Amritsar district. The ERT images in the Muktsar district clearly brought out the salinity condition in the top formations as indicated by very low resistivity < 8 ohm m which is extending up to 30 to
32 m depth.
