57 GROUND WATER INVESTIGATIONS USING ELECTRICAL RESISTIVITY SURVEY IN RECHNA DOAB, PUNJAB, PAKISTAN By Ghulam Zakir Hassan 1 , Faiz Raza Hassan 2 and Saleem Akhtar 2 ABSTRACT Ground water quality is deteriorating in certain areas of the Punjab owing to excessive pumping by tubewells and many other factors. Electrical Resistivity Survey (ERS) is a technique which is applied to investigate the potential of fresh ground water in an aquifer. Electrical Resistivity Survey was carried out at nine locations upto a depth of 250-300 m on the left side of Jhang Branch Canal (JBC) in the vicinity of Faisalabad city in Punjab Province of Pakistan. The equipment used for ERS was ABEM, Terrameter SAS 1000 IP, SP, and Resistivity System. The resistivity data collected has been interpreted by computer-aided techniques using computer software. The Quality of ground water from 10 to 60 meter depth is marginal to saline which improves afterwards gradually upto the depth of 150 m and afterwards deteriorates at locations R-1 and R-2. At site R-3 it contains top surface material upto 12 m and afterwards there is marginal to saline water. At sites R-4, R-6, and R-9 resistivity value is in the category of Low Resistivity Zone only a small layer contains fresh quality water and the remaining three sites also fall in Low Resistivity Zone. Key Words: Resistivity, Ground water; Aquifer, Quality; ERS; Rechna Doab, Punjab, Faisalabad, Pakistan. 1. Introduction Faisalabad is the third largest city of Pakistan with a population of 6.047 M and is the hub of industrial activities in the country. Ground water underlying the city is brackish and water is transported by means of underground piping network from the nearby aquifer near the Chenab River on Western side of the city mainly for drinking purposes. Already a well field is working since 1992 at a discharge capacity of 1, 55,351 m 3 / day on the Western side of Jhang Branch Canal (JBC) near the village Rajoa. Recently a new well field with an anticipated pumping capacity of 180,000 m 3 / day with funding from JICA along left bank of JBC is almost near commissioning. In addition to these pumpings, the area surrounding the city is agricultural area and private farmers tubewells are also pumping ground water to meet with the crop water requirements. Faisalabad Development Authority (FDA) has launched a housing scheme namely “FDA City Housing Scheme” to meet the housing demand for ever increasing population of Faisalabad. The housing scheme is located on Faisalabad-Sargodha road near motorway (M3) interchange at Faisalabad spreading over an area of 1,256 acres. FDA is interested to install tubewells along the Jhang Branch Canal near RD 209-216 of proposed capacity of 20,000 m 3 / day to meet the water requirements of this new housing scheme. Keeping in view the socio-environmental impacts of the existing well field it was deemed imperative to get the seepage and ground water investigations carried out before installation of the proposed well field. Accordingly, Irrigation Research Institute (IRI) of Punjab Irrigation Department was assigned the job. Main objective of the study was to assess the possibility of development of environment friendly well field and safe abstraction of ground water for water supply to FDA-City housing scheme. Current study on performance of Electrical Resistivity Survey (ERS) in the field has been accomplished as a part of the main study on ground water investigations. Some uses of ERS method in ground water are: determination of depth, thickness and boundary _____________________________________________________________________________________________ 1. Director, Irrigation Research Institute (IRI), Government of the Punjab, Irrigation Department, Library Road Lahore, 54000, Pakistan. Corresponding author’s e-mail: zakirjg@gmail.com 2. Assistant Director, Irrigation Research Institute (IRI), Government of the Punjab, Irrigation Department, Library Road Lahore, 54000, Pakistan. Corresponding author’s e-mail: faizrazahassan@gmail.com