Over Exploitation of Groundwater Resources and Their Influence on Groundwater in Peshawar Valley

Abstract

In this study the objective is to find the impact of the rainwater recharge on the ground water table fluctuations. For this purpose the data about different sources of discharge from the ground water as well as the sources of water recharged into the ground water was collected. The discharge of these Tube wells ranges from 1200 gallons per hour for a Tube-well in Pishtakhera Payan to 50625 gallons per hour from an Irrigation Tube well in Lakaray. It was also observed that both turbine and submersible pumps are used in these tube-wells. After summing up all the discharges from all the tube wells it was found to be 7,401,684 gallons per hour (7.78m³/sec). According to PDA report area of Peshawar is 1257 Km². Since Depth of water per unit time is total discharge / total Area, therefore depth of water per second is 7.77 / (1257*1000^2) = 6.18 * 10^-9 m/sec. Depth of water per year = 6.18 * 10^-9 * 3600*12*365= 0.098 m /year= 98 mm / year. The average discharge of each commercial well was found to be 0.38 Liters / second. Since ttal number of union councils in Peshawar region are 92, therefore on average total number of commercial/community tube wells are 552. Taking average discharge for each tube well as 0.38 Liters / sec, total discharge from the commercial wells in Peshawar region will be 552*0.38=209.76 Liters per second which is equal to 0.2098 cubic meter per second. Discharge from commercial wells per year=0.2098*3600*4*365= 1102498.6 cubic meter per year.Total depth of water discharged by the commercial wells from the Peshawar region is Depth of water = 1102498.6 / 1169*1000^2=0.94mm/year.Assuming two hours operation of hand pump daily, total outflow of water from town-II is equal to 22873905.7 cubic meters per year. Total depth of water discharged from town-II using hand pumps was found to be equal to 52.28 mm per year.So total annual depth of water discharged out through hand pumps from three towns (II, III, and IV) is equal to 171.05 mm.

Keywords: Rainwater, Recharge, Hand Pump, Tube well, Discharge, Total Depth