'Lei' drainage system (Islamabad-Rawalpindi, North Pakistan) with special reference to the possibilities of natural and artificial groundwater recharge

摘要

The average precipitation is about 1,219 mm, of which 30 % (363 mm) flows off, 56 % (684 mm) evaporates and 14 % (171 mm) recharges groundwater in the Lei-Basin area of Islamabad and Rawalpindi. The periodic variability of precipitation, floods and droughts, aquifer over-mining and contamination are few of the important challenges of water resources management in this area. The groundwater recharge would not only be a reliable reserve in times of droughts but also compensate the anthropogenous influences in the south and the geogeneous burden of gypsum layers in the west. All in all the chessboard regional city planning of Islamabad, as laid down in the Master Plan (1960), has to be re-planned inter-disciplinarily according to topographical, geological, meteorological, hydrological and hydrogeological investigations for the long term environmental sustainability.