d for irrigation. Yet, Pakistan currently lacks the necessary storage capacity, in part because of heavy silting of reservoirs,. The absence of this water is one of the factors preventing the nation from attaining food self-sufficiency.The existing irrigation system is also highly inefficient. Of the 128 billion cubic meters diverted for irrigation, about 52 billion cubic meters is lost to seepage and evaporation from canals and watercourses. This loss is a major cause of waterlogging and salinity of soils in the Indus Basin. Vertical pumping systems used for drainage are proving unsustainable: the recycled water contains chemicals that produce sodicity and reduce the life of pumping machines.No serious effort has been made to develop a drainage system to parallel the irrigation system. In Punjab alone there are about 280,000 tube wells pumping 51 billion cubic meters of water and using about 2,400 megawatts of subsidized power. One hundred million metric tons of salts have been pumped up in the process. The salts have decreased crop productivity in 1.2 million hectares of prime land in the Canal Command Area, which is about 5 percent of the total agricultural land in Pakistan. Another 2.1 million hectares of salt-affected lands exist in Punjab's non-sweet water areas. The result is lower crop productivity.Beyond the Indus Basin, sharp drops in the water tables of underground aquifers - of 15 centimeters to over 60 centimeters (cm) per year - are occurring in a number of areas. The water table in the Northern Basin of the Quetta Valley is falling at the extraordinary rate of 200 cm per annum, while the Southern Basin has registered a yearly decline of 60 cm. The groundwater table in Lahore is falling at a rate of 30 cm per year in the central part of the city due to excessive withdrawals by a growing urban population.67An inadequate sewage treatment infrastructure adds to problems. Many of Pakistan's rivers are now badly polluted with d...
