Hydrology research in the upper Indus basin, Karakoram Himalaya, Pakistan

Abstract

G.J. YOUNG and K.HEWITT Cold Regions Research Centre, Wilfrid Laurier University, Waterloo, Ontario, N2L 3C5, Canada ABSTRACT This paper examines the hydrological, meteoro­logical and glaciological characteristics of the Upper Indus Basin, Pakistan as they influence water supply. In the past, apart from some long-term discharge records for the Indus and some of its major tributaries, hydrological measurements were very scarce. Meteorological measurements were almost wholly confined to valley bottom locations thus missing the hydrologically most active zones above about 30O0 m elevation. Glaciological investigations have largely been confined to work done on an ad hoc ba­sis and in a limited number of basins by international expeditions. A joint Pakistan-Canada research effort during the last three years represents a concerted effort to remedy these deficiencies. The aim of this cooperative project is to build up a systematic and long term data base to understand, in particular, the relative contributions to streamflow of rainfall, snowmelt and glacier ice melt. This understanding should allow more rational planning and more effective operational streamflow forecasting. Models being developed or applied to the basin at the present time are described. THE GENE-RAL IMPORTANCE OF WATER IN THE INDUS BASIN While some of the headwaters of the Indus River lie within China and India, most of the Indus Basin lies within Pakistan. The water supply provided by the river is critical to most aspects of the country's economy. Large areas of the Punjab are irrigated by Indus waters. A major part of the country's hydro power is derived from the iriver, while groundwater supplies are argumented by streamflow. They supply much of the country's electri­city ,. major irrigation works and regulate flows in order to alleviate flood hazards. Most of Pakistan's population lives in the desert or semi—desert Indus plains. The bulk of the Indus waters are derived from the river's high mountain headwaters. The main stem of the Indus above the Tarbela dam pro­bably receives as much as 80% of its flow from snow and ice melt as do other western tributaries, the Kabul and Swat. Most of the flow of the left bank tributaries, traversing the Punjab, is derived from snow melt during 139