An Ecological Survey of Land Use and Soil Erosion in the West Pakistan and Azad Kashmir Catchment of the River Jhelum

Abstract

This survey is a by-product of the Indus Waters Agreement between India and Pakistan, which provided for a reallocation of the waters of the major left bank tributaries of the Indus. Before partition these rivers provided the water for a unified irrigation system in the Punjab. Partition left the headwaters of the major tributaries in India and created a political frontier which cut across both the rivers and the canal system. Under the Indus Waters Agreement India retains control and use of the waters of the southern tributaries, mainly the Sutlej, Beas and Ravi. The supplies from these rivers, which Pakistan would lose, will be replaced by storage on the remaining major tributary, the Jhelum, and possibly later by other storage on the Indus itself. Thus the major and immediate 'replacement work' for Pakistan (apart from the complex link canals required to transport Jhelum water to areas previously supplied by the Ravi, Sutlej and other rivers) was a storage dam on the Jhelum. The obvious site was at Mangla. The consulting engineers appointed to design this major structure recognized at an early stage that silt derived from sediment eroded in the catchment above the reservoir site would produce serious difficulties. Silt loads in the Jhelum and its tributaries had been recorded by the engineers for a number of years. These recorded silt loads were likely seriously to decrease the useful life of the reservoir if (as seems unlikely) the rate of erosion did not increase. Accordingly the consulting engineers recommended a study of watershed management measures which might be taken in the catchment and which might reduce substantially the rate of sedimentation. In July 1959 the authors' firm was appointed by West Pakistan Water and Power Development Authority (WAPDA) to carry out this study: the report was presented in August 1961.