Closing of the Krishna Basin: irrigation, streamflow depletion and macroscale hydrology

This paper summarizes research on the Krishna River Basin in southern India, including physical and agricultural geography, remote sensing, hydrology, water management, and environmental issues. Discharge from the Krishna into the ocean decreased rapidly from 1960-2003 due to irrigation expansion. Annual runoff to the ocean fell from a pre-irrigation average of 56 cubic kilometers (km3)(1901-1960) to 13 km3 (1994-2003), despite no significant change in rainfall. By the late 1990s, the cumulative reservoir capacity in the basin approximated the annual runoff volume. Distributed runoff data shows that this closure happened not only in downstream reaches, but also in upstream tributaries. The basin closure has resulted in interstate disputes over water and an increased need for basin-scale water resources assessment and modeling.