Inter basin water transfer and its impact on water availibility

Abstract

The water availability in a river influence significantly due to change in flow regime because of water transfer from external sources or regulated operations like river diversion, construction of dam, onstream uses, etc. Present paper deals with the water availability assessment in Kharun river of Chhattisgarh state which has been found strongly influenced by regulation operations associated with river and the complex system of water transfer from Ravishankarsagar reservoir to Kharun river and its supply through the series of anicuts to meet various water user demands in the basin. The study indicated that the Kharun river is originally an intermittent river having flow mainly during monsoon season with an average annual yield 1802 MCM. The river receive average 116 MCM of water from Ravishankarsagar reservoir through direct link and in the form of irrigation return flow, thus river experiences significant rise in dependable flow throughout the lean period which is being used to meet various user demands. The river which runs dry during summer season under virgin condition has found significant rise in stream flow due to water transfer in to the river and dependable flow even at 90% probability of exceedance has been observed between 2.83 to 3.26 m3/s.