Environmental water requirements, also referred as ‘environmental flows’, are a compromise between water resources development and the maintenance of a river in ecologically acceptable or agreed condition. Managing environmental water flow is a complex task because the change of quantity of water occurs as the flow moves downstream. In this work, an attempt has been made to evaluate the existing conditions of the water flow in the Bhadra River at Lakkavalli, Shimoga District, Karnataka State, India and the significance of the ecosystem services through environmental flows. The possible impacts from the absence of environmental flows have also been recorded. The study involves an analysis of water flow status of Bhadra River for thirty years and also the field investigations which cover complete livelihood dependent fishermen communities and command area dependent agricultural communities. The upper catchment of the river is covered with good vegetation; the downstream of the river for 40 km has shrunken in its river bed due to the Bhadra dam, the river flow is completely irregular over a period of years. It has altered the natural flow, resulting in massive loss of riparian, aquatic habitat and water quality. Local communities are aware of the importance of environmental flows and have also realized the damages done by themselves through encroachments of flood plains and river bed for agricultural activities. More than 60% of the downstream dwellers have changed their livelihood occupations, and also migration level has increased in the fishermen communities. Communities have been impacted by irregular dry season water level fluctuations, which are characterized by extreme highs and lows, and rapid changes in water levels.
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