ASSESSMENT OF ENVIRONMENTAL FLOW FOR SARYU RIVER IN UTTARAKHAND

Abstract

Environmental flow refers to the flow regime required for maintaining all river ecosystem functions. The environmental flow, in general, should at least include the water required for the assimilation of pollutants, evaporation, groundwater conservation, and aquatic-habitat conservation. An environmental flow is the provision of water within rivers and groundwater systems to maintain downstream ecosystems and their benefits, where the river or groundwater system is subject to competing water uses and flow regulation. Since flow can be regulated directly through infrastructure (like on-stream dams/weirs/ban-ages) as well as through diversions of water from the system (for example by pumping water away), there are different ways in which environmental flows can be provided. The study Area includes the Saryu River Basin in Bageshwaer district of Uttarakhand. A large number of people (about 259,840; Census 2011) rely on the Saryu Rive in terms of their various functions including biodiversity and conservation, irrigation and domestic water supply and so on. Hence the rivers and streanis need to be healthy to provide these functions. The natural flow in River Saryu is highly variable. It has periods of both very low and very high flows. Flows in the river vary seasonally with the higher flows usually occurring in the monsoon months. The Environmental Flow Guidelines need to identify those components of flow from this variable flow regime necessary to maintain stream health. The purpose of this project is to determine the minimum flow for the river and to describe the process and methodology used in order to facilitate Environmental Flow Assessment. This study evaluated the minimum flow requirements in the river, i.e. the environmental flow, by using different Hydrologic Methods at different sites of Saryu River and suggested suitable environmental flows at various locations of the river.