Effective framework for Environmental-flows estimation for data deficient Indian rivers

Abstract

Data deficiency is a major problem in recommending appropriate environmental flows (e-flows) requirements for rivers in many parts of the world. Several studies have been done using a variety of e-flows assessment methodologies. Large dams and hydropower projects are major manipulators of the flow regimes resulting in degraded ecosystems ubiquitously. In India attempts have been made to develop e-flows requirements of rivers to maintain a good riverine ecosystem. Most of the studies are based on hydrological methods, which do not take all the variables affecting flow-regimes into consideration. This paper highlights the problems in assessment of e-flows and their on-ground implications in India. In this study, probable solutions to these problems are suggested a conceptual framework for data deficient areas is proposed. This framework is based upon extensive baseline surveys of fluvial morphology, ecology and of indigenous population. Framework has six steps namely: monitoring the baseline conditions, setting up objectives, hydrological analysis, ecological analysis, climatic anomalies incorporation and recommendations. Finally, e-flows recommendations are made based on hydrological studies, habitat suitability curves and area of inland water body which should be maintained in the river basin. All these recommendations are compared and suitable e-flows recommendations are made based on studied variables. The review also suggests for bottom-up approach for e-flows assessment i.e. e-flows assessment and application should be done on small tributaries of rivers in initial phase of projects and those methods which deliver satisfactory results should only be applied to larger rivers.