Abstract:
The strong wet and dry seasons of tropical monsoon hydrology in India necessitate development of
storage and flow diversion schemes for utilization of water to meet various social and economic needs. However,
the river valley schemes may cause adverse flow-related impacts due to storage, flow diversion, tunnelling and
spoil disposal. There may be critical reaches in which altered flows are not able to sustain the river channel
ecology and riparian environment that existed prior to implementation of the storage and diversion schemes. In
the past, environmental flows in India have usually been understood as the minimum flow to be released
downstream from a dam as compensation for riparian rights, without considering the impacts on the river
ecosystem. Rivers in India have been significantly influenced by anthropogenic activities over the past 60
years and have great social and religious significance to the vast population. This paper explores various aspects
of past, present and future environmental flow assessment (EFA) in India highlighted by case studies from rivers
across the nation. It demonstrates that multidisciplinary studies requiring expertise from a range of fields are
needed for EFA, and that environmental flows are necessary for aquatic ecosystems to remain in a healthy state
and for the sustainable use of water resources. The major focus areas for the development of EFA research in
India are the creation of a shareable database for hydrological, ecological and socioeconomic data, developing
hydrology–ecology relationships, evaluation of ecosystem services, addressing pollution due to anthropogenic
activities and promotion of research on EFA. At the same time, efforts will be needed to develop new methods or refine existing methods for India.
