Estimation of environmental flows for river Ganges, and drawing a comparison between the current and naturalized flows
Student name: Ms Kanika Mehra
Guide: Dr Prateek Sharma
Year of completion: 2014
Host Organisation: International Water Management Institute, Hyderabad
Abstract: Environmental Flows, although no more a pioneering concept, is yet to find its footing in the Indian context. The
idea, although simple, can come out to be a vital tool in restoring new lease of life into rivers that face lean periods
of flows. Often misunderstood as “minimum flowsâ€, environmental flows are flows required for maintenance of the
ecological integrity of the rivers, their associated ecosystems, and the goods and services provided by them. They
can also be understood as a compromise between river maintenance and water resource development. This study is
a simple, basic exercise to estimate environmental flows in the Gangetic basin in “naturalized†conditions, wherein,
the development and urban extractions where much less. The present flows conditions are then compared with the
naturalized scenario in order to gauge the ecological health of the current situation. This is done using the
Smakhtin’s Method of shifting Flow Duration Curves. Flow time series for 30 years are simulated using SWAT
model for present and naturalized conditions, and then Flow duration Curves are generated for the reference
conditions and various Environmental Management Classes (which ranges from largely natural to critically
modified). Current flow are then compared with Environmental Flow duration curves of naturalized conditions in
order to assess the health of present flows.
Key words: Environmental Flows, Environmental Management Classes, Flow Duration Curves, Building Block
Methodology, SWAT Modelling
