“Environmental flows” is a system for managing the quantity, timing, and quality of water flows below a dam, with the goal of sustaining freshwater and estuarine ecosystems and the human livelihoods that depend on them.
Water systems have limits to how much they can be altered before people who depend on them lose the services that they provide. The Environmental flows can support:
Fishing, Farming, Drinking Water Supply, Grazing land, Pollution control, Navigation, Endangered Species, Cultural and Spiritual Values.
The most ecologically important aspects of a river’s flow are extreme low flows, low flows, high flow pulses, small floods, and large floods. Examples of important flows are:
Large flood - Fish spawing, New sediment
Low flows - Habitat for aquatic species ,water for livestock
There are now over 200 methods to set environmental flows from over 40 countries. Transforming environmental flow studies and policies in to action is not easy. It needs commitment from governments and stakeholders, sufficient resources and training and institutional capacity to manage water resources.
Image source: www.internationalrivers.org
Image license: CC-BY-NC-SA