When a river has been dammed, one of the most obvious changes is the disruption to the amount and timing of its flow. “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. The most ecologically important aspects of a river’s flow are extreme low flows, low flows, high flow pulses, small floods, and large floods. Environmental flows can be designed to restore any of these, with the goal of improving water quality, restoring sediment deposition, addressing the life-cycle needs of fish and wildlife, and restoring the livelihoods of river-based communities.
Many governments and river-management agencies around the world have developed policies to protect environmental flows, and more are doing so all the time. Yet implementation of these policies remains weak. Learn more about efforts to ensure compliance with e-flow policies .
While more effective management of dams can help to mitigate environmental impacts, it should be noted that many dams around the world presently lack the mechanisms needed to control water discharge.
Learn more about how we can move Towards Restoring Flows Into the Earth's Arteries