The two graphs below
show how a dam can regulate flow in a river system. The graph
to the left is a hydroelectric dam that is operating at peak
discharge. When a dam operates at peak discharge
there are large fluctuations of water in the river. The river
may increase and decrease quickly, affecting the fish and wildlife
community where this is occurring.
The graph to the right
is a river which is operating near run-of-the-river conditions.
This dam is not drastically increasing or decreasing the amount
of water in the river, but is trying to mimic the river's flow.
More dams are continuing to operate at natural flow, which
may be less harmful to the fish and wildlife communities in and
around the river.
Click on the graphs to enlarge.