Run, river, run: how dams affect flows
An innovative new website graphically illustrates how reservoir storage and water releases from storage during power generation change a river’s flow. On large rivers, the physical and ecological effects of flow regulation can be experienced several hundreds of kilometers downstream, and the effects are multiplied on river systems with series of dams.[1] The end result? Profound impacts on fish and biodiversity.
To see how this works, try this website. By clicking on one of DamEffects’ three tabs : “natural river,” “poorly run hydro” and “well run hydro” you can see the effects of a dam on issues like riparian areas, water quality, river flows, fish passage, recreation, and sediment and debris transport, as you are linked directly to sites showing scientific approaches for evaluating hydroelectric project effects. And when you click on “remove dam” you can watch the river revert to its natural state.
Natural River (c)Hydropower Reform Coalition
DamEffects is a project of the Hydropower Reform Coalition, a U.S. nonprofit composed of over 150 groups who joined forces to spread the message that: “The good news is that we can keep our rivers healthy and keep the lights on by bringing hydropower projects up to modern standards.”
Here in Canada, laws and policies for hydropower production are evolving to require more consideration of environmental flow protection.
BC, for example, restricts dam building on fifteen major rivers, like the Adams, Stikine and Taku.
Water licencing procedures are also designed to minimize hydroelectric facility impacts on flows. A Guidebook on water licensing procedures for independent power producers (IPP) in BC sets out specific environmental flow calculations and requirements. BC Hydro’s water use planning (WUP) process is another example of reform to dam operations to increase flows. In most cases, BC Hydro agreed to voluntarily reduce its licensed allocations, which then resulted in an amendment to each facility’s provincial water license. The WUPs resulted in many cases in improvements for fisheries conservation. In the upcoming BC Water Sustainability Act, even more protections for environmental flows are promised.
A few simple changes to dam operations can make an enormous difference in the health of a river. We’re working in across Canada to make this happen.
[1] Terry D. Prowse, Fred J. Wrona and Geoff Power “Dams, Reservoirs and Flow Regulation” in Environment Canada. 2004. Threats to Water Availability in Canada. National Water Research Institute, Burlington, Ontario. NWRI Scientific Assessment Report Series No. 3 and ACSD Science Assessment Series No. 1.
