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| Why care about dams? |
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There are dozens of hydropower projects throughout Idaho. The dams and reservoirs associated with these projects have often wreaked havoc on Idaho's rivers and fish. While some dams have proven beneficial, others, such as the Lower Snake River dams, have caused a steady decline in salmon populations while providing few concrete benefits. Hundreds of river miles have been impacted and entire ecosystems have been destroyed.
The ecological impacts these projects have on rivers include:
- By creating a barrier to the natural flow of rivers, dams are detrimental to salmon and other aquatic species that rely upon unobstructed passage through rivers for survival and reproduction. Hydroelectric dams also inhibit the health of aquatic populations as fish can be killed by turbines when passing through hydroelectric dams.
- As dams alter water levels, they pose a threat to riparian life along rivers. The fluctuating levels of water in reservoirs behind dams strip away naturally occurring populations of vegetation. Downstream, dammed rivers often experience unnaturally high rates of bank erosion as well as vegetation growth in riverbeds. This is due to irregular flows of water.
- Dams result in a build-up of sediments in rivers. As water flows are slowed down by dams and fill reservoirs, materials such as rocks, sand and wood are amassed. These materials remain trapped behind dams rather than serving their natural role of building habitat structure downstream.
- Dams are detrimental to river water quality particularly in terms of temperature and dissolved oxygen. The speed and volume of the flows in a river altered by a dam results in either unnaturally warm or unnaturally cool water. Also, accumulated organic material behind a dam consumes heavy amounts of dissolved oxygen. Dams harm fish and other aquatic life forms that require natural water temperatures and levels of dissolved oxygen.
For further information on the impacts of dams on rivers, explore the Dam Effects website.
Alternatives to dams
Constructing new dams is not the best solution to water resource issues in Idaho. Not only are dams detrimental to the health of river habitats and species such as salmon and steelhead, their reservoirs are not currently filling to capacitymaking the need for additional storage space provided by new dams unnecessary. Rather than investing millions of taxpayer dollars in expensive, harmful dam projects, alternative approaches such as implementing water conservation and efficiency, water use options, and alternative storage options such as aquifer storage can be explored.
Idaho Rivers United works to ensure that all possible river-friendly alternatives are considered for water storage, irrigation, and energy generation before new dams are constructed in Idaho. In addition, we encourage the re-licensing of existing hydropower dams to ensure higher water quality standards, better flows, and other essential protections.
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