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Biological Benefits

of restoring the similkameen river

When a dam provides hydropower, flood control or other benefits, environmental impacts can be viewed as tradeoffs. Enloe Dam no longer provides these benefits, making the environmental and economic cost of keeping it in place too high.

Dams change the natural river environment by flooding areas, turning rivers into impoundments that are deeper, wider and slower than they are naturally. Because they are artificial they also require costly maintenance to keep them in safe and useable condition. 

Scientific research on rivers in recent decades has shown that rivers play a critical role in ecosystem health. Rivers, associated riparian areas, and the lands near them contain some of the highest numbers of species of any ecosystem on earth. When rivers and adjacent lands are healthy, the fish and wildlife that depend on them are also healthy. 

Dams harm water quality, both above and below the structure.

  • Dams can negatively change water temperatures, dissolved oxygen content, turbidity, and salinity. Check out this study about the impact of small dams (click here)

  • Dams also equal water loss, and worsen the impact of climate change. They release greenhouse gases, destroy carbon sinks in wetlands and oceans, deprive ecosystems of nutrients, destroy habitats, increase sea levels, waste water, and displace poor communities. (source)

Dams impede the river’s natural “flushing” functions

  • Dams change the river’s ability to move sediment and other nutrients downstream. Sediments then build up behind the dam, causing a variety of problems. 

    • These sediments get built up behind dams and start to consume a large amount of oxygen as they decompose. In some cases, this triggers algae blooms which, in turn, create oxygen-starved “dead zones” incapable of supporting river life of any kind. (learn more)

Dams are often built on prime spawning habitats.

  • Prime fish spawning habitats tend to be places where there is a high gradient to the river, resulting in well-oxygenated waters and gravelly streambeds.

    • Less than 300 natural (wild) -origin steelhead have returned to the Okanogan River from 2019-2021 (OBMEP, 2021) 

    • An estimated 98,000 adult steelhead could be supported by habitat upriver of Enloe Dam.  (Beak, 1983)

69 dams were removed in 2020, CLICK HERE to learn about where and why.​

evidence of fish jumping at the base of enloe dam

Importance of Lamprey survival

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To learn more about Lamprey making a comeback in Washington State after dam removal, click HERE

"Lamprey enhance the surroundings at both ends of their life cycle— cleaning up streambed sediment, recycling nutrients, serving as food for other fish as larvae and adults, and transporting minerals from the sea up into the tributary systems of the Columbia drainage when they die. They also form a protective buffer for salmon because they are easier for predators to catch. So no matter how unattractive they might seem, there are many reasons to honor the lamprey and encourage their recovery. Native Americans view the lamprey as a First Food, a creature that gave up its life to humans in exchange for human environmental stewardship." - The Amazing Ancient Lamprey (Valerie Brown- Feb. 8, 2018)