Dam removal

Removal of the Marmot Dam, Sandy River, Oregon

Dam removal is the process of removing dams from river systems. Many are seen as dated, dangerous, or ecologically damaging.

Dams are demolished for three reasons: environmental rehabilitation, the risks of dam failure, and economic reasons. Around the world, a growing number of 20th-century dam construction projects are reaching the end of their design lives: as of 1996, 5,000 large dams around the world were more than 50 years old.[1]

Since around 2000, most major dam removal projects, and the largest single project, the $350M removal of two Olympic Peninsula dams as part of the Elwha Ecosystem Restoration, have been driven by restoration of river habitat and fish passages. Inspired by the Elwha project, a French group called SOS Loire Vivante successfully lobbied for the removal of two dams in the Upper Loire Valley, and the re-engineering of a 1941 hydroelectric dam on the Allier River to restore habitat for Atlantic salmon. [2]

In the United States roughly 900 dams were removed between 1990 and 2015, with another 50 to 60 more every year. [3] France and Canada have also completed significant removal projects,[4] and Japan's first removal, of the Arase Dam on the Kuma River, began in 2012 and is scheduled to complete in 2018. [5]

Purposes and effects of dams

Grand Coulee Dam, Columbia River, Washington, United States

Many of the dams in the eastern United States were built for water diversion, agriculture, factory watermills, and other purposes that are no longer seen as useful. Because of the age of these dams, over time the risk for catastrophic failure increases. In addition, many of these dams block anadromous fish runs, such as Atlantic salmon and American shad, and prevent important sediments from reaching estuaries.

Many dams in the western United States were built for agricultural water diversion in the arid country, with hydroelectric power generation being a very significant side benefit. Among the largest of these water diversion projects is the Columbia Basin Project, which diverts water at the Grand Coulee Dam. The Bureau of Reclamation manages many of these water diversion projects.

Some dams in the Pacific Northwest and California block passage for anadromous fish species such as Pacific Salmon and steelhead. Fish ladders and other passage facilities have been largely ineffective in mitigating the negative effects on salmon populations. Bonneville Power Administration manages electricity on 11 dams on the Columbia River and 4 on the Snake River, which were built by the Army Corps of Engineers.

Clear water below Glen Canyon Dam, Arizona, United States

In the Desert Southwest, dams can change the nature of the river ecosystem. In the particular case of the Glen Canyon Dam, the originally warm, sediment-filled, muddy water, instead runs cold and clear through the Grand Canyon, which has significant impacts on the downstream ecosystems. Three native fish species have become extinct in the Grand Canyon and others are endangered since the dam was completed, including humpback chub and razorback sucker.

Some dam projects, such as those on the Salt River Project in Arizona, eliminate the flow of the river downstream, by diverting the flow into the Arizona Canal system for use in agriculture and urban usage, such that only a dry channel or arroyo heads out across the desert.

So much water is taken out of the Colorado River for agriculture, urban use, and evaporation behind the dams, that the river no longer flows into the Gulf of California.

Completed dam removal projects

Condit Dam, Washington, United States

Proposed removals

Lower Snake River Dams, Washington, US

Little Goose Dam, Washington, USA

Four dams along the lower Snake River, built and still operated by the United States Army Corps of Engineers, serve as hydroelectric power sources as well as maintaining an inland port at Lewiston, Idaho for agricultural barge traffic. The four are candidates for removal because of millions of cubic yards accumulated behind the dams, which are raising water levels for riverside cities. They include: the 1975 100 ft (30 m) Lower Granite Dam, the 1970 98 ft (30 m) Little Goose Dam, the 1969 100 ft (30 m) Lower Monumental Dam, and the 1962 100 ft (30 m) Ice Harbor Dam.

Three million new cubic yards of sediment are deposited behind the lower four dams on the Snake River annually.[13] The city of Lewiston, Idaho and others along the Snake have built a system of levees maintained by the Army Corps of Engineers. The levees in Lewiston were designed to leave five feet between water levels and the top of the levees. Today, two feet remain. As water levels continue to rise, either some of the dams must be removed or dredged, or the levees will continue to grow. The Corps admits that the amount of sediment in the riverbed is too great for dredging to be effective, and Lewiston community leaders are worried that higher levees will further cut the town off from its rivers.[14]

Rindge Dam and Matilija Dam, Southern California

Rindge Dam near Malibu, California, built in 1924, completely silted and abandoned by the 1950s

The 100 ft (30 m) privately-owned Rindge Dam on Malibu Creek in the Santa Monica Mountains of California was built in 1924 and has been allowed to completely fill with sediment, making it functionally obsolete but still a potential hazard. Malibu Creek once supported the southernmost steelhead population in the world. But today, steelhead no longer occupy the creek.

The similiar 1947 Matilija Dam near Ojai, California was built against the advice of the U.S. Army Corps of Engineers, among others, and also blocked steelhead trout spawning grounds. After being notched twice and largely silted up, 90% of its design capacity has been lost. As of 2013 stakeholders agree that the dam and its sediment be removed, but no funding source has been identified. [15]

Klamath River Dams, California / Oregon border

Demonstrators calling for removal of dams on the Klamath River in Oregon and California, USA

As resolution of several long-range issues centered on water rights in the Klamath Basin, the multi-party Klamath Basin Restoration Agreement was signed in early 2008. Parties to the agreement included the state of California, the state of Oregon, three Native American tribes, four counties, and 35 other local organizations and individuals.[16]

This agreement called for the removal of four of the Klamath River Hydroelectric Project dams: the 1958 John C. Boyle Dam, the 1922 Copco Number 1 and Copco Number 2, and the 1964 Iron Gate Dam. All four are privately owned by PacifiCorp. At the time PacifiCorp faced a relicensing cycle with Federal Energy Regulatory Commission, with potentially expensive fixes for salmon passage and to address the growth of the toxic bacteria Microcystis aeruginosa in the Copco and Iron Gate Reservoirs.

On September 29, 2009, Pacificorp reached an agreement in principle with the other KBRA parties to remove the four dams, pending Congressional approval.[17]

Congress did not act, so as of February 2016, the states of Oregon and California, the dam owners, federal regulators and other parties reached a further agreement to remove all four Klamath basin dams by the year 2020, contingent only on approval by the Federal Energy Regulatory Commission.[18] The new plan has been endorsed by the governors of California and Oregon, as well as the U.S. Secretary of the Interior.[19]

Glen Canyon Dam, northern Arizona

Glen Canyon Dam

The 710 ft (220 m) Glen Canyon Dam has been proposed for removal because of the negative effects it has on the water quality and riparian habitat of the Colorado River in Grand Canyon National Park. In addition, the reservoir impounded behind it, Lake Powell has filled all of the canyons for up to 160 miles (260 km) above the dam. This lake, while providing recreational opportunities, has eliminated more than 160 miles (260 km) of habitat for endangered Colorado River fish species.

The reservoir also loses more than 6 percent of the total annual flow of the Colorado River to evaporation and seepage.[20] Advocates of dam removal such as the Glen Canyon Institute also cite these losses of stored water as reason to decommission the dam. If it were to be removed, it would dwarf any completed dam removal project in history.

O'Shaughnessy (Hetch Hetchy) Dam, California

O'Shaughnessy Dam in California was completed in 1923 and represented the first great environmental controversy in the US as it was constructed in a national park.[21] The debate over the dam and reservoir continues today. Preservationist groups such as the Sierra Club lobby for the restoration of the valley, while others argue that leaving the dam in place would be the better economic and environmental decision.[22]

Kinnickinnic River Dams, Wisconsin

The Upper "Junction Falls" Dam on the Kinnickinnic River in River Falls, Wisconsin as it appears today. The Historic Junction Falls are obscured by its presence, the lowest ledge of the Junction Falls now sits as the dry ledge below the base of the dam.
The historic Junction Falls of the yet-undammed Kinnickinnic River in River Falls, Wisconsin. Photograph taken by John Carbutt between 1864 - 1865 and published as a stereoview in a set of scenery pictures of "The Upper Mississippi, Minnesota and the Vicinity".[23]

The two remaining dams on the Kinnickinnic River in River Falls, Wisconsin are being considered for removal in order to completely restore the Kinnickinnic River to its natural state.[24] The Kinnickinnic River, called the Kinni for short, is a 22-mile-long (35 km)[25] river in northwestern Wisconsin in the United States. The Kinni is a cold water fishery supporting a population of native Brook Trout and naturally reproducing Brown Trout. The Kinnickinnic River is officially designated as a Class I trout stream by the WI DNR, indicating it is a "high quality" trout water that has sufficient natural reproduction to sustain populations of wild trout, at or near carrying capacity.[26] The Kinnickinnic is also designated as an Outstanding Resource Water (ORW) by the WI DNR both above State HWY 35, and below the Powell Falls Dam, however, the stretch of the Kinni through the City of River Falls is not included in this designation where the river is impounded into two reservoirs which do not support a fishery. This ORW designation indicates the Kinni provides outstanding recreational opportunities, supports valuable fisheries and wildlife habitat, has good water quality, and is not significantly impacted by human activities.[27] This designation indicates that the State of Wisconsin has determined the Kinnickinnic River warrants additional protection from the effects of pollution. These designations are intended to meet federal Clean Water Act obligations requiring Wisconsin to adopt an “antidegradation” policy that is designed to prevent any lowering of water quality – especially in those waters having significant ecological or cultural value.[27]

Local stakeholder organizations in the FERC relicensing process include the Friends of the Kinni, the Kiap-TU-Wish Chapter of Trout Unlimited, the Kinnickinnic River Land Trust, and the River Alliance of Wisconsin. Government agencies also serving as stakeholder organizations include the Wisconsin DNR, the US Fish and Wildlife Service, and the National Park Service.

See also

References

  1. ↑ McCully, Patrick (1996). Silenced Rivers: The Ecology and Politics of Large Dams. London: Zed Books. Retrieved 8 April 2016.
  2. ↑ Xin, Guo (5 March 2012). "French Dam Removal Opens Way for Atlantic Salmon". internationalrivers.org. Retrieved 9 April 2016.
  3. ↑ Struck, Doug (3 August 2014). "Setting rivers free: As dams are torn down, nature is quickly recovering". Christian Science Monitor. Retrieved 9 April 2016.
  4. ↑ Zhao-Yin Wang, Joseph H.W. Lee, Charles S. Melching (24 September 2014). River Dynamics and Integrated River Management. Springer Science & Business Media. p. 437. Retrieved 9 April 2016.
  5. ↑ Suwa, Yuzo (19 December 2013). "River’s savior still sees work ahead". Japan Times. Retrieved 9 April 2016.
  6. ↑ "Dams and Hydropower".
  7. ↑ "Embrey Dam just a memory". Fredericksburg.com.
  8. ↑ "dead link" (PDF).
  9. ↑ Dennen, Rusty (2008-09-23). "Rapids to be named for John Warner".
  10. ↑ http://www.elwhascienceed.org/project-update/elwha-salmon-populations
  11. ↑ Crane, Misti (December 28, 2015). "River ecosystems show 'incredible' initial recovery after dam removal". phys.org. Retrieved December 28, 2015.
  12. ↑ "Carmel River diverted to demolish San Clemente Dam". SFGate. Retrieved 2016-03-02.
  13. ↑ Barker, E. (2007, February 16). Corps of engineers gets earful about sediment problems. Lewiston Tribune.
  14. ↑ "Why Restore Wild Salmon?" Save Our Wild Salmon. Retrieved 18 May 2011. <http://www.wildsalmon.org/index.php?option=com_content&view=article&id=94&Itemid=62>.
  15. ↑ Carlson, Cheri (3 March 2013). "Delayed plan to remove Matilija Dam near Ojai will get new studies". Ventura County Star. Retrieved 11 April 2016.
  16. ↑ "Klamath Basin Restoration Agreement" (PDF). Klamath Restoration. Retrieved 8 April 2016.
  17. ↑ Fimrite, P. (30 September 2009). "Deal to raze 4 Klamath dams". San Francisco Chronicle.
  18. ↑ Lochhead, Carolyn (3 February 2016). "New plan to remove Klamath River dams without help from Congress". SFGate.
  19. ↑ Houston, Will (7 April 2016). "Klamath River dam removal deal signed by top federal, state officials". Eureka Times-Standard.
  20. ↑ "Why Glen Canyon?". Glen Canyon Institute. Retrieved 15 February 2013.
  21. ↑ "Hetch Hetchy Environmental Debates". The Center for Legislative Archives. National Archives. Retrieved 2014-04-12.
  22. ↑ Rogers, Paul (2012-09-30). "Hetch Hetchy controversy: Could Yosemite's 'second valley' be restored?". San Jose Mercury News.
  23. ↑ Palmquist, Peter (2005). Pioneer Photographers from the Mississippi to the Continental Divide: A Biographical Dictionary, 1839-1865. Stanford University Press. pp. 146–147.
  24. ↑ Pfueler, Phil (2015-01-22). "For River Falls, it’s dam right…or wrong?". River Falls Journal.
  25. ↑ U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data. The National Map, accessed October 5, 2012
  26. ↑ "Trout stream classifications - Wisconsin DNR".
  27. 1 2 "Use Designations - Wisconsin DNR".

External links

Wikisource has the text of the 1911 Encyclopædia Britannica article Dams.
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