Lab 9 A River Reborn

http://www.mthoodmagazine.com/summer/77-events/74-mt-hood-weddings (5)

Sandy River, Oregon

Sandy River flows from Mount Hood, Oregon to the Columbia river. The rivers volcanic and glaciated headwaters produce abundant coarse sediment.

Marmot Dam, located 45 kilometers upstream from the Columbia river confluence, was the only dam constructed on the main stem of Sandy river.



The Sandy river drains 1,300 kilometers of western Cascade Range in Oregon. Including the west-southwest flank of Mount Hood volcano, before joining the Columbia river 20 kilometers east of Portland.

http://en.wikipedia.org/wiki/Sandy_River_%28Oregon%29

Biome defined as an Alpine Tundra by

BIOMES OF THE WORLD (4)  

http://www.thewildclassroom.com/biomes/travelinfo/alpinetundra.html

Originally completed in 1913 as a rock-and-timber crib structure (Fig2), but was replaced by a comparably sized 14 meter-high, 50 meter-wide concrete dam in 1989. Portland General Electric (PGE) owned and operated the dam and used it to divert water from Sandy River as part of the companies 22-mega watt Bull Run Hydro-power Project. The bypass channel was created to allow fish, like  steel-head and salmon to go upstream. (Fig1)

Fig 1

Facing an expiring of U.S. Federal Energy Regulatory Commission license and substantial fish passage upgrades and future maintenance costs , PGE opted to surrender its operating license and agreed in 2002 to a decommissioning schedule that culminated in the 2007 dam removal.The decommissioning restored the Little Sandy River to steelhead and salmon runs for the first time in a hundred years. Marmot Dam had always contained a fish ladder. Portland General Electric, the dams' owner, donated 1,500 acres (6.1 km²) of land near the dams to a nature reserve. The final phase of the Marmot Dam removal was completed on October 19, 2007, when the temporary dam was demolished and the river started to flow freely for the first time since 1912. (Wikipedia 1)

Fig 2

PGE with U.S. Geological Survey (USGS), 
U.S. Department of Agriculture (USDA),
Forest Service, U.S.. Bureau of Recreation and U.S. National Oceanic and Atmospheric Administration performing broad study of the physical, biological and ecological impacts of this dam removal.
While other researchers examine effects on fish and related aspects of the rivering ecosystems, this organization as posted in the article (2)
EOS TRANSACTIONS, AMERICAN GEOPHYSICAL UNION
monitor the geomorphic effects of the Marmot Dam removal. With analysis over coming years of transient, storm-driven changes and cumulative consequences should shed the light on the progress and rates by which a high-gradient mountain river can respond to dam removal and consequent voluminous sediment input.


If you would like , here is a YouTube video of this process :
Marmot Dam Removal
<https://www.youtube.com/watch?v=i1NI2ia3nDw>

Sources:

1 )     "." . N.p., n.d. Web. 9 July 2014. <http://en.wikipedia.org/wiki/Sandy_River_%28Oregon%29>.


2 )      "." . N.p., n.d. Web. 9 July 2014. <http://or.water.usgs.gov/proj/marmot/Major_et_al_EOS_2008.pdf>.
  EOS, Vol.89, No 27, 1 July 2008

3 )      US Geological Society
"Dam Removal and Sediment Transport in the Sandy River Basin, Oregon." USGS Study of Marmot Dam Removal. N.p., n.d. Web. 9 July 2014. <http://or.water.usgs.gov/projs_dir/marmot/>.

4 )       Biomes of the world
"Biome Travel Information." Biome Travel Information. N.p., n.d. Web. 9 July 2014. <http://www.thewildclassroom.com/biomes/travelinfo/alpinetundra.html>.

5 )      Mt.Hood Magazine
"Mt Hood Magazine 2011." Mt Hood Weddings. N.p., n.d. Web. 9 July 2014. <http://www.mthoodmagazine.com/summer/77-events/74-mt-hood-weddings>.