Quoting the article from the US Fish and Wildlife Service: The removal of larger hydroelectric dams, such as those on the lower Snake River, has been very controversial and currently is not being considered as an option. Its time removal of the lower Snake River dams IS considered an option. We hear that theres no need to take down the dams, because we just had record salmon runs up the Columbia River. The record runs go back to 1938, when the first dams went in. Now there are 8 dams between the Pacific and the upper Snake River. In 1938 and until about the 1990s environmental devastation and overharvesting were rampant. In the 1990s most runs of Chinook were listed as endangered and since then there have been massive restoration efforts, which are now having a good effect in stronger runs. Also, since 2006 the BPA has been required by court rulings to allow increased spillage over the dams, allowing far more juvenile salmon to get to the sea, which has helped increase runs. Add in favorable ocean conditions and we have the ingredients for record runs, but only if you start your baseline from 1938 when runs were in terrible shape already. If you go back another few decades (although the destruction was well underway 150 years ago) there were many millions more salmon, especially Chinook, per year. These record runs are equivalent to the terrible runs in 1938, and are the best we can hope for, unless the four lower Snake River dams are removed or bypassed. Then the runs could easily double or triple, with access to 140 miles of now flooded mainstem riverbed, where Chinook prefer to spawn, and to the 5500 miles of upstream spawning beds. As it is, very few fish can make it up there to spawn right now, and very few smolts can make it downstream to grow into new generations. fws.gov/salmonofthewest/dams.htm
Posted on: Sun, 21 Dec 2014 19:11:39 +0000
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