Deep in the Ansel Adams Wilderness
View of Rush Meadows in the Fall, a clearcut mudflat deep in
the Ansel Adams Wilderness. Mt. Lyell, the highest peak in
Yosemite National Park, is visible in the background.
Rush
Creek Meadows is a place that was clearcut, then dammed, and is now inundated
with water in Waugh Reservoir for four months of the year. From late September
to April of each year, the reservoir is drained, and crystal clear Rush Creek
flows through a clearcut mudflat with glistening ponds. You can just imagine the
glorious meadows that used to be there... and can be there once again, if we
remove this unnecessary dam that is only used 1/3 of the year.
Waugh Reservoir holds only about 5,500 acre-feet of water, and is filled in spring and emptied in late summer. In average and wet years this allows Southern California Edison to generate more electricity at the Rush Creek Powerhouse, and allows Gem Lake Reservoir to be kept higher in September. It also tends to keep Gem Lake lower in dry years during the summer, and in average and wet years it keeps Grant Lake Reservoir lower in the summer.
The average annual flow of Rush Creek is about 59,000 acre-feet. Just to do some back-of-the-envelope calculations, let's assume that in an average year about 45,000 acre-feet flows through the Rush Creek powerhouse, and without Waugh Dam only 40,000 acre-feet would (with the additional 5,000 acre-feet spilling over beautiful Horsetail Falls during spring runoff). Waugh would then increase the electricity production of the power plant by 25%. In dry years the reservoir is unnecessary--downstream storage allows full flow through the powerplant.
Coming
soon I'll have exact numbers, along with how many light bulbs we need to turn
off to make this dam totally unnecessary.
Waugh Reservoir is the only reservoir in the Mono Basin that is not an enlarged natural lake.
A full cost-benefit analysis will show that this dam should be removed. It can be removed slowly, with the spillway notched a foot lower each year, allowing restoration of the inundated area to proceed in a manner that will prevent large scale erosion. Bare areas will be colonized by plants as the water level recedes more each year until the dam is no longer used and the meadows are restored to their natural glory. The remaining dam structure can be left as a monument to the dam building era of the 20th century.
The nearest extensive high-elevation meadow is along the Lyell Fork of the Tuolumne River, just over Donohue Pass in Yosemite National Park. To get an idea of what Rush Meadows could once again be like, take a hike up the Lyell Fork from Tuolumne Meadows. It would be more the size of Glass Creek Meadow, on the back side of June Mountain. Better habitat, better scenery (especially in fall), and better water management will be the result of removing this dam.
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Copyright © 1998-2008
Gregory J. Reis
