Oregon's desiccating lakes are in the news again. Two years ago I reported on an article from The Oregonian and threw in my ten cents as well regarding the desiccation of Lake Abert and whether it was due to natural processes or upstream water withdrawals.
In the current issue of the High Country News Hillary Rosner writes extensively about the situation in her article, When Water Turns to Dust. She alludes to a paper by Dr. Johnnie N. Moore of the University of Montana that suggests that climate forcing is less an issue than upstream water withdrawals.
I received Moore's paper: Recent Desiccation of Western Great Basin Saline Lakes: Lessons from Lake Abert, Oregon, U.S.A and have posted it below.
Although extremely important to migrating waterfowl and shorebirds, and highly threatened globally, most saline lakes are poorly monitored. Lake Abert in the western Great Basin, USA, is an example of this neglect. Designated a critical habitat under the Western Hemisphere Shorebird Reserve Network, the lake is at near record historic low levels and ultra-high salinities that have resulted in ecosystem collapse. Determination of the direct human effects and broader climate controls on Lake Abert illustrates the broader problem of saline lake desiccation and suggests future solutions for restoration of key habitat values. A 65-year time series of lake area was con- structed from Landsat images and transformed to lake volume and salinity. “Natural” (without upstream withdrawals) conditions were calculated from climate and stream flow data, and compared to measured volume and salinity. Under natural conditions the lake would have higher volume and lower salinities because annual water withdrawals account for one-third of mean lake volume. Without withdrawals, the lake would have maintained annual mean salinities mostly within the optimal range of brine shrimp and alkali fly growth. Even during the last two years of major drought, the lake would have maintained salinities well below measured values. Change in climate alone would not produce the recent low lake volumes and high salinities that have destroyed the brine shrimp and alkali fly populations and depleted shorebird use at Lake Abert. Large scale withdrawal of water for direct human use has drastically increased the imbalance between natural runoff and evaporation dur- ing periods of drought in saline lakes worldwide but could be offset by establishing an “environmental water budget” to lay a foundation for the conservation of saline lake habitats under continued threats from development and climate change.
Here are the paper's highlights:
A variety of hydroclimate data is used to calculate a “natural” water balance.
Upstream water withdrawals, not climate forcing, dominate recent desicca-tion.
Without withdrawals, salinity would remain tolerable even under recent drought.
Present water use threatens shorebird habitat in western North America.
Moore does a very good job and he's a smart guy. I lean toward climate forcing but that's just a gut feeling from my days in northern Nevada and its pluvial lakes.
“The biggest problem in the environment is people's quest to find the biggest problem in the environment." -- Jared Diamond