Dear EarthTalk:

Why is the Great Salt Lake shrinking so much and can it be saved?

E.T., via email

Utah’s Great Salt Lake is the largest saltwater lake in the Western Hemisphere. It is a remnant of Lake Bonneville, which dried up 14,000 years ago due to extreme drought. It contributes $1.9 billion annually to Utah’s economy and provides 7,700 jobs. Over 10 million birds rely on this lake for their survival.

Apart from natural fluctuations, the Great Salt Lake’s water level has dropped continuously since 1870, mainly due to the desiccation of the lake in the diversion of upstream water. The Great Salt Lake gets most of its water from the Bear, Weber and Jordan rivers, but now a significant portion of water is being diverted for agricultural and industrial use. Climate change and increase in temperature are also contributing to the Great Salt Lake’s desiccation. Due to temperature increases, the rate of evaporation has also increased, impacting the salinity of the lake. Agriculture dominates water use by 74 percent, nine percent by mineral extraction, nine percent by industrial use and eight percent by evaporation.

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“The lake has a lot of social and economic relevance for the region and Utah,” says Siiri Bigalke, a climate scientist at Portland State University who has studied recent volume levels of the Great Salt Lake. Indeed, the cost of the Great Salt Lake drying—including loss of mineral extraction, landscape mitigation costs, the loss of lake recreation and economic value, the loss of brine shrimp, health costs, and impacts to ski resorts—could total as much as $2.17 billion per year. The decline in Great Salt Lake water levels could kill some 6,500 jobs, most of which stem from a loss of mineral extraction output. Researchers say the tax rate in Utah would have to increase by more than 50 percent to make up for these potential losses.

The desiccation of the Great Salt Lake will lead to air and water pollution, a decline in agricultural productivity, loss of industry, and economic devastation. Even if the lake is not completely lost, the shrinkage can expose lakebed sediments containing heavy metals and organic pollutants which could significantly deteriorate air quality.

To save the lake, a minimum streamflow of 2.5 million acre-feet per year must be maintained. Ensuring that river flow remains at or above this threshold is essential for stabilizing the lake’s water levels. Water flow to upstream farms should be limited. Local governments should coordinate with state and federal programs to expand water conservation awareness. You can get involved by creating and sharing media on this issue to raise awareness. Additionally outdoor vegetation should be converted to drought tolerant to conserve water.

CONTACTS

• The Aridification of the Great Salt Lake, https://ballardbrief.byu.edu/issue-briefs/the-aridification-of-the-great-salt-lake.

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