Water Development, Consumptive Water Uses, and Great Salt Lake

Abstract

Great Salt Lake (GSL) covers 5500 km² (2100 mi²) at its unimpacted elevation and is the eighth largest saline lake in the world. Its highly productive food web supports millions of migratory birds and the economic value of the lake is estimated at $1.5 billion US dollars in 2019. Droughts and wet cycles have caused huge fluctuations in lake level, area, and salinities, and this variation has masked anthropogenic impacts. Recent work, however, has determined that consumptive water uses in the watershed have depleted inflows by approximately 39%, with 63% used by agriculture, 11% by cities, 13% by solar ponds, and 13% by other uses. This has lowered the lake by 3.4 m, decreased its area by 51%, and reduced its volume by 64% as of 2019. Projected water development of the lake’s primary tributary could lower the lake approximately 1.5 m more. Climate change, to date, has not noticeably influenced lake level. Per capita water use in Utah is the second highest in the nation and is 2.6-fold higher than other semiarid nations. Potential solutions exist to reduce consumptive water uses and stabilize or increase the GSL water level. Water conservation is likely the most economical solution, with permanently mandated water cutbacks costing $14–96 million ($5–32 per person). Water conservation paired with water markets reduce costs further, costing between $2 and $16 per person. Descriptions of potential solutions to reduce consumptive water uses and stabilize GSL level are a starting point to encourage discussion. Strategies have yet to be prioritized or thoroughly evaluated. Quantifying water diversions from rivers that feed GSL and consumptive water uses will allow Utahns to make defensible decisions to manage water resources and the lake’s biology for long-term ecological, recreational, and economic benefit.