A Terminal Lake’s Fate

May 24, 2017

The Salton Sea is a terminal lake with no outlet. It was created by accident between 1905 and 1907, when water from the Colorado River flooded the basin. Since then, it has been fed largely by water flowing from the Imperial Valley’s farms. And today this desert lake is the keystone in a complex puzzle of policy decisions concerning water supply for several southwestern states.

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Here’s why: The Colorado River is over-allocated. It feeds Lake Mead, a primary water source for Southwestern states. In an effort to prevent Lake Mead from reaching dangerously low levels, California, Arizona, and Nevada are working to negotiate a drought contingency plan to reduce diversions from the Colorado River. When the lake drops to elevation 1,045 in the coming years, California will reduce its water withdrawal by 200,000 acre feet.

The Imperial Valley Irrigation District (IVID) is the largest single diverter of Colorado River Water. Therefore, the State of California will rely on the district to make a significant reduction in its water withdrawals. However, as Michael Cohen of the Pacific Institute explained to Water Deeply’s Matt Weiser, 85 % of the water flowing to the Salton Sea comes via runoff from the Imperial Valley. If the district reduces its Colorado River diversions, less water will drain into the Salton Sea.

At the end of 2017, flows will decrease. Consequently, the Salton Sea’s water level will decline, setting into motion a series of ecological issues including dust and air pollution from the drying lake bed, dying fish, and loss of bird habitat. As the water recedes, the rate of exposure is estimated at 3,000 to 5,000 acres a year, to create a total of 48,300 acres of dry lakebed by 2028.

To further complicate the matter, as the sea shrinks, it will represent a cost to the IVID since under air district regulations, dust control is the responsibility of the landowner and the district owns a significant amount of acreage along the lake’s southern end. Although the state has pledged to help, mitigating the dust from miles of exposed playa will be expensive for IVID.

In March, the State of California laid out a revised plan that allocates $383 million to build 29,800 acres of “constructed habitat” along the Salton Sea’s shore over the course of ten years. Next year it will begin design and construction of a network of ponds and wetlands for which water will be diverted from the Alamo and New rivers. While not a long-range solution, the plan is considered a viable strategy to protect public health and wildlife and mitigate harm to surrounding ecosystems.

According to historical accounts, the desert basin has been dry at times and at others, filled with water. Water-lined rocks remain as visible evidence of these shifting levels. It seems a hydrologic puzzle that even nature has struggled to solve. What recommendations to do you have for the Salton Sea’s shell game?
About the Author

Laura Sanchez

Laura Sanchez is the editor of Distributed Energy and Water Efficiency magazines.