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SALT LAKE CITY — Authorities now believe enough time has passed to breach the Union Pacific causeway at the Great Salt Lake without detrimental effects to the ecosystem.
The causeway, which has sunk 15 feet since it was last replaced in 1959, is in danger of collapsing, making its use unsafe for trains.
Union Pacific worked with the U.S. Army Corps of Engineers to get necessary approval for the breach to conduct repairs, which include the installation of an 180-foot bridge and an earthen control berm to facilitate the right salt balance between the southern and northern arms of the lake.
The railroad planned to carry out the breach in October but delayed the action for 60 days because of concerns that increasing salinity would harm brine shrimp during their reproductive cycle and also impair migratory birds.
Laura Ault, sovereign lands program manager for the Utah Division of Forestry, Fire and State Lands, said there were two models used to calculate impacts of the breach, including a traditional simulation put together by the U.S. Geological Survey and a newer, interagency model developed particularly for the Great Salt Lake.
Both models demonstrated the effects of the breach on water and salinity levels. The breach is expected to lower the water level of the south arm by a foot and increase the level in the north arm by 18 inches.
Ault said the passage of time means threats to the brine shrimp and migratory birds have diminished.
More than half of the world’s eared grebes population migrates to the Great Salt Lake in late summer and feeds exclusively on brine shrimp. While there, the birds undergo a feather molt and become flightless.
The lake’s brine shrimp population dies off each December as lake temperatures drop. Eared grebes continue their migration south once their food source is gone.
“Union Pacific’s willingness to delay the breach significantly helped avoid risk to about 5 million eared grebes at a critical and sensitive time,” said John Luft, Great Salt Lake ecosystem project manager. “Opening the causeway at this point in time shouldn’t affect the brine shrimp or the grebes since the lake is entering a natural transition period.”
Water levels at the steadily vanishing Great Salt Lake are 11 feet below their historic level, and water at Farmington Bay since 2011 has plummeted to expose three-quarters of the lake bed.
The drought-fueled demise of the Great Salt Lake threatens a $57 million brine shrimp industry and $70 million hunting industry.
Overall, the Great Salt Lake, the fourth-largest terminal lake in the world, is estimated to contribute $1.2 billion per year to Utah's economy.
Wildlife biologists, scientists and hydrologists worry that the lake's continuing decline spells a vicious cycle of concerns — from increased air quality issues from wind-blown dust churned up from exposed lake beds, to less possibility of lake-effect snow because of the lake's meteorological role.
Ault said the breach will restore free flow of water between the north and south arms and could be carried out as early as Dec. 1. The process will take anywhere from a few days to a couple of weeks, she added.
