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How much water flows to the Great Salt Lake? New streamgages might have the answer, officials say.

“You can’t manage what you can’t measure, and I think that’s the theme of the last few years,” said Deputy State Engineer Blake Bingham.

This article is published through the Great Salt Lake Collaborative, a solutions journalism initiative that partners news, education and media organizations to help inform people about the plight of the Great Salt Lake — and what can be done to make a difference before it is too late. Read all of our stories at greatsaltlakenews.org.

Before a newly installed streamgage went into the North Fork Weber River, the closest measuring device to the Great Salt Lake was in Plain City.

That gage is about 10 miles from the lake, said Deputy Great Salt Lake Commissioner Tim Davis, adding streamgages along the Bear and Jordan rivers also aren’t close to the lake.

“We basically had our backs turned to the lake” when streamgages went in, Davis said. “Historically, water that got to the lake was seen as wasted.”

There’s been a lack of information about exactly how much water is flowing to the lake, he said, but the state has started to realize the importance of better data over the past five years.

Officials have dedicated millions to figuring out the gaps in measurement, and now filling them — including $3 million from the U.S. Bureau of Reclamation to install and maintain 13 streamgages. The state will use $1 million more each year to install dozens more measuring devices in tributaries, said Deputy State Engineer Blake Bingham.

More than 200 additional devices are necessary to ensure water is getting where it needs to go and understand how it flows through the massive lake basin, Bingham said.

“It’s critical,” he said. “You can’t manage what you can’t measure, and I think that’s the theme of the last few years.”

No longer a rounding error

Though two good winters have helped the lake recover slightly, water levels are still below the 30-year average and a target level the state has defined as healthy.

The Department of Natural Resources has developed an elevation matrix for the Great Salt Lake identifying its healthy range — when islands are islands again, salinity levels help brine shrimp and brine flies thrive, and bird habitat is abundant — but the water is not so high that it causes the flooding and havoc, like that seen in the 1980s. That ideal level is between 4,198 and 4,205 feet above sea level.

As of Friday morning, the south arm was at 4,192.4 feet, while the north arm was at 4,191.6 feet. A rock-filled railroad causeway bisecting the lake restricts water from flowing north, which means the elevations in the two halves sometimes vary.

Measuring what used to be rounding errors when tracking water levels and how billions of gallons of water flow to the lake “gets more and more critical” as we try to save it, said David O’Leary, who heads the U.S. Geological Survey’s Utah Water Science Center.

But there are dozens of gaps in the system measuring hydrology in the basin, according to a report that analyzed 18 creeks and rivers in the watersheds that feed the Great Salt Lake as well as bird refuges, wildlife management areas, duck clubs and property around mineral extraction facilities.

(Rick Egan | The Salt Lake Tribune) David O' Leary, USGS Utah Water Science Center Director, talks about the monitor in the North Fork of the Weber River, on Monday, Nov 25, 2024.

Two types of information gaps

The gap analysis completed over the summer prioritizes where the state should update or add measuring devices in tributaries, Davis, the deputy commissioner, said, and there’s a second analysis going on now to determine where equipment should go on the lakeshore.

There’s a lot of desire to understand how water moves in the Great Salt Lake basin, engineer Bingham said, but officials “didn’t want to just start putting measuring devices in places without a deliberate approach.”

There are two types of gaps, he said, explaining some equipment is used to measure the water delivered to those who hold the water rights and others help officials better understand how water moves through the system.

The new North Fork Weber River gage installed in November in the Ogden Bay Waterfowl Management Area is the latter type, Bingham said.

It will help researchers understand water flow, salinity and other ways to monitor the Great Salt Lake’s health, O’Leary said.

(Rick Egan | The Salt Lake Tribune) Noah Lebsack pulls a streamgage monitor in the North Fork of the Weber River, to help understand streamflow, lake temperature, on Monday, Nov 25, 2024.

Those gages are expensive, Davis said, and the $3 million from the U.S. Bureau of Reclamation for 13 gages and other specialized monitoring equipment to help predict future lake levels and salt levels will run out in five years.

The Great Salt Lake Commissioner’s office will help find and leverage funding to keep those going past that point, Davis said, including the state agency’s funding from the Legislature or the $50 million the state is receiving from the Inflation Reduction Act through the Bureau of Reclamation.

Utah’s Division of Water Rights installs and manages diversion instrumentation that will fill other gaps, Bingham said. The team dedicated to doing that will have $1 million per year to spend, he said, adding that’s “a lot of money to spend in one year with the team we have.”

Some of those funds could help install larger streamgages through partnerships with other government agencies, Bingham said, to target key areas like the Spanish Fork River where it spills into Utah Lake or where that smaller lake releases into the Jordan River toward the Great Salt Lake.

Once streamgages and other equipment are installed and start taking measurements, that data will go to the Great Salt Lake Hydro Mapper.

That will fulfill a “huge public demand for water data,” Bingham said, and can serve a variety of needs for different government agencies and stakeholders.

Megan Banta is The Salt Lake Tribune’s data enterprise reporter, a philanthropically supported position. The Tribune retains control over all editorial decisions.