Andy Larsen: Yes, we can save enough water to preserve the Great Salt Lake. Here’s how.

If you’re reading this column, you’re probably concerned about the declining tides of the Great Salt Lake. After all, 80% of Utahns are — and I’m guessing that percentage rises when you consider newspaper readers.

I wanted to highlight some visuals from the Great Salt Lake Strike Team’s recent report. Researchers from the University of Utah, Utah State University, the Utah Department of Natural Resources and the Utah Department of Agriculture and Food combined to give an encompassing view of the lake’s plight, along with the various policy levers that can be applied to it.

The current state

The Great Salt Lake dropped last year to its lowest point in more than 150 years.

That has all sorts of impacts. It hurts the brine shrimp. It hurts the overall ecosystem. It hurts our ability to use the lake for recreation. We’re now in the “severe adverse effects” range, which means additional woes in terms of using the lake for mineral production and, in fact, it’s low enough to damage our air quality.

With low levels, more lakebed is exposed. That creates dust “hot spots,” which in turn will likely lead to violations of the National Ambient Air Quality Standards created by the U.S. Environmental Protection Agency. Bonus badness: The dust also contains high levels of arsenic that can cause cancer.

Why this is happening

The report shows that the shrinking lake isn’t primarily due to changes in the natural flow of water in the Great Salt Lake Basin. In fact, it states, “natural flow in the basin does not show a declining trend over the last 30 years.”

So why is the lake shriveling? The end stream flows into the lake have reduced, due to natural and human factors. Research indicates that 8% to 11% of the lake’s decline is from increased evaporation as a result of climate change, with a further 15% to 23% due to natural variability in rain patterns and runoff efficiency.

That leaves 67% to 73% of the lake’s downfall as a result of natural and human consumption of the stream flows — choices we’ve made with our water usage that we can impact.

The vast majority of the consumption — about 1.3 million acre-feet of water — is from agriculture. All commercial, industrial, institutional and residential uses combined are less than a third of that. Reservoir evaporation and managed wetlands use another chunk, as do the companies that extract mineral resources from the lake.

How much water do we have to give back to the lake?

So now we know why the lake is going down. But how much water would we have to give back for it to fill to an acceptable level?

The researchers studied that, too:

If we wanted to get the lake back to the optimal range at 4,198 feet in the next five years, we would need to save 1.3 million to 1.9 million acre-feet of water a year. If, instead, we want that to happen in 20 years, we need between 540,000 and 1.1 million acre-feet a year.

Once we get there, we would need to maintain that level by saving between 494,000 and 1.02 million acre-feet a year.

How we can save that much water

To its immense credit, the report is solutions-focused, evaluating multiple paths to saving water. It creates four scenarios.

• Scenario 1 saves the amount of water needed to prevent further drops in lake elevation by spreading reduction evenly among agriculture, municipal and industrial, along with extraction companies.

• Scenario 2 saves the amount of water needed to bring the lake up to a somewhat acceptable level in 20 years — about 600,000 acre-feet — by spreading reduction evenly among the three human contributors.

• Scenario 3 saves the 600,000 acre-feet by primarily putting the burden on municipal and industrial water use.

• Scenario 4 saves the 600,000 acre-feet by primarily putting the burden on agricultural water use.

Here’s one lesson I took away from all this: No matter what we do, agriculture needs to save a whole lot of water. Even if we want only to stop the lake from shrinking further, it needs to save 208,000 acre-feet of water a year. And, in a recovery mindset, even if we put the burden on every other user of water, agriculture would need to save 238,000 acre-feet of water a year. If we ask agriculture users to contribute their fare share of water reduction, they would need to save at least 416,000 acre-feet.

What are some solutions?

The report focuses on 11 potential solutions for the Great Salt Lake. Pages 20 to 33 zero in on these solutions, and I encourage you to read those pages. But here’s a summary:

The first listed solution is kind of bedrock for the other 10: ensuring that conserved water through these other efforts actually ends up in the Great Salt Lake. Right now, conserved water may not be rerouted to the lake — water commissioners need to ensure that it gets there rather than heading to other uses.

Of the remaining 10, seven are classified as a 1 on a 1 to 5 scale of how much water they would bring to the lake, meaning they only help the water problem “a little.” Those seven solutions are: optimizing municipal water pricing; limiting municipal water growth; thinning Utah forests; optimizing mineral extraction processes; increasing winter snowfall with cloud seeding; raising and lowering the railroad causeway that bisects the lake; and mitigating the dust hot spots. Those may well be solid ideas, though all come with costs. Some come with risks, too. Thinning Utah’s forests, for example, may not work as intended.

One solution would deliver a huge amount of water to the Great Salt Lake but is crazy and expensive: a 13-foot diameter pipeline from the Pacific Ocean could add about 500,000 acre-feet a year. It would also cost more than $100 billion, plus there would be the ecological impacts of building a pipeline hundreds of miles long delivering differently saltwater to the lake.

So we’re left with two potential solutions that make more than “a little” difference without being insane: “water banking and leasing” and “agriculture water optimization.”

The strike team estimates that the state could lease 200,000 to 300,000 acre-feet of water rights from mostly agricultural users at a cost of $150 to $300 per acre-foot, and then distribute that to the lake. We should do that.

And with regards to water optimization, experts estimate that measures like improving water conveyance systems and improving on-farm water use could save 10% to 15% of water used, or 180,000 acre-feet a year, with minimal crop loss.

If we want to save more than that, according to the report, we’d likely need to pay some farmers not to use some of their land to grow crops — especially water-thirsty alfalfa. This approach would also act as an adjustable lever. If we want the lake to be higher, simply pay more farmers to fallow their land. (Part of me wishes we could limit alfalfa grown by statute rather than through economic incentives, but I realize that’s a political no-go in Utah.)

In the end, the report estimates that these measures would cost the state between $60 and $400 per acre-foot of water.

Regardless, the report is as clear as can be. It outlines our current problem, the amount of water that needs to be saved, and the potential solutions — some that will work and some that won’t be enough — that can fix our lake.

Now, it’s up to our politicians and policymakers to implement those fixes — before it’s too late.

Andy Larsen is a data columnist for The Salt Lake Tribune. You can reach him at alarsen@sltrib.com.

Editor’s note • This story is available to Salt Lake Tribune subscribers only. Thank you for supporting local journalism.