3 charts that show why Great Salt Lake is still in trouble

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Hi, Leia Larsen here, The Salt Lake Tribune’s water and land use reporter. Happy Tuesday.

There’s a gorgeous waterfall at the mouth of Ogden Canyon. It lures hoards of drivers who pull off the road and marvel at the landmark, snapping a few selfies and landscape shots.

But it’s rare to see the waterfall running this time of year.

(Here’s what the waterfall looked like Thursday, when I snuck away from my desk to get a couple laps in at the mountain. Don’t tell my editor.)

That’s because the Ogden Canyon waterfall isn’t a natural feature. It’s the result of a flume carrying water from Pineview Reservoir down to canals running north to Box Elder County and south to communities in Weber and Davis counties.

“It’s an overflow, basically,” Scott Paxman, general manager of Weber Basin Water Conservancy District, told me last week. “Like a pressure release.”

Water managers don’t typically “turn on” the waterfall until irrigation season begins in the late spring. This year, they started releasing water from Pineview and other dams along the Weber watershed around mid-February, however, in anticipation of the massive runoff season we’re expecting after an epic winter.

“Our reservoirs, on average, are about 50% full right now,” Paxman said. “So we’ve got lots of room, but there’s still lots of snow and water up there that’s got to come down.”

And with no one irrigating downstream just yet, all that surplus water is making it all the way down to the Great Salt Lake. The lower Weber River, just one of three tributaries to the lake, is currently gushing at 600 cubic feet per second, Paxman said, or around 270,000 gallons per minute.

So, with the coming deluge of snowmelt this spring, how much can we expect the Great Salt Lake to rise?

It’s tough to say, since there’s still plenty of time for more snow to accumulate. Utah Snow Survey data show Utah’s snowpack currently sits an impressive 169% of average. After the weekend’s storms, watersheds within the Great Salt Lake basin range between 154% and a whopping 201% of average. And we still have 20 days until our snowpack reaches its typical peak.

(The Bear, Weber-Ogden, Provo-Utah Lake-Jordan and Tooele Valley-Vernon Creek watersheds fall within the Great Salt Lake basin.)

All these storms and early season releases have already given the Great Salt Lake a boost. It’s currently a couple feet higher than it was in November, when it bottomed out at a historical low of about 4,188.5 feet above sea level. As of Monday, it’s at about 4,190.5 feet.

In terms of how much more the lake will rise, we can glean a few clues by looking at other big winters in recent years.

Snow totals are a bit higher than the winter of 2017, which caused devastating flooding and landslides in Box Elder County. But then the average annual elevation of the lake only rose by about 8 inches.

The winter of 2011 also saw an astounding amount of snowpack. The ensuing runoff breached a levee on the Weber River, flooding homes and farms.

(“SWE” means “snow water equivalent,” or the amount of water contained in the snow when it melts.)

All that inflow raised the lake another 3 feet by the 2012 water year. Utah’s snowpack is also currently higher than at this time in the 2011 season, but that particular snow year saw a whole bunch of accumulation in April.

Then, of course, is the catastrophic flooding of the mid-1980s that caused havoc across the Wasatch Front, including downtown Salt Lake City. That torrent came after many years of above-average snowpack, lasting from 1982 and until 1986, and it made the lake rise to its highest point in recorded history. Given our prolonged drought and meager snowfall up until this year, that scenario looks pretty unlikely.

Even if this spring’s snowmelt compares to 2011 or is slightly better, the Great Salt Lake needs to rise by about 8 to 10 more feet to reach a healthy level, where all the dust-generating lakebed is covered, salinity levels are low enough to support brine shrimp and brine flies, and mineral companies can sustainably harvest the lake’s brine.

(Notice that even with a handful of good snow years in the last few decades, the lake’s long-term trend is one of decline.)

In sum, we’re going to need more consecutive winters of epic snowfall for the lake to be in the clear. The same goes for Lake Powell in the Colorado River basin.

“Even in wet years, conservation is crucially important,” Paxman said. “We’re still in a drought, we still have issues with the Great Salt Lake, we still have declining groundwater levels.”

Climate change means Utah’s snowpack will become less reliable over time. Warmer temperatures mean more evaporation off the lake and reservoirs.

With that in mind, conservation needs to be a “way of life,” Paxman said, “not just a drought response.”