August rains improve soil moisture in Utah
Sep 28, 2021, 10:00 PM | Updated: 10:46 pm
SALT LAKE CITY — The water year in Utah comes to an end this week, and there’s not a lot to celebrate, but there is a little bit of hopeful news in the midst of this extreme drought — Utah’s soil moisture is now better than it was a year ago.
The new water year in Utah starts Oct. 1. That allows hydrologists to measure water resources at the beginning of the snow season, instead of the calendar year.
As the end of the water year nears, Utah will finish with 77% of average precipitation, in the bottom 10th percentile, all time.
Jordan Clayton, the snow survey supervisor for Utah, said the state’s reservoirs will finish the water year just below 50%.
“That’s pretty low for this time of year,” Clayton said. “It’s definitely lower than it was last year, but that’s not the worst that they’ve ever been. So again, it sounds bad, but not the worst.”
But, soil moisture, for most of the year, was the worst it’s ever been since snow survey hydrologists started measuring it a couple of decades ago.
“Up until somewhat recently, the driest on record,” the hydrologist said.
Then, rain arrived in August.
“More recently, when we got the monsoonal rain, it was unusually strong this year. That was quite helpful and actually pushed our soil moisture in the other direction,” said Clayton.
Now, soil moisture is about average, which seemed nearly impossible only six weeks ago.
When snow starts to accumulate, soil moisture stays about the same, until the snow melts in the spring and the runoff heads downstream.
“If we can go into our winter snow pack season with average, or above-average, soil moisture, we’re going to get a better delivery of that snow melt when it happens in the spring,” Clayton said.
When the soil is moist, runoff does not soak in. That’s what Utah needs to start refilling the reservoirs to recover from drought.
“What we are obviously hoping for is what we hope for every year: well above-average snow pack. Unfortunately, it’s going to take more than just one year of above-average snow pack to get us back on track.”
The hydrologist said it will likely take several above-average snow years to refill Utah’s reservoirs.
