High temperatures and low precipitation have Utah water experts mentioning the ‘D-word’ again
St. George • When talk in southwestern Utah turns to “trickle down,” it is not centered on the November election or economic policies that lavish largesse on the rich and leave little for the poor.
That’s because the liquid assets most in the St. George area are concerned about is precipitation or, more precisely, the lack of it. In fact, there’s been so little of it that some are mentioning the D-word.
“As far as southwestern Utah goes, a majority of Washington County, a small portion of southern Iron County and the eastern half of Kane County are in the abnormally dry, low-drought category,” said Sam Webber, a meteorologist with the National Weather Service’s Salt Lake City office.
Southwest Utah is not alone. With a little over 2 ½ months to go until the start of the new water year in October, roughly 59% of Utah is abnormally dry, the lowest level drought category, and 4.7% of the state – largely in Tooele County – falls in the moderate drought category, according to the U.S. Drought Monitor.
Overall, precipitation in Utah stands at 102% of what is typical this time of year. But Laura Haskell, drought coordinator with the Utah Division of Water Resources, says that is a bit deceiving.
“Although precipitation is close to normal for parts of the state,” she said,” evaporative demand, or how thirsty the air is for water, has increased due to high temperatures.”
The heat is on
Last month, daytime high temperatures in St. George averaged 107.9 degrees, making it the hottest July on record, according to the weather service. Daytime highs in Washington County’s largest city have topped 100 degrees every day since June 21.
While Mother Nature has poured on the heat in southwest Utah, it has not put out much rain recently. Precipitation levels are currently 80% of what the region typically has received this time of year and about 69% of the total tallied by the state as a whole.
Other than a combined three-tenths of an inch of rain that fell in the St. George area between July 19 and July 25, along with a trace in late May, the area has not received any significant rainfall since April 28.
“There’s been almost no measurable precipitation,” lamented Jordan Clayton, supervisor of the Utah Snow Survey. “We have had well below-normal precipitation in [southwestern Utah] valleys for more than two months … and we are now between the 10th and 30th percentile range for precipitation in the mountains.”
Especially worrisome to hydrologists and meteorologists is the low soil-moisture levels in southwest Utah.
“We are concerned about soil moisture because it has been so hot and dry,” Haskell said. “Having wet soil is very important, especially in the fall, so that water during spring runoff is free to replenish reservoirs instead of having to go back into the soil.”
Unfortunately, Clayton said, soil-moisture levels in southwest Utah valleys are at or near historic lows for this time of year, which hydrologists began tracking when soil-moisture sensors were installed in 2005. Soil-moisture measurements in the mountains surrounding St. George, he added, are equally dire.
Weak monsoon, weather models stoke drought concerns
Still, thanks to two great water years preceding the current one, there is good news to report. While the heat and dearth of rain have taken a toll on reservoirs, the state’s stashes of water are still in relatively good shape. The water levels in Washington County Water Conservancy District’s two largest reservoirs are a bit lower than a year ago.
Sand Hollow is at 89% capacity, down 7% from a year ago, and Quail Creek stands at 67% capacity, down 8% over the same timeframe.
“We currently have a little over 80,000 acre-feet of water stored in district reservoirs, so we do not anticipate any municipal water supply shortages in the near future,” Washington County Water Conservancy District spokesperson Karry Rathje said in an email. “But we are always preparing for a drought. Washington County has been in some form of drought 80% of the time over the last 22 years.”
An acre-foot totals approximately 326,000 gallons, enough water to cover an acre of land about a foot deep.
In southwestern Utah, capacity at reservoirs currently averages 76%, compared to 83% at the end of June. Statewide — excluding Lake Powell and Flaming Gorge, which are part of the Colorado River water system — water levels at Utah’s reservoirs average 84%, down from 91% on July 1, according to Haskell.
Contributing to the dip in reservoir water levels and the lack of rain is Utah’s summer monsoon season, which has been weak thus far.
“We have seen monsoon activities, but it has been largely confined to Arizona and New Mexico, and has not reached Utah very much,” Webber said.
Nonetheless, above-average fall rains can ease concerns. Unfortunately, Webber noted, that might be wishful thinking. Current weather models call for between a 33% and 40% chance of below-normal precipitation in southern Utah over the next three months and between 40% and 50% of subaverage precipitation over much of the rest of the state.
“We are looking at the potential of the current La Nina weather pattern to continue through the winter, which generally favors below-normal precipitation in the [American] Southwest,” he said.
Relief may be in sight over the short term for most of Utah. Forecasts show a chance for thunderstorms over the weekend and early next week.
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