Despite a wet winter and spring, Tooele County dried out over the summer, finishing the official water year slightly below average.
Tuesday marked the end of the water year, which began Oct. 1, 2007. According to Randy Julander, snow survey supervisor at the Salt Lake City office of the Natural Resources Conservation Service, the basin average for precipitation in Tooele County for the water year ended up being 89 percent of normal. That still marked an increase from the previous water year, which was only about 75 percent of normal.
He said 1999 to 2004 were basically below-average years. In 2005, precipitation was at 133 percent of normal in Tooele County, and in 2006 it was at 110 percent.
“We bounce around in the 80 percent to 120 percent range most frequently,” he said.
Julander said the Rocky Basin measuring station in the Oquirrh Mountains was at 91 percent of normal; Vernon Creek was at 89 percent of normal; and Mining Fork in the Stansbury Mountains was at 82 percent of normal. “It’s pretty close to an average year,” he said. “It’s right on one of those thresholds. We consider average anywhere between 90 and 110 percent.” He said Settlement Canyon Reservoir is at 30 percent of capacity; Vernon Reservoir is at 0; and Grantsville is at 18 percent of capacity.
Those low numbers are typical at this time of the year. In addition, Vernon Reservoir was drained, beginning in mid-September, to clear out debris blocking the reservoir’s outlet to allow for better water flow. “Snowfall-wise we actually did OK,” he said. “We were close to average there as well.”
Julander is paying attention to several climatic trends that could affect the water year ahead.
The Pacific Decadal Oscillation (PDO) — an index based on variation patterns in sea surface temperature — has shifted from a warm phase to a cold phase, Julander said. “Typically when that happens you get more snow on average in the Pacific Northwest,” he said, adding that may lead to more precipitation in Utah. “We’ll see what it brings to us as well.”
However, Julander said since Utah is in a neutral zone, “sometimes El Nino/La Nina hits us hard and sometimes they don’t. The same is true for PDO. Sometimes it comes in big time, sometimes it just kind of fades along.”