Reservoir levels bounce back
June 13, 2014
Water in Jordanelle Reservoir just reached 85 percent of capacity after stopping at a paltry 71 percent last summer. Rockport Reservoir — a source of Park City’s drinking water — currently sits at 88 percent. Deer Creek Reservoir topped out at 90 percent on April 30.
After two years of drought, life seems to be going swimmingly in 2014 in Utah’s high desert. Time to roll out a couple more golf courses, right?
Well, don’t start the earth movers just yet. A trio of area water experts says the area is still not out of the sagebrush, though two of the three acknowledge that there’s some improvement from a year ago.
The good news is that some "SNOTEL" automated measurement stations in the High Uintas reported at least average snowfall last winter. Among them were the Trial Lake and Beaver Divide stations that contribute a significant amount of water to the Provo River. The Provo, in turn, is the major source of water for both Jordanelle and Deer Creek reservoirs.
Last winter, the snowpack at Trial Lake topped out at about 114 percent of normal, according to Daryl Devey, Bonneville area operation and maintenance manager for the Central Utah Water Conservancy District.
"When you narrow it down to Jordanelle, we pretty much fill on what happens at the Trial Lake/Beaver Divide SNOTEL stations, and those stations were much better than the rest of the area, and (provided) much better streamflows than the rest of the area because of the good snowpack we had at Trial Lake," Devey said.
During a six-week period starting May 1, levels at Jordanelle rose about a foot a day, easily eclipsing the high-water mark from 2013. However, that increase has slowed to a trickle in recent days.
"It may go up just a tiny bit more, but that will be it," Devey said Thursday. "We expect it to start coming down in the next two weeks."
Devey said the majority of the water in the Jordanelle goes to culinary water systems along the Wasatch Front and irrigation companies in the Heber Valley. Devey said the Provo River Water Users’ Association, which allocates the irrigation water, is currently limiting users to 50 percent of their full allotment, although that percentage is expected to rise after the group’s next board’s meeting scheduled on June 26.
Less flush than the reservoirs on the Provo River are those in the Weber River drainage, which includes much of Summit County. In spite of encouraging numbers at Rockport Reservoir, storage in the Weber system as a whole is only slightly improved over last year, according to Mark Anderson, assistant general manager and chief engineer for the Weber Basin Water Conservancy District.
"This year we had about 11,500 more acre-feet than last year in our Weber system," Anderson said. "When I say Weber, that’s Wanship (Rockport), Echo, and we also include Lost Creek, East Canyon and Smith & Morehouse in that mix. So all those reservoirs added together — that’s why I say we’re slightly improved from last year."
As a point of reference, 11,500 acre-feet is less than 20 percent of the capacity of Rockport Reservoir alone. One acre-foot is about 326,000 gallons.
But the improvement over 2013 is enough that the district plans to operate in 2014 without "enforced restrictions of water allotments," he said
"In other words, last year we did reduce water companies by 20 percent. This year we will not do that. However, we intend to cease irrigation deliveries on Oct. 1, 2014. And we cannot overemphasize the importance of wise outdoor water use and voluntary reduction of use by our customers in order to protect this vital resource."
Three reservoirs on the Weber system, including Echo and Smith & Morehouse, filled this spring but "are starting to trend down now," Anderson said.
For the third year in a row, he said, runoff from the winter snowpack was below average.
"We had normal snowpacks in the upper elevations, but the intermediate snow was not there. It just didn’t materialize," Anderson said.
The missing snowpack at those intermediate altitudes is a concern to a Brian McInerney, a National Weather Service hydrologist who lives in the Park City area. McInerney said that a series of storms during February paid off at higher elevations such as Trial Lake but did little to benefit elevations below 8,000 feet.
"If you look at the entire water year, we got 85 percent of the water we would have liked. But if you were below 8,000 feet during those really good February storms, it fell in the form of rain. And when that happens, you don’t store it as snowpack in the mountains and then have it run off in the spring. It runs off right away. It goes into the upper levels of the soil, evaporates, the plants take it up if there’s any still not dormant during that time, and it just goes away," McInerney said.
"And then what happened was, we started going warm and dry into March, April and May. And we really needed to continue wet, cold spring conditions to pump up the water supply. But when you look, (streams in) the Weber Basin, which Park City is part of, on average they only received 65 percent of the water they typically get."
For the most part, municipalities won’t be affected by water shortages this summer, he projected. It’s the farmers who have lesser water rights who will feel the pinch.
"Suffice it to say, people in Park City will do fine. But we just don’t want to keep doing this. This is our third year in a row below average."
If the earth continues to warm, McInerney expects the mountains of northern Utah will see a shift away from what he calls a snow-driven hydrology.
"This year the percentage of that precipitation was greater than what we’ve seen in the past in the form of rain. And as a result we don’t have it to run off in the spring. And that fraction of rain to snow, the rain element, is pumping up," he said.
"Some of the studies I’ve seen from NASA and NOAA (the National Oceanic and Atmospheric Administration) indicated that by 2070 or 2080 we’ll be in a rain-driven hydrology, meaning we won’t have snow. We’ll be getting rain."