As Arizona Nears Record Low Snowpack, Water Managers Urge Caution, But Not Panic
The Salt River Project (SRP) puts on an annual water expo, and this year’s featured a pile of cold, wet, white powdery stuff on a hot sunny day in Tempe.
SRP Hydrologist Andrew Volkmer put snowshoes on two young boys while their guardian looked on.
This is the first time they’ve worn snow shoes, they said, and their guardian said someone might need to explain to them first what snow is.
Volkmer’s job today is to explain exactly what snow is, and why it’s so important for the state’s water supply.
“You guys want to measure some snow while you’re in them?” he asked.
“Yeah,” they said in unison.
Volkmer plunges a hollow aluminum tube into the waist-high snow pack simulator. He pulls it out and looks at a slot in the pole with a ruler on it. That shows how deep the snow is. Then, he puts it on a scale and weighs it; that shows how much water would be in the snow once it melts.
This is the same process used everywhere snow is measured, weighed and recorded to calculate the eventual runoff when it melts.
Volkmer was happy to explain it to people of all ages. One group, Zarena Brotestante and her mother, were wide-eyed as they learned how the snow melts to become the water they use.
“And then we use that to run into our models to determine how much is in our reservoirs,” Volkmer said. “And that gives us a good idea of where our reservoir levels are going to be at the end of winter.”
“Oh wow,” Brotestante said.
Right now, SRP reservoir levels are 61 percent full. Not great, but not terrible either, according to SRP Surface Water Resource Manager Charlie Ester.
“We’re actually in pretty good condition,” Ester said.
That’s all because of planning. Ester said SRP plans 11 years ahead for water supply.
However, this year’s snowpack has been severely dry. Ester said without late-in-the-season snowstorms, the 2018 total runoff from that snowpack could be one of the driest on record in 105 years.
“While we’re increasing the amount of groundwater we’re going to use this year that’s not because this year is dry,” Ester said. “We’re looking out to next year. What if next year is just as severely dry and maybe even worse?”
Water Comes From Snow In High Country
The winter snow in Arizona’s high country melts and goes into the Salt and Verde Rivers. SRP has dammed up those rivers to fill reservoirs, which are managed and sent through canals for city use. Since there is less than half of the snow melt amount typically flowing into those reservoirs, Ester said the company will use more groundwater as a supplement.
Ester said everyday water users don’t have to worry about cutbacks now. But, he said, water in the desert is a luxury.
“We have enough water to use but not to waste” Ester said. “We should treat every drop of water like it’s a precious resource — because it really is.”
Ester said it's also important to educate Phoenix-area residents to where their water comes from because so many people that live here are from somewhere else.
"The Valley of the Sun has such a dynamic population," Ester said. "So that means people are coming from all over the United States and hopefully they knew where their water came from in those places but it's more than likely not going to be the same here."
Most of the Valley’s water starts 100 miles away as snow falling in the mountains near Pine, east of Camp Verde where U.S. Department of Agriculture engineer Travis Kolling drives an all-terrain vehicle to get to a testing site.
“The was actually an old forest road,” he said on the ride up.
That old forest road ends and the evergreen trees grow tall and thick where there’s practically no snow.
Finally, sparkly white patches appear closer to the site and the snow crunches underfoot.
Kolling and his partner are with the USDA's Natural Resource Conservation Service in Arizona. They went from spot to spot collecting data. Their boots sank into the snow and the shallow pack today is another example of how dry this year has been.
“Usually we have to wear snowshoes for this,” Kolling said, laughing.
His partner jotted down the inches of snow before Kolling poured it into a bag for weighing.
“This is our official snow survey Walmart bag,” he said.
Last year was a wet winter, but this year looks like drought conditions again.
“It’s pretty low,” Kolling said. “Normally this is the peak snowpack, and it’s already melting out.”
Arizona’s snowpack this year is far below normal at 28 percent of the normal snowpack as of March 1.
Report: Western Snowpack Shrinking Due To Climate Change
Collecting snow data is a low-tech test that’s been practically the same since measurements began in the 1920s. That makes for an appealingly standard data set for scientists like Director of Oregon Climate Change Research Institute at Oregon State University Philip Mote.
“The number of trends going down a lot relative to [the data’s] variability were much much greater than what you expect by chance,” Mote said.
Mote led a study that found the Western snowpack across the board is declining due to climate change. Arizona showed more of a decrease than most.
Mote’s not sure why Arizona stands out, but overall the reasons for less snow and therefore less water runoff on average are those warmer surface temperatures.
“Indeed the warming trends we have observed are the culprit in the decreases in snowpack that have been observed,” Mote said.
Mote ran the weather data through a model twice: once with observed climate warming trends and again without those trends. Only the climate change simulation mirrored real-life snowpack numbers.
Water managers like SRP’s Charlie Ester will keep worrying about water supply, like they do every year.
“I don’t think we need to be worried now at this point. But managing water is always — ” Ester paused. “There’s that uncertainty of climate. And we don’t know what the future’s going to bring.”
Unless a major snowstorm comes through, it’s likely that the snow and the runoff are going to be near record lows again.
This story is part of Elemental: Covering Sustainability, a new multimedia collaboration between public radio and TV stations in the West, and part of ongoing Colorado River coverage in partnership with KUNC.