In years that start with a water deficit, like this one, melting snowpack saturates the soil first.
“In order to have a normal runoff season and get what you need into the reservoirs, you need above-average snowpack,” Bolinger said.
Bolinger said the Colorado Climate Center is working on a project that looks more closely at how much soil moisture plays a role in the snowmelt season.
Michael Elizabeth Sakas/CPR News
The effects ripple downstream
Poor snowpack efficiency doesn’t just impact Colorado. Reservoirs Lake Powell and Lake Mead are projected to shrink to historic lows in the coming months, which could trigger the federal government's first-ever official shortage declaration. That would mean mandatory water cutbacks in Arizona and Nevada.
The Colorado River, which starts in the Rocky Mountains of Colorado, feeds those reservoirs. The snowmelt supplies water to millions of people downstream. The forecast for Lake Powell is just 28 percent of average levels.
“This wouldn’t be a concern if Lake Powell and Lake Mead had more water in them, but they are already at critically low levels,” Bolinger said.
The record lowest inflow for Lake Powell was in 2002, a historic drought for the West. But Bolinger notes that Powell and Mead were “quite full at the time,” and believes there’s a chance this year could rival the record.
“We have not recovered from that 2002 drop,” she said. “I am extremely concerned about what this is going to mean for Lake Powell and Lake Mead.”
Michael Elizabeth Sakas/CPR News
From recreation to ranching
Some parts of Colorado rely on snowpack as its central water source. Sonja Chavez manages the Upper Gunnison River Water Conservancy District, where snowpack levels are around half of normal. With less snow melting off quicker, Chavez said it’s shortening the recreational season. If the snowpack was above-average, she said there could be six months of a season on the rivers.
“When you're in drought like we are right now, that season is concentrated into maybe four months,” she said. Low river flows can mean bad water quality from higher concentrations of metals and other contaminants, she said.
The lack of snow and monsoon rains also has a big impact on ranchers in the area, who are reporting lower hay production and smaller herd sizes.
“So this year we're starting to see our producers reduce their number of their cattle herd, and that has trickling economic effects throughout our basin,” she said.
Chavez said the Bureau of Land Management has reported that water wells drilled on federal grazing land are starting to dry up. “The groundwater supplies and levels are actually falling,” she said. “The city of Gunnison is actually dependent upon groundwater well supplies for our municipal water uses.”
Chavez said there’s a sense of urgency for water managers to plan for worst-case scenarios. She said more people have moved to the Gunnison area because of the COVID-19 pandemic allowing for remote work. Some of the water rights on those homes are newer.
“Some of those junior water right holders, they just may not get their water at all which is a concern,” Chavez said. That situation has been avoided in the past by educating folks on how to best use the water they do have.
Michael Elizabeth Sakas/CPR News
What it means for fire season
Chavez said there’s a lot of worry about wildfires since the Gunnison River Basin is surrounded by federal lands. Kelly Gleason is an assistant professor of ecohydrology at Portland State University. She’s researched how the effects of climate change on snowpack influence wildfire activity.
Gleason said that snowpack has declined dramatically across the West and other mountain states. When that snow melts earlier, it’s like opening a dam in the spring, she said. The result is less water available in the summer months for both people and ecosystems. Another symptom of snow disappearing from the landscape earlier is an extended drought and fire season, Gleason said.
“The earlier the snow melts, the drier the landscape becomes in that late summer period before fall rains sort of drown the system again,” she said.
Without the slow trickle of moisture from melting snow, vegetation in the forest dries out, creating fuel sources primed for wildfires. Snowpack that collects in areas of the forest that have recently burned collects black carbon and is exposed to more sunlight, Gleason said.
“That blackened gunk acts like a black t-shirt on a sunny day, absorbing solar radiation,” Gleason said.
Gleason said that snowpack behavior and reliability are no longer "business as usual" due to climate change.
The Link LonkMay 17, 2021 at 07:55PM
https://www.cpr.org/2021/05/17/dry-soils-and-drought-mean-even-normal-snowpack-cant-keep-up-with-climate-change-in-the-west/
Dry Soils And Drought Mean Even Normal Snowpack Can't Keep Up With Climate Change In The West - Colorado Public Radio
https://news.google.com/search?q=dry&hl=en-US&gl=US&ceid=US:en
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