At the moment, Colorado finds itself grappling with its worst wildfire season ever. Hundreds of thousands of acres burned in eight significant fires this fall, including the three largest on record, as all of the state drifted into drought status for the first time since 2013.
“So much of this is happening in real time and on scale that makes it difficult to pause long enough to figure out a long-term strategy because they are dealing with these impacts every day – though many are trying,” Smith said.
In real time, the threat to water supplies by forest fires is front and center.
Over the past few decades, forest fires have been more frequent and larger in a hotter, drier West. This year’s unparalleled wildfire season Colorado coincided with the state’s warmest August on record.
Studies have shown that average summer temperatures in Colorado have risen by more than 2.5 degrees Fahrenheit since 1986. The growing heat creates drier soils, lower snowpack, earlier thaws, lower stream flows.
All those add up to increased risk of wildfires and, according to one study, added 26 days to the average fire season in the West between 1979 and 2015, a 41% increase.
There are serious risks when wildfires fires damage or destroy the watersheds towns and cities rely upon for their drinking water.
“Burned watersheds are prone to increased flooding and erosion, which can impair water-supply reservoirs, water quality, and drinking-water treatment processes,” according to the U.S. Geological Service.
The 2010 Fourmile Canyon fire, for example, burned just 23% of the watershed near Boulder, still a USGS study found that after severe thunderstorms the water heading to the city’s water treatment plant was laden with mud, nutrients and metals – some at levels four times normal.
After the High Park fire burned more than 87,000 acres in Larimer County in 2012, the Poudre River ran black after heavy rains and choked the intake pipes of Fort Collins’ water treatment plant. The water smelled and tasted like smoke.
The city now has sensors in 10 locations in the Upper Poudre to alert the treatment plan if there is a water quality problem and Fort Collins Utilities runs an average of 110 lab tests a day on its water.
Fort Collins is now “very concerned” about the Cameron Peak fire, the state’s largest fire ever, burning west of the city, Gretchen Stanford, a utility spokeswoman, said in an email.
The utility’s Horsetooth Reservoir is out of commission for upgrades, leaving it only with Poudre River water. Stanford said processes are in place to deal with any water quality, odor or taste problems.
And the effects of these fires can last for years. Five years after the 2002 Hayman Fire, Denver Water was still dealing with water quality problems created by the wildfire, including a $30 million project to remove tons of sediment from the Strontia Springs Reservoir
“We didn’t need that fire”
Glenwood Springs’ economy was already suffering from the coronavirus when the 32,600-acre Grizzly Creek fire – the biggest in the history of the White River National Forest – closed Interstate 70 for two weeks. “It has been a tough year for everybody and we didn’t need that fire,” Kaup said.
While the city has good water rights from the Grizzly Creek and No Name Creek drainages, it was already looking for back-up supplies, Kaup said.
Glenwood Springs has the ability to draw water from the Roaring Fork River, but not the ability to combine it with the city’s existing supplies – that is the goal of the multimillion-dollar upgrade.
“We can’t put any one event on climate change, but my goal is to see Glenwood as resilient and responsible as it can be,” Kaup said. “There is a rising awareness that we need more storage.”
Even before the Grizzly Creek fire, concerns were rising about the impact of climate on the city’s water supplies. “In 2018 No Name Creek came close to not having enough water, that only happened one other time in the history of the city,” Kaup said.
In Carbondale, dwindling flows in the Crystal River created a near crisis in 2018 and accelerated changes to the town’s water system.
The low flow in the Crystal River, a tributary of the Roaring Fork River, led to the Ella Ditch exercising its senior water rights on Nettle Creek so it could meet the needs of one of its ranchers.
Nettle Creek feeds into the Crystal and the call would have left about 50 homes on the Nettle Creek pipeline with no water. Carbondale was able to get an emergency substitute supply.
“We’ve always had droughts, but the frequency is increasing and the water budget is changing,” said Jay Harrington, Carbondale town manager, referring to the amount of water that is available to the city.
A warming world will create drier soils, more evaporation and more water sucked up by plants and all that led to lower stream flows, according to several scientific studies.
“There is no question that climate change is affecting stream flow,” said Brad Udall, a senior researcher at Colorado State University’s Colorado Water Institute.
Heat, not a lack of precipitation, was the key driver in a 20% decline in Colorado River flow between 2000 and 2014, compared to 20th century averages, and if the current trends continue, it will decline another 20% by 2050, according to a study co-authored by Udall.
Since 2000, the Roaring Fork’s streamflow has been about 13% lower than the 20th century average, according to a study done for Carbondale by the Western Water Assessment, an affiliate of the University of Colorado.
The study found that while there was no appreciable change in the average snow and rainfall the average temperature for the area increased 2.2 degrees Fahrenheit above the 20th century average.
That trend is projected to continue. “All climate models indicate that the climate of the Roaring Fork Valley will continue to warm well into the 21st century. Under the lower-emissions scenario, by 2050, average temperatures are projected to be 3-5°F warmer than the late-20th century average,” the study said.
This has spurred Carbondale to action. The Nettle Creek pipeline is being retrofitted to be able to pump water up the line from the Roaring Fork River, as well as taking it from a Crystal River well.
“We had plans to expand our treatment plant and well capacity in the Roaring Fork River drainage,” Harrington said, “but after 2018 we accelerated the $600,000 project.” The upgrades are slated to be completed before the end of the year.
It’s a problem on the Front Range, too
The Carbondale and Glenwood Springs water projects are a sign of things to come. “What people are looking for now is redundancy, multiple sources of water supply,” Udall said. “One source, one pipeline has become a risk. It’s like betting on one stock.”
It is not only low stream flows but the timing of those flows that are presenting problems for some communities, such as Northglenn.
“Climate change isn’t going to impact Northglenn from a quantity perspective, but from a timing perspective,” said Tamara Moon, the city’s environmental manager. “The city has water rights that come into priority in the fall and rights in late May and early June. A concern is we may not have the availability of water in the fall that we have now.”
Northglenn’s worries are prompted by three trends associated with climate change: lower snowpack, earlier thaws and hotter summers. They could add up to less water in the fall.
One study led by John Abatzoglou, a University of Idaho geography professor, used 20 different climate models and federal data on snowpack to assess potential changes and projected a 5% to 20% decline in snow levels in the central and southern Rockies by 2050.
The snow season will also shorten, with more precipitation coming as rain instead of snow and earlier thaws of the snowpack, according to the study. All this could change the timing and availability of water supplies creating a need for alternative supplies or more storage.
“It is entirely possible if the runoff is early, we may not get our full quantity,” Moon said, “and in dry years we may not get the fall water.”
This scenario has Northglenn looking for ways to capture and store more water during the spring.
“We are trying to find alternative water resource storage,” Moon said. “We are looking at alternatives along the South Platte and working with other communities in the area.”
Standley Lake is Northglenn’s primary storage site. The city has 7,000 acre-feet of capacity in the 42,000-acre-foot reservoir in Westminster. Westminster and Thornton have the rest of the lake’s capacity.
An acre-foot is enough water to serve two Colorado families – or eight to 10 people – for a year, Northglenn has 37,000 residents.
The city is also developing underground storage in town using some existing wells to inject the water into the aquifer. “We could pump in 200 acre-feet a year,” Moon said. “It’s not a ton of capacity but could help us bridge some gaps during drought.”
Summit County’s problem in the future – as it was in 2019 – may not be too little snowpack, but what happens to that snowpack during the winter.
Between March 7 and 9, 2019, the county experienced a rash of avalanches, the biggest dumping more than 20 feet of snow and debris on I-70 west of Frisco.
After the Colorado Department of Transportation dug out the highway and started avalanche mitigation, there were 21 avalanches in a matter of weeks.
“Silent Bob, an avalanche path just outside of Frisco, hadn’t run in a hundred years and one night it did,” said Michael Wurzel, the county’s sustainability coordinator. “The whole town of Frisco woke up, looked up and said “What happened?’”
There were avalanches unleashed all over the state that March. In a two-week span 1,000 avalanches were reported, including an unprecedented 87 major ones, closing roads, damaging homes and killing four. The biggest was southwest of Aspen, the Conundrum Valley avalanche, a mile-wide and 3,000 vertical feet.
“We’ve never seen an avalanche cycle like this,” said Brian Lazar, deputy director of the Colorado Avalanche Information Center. “Not only was it the historic size of the avalanches, but that they covered most of the mountainous terrain in Colorado. … That hasn’t happened in living memory.”
There was a series of events that led to the avalanche of avalanches – early October snow that created a weak layer, followed by a steady buildup of snow in mid-winter, and then a series of “atmospheric river” storms for 12 days in March.
An atmospheric river is a narrow jet of air, from 250 to 350 miles long, laden with moisture from the tropics. One such atmospheric river reached Colorado, dumping wet, heavy snow atop the large snowpack and the weak layer beneath.
A NASA study projects that in a warming world, these atmospheric rivers will intensify and while they are a bigger concern for flood events on the West Coast, Lazar said “they do make it through to the mountains.”
There are other forces at work that may change avalanche risks in Colorado as climate changes. Abatzoglou’s analysis of snowpack shows that for the Rockies, snow will come less frequently but in larger storms. Lazar said rain-on-snow events or melting and freezing of snow could contribute to creating weak layers, a key ingredient for avalanches.
“Avalanche activity is driven by weather and snow pack conditions,” Lazar said. “If the climate is changing, the weather is changing.”
The aftermath of the cascade of avalanches left Summit County with one big challenge: its Ten Mile Canyon Recpath, a bike trail between Frisco and Copper Mountain, was buried under more than 20 feet of snow and debris.
“The Recpath is a huge part of the summer economy and we had to get it open by the Fourth of July,” Wurzel said. “There was so much snow on it probably wouldn’t have melted out through the whole summer.”
The county hired a contractor to clear the 7-mile bike path — at a cost of $87,500. Copper Mountain ski resort and the National Forest Service each chipped in for the project.
That, however, wasn’t the end of it. After the 2019 avalanches, CDOT has been more active in avalanche control in the Ten Mile Canyon area, which has repeatedly left more snow and debris on the Recpath.
“Now we have ongoing, increased maintenance costs to clean up the snow,” Wurzel said.
Changing climate has also taken its toll on little things. Every Fourth of July Glenwood Springs set off a firework display over the Colorado River, but after repeated years with hot, dry conditions and red flag warnings on the holiday, the city abandoned the tradition.
“Most of the town would walk down to the park to watch, but the fireworks are a thing of the past,” Kaup, the Glenwood mayor pro tem, said. “There were just too many years where it was canceled.” A laser light now fills the bill.
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