Climate change threatens Colorado River Basin's water supply
Recent national report addresses environmental risks and resilience ideas
By Sophie Stuber, Telluride Daily Planet
Despite a strong snowpack last winter, climate researchers and hydrologists have concerns about the long-term viability of the Colorado River Basin’s water supply, especially as run-off has fallen under model predictions in recent years.
With climate change leading to more extreme temperatures and drier periods, environmentalists are proposing ways to rethink water use in the West, including in the San Juans.
The Biden-Harris Administration and the U.S. Global Change Research Program (USGCRP) published the Fifth National Climate Assessment (NCA5) in mid-November, which details the effects of climate change. The report also addresses ways to adapt to future warming and increase climate resilience in regions across the U.S.
Along with the report, President Biden also announced a $6 billion investment to help communities become more resilient to climate change.
Although emissions have decreased since 2007 in the United States, the country is far behind the reductions needed to minimize climate change. Since 2000, Colorado has seen the highest average spring and summer temperatures in the historical record. Across the state, annual average temperatures have increased by approximately 2°F over the past 30 years.
The local impacts are already noticeable. In southwest Colorado, average temperatures are expected to go up anywhere from 1.5°F to 3.5°F by 2025 and 2.5°F to 5.5°F by 2050, according to recent climate models.
The San Juans are experiencing warmer temperatures, which puts the snowpack and water supply at risk. Right around Telluride, the mean annual low temperature has crept up from the low 20s to mid 20s.
“When those night-time temperatures are hovering around freezing, that’s when we’re going to start seeing loss of snowpack earlier in the season, especially up into the higher elevations,” Adrian Bergere, executive director of the San Miguel Watershed Coalition, told the Daily Planet. “When we are losing that snowpack quickly, a lot of the snowpack is sublimated into the atmosphere and it never hits the river,” Bergere added.
Even in higher snow years, in the San Miguel watershed, water run-off has not been meeting projections in recent years. Last year, there was a 9% difference in the forecasted amount of run-off, compared to what actually flowed through the watershed, according to Bergere.
“Some of these trends are becoming decoupled. Even if we have a normal winter, not all of that water is making it downstream, meaning a lot of our soils will dry out more quickly and our forests are more susceptible to wildfires,” Bergere said.
With more sublimation and less going into the watershed, soil becomes drier, which can also exacerbate temperature extremes.
“It’s a feedback loop because water in the soil can absorb temperature swings. When the soils are dried out, you will be much more susceptible to temperature swings,” Bergere added.
Some of the greatest implications of climate change, increasing temperatures and drier years, will be felt farther downstream in the Colorado River Basin.
“Unfortunately, a lot of these climate impacts will be felt downstream, but I think efforts to bolster climate resilience every year for headwater communities like Telluride are really important,” Mason Osgood, executive director of Sheep Mountain Alliance, told the Daily Planet.
“I think San Miguel County is on the right path, and hopefully we can remain proactive rather than reactive. I think a lot of communities faced with wildfires end up in that reactive path,” he added.
The NCA5 report highlights drought in the river basin as one of the most serious climate risks in the southwest. Snow in the Colorado River Basin is expected to shrink 24% by the year 2050. This could lead to water cuts or diversions and not enough water for agriculture or cities.
“It’s not good for the economy. You don’t want to see agricultural fields intentionally dried out or taken out of production,” Bergere said. “We don’t have a bunch of water reservoirs in our water basin. Colorado is really subject to ebbs and flows of the water supply.”
Despite the challenges, Bergere does believe that with efforts to reduce greenhouse emissions and improved technologies, there can be enough water in the Colorado River Basin to meet economical and human needs.
“Every year in the American West, we do get better at using our water. We can live within our means, but we do need to make some changes,” Bergere said.
The San Miguel Watershed Coalition is working on several projects to improve the health and sustainability of the water system, with a focus on improving wetland health.
“This is where the most carbon is sequestered. Our forests grow really slowly, so the highest potential for carbon sequestration is wetlands and wet meadows,” Bergere said. “When carbon does not interact with oxygen, CO2 won’t form.”
Wetlands also create a healthy habitat buffer for many species and they slow down the flow of water, which contributes to longer irrigation seasons and cooler environments.
In terms of the economics of promoting the energy transition, Osgood highlighted the importance of local energy networks.
“It’s important to empower community energy co-ops like the San Miguel Power Association to pursue renewable energy solutions. I recognize it will be a monumental effort in rural communities, but these co-ops play an instrumental role,” Osgood said. “And in coal and former coal communities, we need to recognize the economic impact of this transition.”
Read the article here.