From The Colorado Springs Gazette (Mary Shinn):
The hot dry conditions that melted strong snowpack early in 2020 and led to severe drought, low river flows and record setting wildfires across the state could be a harbinger of what is to come in Colorado.
Climate change is likely to drive “chaotic weather” and greater extremes with hotter droughts and bigger snowstorms that will be harder to predict, said Kenneth Williams, environmental remediation and water resources program lead at Lawrence Berkeley National Laboratory, headquartered in California.
“We are looking to be moving toward a future that is really decoupled from the past,” said Williams, who is leading a long-term watershed research project in Crested Butte.
In 2020, the Colorado River system had 100% of average snowpack on April 1 but then thwarted expectations when it didn’t deliver the 90% to 110% of average runoff that water managers could typically predict. The river system only saw 52% of average runoff because water was soaked up by dry soils and evaporated during a dry, warm spring, said Brad Udall, senior water and climate research scientist at Colorado State University.
“It’s not typical, but it could very well be our future,” he said.
The 2020 drought will end at some point, but that appears unlikely this spring with the National Oceanic and Atmospheric Administration forecasting above-normal temperatures and below-normal precipitation through March, April and May.
Conditions could improve more rapidly on the eastern plains with big spring and summer rain, said Russ Schumacher, Colorado’s state climatologist.
In the larger picture, breaking the drought across the vast Colorado River Basin will likely take a string of winters with much above average snowfall, Schumacher said.
In the long term, conditions across the Southwest are going to become more arid as average temperatures rise, driven by greenhouse gas emissions, Udall said, with lower soil moisture and stream flows among the negative impacts.
The 19-year stretch of only intermittingly interrupted drought from 2000 to 2018 in the Southwest U.S. was exceeded only by a late 1500s megadrought, the journal Science reported in a paper this year…
New reservoirs could play a role in the future, but construction alone cannot resolve the coming water woes.
“Anyone who thinks they can build themselves out of climate change is nuts,” Udall said. “There is a limit to the amount of storage that’s helpful.”
Too much storage can sit empty and if the water is allowed to sit for too long a valuable portion is lost to evaporation, he said.
In the highly variable years of climate-related weather to come, keeping water flowing to homes and farms will take better planning and a much better understanding of the “water towers of the West,” the remote peaks where significant amounts of snow accumulate above 8,000 feet.
Water managers are keen to know not just how much water may flow into rivers and streams, but when, and also what it might contain because as water flows drop water quality is also likely to be more of a concern…
The rapid change has left water managers and researchers in need of better data to understand short-term trends, such as how much runoff to expect this year and longer-term shifts.
Traditionally Colorado and the West have relied on a network of more than 800 snow telemetry sites — SNOTELS, as they are called by the Natural Resources Conservation Service — that automatically collect snowpack, temperature and precipitation. But now more snow is falling at elevations above the SNOTELS and aerial observations are needed to provide an alternative source of data on snowpack utilities and others wouldn’t otherwise know about, Williams said…
So Denver Water is forming a new collaborative to bring utilities, including Colorado Springs Utilities and other water users, such as water conservancy districts that serve farmers and ranchers, together to fund statewide flights, which can be quite expensive, she said.
The formal planning work around what data to collect and funding flights is set to begin in April and already the collaborative has attracted members from across the state, Kaatz said.
The group hopes to start funding the flights in about a year to provide the high quality data to water managers, Kaatz said. Having that data will be a valuable asset in Colorado’s semi-arid climate as it warms, she said.
“Warming is here and now. It’s not the next generation’s challenge.”
The rapid spring runoff is often the star in the water world. But high elevation groundwater is key to feeding streams in the late summer and winter, helping to sustain fish and late season irrigation. It is also an important source for reservoirs, said Rosemary Carroll, a hydrologist with the Desert Research Institute and collaborator on the Department of Energy projects in Crested Butte.
When Carroll started studying groundwater in the upper Gunnison watershed, she expected to find water that had percolated through the soil for two or three years before reaching streams. Instead, she’s found groundwater about a decade old, which has benefits and drawbacks during dry times, she said.
If the watershed is in a shorter drought, the groundwater can act as a buffer supplying old water that fell as snow and rain years ago, she said. But if it is a sustained drought then the absence of water from the system persists through a lack of groundwater, she said.
If the area continues to see hotter drier conditions, it’s likely that groundwater coming to the surface would be older and there will be less groundwater available to support streams, she said.
From The Colorado Springs Gazette (Mary Shinn):
As Colorado Springs Utilities braces to absorb hundreds of thousands of new residents in the coming decades amid hotter weather, it is looking to conservation, agriculture, and new water supplies from the Colorado and Arkansas rivers to help fill the gap.
Utilities examined 50 future climate scenarios to prepare its latest 50-year plan and settled on a future that will be on average 3 degrees Fahrenheit warmer with no change in average precipitation, instead of relying on historical weather trends to make projections, said Kevin Lusk, a water engineer with Utilities…
As new neighborhoods take shape, particularly in Banning Lewis Ranch, Utilities is planning for the city’s population to increase 53% from about 470,000 people to 723,000, the 50-year plan states. As those residents move in, the city’s annual water demands are expected to rise from 95,000 acre feet a year to 136,000 acre feet a year…
For Colorado Springs, reservoirs are already a key piece of a complex water system that brings 80% of the 95,000 acre feet of water the city uses annually into the area.
The largest amount of new water supply, 90,000 to 120,000 acre feet of water, is expected to come from the new or enlarged reservoirs or water storage within the Arkansas River basin, according to the 50-year plan. One of those projects could be a new reservoir or gravel pit complex between Twin Lakes and Pueblo Reservoirs, the plan states.
Utilities may also build additional reservoir space in the Colorado River watershed, and it is working with Aurora on a highly controversial new reservoir in the Holy Cross Wilderness in Eagle County. The U.S. Forest Service is expected to make a decision soon on whether to permit the exploration of the new reservoir’s feasibility…
Through conservation, Utilities expects to save 10,000 to 13,000 acre feet of water annually, said Patrick Wells, general manager with Colorado Springs Utilities Water Resources and Demand Management. The city’s watering restrictions adopted last year that limit outdoor watering to three days a week from May 1 to Oct. 15 are meant to help achieve long-term water savings and more than 550 acre feet of water was saved in the first year, he said.
In the future, water owned by agricultural interests, particularly farmers and ranches in the Lower Arkansas River basin, will also play a key role. But rather than purchase it outright, Utilities is looking to lease 15,000 to 25,000 new acre feet of water annually.
The leases are a move away from purchasing farms and their associated water rights outright and transferring that water to the city, a practice called buy and dry. In the 1970s, farmers sold the water rights that previously served 45,000 acres in Crowley County leaving only 5,000 acres in production, The Gazette reported previously.
Cities bought water outright from agriculture through the early 2000s as the primary means of transfer, said Scott Lorenz, water sharing senior project manager with Colorado Springs Utilities.
Now, the state and city are focused on lease agreements that can serve farmers in dry times, he said. For example, in a dry year a farm may not have enough water to put all the fields in production, the producer can lease some water to the city and earn money through the water instead, Lorenz said.
Compensating farmers for their water and taking land out of production can have consequences, however, because it can disrupt the overall agriculture market when farmers aren’t buying seed or materials or employing laborers, said Brad Udall, senior water and climate research scientist at Colorado State University. The buyers the farms supply may also go elsewhere for products if farms aren’t producing annually, he said.
Utilities’ already has several lease agreements in place, including one in perpetuity with the Lower Arkansas Water Management Association, a group that replaces the water taken from the Arkansas River through wells. As farmers pump from ground wells supplied by the river, the association ensures water flows back into the river so that downstream residents in Kansas receive their full water rights.
The city has agreed to lease water from the association five out of every ten years and pay for its water every year, said Bill Grasmick, association president. The city also paid for a new reservoir that the association is already using.