Here’s the release from the Colorado Water Conservation Board:
Colorado Water Conservation Board Hosts Two-Day Forum
On March 4 – 5, Colorado continued to carve the path forward in its Demand Management Feasibility Investigation during a two-day joint meeting between the Interbasin Compact Committee (IBCC) and eight Demand Management Workgroups.
Hosted by the Colorado Water Conservation Board (CWCB), this was the first workshop convening all eight Workgroups – together representing diverse water-related interests across the state. Workgroups reflected on the past year of discussions and presented on challenges and benefits they foresee in a potential temporary, voluntary, compensated program to address Demand Management.
Demand Management is the concept of temporary, voluntary, and compensated reductions in the consumptive use of water in the Colorado River Basin. Any water saved would only be used to ensure compact compliance and to protect the state’s water users from involuntary curtailment of uses.
“We appreciate the focus, dedication and collaboration of our Workgroup members who gathered this week from across Colorado to move this important conversation forward,” said CWCB Director Rebecca Mitchell. “This workshop was the next step in sharing ideas for Colorado’s water future, and positioning our state as a national leader for cooperative problem solving.”
IBCC Director Russell George said, “We began this process of meeting as individual Workgroups in order to begin exploring concerns and benefits of a potential Demand Management Program. The next step in the process was bringing these Workgroups together in this larger forum, which has fostered the critical conversation needed to ensure we are using a grassroots approach. This approach will help inform our state’s decision-makers as they consider options for a possible Demand Management program.”
Demand Management Workgroups include:
Administration & Accounting
Economic & Local Government
Education & Outreach
Law & Policy
Monitoring & Verification
As a headwaters state, Colorado is thoroughly exploring potential tools for managing water in the western United States, and will continue to inform Coloradans throughout the investigation and during the decision-making process.
On Feb. 20, the University of Utah Center for Colorado River Studies hosted a presentation and panel discussion in Moab on research being conducted on and policies being considered for Lake Powell. Scientists, activists, authors, and historians shared their perspectives on various aspects of the river, the dam, and the reservoir to a full house at Star Hall. The complicated history of river engineering and water allocation sets the stage for an uncertain future of the management of the West’s precious resource.
“We can’t talk about the future of this reservoir and how its managed unless we digest some basic facts,” said Dr. Jack Schmidt, professor of watershed sciences at Utah State University, at the presentation, before he and others gave an overview of the reservoir’s history and parameters.
The presentation was part of an effort by the Center for Colorado River Studies to help the public understand the complexity of the natural systems and political agreements surrounding the Colorado River…
Water levels in Lake Powell and Lake Mead have reflected this decreased flow. In 2005, Lake Powell dropped to its lowest level since it first filled up in 1963, sinking to 3,555 feet above sea level, just barely high enough to keep from exposing the intakes for the hydroelectric generator at the dam and causing damage to the facility.
“Here’s an important number,” Schmidt told the audience at Star Hall. “If the reservoir elevation gets lower than 3,490 feet above sea level, then water cannot be taken into those penstocks, because then air is entrained, and if air is entrained, you get the phenomenon of cavitation in the turbines, which will destroy the turbines.”
He went on to explain that water managers don’t want to get too close to that absolute limit, and they set a bottom threshold of 3,525 feet above sea level for Lake Powell.
Policymakers must constantly consider how supply and demand are affected by climate and natural systems, new infrastructure and aging infrastructure, population growth and changes in land use, and scientists’ and researchers’ evolving understanding and modeling of how these factors will play out in the future…
To prepare for a renegotiation of interstate agreements, scientists and researchers have been studying the Colorado River basin and all the systems that comprise it. The presentation at Star Hall illustrated just how complex the issue is. Glen Canyon Dam itself has been controversial nation-wide since its inception. Environmentalists, river runners, and archaeologists to this day lament the loss of the natural canyon flooded by the dam, which was filled with Native American artifacts and wild riparian ecosystems. That dam and other infrastructure have changed many properties of the river, from flow rate, to temperature, to fish populations, to evaporation patterns, to the shape of the riverbed. As scientists study the new patterns of the river, they try to create models that can accurately predict future behaviors and conditions of the river. For example, by studying how the river moves and deposits sediment, scientists have variously predicted an operable life span for Lake Powell of 100 to 150 years. These models and data sets can help steer management agreements.
“The current interim guidelines aren’t going to work forever,” said Erich Balken, executive director of the Glen Canyon Institute, a Salt Lake City-based nonprofit devoted to the restoration of Glen Canyon and the Colorado River.
The organization is advocating for a policy they call “Fill Mead First,” which Balken briefly discussed at the Star Hall event. The policy would allow the downstream Lake Mead to be filled to capacity before starting to store water in Lake Powell. The group recommends not decommissioning Glen Canyon Dam, a step that has been taken at other dam sites around the country, but drilling diversion tunnels around it to allow the river to return to its natural flow.
The hydroelectric power plant driven by Lake Powell would be temporarily shut down, and intakes to power the facility would be installed in the diversion tunnels. Glen Canyon would be returned to its natural state until the necessity arose to store more water than Lake Mead could hold.
The idea is politically difficult because Lake Powell serves as a kind of “bank account” of water that helps upper basin states ensure that they meet their water obligations to the lower basin states. Beyond Lake Powell, the water essentially belongs to the lower basin. The dividing line maintains a tension between the regions…
At the same time that Colorado River users are beginning the renegotiation process, the state of Utah continues to pursue water projects that affect the Colorado River and Lake Powell. Local leaders in Washington County are exploring a “Lake Powell Pipeline,” a 140-mile pipe that would pump water from Lake Powell to the St. George area.
Lawmakers in Salt Lake City are considering the possibility of diverting water from the Green River and the Bear River, the former of which is a tributary to the Colorado and eventually feeds Lake Powell, to water users on the Wasatch Front. More water rights have been allocated from the Colorado River than there is actual water to distribute, and historically, the first users of the existing water, and the owners of water infrastructure, retain the rights to continue using the water.
…the Utah House of Representatives on Tuesday passed HCR22, which makes clear to neighboring states and policymakers that Utah will someday develop its unused portion of the Colorado River…
Utah has not fully developed its full 23% allocation of the river, with much of that unused water flowing downstream to lower basin states.
Rep. Brad Last, R-Hurricane — who lives in southern Utah where the proposed Lake Powell Pipeline would take the unused allocation — said it is important Utah send a message to its neighbors that the resource will be developed…
The resolution passed on a 57-13 vote because the Lake Powell Pipeline — and development of the Colorado River in light of drought and a changing climate — has stoked opposition by some groups that assert it’s a failed proposal that will drain an already struggling river.
Last’s measure urges development of the water in the most expeditious fashion, and Rep. Joel Briscoe, D-Salt Lake City, questioned what those parameters might be.
“As soon as we can effectively use it,” Last told him.
Briscoe added that conservation practices should have been emphasized more in the resolution and addressed higher in the language of the measure.
But Rep. Lowry Snow, R-Santa Clara — another lawmaker who lives in the Utah region where the pipeline would deliver water — said the resolution is a critical message that merits support.
“It is important as a state that we indicate our intent to preserve our allocation,” Snow said. “I can’t begin to evaluate the monetary value of our water right in the Colorado. It is invaluable and will become more so in the future.”
The resolution is now awaiting action in the Senate.
Climate change is increasing the variability of the Colorado River so much so that the river could lose one-fourth of its flow by 2050, according to a new government study.
As plans for the 140-mile Lake Powell Pipeline — which would divert over 86,000 acre-feet annually from the reservoir to southwestern Utah — are under review by the Bureau of Reclamation, what does the Colorado River’s diminishing flows mean for the project?
The new report, produced by the U.S. Geological Survey and published in Science, attributes a 16% decline in the river’s flow from 2000-2017 to rising temperatures. The Colorado River hydrates seven downstream states, storing water in shrinking Lake Powell and Lake Mead reservoirs.
Washington County Water Conservancy District Manager Zach Renstrom said he thinks the variability of climate change provides even more reason for the county to pursue the pipeline.
“Climate change is a big deal to us, we are very concerned about it, and specifically how it’s going to affect our watershed,” Renstrom said. “When we look at these dynamics, they’re one of the strong arguments for the Lake Powell Pipeline because we need to make sure to have a robust infrastructure in place so we can adjust for (climate change).”
Rising temperatures, less snow
USGS scientists considered two scenarios of climate change in the Colorado River study. In one, warmer temperatures by 2050 would reduce the amount of water flowing in the river by 14-26%. In the other scenario, warming would take away 19-31% of the river’s flow…
Milly and fellow USGS scientist Krista Dunne focused on the reflectivity of snow, known as albedo, as a key element in the river’s sensitivity to warming. They zeroed in on the role of snow cover as a “protective shield” for water in the river basin.
Milly likened the flowing river to the leftovers of the “meal” of snow and rain that falls across the basin after evaporation has “eaten” its share…
And the amount consumed by evaporation is driven by how much energy the basin absorbs in the form of sunlight. The snow cover in the Rocky Mountains reflects back to the sky and space a significant fraction of the sunlight.
As the world gets hotter with the burning of fossil fuels, more of the precipitation falls as rain instead of snow. And the snow melts away earlier in the year. As the snow cover in the mountains is progressively lost, the river basin absorbs more energy…
“When we talk about structural deficits and overuse of the Colorado River system, it’s exclusive to the lower basin,” WCWCD spokesperson Karry Rathje said.
Washington County’s population is projected to grow 229% by 2050, but Renstrom says he’s worried that growth may come sooner than expected. He’s pushing to get the pipeline going in the next 10 years in order to diversify the county’s water supply.
“Even when we look at reduced flows … the water in the Lake Powell Pipeline should be available for us to withdraw,” Renstrom said. “As the guy who has to worry about where water is coming from in 30 years if some of the higher-end climate models come to pass, and the Virgin River is dried up, it makes me feel very secure that we’ll have another tool in that toolbox.”
The loss of the reflective snowpack drives evaporation and reduces the flow of water, the study found.
The 40 million people who rely on Colorado River water need to prepare for a drier future.
Global warming is shrinking the Rocky Mountain snowpack that feeds the river and flows are declining at a rate of about 9.3 percent for every 1.8 degrees Fahrenheit increase in temperature, according to a new study that “identifies a growing potential for severe water shortages in this major basin.”
The decline is “mainly driven by snow loss and consequent decrease of reflection of solar radiation,” a pair of scientists with the U.S. Geological Survey wrote in a new paper published Thursday in the journal Science. The study helps resolve a “longstanding disagreement in previous estimates of the river’s sensitivity to rising temperatures.”
The study links dwindling flow of water with the loss of albedo, a measure of the snowpack’s reflective quality. Like ice in the Arctic, white snow reflects solar radiation back to space. But as the snowpack in the Colorado River declines, the ground and, crucially, the air directly above the ground, warm up. Water from the melting snow or from rain evaporates from the soil, rather than trickling into the streams that feed the Colorado River.
The scientists found the link by measuring the relationship between the amount of water in the snow, the amount of the sun’s incoming radiation and how much of that was reflected back by the snowpack’s albedo, showing that, as the snowpack dwindled, the river’s flow declined.
Brad Udall, a climate scientist with the Colorado River Research Group, said the study “adds another brick in the wall of evidence that it’s very likely we’re going to see significant declines in Colorado River flows.
“Scientists have been trying to figure out how sensitive the river is to global warming,” he said, “and these numbers put the sensitivity at the upper end of what’s possible.”
The research divided the Colorado River Basin into 960 sub-areas and broke down the data, including satellite measurements of albedo, month by month. That enabled the scientists to see that the effect was dominant in the late spring and early summer, when the snowpack was being depleted, said Chris Milly, the senior U.S. Geological Survey researcher who led the new research. Previous studies on the Colorado River’s climate sensitivity focused primarily on precipitation and temperatures, without considering the radiation balance, he added.
“Before our study there was a huge range of estimates of how sensitive Colorado River flows are to warming, from 2 percent to 15 percent for every 1 degree Celsius of warming. We really wanted to try and understand and narrow that uncertainty,” Milly said.
It’s not just a Colorado problem. “Many water-stressed regions around the world depend on runoff from seasonally snow-covered mountains,” the authors wrote in the journal report, “and more than one sixth of the global population relies on seasonal snow and glaciers for water supply.”
The findings suggest that the snow cover offers a “protective shield” that limits evaporation from this natural reservoir, the scientists wrote in the study. As the shield shrinks, it will crimp water availability in snow-fed regions that are already stressed, including the Colorado River Basin…
Unending Stream Flow Decline
University of Michigan climate researcher Jonathan Overpeck said the new study is valuable because it details the mechanism “by which regional human-caused warming is reducing flows in the Colorado River.”
Continued warming, he said, “will lead to significant and unending reductions in river flows. Until global warming is stopped, the Colorado and other key rivers of the Southwest will continue to provide less and less water to the region.”
Research since then has confirmed that global warming is affecting water supplies in the West in several different ways. As early as 2013, U.S. Geological Survey research showed that warmer spring temperatures since 1980 have cut the Rocky Mountain snowpack by 20 percent.
A 2016 study in California’s Sierra Nevada Mountains showed how the snowfall line is speeding uphill. At lower elevations where the mountains aren’t so steep, tens of thousands of square miles that used to be white all winter now stay brown and heat up, and the moisture in the soil evaporates.
In 2017, Overpeck, along with Udall, showed a clear relationship between warming temperatures and less water in the Colorado River Basin, as they studied the Colorado River’s 21st century “hot drought.”
The new study doesn’t take into account extreme events like the crippling 2012 drought that sent Colorado River flows to record lows while reservoir storage plummeted.
By the end of May that year, 100 percent of Colorado was in some stage of drought, including the mountains that supply more than three-quarters of the Colorado’s total flow. It would end up being Colorado’s hottest year on record, as well as one of the state’s worst wildfire seasons, burning a quarter million acres and causing temporary evacuations of 35,000 people.
But so-called Black Swan climate events like megadroughts lasting several decades have happened regularly in the last few thousand years, and are increasingly likely in a world that’s cooking in a thickening stew of greenhouse gases.
In May 2019, the Colorado River Research Group published a warning about “unexpected shocks from Black Swan events.” That includes megadroughts or extreme floods, as well as “socioeconomic events that might stress the existing legal/management framework beyond any known circumstance,” the report said.
Because of global warming, the chances of such events are increasing at the same time that reservoir storage and groundwater reserves are being depleted, a disconcerting situation “given the role of multiple megadroughts in undermining past civilizations in the region,” the river researchers wrote.
They said planning scenarios should be based on water records that stretch back longer than the last century, and should take into account that “the abnormally wet period of the early 20th century … might be better viewed as a highly unlikely hydrologic event that cannot be assumed to be part of the future.”
The paleoclimate record clearly shows that the first 100 years of the European settlement era in the Colorado River Basin was an unusually stable period of abundant water, and that there were sudden extreme swings between drought and floods during past geologic eras of rapid climate change.
One of most severe drought periods on record in the Colorado River Basin was between the years 900 to 1300, when regional temperatures close to today’s triggered “a period of extensive and persistent aridity over western North America,” according to a 2010 study in the Proceedings of the National Academy of Sciences…
Overpeck said, “The good news is that we understand what is happening to the Colorado River and why. This means we can have confidence on the solution, which is putting a rapid stop to climate change, mainly by ending the burning of fossil fuels.”
He added, “Simply put, the more oil and gas we burn, the less water will be available to the American Southwest.”
Using hydrologic models, researchers with the U.S. Geological Survey, found that the Colorado River basin is extremely sensitive to slight changes in temperature. In their new paper in the journal Science, they show for each degree Celsius temperatures rise, flows in the river are likely to decline more than 9%.
That decline is likely to cause severe water shortages in the Colorado River basin, where more water exists on paper in the form of water rights than in the river itself. Warmer temperatures diminish snowpack, lessening the amount of water available…
The reductions might sound small, Milly said, but they will be felt throughout the basin.
“There’s not a lot of slack in the system,” Milly said. “In the long-term communities, states will be making adjustments to how they allocate water.”
The finding comes as water managers throughout the watershed are gearing up for negotiations over a long-term plan for the river’s management. The Colorado River’s current operating guidelines expire at the end of 2026, and the states that make up the watershed are required to start negotiating new ones by the end of this year.
“The new rules must consider how to manage the river with unprecedented low flows in the 21st century,” Udall said. “The science is crystal clear — we must reduce greenhouse gas emissions immediately. We now have the technologies, the policies and favorable economics to accomplish greenhouse gas reductions. What we lack is the will.”
FromThe Washington Post (Juliet Eilperin, Chris Mooney):
Up to half of the drop in the Colorado’s average annual flow since 2000 has been driven by warmer temperatures, four recent studies found. Now, two U.S. Geological Survey researchers have concluded that much of this climate-induced decline — amounting to 1.5 billion tons of missing water, equal to the annual water consumption of 10 million Americans — comes from the fact that the region’s snowpack is shrinking and melting earlier. Less snow means less heat is reflected from the sun, creating a feedback loop known as the albedo effect, they say.
“The Colorado River Basin loses progressively more water to evaporation, as its sunlight-reflecting snow mantle disappears,” write the authors, USGS senior resource scientist Chris Milly and physical scientist Krista A. Dunne…
Milly and Dunne, who analyzed 960 different areas in the Upper Colorado River Basin to determine how disappearing snowpack influenced the river’s average annual flow, determined that the flow has dipped 9.3 percent for each temperature rise of 1 degree Celsius (1.8 degrees Fahrenheit). The average annual temperature for the area they surveyed has risen 1.4 degrees C (2.5 degrees F) in the past century, Milly said in a phone interview.
The region is poised to warm even more in the years ahead, Milly said, and it isn’t “likely” that precipitation can compensate for these hotter and drier conditions. Comparing the Colorado River’s historic flow between 1913 and 2017 to future conditions, he added: “That flow, we estimate, due to the warming alone would be reduced anywhere from 14 to 31 percent by 2050.”
Colorado State University senior scientist Brad Udall, who has written two papers attributing half of the Colorado River’s lower flows to warming temperatures, said in a phone interview that researchers now “have multiple lines of evidence pointing to a very similar number.”
“And this number is worrying,” Udall said of the new study. “I would say eye-popping.”
Andrew Mueller, general manager for the Colorado River District, said in an email that the new findings provide “confirmation of significantly grim indicators about future flow in the Colorado River.”
The amount of water that would disappear with another 1 degree C temperature rise, he added, is nearly five times what Las Vegas uses each year. “A decline in flows of this magnitude will present a significant challenge to all inhabitants in the Colorado River Basin.”
The current operating rules for the river expire at the end of 2026, and negotiations over how to share the water going forward start this year.
Udall said that in light of current projections, policymakers need to consider crafting an agreement where all the major players in the West will use less water than they do now.
“These projections are dire, but we’re looking at a glass that’s 70 percent full, not half full,” he said. “It could be grimmer.”
Officials at the U.S. Bureau of Reclamation, who brokered a drought contingency plan among seven states and Mexico last year, said that they are continuing to monitor the way climate change is affecting the river.
“Reclamation works closely with leading scientists at the state and federal level, as well as universities to understand the potential impacts of climate change on the Colorado River,” said bureau spokesman Marlon Duke. “We will continue to use the best available science to manage the river to sustain reliable water far into the future.”
Click here to read the newsletter. Here’s an excerpt:
USU TOOLS FOR UNCERTAINTY
Utah State University’s Center for Colorado River Studies has released a new white paper on new approaches and tools to manage the Colorado River for an uncertain future. The paper includes
recommendations for revisions to the guidelines for managing Lakes Powell and Mead, and the authors invite feedback.
Click here to read the White Paper (Jian Wang, David E. Rosenberg, Kevin G. Wheeler, and John C. Schmidt). Here’s the executive summary:
Colorado River managers and stakeholders face many uncertainties—issues like climate change, future water demand, and evolving ecological priorities. Managers and stakeholders are looking for new ways to communicate about uncertain future conditions, help cope with an uncertain future, and develop public policy when future conditions are highly uncertain. Historically, Colorado River managers have operated Lake Powell and Lake Mead under the assumption that the future natural flow regime of the Colorado River at Lee Ferry will resemble the previously observed regime, but most climate scientists believe that the flow regime is changing, and that future flows will be lower, more variable, and more uncertain.
• It is also difficult to predict future demand for Colorado River water, future river ecosystem conditions, or the values that future generations will attach to those ecosystem conditions. These uncertainties present immense challenges when developing river management policies to enhance water supplies and ecosystem condition.
• To help Colorado River stakeholders think about, talk about, and better manage the river in the face of these unknowns, this white paper distinguishes four levels of uncertainty. Future conditions can be described by point estimates with small ranges (Level 1), probabilities (Level 2), scenarios of possible future conditions (Level 3), or a level of complete unknown (Level 4).
• We represent each level with day-to-day and Colorado River examples. These examples illustrate how the further a stakeholder attempts to peer into the future, the greater the level of uncertainty.
• Managers and stakeholders can classify the uncertainty level of each key system factor to guide decisions about which modeling tools and public policies to use. Tools include defining alternative scenarios, Many Objective Robust Decision Making (MORDM), Decision Scaling (DS), and Dynamic Adaptive Policy Pathways (DAPP) for uncertain future conditions that can only be described by scenarios (Level 3).
• There is need to expand the discussion about how to renegotiate the Interim Guidelines and the Lower Basin Drought Contingency Plan (DCP). This discussion should consider uncertainties in future hydrology, demands, and river ecosystem conditions that can only be described by scenarios (Level 3). Revisions to the Interim Guidelines should (1) include more information about future conditions as new information becomes available, (2) define interim decision points (called signposts) when existing policies should be reconsidered, and (3) allow more flexibility in day-to-day management decisions that respond to unforeseen conditions.
• This white paper suggests that new guidelines designed to adapt to uncertain future hydrology, water demand, and river ecosystem conditions are likely to look quite different than the current guidelines, which seek to provide certainty about the amount of water managers can divert.
• New guidelines that acknowledge different levels of uncertainty levels will be more adaptable, more flexible, and will be better able to anticipate and respond to a wider range of future Colorado River conditions. This adaptability and flexibility can help avert future crises.