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AT THE END OF A UNIQUE WATER YEAR, COMES A UNIQUE WATER SEMINAR.
Water year 2021 was a wake-up call for water users across the Western Slope of Colorado. Extreme or exceptional drought conditions persisted for months as dry soils and historic high temperatures lowered streamflow. Agricultural users faced impossible choices while local municipalities dealt with aging water infrastructure in the wake of devastating wildfires. Downstream, Lake Powell dominated national headlines with plummeting levels, and the Drought Contingency Plan played a role years earlier than most expected.
Yet many of the stories which came out of this incredibly difficult year were ones of innovative solutions and never-before-seen partnerships. Collaborative projects upgraded irrigation infrastructure, increased streamflow, and even delisted 66 river miles from the Impaired Waters list.
Setting historic precedents in hydrology, 2021 also did much to highlight the ability of water users to reach across their differences in order to build a future for West Slope water together.
Wake-up Call on the Colorado River is a seminar which will face the harsh economic and environmental realities of this past year, along with a study of practical solutions and future collaboration.
Hannah Holm, the director of the Hutchins Water Center at Colorado Mesa University co-wrote a Colorado River study in collaboration with Kelsea MacIlroy and The Nature Conservancy
As a headwaters state, Colorado has many interstate compacts that set rules for how the state must share the rivers that originate within its borders with downstream states. On several of these rivers, water users have had to modify their water use to meet compact requirements. That day may be coming for the Colorado River. A new report explores what Colorado River water users can learn from experiences with compact administration on other rivers.
Interviewees warned against relying on courts to rule in Colorado’s favor in compact cases or on optimistic estimates of water availability. They also described how communities have developed their own, proactive measures to promote compact compliance and address other water supply challenges in ways that have fewer negative impacts than externally imposed mandates. Necessary conditions for doing so include an ability to work well together, precise water-use measurement and initiating action well in advance of a court order. On a more technical front, interviewees emphasized how accurate measurement of all water use was necessary for enhanced water management, as well as making the Colorado’s case for its own water use in discussions with other states.
This study was conducted by Kelsea MacIlroy, co-written by Hannah Holm and funded by The Nature Conservancy. MacIlroy is a PhD candidate in sociology from Colorado State University and the principal of MacIlroy Research and Consulting, LLC. Hannah Holm directs the Hutchins Water Center at Colorado Mesa University.
The report was presented at the Colorado Water Congress Summer Conference in Steamboat Springs on August 24, 2021, and will be presented at the September Colorado Water Conservation Board meeting.
“Across Colorado and the West, communities are experiencing greater frequency and extent of drought leading to increased variability in streamflows. As water managers grapple with the consequences of changing water supplies, there is great value in looking toward neighboring communities for lessons learned,” Heather Dutton, manager of the San Luis Valley Water Conservation District and the Rio Grande Basin’s representative to the Colorado Water Conservation Board said. “The report detailing “Lessons Learned from Colorado Experiences with Interstate Compact Administration” relies on voices of water users and administrators to detail personal and regional experiences including what has gone well and where they would do things differently if given the chance. While the focus of the report is on compact administration, the lessons learned touch on broader water management topics and highlight how communities are better off when stakeholders are working toward a common goal. Therefore, I feel this report is a must read for all Coloradoans that care about our collective water future.”
Alex Funk, agriculture and rural resiliency policy specialist for the Interstate, Federal, and Water Information Section at the Colorado Water Conservation Board also commented on the recent report.
“The stories shared in this report highlight the value of proactive dialogue and actions on water management challenges ranging from climate change to compact compliance.,” Funk said. “Collaborative, proactive actions and solutions give local communities and water users more agency and opportunities to adapt to changing conditions in ways that provide long-term benefits for all water users.”
Ralph Parshall squats next to the flume he designed at the Bellevue Hydrology Lab using water from the Cache la Poudre River. 1946. Photo Credit: Water Resource Archive, Colorado State University, via Legacy Water News.
On the question of water measurement, John McClow, general counsel for the Upper Gunnison River Water Conservancy District said, “A valuable takeaway from the report is recognizing the importance of accurate measurement. That is a good lesson for Colorado River water users as the State Engineer commences measurement rule making.”
Colorado farmers have begun to seed the 2022 hard red winter wheat crop, according to the US Department of Agriculture’s field office in the state. Colorado producers often are the first to begin planting hard winter wheat. The USDA said in its weekly Crop Progress report issued Aug. 30 that the Colorado crop was 12% planted by Aug. 29 compared with 3% a week earlier and 1% as the recent five-year average for the date. No other state reported progress in winter wheat planting by that date, but this was expected to change very soon…
Colorado soil moisture conditions this year were much better than a year ago but compared unfavorably with the recent five-year averages for the date. Topsoil moisture was 45% adequate, 40% short and 15% very short as of Aug. 29. That compared with 18% adequate, 36% short and 46% very short a year ago. The recent five-year average Colorado topsoil moisture for the date was 2% surplus, 57% adequate, 27% short and 14% very short.
Subsoil moisture as of Aug. 29 was 45% adequate, 36% short and 19% very short. A year earlier, subsoil moisture was 18% adequate, 39% short and 43% very short. The recent five-year average subsoil moisture was 2% surplus, 60% adequate, 25% short and 13% very short.
Winter wheat seeding in Kansas was expected to begin in mid-September. Conditions there were favorable with only 15% of winter wheat expected to be planted in areas experiencing drought (2% severe and 13% moderate), according to the USDA’s analysis of the Aug. 24 US Drought Monitor. There currently were no drought concerns for Texas and Oklahoma. Farther north, though, conditions were much drier. Forty-four percent of Nebraska wheat cropland was in drought (18% severe and 26% moderate). Drought gripped 99% of South Dakota winter wheat cropland (23% extreme, 59% severe and 17% moderate), and all Montana winter wheat cropland (3% exceptional, 33% extreme, 57% severe and 6% moderate).
Temperatures in normally warm Texas plunged into the teens in February 2021, knocking out power for a population unaccustomed to cold, with deadly consequences. Thomas Shea / AFP via Getty Images
In February 2021, in the midst of rapidly warming global temperatures, an exceptionally severe cold wave hit large parts of North America, from Canada to Northern Mexico. It left 10 million people without power. The impact was particularly severe in Texas, which alone had more than 125 deaths associated with the event.
The freezing temperatures were associated with a dip southward in the jet stream, a band of strong winds about eight miles above Earth’s surface associated with the boundary between colder and warmer air.
The jet stream flows from west to east, but that’s not the only direction in which atmospheric waves can move – they can also move up and down over large distances, and that can link the weather and climate in one region, like the Arctic, with regions elsewhere, like Texas.
Surface temperatures on Feb. 15, 2021, at 6 a.m. in Texas. The black lines show the jet stream, and the white line indicates the extent of freezing temperatures. Mathew Barlow/University of Massachusetts Lowell, CC BY-ND
When you throw a rock in a pond, you see ripples – waves – expand away from the initial disturbance. While ripples on a pond are a different type of wave than dips in the jet stream, both types of waves can transmit the effects of a disturbance to faraway areas.
Water ripples in response to a disturbance. Forance/Shutterstock.
In this case, the atmospheric waves transmitted the influence of climate change in the Arctic to parts of North America and Asia.
In a study released Sept. 2, 2021, in the journal Science, we show how that happened and how, counter to what one might expect, events like the February cold wave can actually become more likely with global warming.
This is causing large changes in the region’s climate, including melting sea ice and, in the late fall, increasing snow cover over Siberia.
Ice and snow provide an insulating layer and are highly reflective, so their changes strongly alter the amount of energy and moisture moving between the surface of the Earth and the atmosphere. The atmosphere is sensitive to changes in energy and moisture, so substantial changes provide a “kick” to the atmosphere that results in upward moving waves rippling away from the area.
These waves move upward into the stratosphere and disrupt the stratospheric polar vortex, another band of fast winds that circles closer around the pole in the middle stratosphere, around 18 miles up. In response, the vortex weakens and stretches.
Two circulation patterns of the stratospheric polar vortex: strong (left) and stretched (right). Blue curves indicate approximate edge of the vortex; shown at about 9.3 miles, or 15 kilometers, above the surface. Mathew Barlow, University of Massachusetts Lowell
Not only can the stratospheric vortex be changed by the waves, but the vortex can also change how the waves move, because the waves are influenced by the wind and temperature fields they move through, and the vortex helps determine those winds and temperatures. What differentiates a vortex stretching event from larger vortex disruptions is that upward-moving waves are reflected back down to the surface, where they can influence lower-altitude weather patterns.
A schematic shows wave activity reflecting off the stretched stratospheric polar vortex. Mathew Barlow, University of Massachusetts Lowell
As these downward moving waves collect at lower altitudes over North America, they create a southward dip in the jet stream, bringing cold air farther south than usual. So, the upward and downward movement of atmospheric waves over long distances – like ripples moving across a pond – can link the Arctic to other regions.
Testing cause and effect
We took two different approaches to identifying and examining these relationships.
First, we used a machine learning, a technique in which a computer essentially trained itself to group similar events from the historical data. We then analyzed the stretched vortex events to show that, for those cases, there was a typical sequence of events: first surface temperature changes in the Arctic, then changes in the stratospheric polar vortex, followed by cold waves in North America and Asia – with vertically moving waves providing the connections over the span of a few months. The identified surface temperature changes in the Arctic are similar to those associated with the melting sea ice and increasing Siberian snow cover of Arctic climate change.
We then used a computer model of the atmosphere to evaluate cause and effect and directly test how the atmosphere responds to those Arctic changes. We found that the model reproduced the observed sequence of events.
The machine learning analysis of observations and the computer modeling experiments provide two independent lines of evidence supporting a pathway of influence – from Arctic climate change at the surface up to changes in the stratospheric winds, and finally back down to cold waves in North America and parts of Asia.
A timeline shows the pathway from Arctic climate change to cold temperatures in North America. Red and blue in the third panel indicate differences from average conditions. Mathew Barlow/University of Massachusetts Lowell, CC BY-ND
Implications of these results
Our research reinforces two crucial lessons of climate change: First, the change doesn’t have to occur in your backyard to have a big effect on you. Second, the unexpected consequences can be quite severe.
In this case, large changes in the Arctic are not just a local concern – they also have wide-ranging impacts across North America and parts of Asia. And those impacts are not always what people are expecting. The results highlight another reason to rapidly reduce the greenhouse gas emissions that are driving global warming and at the same time the need to develop better strategies for managing extreme weather events, both hot and cold.
