By now, it's old news that the Colorado River — notwithstanding the current abundant water year — is generally shrinking, and is expected to shrink more in coming decades. The states that share the river completed a drought plan earlier this year that brings them closer to living within currently available supplies, and a new round of negotiations on long-term management of the river is due to begin next year.
However, a new report warns that planning for gradually declining water supplies, as difficult as that is, may not be enough to adequately prepare for the future. In May, the Colorado River Research Group released a report warning that water planners should also take into account "black swan" low-probability, high-impact events. The research group is a consortium of well-known scholars focused on the Colorado River Basin, and all their reports can be found at www.coloradoriverresearchgroup.org.
Longer, deeper, "mega" droughts are one black swan the report discusses. Given the severe drought years we've recently experienced, this is not surprising. But the report warns that extreme floods are also possible, and notes the spectacular damage done to the spillways at Glen Canyon Dam in 1983 and California's Oroville dam in 2017, during high water years. The same warming temperatures that boost evaporation rates, magnifying drought, also enable the atmosphere to hold more water. When this soggy atmosphere lets loose, rainfall is more intense.
Unexpected physical phenomena and socioeconomic events could also put high stress on management systems. Massive pine beetle damage to mountain forests and an earthquake in Mexico that damaged irrigation infrastructure are two examples of relatively recent, unexpected physical phenomena mentioned in the report. Shifts in global markets that affect agricultural production could also affect water demands.
The report is focused broadly on the management of the Colorado River and its tributaries, but individual communities are vulnerable to the same kinds of shocks. I checked in with the largest water utilities on the Western Slope to find out what kinds of "black swan" events worry them, and how they try to prepare. Linn Brooks of the Eagle River Water and Sanitation District, Dave Payne of Ute Water and Randi Kim of the city of Grand Junction put wildfire, landslides, dam breaches, terrorist attacks and power interruption, as well as extreme droughts and floods, on their lists of potential disruptions.
In terms of preparedness, Payne, Brooks and Kim all mentioned the importance of system redundancy, so if something goes wrong with one part of their water treatment and distribution systems, there's a backup. Brooks also noted the importance of keeping on top of infrastructure maintenance and upgrades. Under-resourced utilities with aging infrastructure and outdated equipment are more vulnerable.
As part of its risk-reduction strategy, Ute Water has a diverse portfolio of water sources it can draw on, including several streams on Grand Mesa, the Colorado River and Ruedi Reservoir in the Roaring Fork Valley, as well as interconnects with the city of Grand Junction and other domestic water providers in the Grand Valley. The city also has a diverse portfolio, maintaining water rights in the Gunnison and Colorado Rivers in addition to their primary source, Kannah Creek.
To reduce risks associated with wildfires, the city of Grand Junction has worked extensively with the US Forest Service on prescribed burns to reduce the risk of catastrophic wildfire in the city's water supply watershed. Such fires can damage infrastructure as well as foul source water. Ute Water addresses wildfire risks through making its reservoirs available for fighting fires. Ute also closely monitors the areas around its tunnels and pipelines for landslide activity, the other major natural hazard on Grand Mesa.
To get a better handle on potential supply vulnerabilities, the Eagle River Water and Sanitation District is developing a detailed model of its water rights and hydrology in order to preview the impacts of different scenarios, and anticipates increasing planning for extreme events as the tools to do so become more available. The city of Grand Junction is also engaged in modeling, evaluating scenarios that include successive drought years.
The Colorado River Research Group report acknowledges that water managers can't be expected to address every possible risk. But they call for the inclusion of more extreme events the range of scenarios considered in analyzing system reliability, and for developing the capacity to be agile and manage adaptively as situations change. This in turn requires close monitoring of the key factors that could affect water systems. These are points that people directly responsible for providing water to our taps appear to already understand very well. Applying this level of diligence to system reliability at a basinwide scale would benefit us all.
On a basinwide or local level, developing the capacity to manage black swan events requires not only forethought, but also resources. Redundant systems and constant monitoring don't come cheap. That's worth thinking about when we pay our utility bills.
Hannah Holm coordinates the Hutchins Water Center at Colorado Mesa University, which promotes research, education and dialogue to address the water issues facing the Upper Colorado River Basin. Support for Hutchins Water Center articles is provided by a grant from the Walton Family Foundation. You can learn more about the center at http://www.coloradomesa.edu/water-center.