By Jay Landers
Colorado, like much of the Mountain and Southwestern regions of the United States, has endured prolonged drought conditions throughout much of the past two decades, increasing the strain on the state’s water resources. Ensuring adequate water supplies for agricultural, municipal, industrial, and environmental uses is expected to become more challenging over time in Colorado as climate change disrupts typical weather patterns and complicates efforts to predict future water availability.
Against this backdrop, in January, Colorado Gov. Jared Polis called for a conference focused on drought in the state. The resulting Colorado Drought Summit, which was held May 31-June 1 at the History Colorado Center in Denver, highlighted approaches for maintaining a sustainable future water supply that balances the needs and concerns of different interests across the Centennial State.
Bringing people together
Featuring more than 50 speakers and numerous panel discussions, the Drought Summit included multiple concurrent sessions dedicated to the subjects of vibrant communities, thriving watersheds, resilient planning, and robust agriculture. These four topics constitute the interconnected action areas that are the focus of the 2023 Colorado Water Plan, which the Colorado Water Conservation Board released in January. The CWCB is the agency within the Colorado Department of Natural Resources that oversees the state’s water policy and planning efforts.
An update to the state’s first such plan in 2015, the 2023 version “serves as a framework for statewide collaboration around water planning” and “guides future decision-making and supports local actions to address water challenges with a collaborative, balanced, and solution-oriented approach that builds resilience,” according to the CWCB’s website.
In effect, the Drought Summit offered participants a means to build on the foundation and accomplishments of the Colorado Water Plan while focusing specifically on how to address the persistent threat of drought, says Russ Sands, the section chief for water supply planning for the CWCB, which sponsored the summit along with the engineering consulting firm Brown and Caldwell.
“We know our future's going to be challenged, but if we work together, we can find ways to mitigate the worst impacts,” Sands says.
Overall, the Drought Summit aimed “to bring people together to talk about drought issues, identify collaborative solutions, share success stories, and focus on how to mitigate drought conditions and move forward in a collaborative way,” says Matt Lindburg, P.E., a water resources engineer with Brown and Caldwell.
Certain geographic and legal realities complicate efforts related to water management in Colorado. For example, 80% of precipitation falls west of the Continental Divide, while 90% of the state’s population lives to the east. As a result, a complex network of tunnels and ditches conveys approximately 500,000 acre-ft/year from the Western Slope to the Eastern Slope, according to the Colorado Water Plan.
Statewide, 83% of water used to meet agricultural and municipal needs comes from surface water, while 17% comes from groundwater. In terms of water use by sector, agriculture uses 90% of water in Colorado, followed by municipalities (7%) and large industry (3%), according to the Colorado Water Plan. Because return flows from these sectors to surface waters represent a major source of supply to downstream users and the environment, Colorado water law places strict limits on when water reuse may occur.
“Not every supply can be reused,” Lindburg says. However, “supplies that are not native to a particular basin” may be reused, he says. For example, water conveyed from Colorado’s Western Slope to cities to the east may be reused by those cities to “extinction,” Lindburg notes. “That's actually done in quite a few locations on the Eastern Slope and is a very effective way to make use of those reusable supplies.”
Collaboration is key
In keeping with major themes of the Colorado Water Plan, the Drought Summit focused on the importance of collaboration and the use of multibenefit projects as keys to ensuring adequate future water supplies in Colorado, Lindburg says. “We're at a point in a lot of parts of the state where there's not that much water to go around,” he notes. “We really need to think about how we can meet multiple needs with (water) projects. To the extent that we can have collaborative projects, I think that's going to be beneficial to the state.”
However, collaboration “hasn't always been the way that we've approached water supply projects in the past,” Lindburg says. But given the complex mix of water users and needs across the state, “we really need to look for collaborative solutions,” he says. “We need to get folks around the table early to talk about how a project could meet multiple needs across multiple sectors early on and build that into the project.”
Initiating these types of dialogues sooner rather than later is especially important in light of the fact that, in Colorado, “local water users have a lot of control over their own sources of supply,” Lindburg notes. “It takes time for conversations to occur and for solutions to come to light that everybody can buy into as well as finding that sweet spot between what local water users can best do and then how the state can best support them in that.”
Working with, not against, agriculture
Agriculture and its relationship with water featured prominently during the Drought Summit. “Agriculture and agricultural water use are really important to our state's economy,” Lindburg says.
With the prospect of drought intensifying and Colorado’s water regime changing in the future, agricultural interests in the state are evaluating “how they can increase their efficiency during drought conditions,” Lindburg says. In some cases, agricultural water users are converting from flood irrigation of fields to sprinkler or even drip irrigation systems, he says. In other cases, agricultural water users are enclosing surface laterals and ditches within closed conduits to reduce water losses. “They're doing a lot to be more efficient,” Lindburg says.
Meanwhile, some Colorado farmers have been investigating the possibility of “crop shifting” as they seek to find alternative crops that “bring improved yields while requiring less water,” Sands says. “That savings may just go into growing more crops initially, but it creates some more flexibility in the system in times of scarcity.” And flexibility corresponds to resilience, he notes.
In other cases, more creative approaches to collaborative water sharing agreements could lead to a wider array of benefits involving a greater number of interests, Sands says. Formally referred to as alternative transfer mechanisms, such agreements typically involve the temporary transfer of water from agriculture to other uses, predominantly municipal.
“Are there ways to think about (collaborative water sharing agreements) involving agriculture helping agriculture or agriculture helping the environment?” Sands asks. To succeed, such approaches will require collaboration as well as a “spirit of innovation,” he says.
Although agriculture uses by far the most water of any sector in Colorado, Sands warns other sectors not to view agriculture as a target from which to capture water. “We need to embrace agriculture as partners in this and not just think about what we're going to take from them,” Sands says. “Because taking (water) from agriculture ultimately means we're taking away our gross domestic product as a state. We're taking away our local foods. We're taking away exports.”
Instead of looking to pry water from the agricultural sector, Colorado needs “to flip the narrative and think about what we're going to protect,” Sands says. When farmers and ranchers go out of business because they lose access to affordable water, the resulting ripple effects tear at the fabric of the entire rural economy, he says. “We’re not just drying up a farm,” he says. “It's drying up the health care system in that area and reducing the number of hospitals, or it's drying up specialty jobs that involve engineering and mechanical work or custom farm equipment. It erodes the tax base.”
Flexibility amid uncertainty
As for steps that civil engineers can take to address future water challenges in Colorado, the Drought Summit included discussions about the need to embrace scenario-planning methodologies that “acknowledge the future's uncertain,” Lindburg notes. By acknowledging uncertainty about future climate conditions and population levels, for example, engineers and others need to evaluate a “potentially wider range of conditions in the future,” he says.
At the same time, engineers must take “strategic approaches to not overbuild or underbuild infrastructure,” Lindburg notes. Such approaches involve “not necessarily planning and building for the worst-case scenario but rather understanding that a worst-case scenario could occur,” he says. “But maybe there's a suite of more likely scenarios, and you build a project that could be potentially expanded in the future if that worst-case scenario comes to fruition.” In effect, engineers must consider “ways to be flexible in light of future uncertainty,” Lindburg says.
Another key consideration involves greater use of nature-based solutions, particularly green infrastructure, Sands says. “How do we use our natural systems better to serve us best and provide not just ecosystem benefits but human benefits?” he asks. Nature-based solutions are “often the same tools that can help in flood years or drought years,” he says. “Embracing those natural solutions is a critical part of our future as well.”
Nature-based solutions also offer a means of protecting the “quality of water supplies that are in our headwater streams and then get into the reservoirs that are our critical water supplies for agriculture and for municipalities,” Lindburg says. For example, nature-based solutions “can help mitigate some of the detrimental impacts from wildfire, in terms of capturing sediment, preventing erosion, and debris flow,” he says. “There are a lot of benefits to nature-based solutions that can help us protect our critical water supplies.”
Of course, traditional means of extending and expanding water supplies remain part of the mix, including water conservation. “Conservation is another thing that we need to keep in mind when we’re looking at water supply alternatives,” Lindburg says. “It’s something we need to prioritize.” That said, conservation alone is “not going to get us out of the hole,” he says. “But it is definitely a very important piece to the puzzle.”
Although new dams and reservoirs are “going to play a role in meeting our future water needs, we don't necessarily need to always focus on” those infrastructure components as the main solutions, Lindburg says. Alternatives include expanding existing reservoirs and pursuing aquifer storage and recovery programs, where feasible.
Depending on the location, groundwater may pose a problem or a solution during future droughts. For example, in the San Luis Valley in south-central Colorado, “there's a lot of dependence on groundwater supplies, and those supplies are diminishing,” Lindburg notes. “We're going to need to find ways to reduce our reliance on those supplies in order to create a more sustainable situation. Drought will only make those issues more prevalent.”
By contrast, other parts of the state that rely mainly on surface water also have groundwater supplies that can be relied upon to augment supplies during dry periods. “Drought can impact groundwater supplies by increasing our need to pump groundwater,” Lindburg says. “But in other situations, (groundwater) can be a good buffer that can be used during drought and then maybe not used when other supplies are more plentiful.”
No matter what solutions are pursued in a given location, the sooner stakeholders begin meeting and discussing their options, the better the result, Sands says. “We know that the worst time to plan is when you're right in the middle of a crisis.”
This article is published by Civil Engineering Online.