The Runoff: Releasing cool water to disrupt smallmouth bass sounds fishy to these scientists
Aspen Journalism
At Aspen Journalism — an independent, nonprofit, investigative newsroom based in the Roaring Fork Valley — we’ve been covering water policy and politics in the headwaters basins of Colorado since 2011. Week in and week out, we’re in the room at water meetings, getting our boots dirty seeing where the water flows and doing everything we can to understand the complex issues around water use in our state and the larger Colorado River basin. We created The Runoff as a newsletter for our subscribers in 2022, as a place to share exclusive extras from our reporting, beyond the regular water coverage you’ve read in this newspaper. We offer it today to a wider audience. Thanks for going deeper with us. For more from Aspen Journalism, and to subscribe to The Runoff, visit http://aspenjorunalism.org.
‘We’re reengineering the river in even crazier ways’
In an effort to prevent smallmouth bass — an invasive, voracious predator that feasts on native fish, including the threatened humpback chub — from establishing populations below Glen Canyon Dam, the U.S. Bureau of Reclamation in early July began releasing colder water from Lake Powell via the river outlet works (which are 100 feet lower in a cooler part of the water column) in addition to the hydropower penstocks. Known as the “Cool Mix Alternative,” Reclamation chose this option with the goal of keeping water temperatures below the dam under 15.5 degrees Celsius (60 degrees Fahrenheit), which is too cold for smallmouth bass to thrive.
But a report by a group of scientists at the Center for Colorado River Studies at Utah State University says that factors other than temperature should be taken into consideration when trying to manage the nonnative species. The Western Area Power Administration, which sells the hydropower generated by Glen Canyon Dam, funded the participation of two of the four scientists who authored the report.
The report says the nearest population center of humpback chub is 76 river miles downstream in Grand Canyon water that is too turbid for smallmouth bass to proliferate.
“We think the uncertainty in predictions about smallmouth bass establishment near the downstream humpback chub population centers and their impact on chub populations if smallmouth bass do become established is not adequately recognized,” the report reads.
The report urges water managers to not develop reservoir operation plans that are too prescriptive given the uncertainty about hydrology in the coming years.
“We think the various management actions being considered to control smallmouth bass recruitment are unlikely to be effective given the modest history of success of similar actions in the last two decades in the Colorado River ecosystem,” the report reads. “We recognize that our report differs from the dominant paradigm related to smallmouth bass in the Colorado River basin and that even suggesting this alternative paradigm will likely create disagreements among scientists and … stakeholders.”
Jack Schmidt, a Colorado River expert, professor and lead author on the report, said that it’s ironic that in order to preserve one of the last remaining native components of the river’s natural ecosystem (humpback chub), water managers are looking to increasingly unnatural actions on the already highly engineered river. Messing with nature only begets more messing.
“We’re making the river more unnatural, and we’re reengineering the river in even crazier ways to try to protect the remaining elements of the native ecosystem,” Schmidt said. “And although the intentions of that are incredibly well-meant, over the long run, that may not be possible. … At what point does making the river more unnatural just not make sense anymore?”
What is another way to ensure that releases out of Lake Powell’s hydropower penstocks are cold enough to prevent the establishment of smallmouth bass? Keep the reservoir more full. But with the effects of steady demand, drought and climate change, that’s easier said than done.
Don’t call it demand management
Over the System Conservation Pilot Program’s two years so far, the 101,000 acre-feet of conserved water simply flowed downstream to be picked up by the next users in line, with no accounting for where it ended up. But water managers want to change that. In June, the Upper Colorado River Commission decided to explore creating a way to track, measure and store conserved water in Lake Powell and other Upper Basin reservoirs. Officials said water users across the Upper Basin states (Colorado, New Mexico, Utah, and Wyoming) wanted a way to “get credit” for water they saved by participating in the SCPP and protect that water in Lake Powell.
One could be forgiven for having déjà vu. I wrote many stories in 2019, 2020 and 2021 about this concept — then called demand management — which would pay water users on a temporary and voluntary basis to cut back and store that saved water in a special pool in Lake Powell. Demand management was explored extensively by the state of Colorado for two years before being shelved in 2022. The intent of the stored water would be to protect the Upper Basin states in the event of a compact call. Water could be released from this pool instead of shutting off cities and irrigators. Now, the concept is back, except no one is using the term demand management.
Attorney James Eklund was Colorado’s lead negotiator on 2019’s Drought Contingency Plan, which created the demand management pool in Lake Powell, and his family ranch near Collbran is participating in SCPP this year. He thinks the reason the Upper Basin states, led by Colorado, have been slow-walking setting up a demand management program for the past five years is because officials think it gives them an edge in negotiations with the Lower Basin states (California, Arizona and Nevada). The seven Colorado River basin states are currently in the midst of figuring out how the nation’s two largest reservoirs will be operated after 2026 and which water users will be cut by how much in dry years.
“I think there’s this concern that if we basically show that we can conserve water at scale that we would be kind of implicitly admitting to the feds and the Lower Basin that that was possible,” Eklund said.
The Upper Basin’s refrain has long been that the crisis on the river is driven by Lower Basin overuse and that the Upper Basin has little water to spare; users already take unavoidable cuts in dry years because the water simply isn’t there. But Eklund says the existence of a demand management pool in Lake Powell could actually strengthen a negotiating position with the Lower Basin , which is demanding that the Upper Basin share in future cuts.
“I think we strengthen our negotiating position if we demonstrate that we have water banked in an account that we control and that we are happy to make releases from in a crisis,” Eklund said. “But that’s our contribution. There’s not going to be a draconian, apocalyptic compact curtailment scenario that we are going to administer up here. We are going to point back to this water that we conserved over the course of those crises as our main source of leverage.”
We may know more about the future of an Upper Basin conservation program Aug. 12, when the UCRC plans to hold a special meeting. This is the deadline for a proposal from staffers and state advisers that outlines a mechanism for generating credit from water conservation projects and protecting the water in Lake Powell. Since this mechanism already exists (it’s called demand management), it will be interesting to see what else water managers come up with.
Lincoln Creek consultant chosen
The Lincoln Creek Workgroup, led by Pitkin County, has chosen a consultant for what they are calling Phase I of addressing contamination in the creek. LRE Water, which has an office in Glenwood Springs, will review the existing Environmental Protection Agency report and other data, make a site visit, and comment on the water quality sampling plans of five different entities taking samples of Lincoln Creek this summer: Colorado Parks and Wildlife; U.S. Forest Service; Institute of Arctic and Alpine Research at University of Colorado Boulder; the Roaring Fork Conservancy; and Pitkin County Environmental Health. Pitkin County Healthy Rivers has committed to funding between $10,000 and $16,000 of the work. The Independence Pass Foundation is also contributing.
Local and state water managers have been trying to figure out how to address metals contamination in Lincoln Creek, which has turned the waterway orange and is toxic to fish. LRE Water’s work will inform ideas about future mitigation or restoration efforts, if any are possible.
Wild Horse Reservoir off and running
Aurora Water is moving closer to building what would be its largest bucket for storing more water from the Colorado River basin. The Front Range water provider said in a news release that it has selected construction companies Flatiron, Dragados USA and Sukut Construction as general contractors for the proposed Wild Horse Reservoir, near Hartsel. The team has been hired for three years at a cost of $6.5 million.
Wild Horse would store water from the Arkansas and Colorado river basins — some of the Western Slope supply comes from the headwaters of the Roaring Fork and Fryingpan rivers — and would not involve new water rights. Planned for about 6 miles west of Spinney Mountain Reservoir, Wild Horse would hold up to 93,000 acre-feet of water. For comparison, Ruedi Reservoir holds about 100,000 acre-feet. The reservoir would be off-channel, with water pumped from Turquoise and Twin Lakes reservoirs via the Otero Pipeline.
Officials say Wild Horse is needed to bolster the reliability and resilience of Aurora’s water supply and will provide water for 280,000 households. The project is in the early permitting stage and requires review under the National Environmental Policy Act. It is slated for completion in the 2030s and is estimated to cost between $600 and $800 million.
‘Bucket 2″ funding deadline’
On July 22, the U.S. Bureau of Reclamation announced it is taking applications through Oct. 14 for projects in the Colorado River’s Upper Basin that aim to address issues caused by drought. Projects must provide environmental benefits or involve ecosystem/habitat restoration. This funding is the second phase of the Inflation Reduction Act funding in the Upper Basin. The other component of the second phase, called “Bucket 2,” will be focused on water conservation projects that achieve long term reductions in use or demand and that funding will be released later this year.
Applicants must be public entities or tribes, but they may partner with nonprofit organizations. The funding is intended for larger-scale projects, with a minimum ask of $300,000.
“I think it’s really exciting in terms of identifying projects that can be thought about at a bigger watershed scale,” said Fay Hartman, southwest regional program conservation director with American Rivers.
The funds are expected to be awarded in the spring.
Aspen Journalism is a nonprofit, investigative news organization covering water, environment, social justice and more. Support and subscribe at http://aspenjournalism.org.
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