The Runoff | Big water year begins to fade away

As water year 2023 wraps up, water managers are coming off a high, with the Colorado River crisis temporarily warded off thanks to a record-breaking snow year. But the basin may already be slipping back into conditions reminiscent of 2019, another big snow year that was followed by dry conditions, which set the basin up for a disastrous 2020 and 2021. Despite a few afternoon rain (and hail) storms, the monsoon in western Colorado has not set up with any consistency; aside from a few north-facing gullies, the snow has all melted in the high country; and abnormally dry and moderate drought conditions have crept back into southwestern Colorado, according to the U.S. Drought Monitor. Not to mention that in terms of global average temperature, it was the hottest July ever recorded. Next year’s conditions depend not solely on snowpack, but on what the rest of this summer and fall bring, and water managers are eagerly watching the forecasts.

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– Heather Sackett
Managing Editor and Water Desk Reporter

Non-depletion vs. delivery obligation

Colorado River politics is heating up with the looming negotiation of the post-2026 operational guidelines and state representatives are laying the groundwork to get Colorado’s water world on the same page regarding the state’s position and talking points. 

Colorado’s now full-time commissioner to the Upper Colorado River Commission Becky Mitchell has embarked on what she called a road show, meeting with water managers and organizations around the state to open the lines of communication and share news related to the negotiations. Among what she called her “irrefutable truths” is that according to the 1922 Colorado River Compact that divided the waters equally (7.5 million acre-feet per year to each) between the upper and lower basins, the upper basin states (Colorado, Utah, New Mexico and Wyoming) do not have an obligation to deliver 7.5 million acre-feet of water per year to the lower basin. What they have is a “non-depletion” obligation. So long as the upper basin uses less than 75 million acre-feet over 10 years, there’s no compact violation. I doubt the lower basin sees it that way.

What the compact actually says is this: “The States of the Upper Division will not cause the flow of the river at Lee Ferry to be depleted below an aggregate of 75,000,000 acre-feet for any period of ten consecutive years…” 

Its actual meaning has long been a point of contention for Colorado River scholars. Many people believe the language represents a de facto delivery obligation, with the upper basin required to send 75 million acre-feet over 10 years to the lower basin. 

This delivery obligation interpretation favors the lower basin and the non-depletion obligation interpretation favors the upper basin. It’s important because whether the upper basin violates the compact, which would trigger mandatory cutbacks, may hinge on this interpretation.

Also, presumably in an effort to communicate the state’s positions going into the post-2026 negotiations — while presenting it as the Law of the River 101 — representatives from the Colorado Attorney General’s office made an appearance at the Colorado Basin Roundtable meeting in July and pushed the non-depletion point of view as the law of the land. While seeing it as a non-depletion obligation is a very good political messaging strategy for the upper basin, it is in fact an unsettled legal argument. 

Another wrinkle in the non-depletion vs. delivery obligation debate is climate change. Scientists have found that Colorado River flows have declined nearly 20% from the 20th century average and that higher temperatures are responsible for about one-third of that. The compact clearly says that the states of the upper division will not cause flows to be depleted, but what if it’s not the states’ water use (which remains well below their 7.5 million acre-feet per year allocation), but climate change that causes flows to be depleted? Would that still be considered a compact violation? Colorado River expert and author Eric Kuhn has been asking this question for years, but he isn’t ready to test it. 

“Will it survive legal scrutiny? I’m not sure I would want to be the attorney that leads with that argument,” he said.

Ruedi meeting

The Bureau of Reclamation held its annual public meeting on Wednesday to recap Ruedi Reservoir operations for the year. With a big snowpack and long, sustained spring runoff with no big warm ups that caused fast melting, reclamation hydrologist Tim Miller said it was one of the most manageable years ever for the reservoir.

“This is one of the best years for how full we’ve had the reservoir and for how long the reservoir has stayed full,” he said.

The meeting also highlighted one of the interesting tensions in water management: fishing in the Fryingpan River versus endangered fish in the 15-mile reach of the Colorado River. Four species of endangered fish — humpback chub, bonytail, razorback sucker and pikeminnow — live in a chronically dewatered stretch of the Colorado River in the Grand Valley between big agricultural diversions and the confluence with the Gunnison River. In an effort to keep water in this stretch for the fish (and ensure water users’ compliance with the Endangered Species Act) the Colorado River Endangered Fish Recovery Program finds upstream water to send downstream through coordinated reservoir releases for the fish. One of the main sources is Ruedi Reservoir. 

When flows get low, the recovery program works with entities that have water stored in Ruedi to allocate water for the fish. The problem? When flows increase out of Ruedi and down the Fryingpan, it can have a negative impact to that river’s Gold Medal trout fishery, which by some estimates contributes $4 million a year to the local economy. Anglers generally agree anything over 300 cfs makes the waters unwade-able. Reservoir managers try not to go above this mark, but it’s a delicate dance and sometimes it’s unavoidable.

Water managers heard complaints from some anglers on Wednesday who said the fishing isn’t nearly as good as it used to be. General Manager of the Colorado River Water Conservation District Andy Mueller jumped to the Recovery Program’s defense, saying it protects Western Slope water users. The implication was that the Recovery Program ensures irrigators do not violate the Endangered Species Act. If the endangered fish didn’t have enough water as a result of diversions, irrigators might have to cut back. 

In a heavily managed system like the Colorado River where there’s hardly a river left with a natural hydrograph, it’s always a values trade-off for water managers when deciding who gets how much water when.

Grizzly Reservoir work postponed

Last summer Aspen Journalism reported on a project at Grizzly Reservoir to rehabilitate the dam and outlet works that takes water into the Twin Lakes Tunnel and under the Continental Divide. The reservoir was slated to be drained this year after spring runoff and work completed by October. But that project has now been postponed until next year. 

Twin Lakes Reservoir and Canal Company Interim Manager Matthew Heimerich explained it was a matter of logistics: getting the special membrane from Europe and other materials on site and completing construction during the short summer window just wasn’t going to happen this year. The project involves installing a membrane over the steel face of the dam, which was constructed in 1932 and is corroded and thinning. 

“The board of directors and project manager are working hard to make sure it happens next year,” Heimerich said. 

Lincoln Creek water quality testing

Since the rehabilitation work is now delayed by a year, the Pitkin County Environmental Health Department is going to take water quality samples before, during and after the construction to determine if there are any adverse impacts when the high-alpine reservoir is drained. Pitkin County Healthy Rivers board recommended funding a $15,000 request from county Environmental Health Manager Kurt Dahl for lab testing for three to four sites with four different sampling times (pre-draining of Grizzly Reservoir, during draining, during a change in creek diversion and post-construction). 

Previous water quality testing has found that Lincoln Creek has high levels of copper and aluminum, which could impact aquatic life and downstream water quality in the Roaring Fork. Last summer agencies began taking a closer look when Lincoln Creek below the reservoir turned a milky green color. The Environmental Protection Agency has also done water quality testing, the results of which are not yet public. It’s unclear if the source of the contamination is from upstream mine drainage, if it’s naturally occurring as a result of the area’s geology, or a combination of both. 

Twin Lakes diversion

In more upper Roaring Fork watershed news, Twin Lakes is currently not taking water through the tunnel and hasn’t been since Aug. 4. This is because the water that would otherwise be flowing through the tunnel now is currently being sent downstream as part of a 2018 water court settlement in which Pitkin County received 800 to 1,000 acre-feet of water from the Twin Lakes system. The county usually tries to time this “bypass” flow so that it’s sandwiched between the end of spring runoff and the beginning of the Cameo Call to keep the most water possible flowing down Lincoln Creek to the Roaring Fork. The bypass flows are timed to mirror the descending natural hydrograph and give it a boost.

As of Wednesday, the stream gauge on the Roaring Fork near Aspen was reading 66 cfs, about half of which Assistant Pitkin County Attorney Laura Makar said is due to the bypass agreement. 

“It’s what allows the Roaring Fork to have any water in it,” she said. “It’s wild how much it ends up mattering.”

Four urban Front Range water providers own 95% of the shares of Twin Lakes water; Colorado Springs Utilities owns the most at 55%.

Cameo call

Speaking of the Cameo call, according to Colorado Division of Water Resources staff, it’s not expected to come on until the first or second week of September, thanks to this year’s strong runoff. The Cameo call is the name given to the group of big senior agriculture diversions in the Grand Valley. When they aren’t getting their full share of water, which often happens late in the irrigation season when spring runoff is over and conditions are hot and dry, they place a “call,” meaning upstream junior water users have to cut back so the Grand Valley can get its full amount of water. 

Roaring Fork river lovers like to see the Cameo call come on because it means junior water users, including the Twin Lakes Tunnel transmountain diversion, have to shut off, leaving more water in the Fork. So with the Cameo call coming later than usual this year, that water sent down the Fork from the above-mentioned Pitkin County settlement is even more important. 

Last year, the Grand Valley summer call was first placed on July 30; in 2021 it was July 11. In 2019, another big snowpack year, it didn’t come on until near the end of irrigation season, Sept. 25.

Janeway on KDNK

Aspen Journalism reported on an augmentation study that identified a historic floodplain next to the Crystal River as a potential site for a water replacement project. It’s a complicated subject, but I attempt to break it down with the help of the Sopris Sun’s James Steindler in Everything Under the Sun on Carbondale’s community radio station KDNK. Listen to the recording on KDNK’s website. 

Since the last edition of The Runoff, Aspen Journalism’s Water Desk has reported the following stories. If you are not already, subscribe to The Roundup to get our weekly rundown of new news and insights: