The Colorado River’s confounding math problem — @BigPivots #COriver #aridification

Nook on Lake Powell. Photo credit: Allen Best/Big Pivots

Click the link to read the article on the Big Pivots website (Allen Best):

Spring runoff last year in the Colorado River Basin was a bust, with snowpack of almost 90% of average reduced to a 30% inflow at Lake Powell.

Nobody yet predicts another bust this year. Maybe a meteorological March madness will compensate for last year. While we wait, water managers talk about “the math problem.”

The gap between water flows and demands in the Colorado River is enormous and likely to widen. The dysfunctional equation begins with 20 million acre-feet, the average annual flows assumed by the Colorado River Compact that was crafted 100 years ago by delegates from the seven basin states.

Eugene Clyde LaRue measuring the flow in Nankoweap Creek, 1923. Photo credit: USGS via Environment360

This cheerful assumption was based on early 20th century flows. It was made with almost willful disregard of evidence available even then of the river’s lesser flows during the prior half-century. The delegates who met at a lodge near Santa Fe in 1922 were determined to yoke all irrigable acres into agricultural production.

In this math problem, another key number is 12.3 million acre-feet. That’s been the river’s average flow in the 21st century. Some of this reduced flow seems to be entirely natural, what we call drought, if exceptional in duration.

Something else has been going on. Temperatures have risen 3 degrees C altogether since 1970. By some estimates, half or more of the reduced flows can be attributed to this global warming effect. This warming explains the grand larceny in the Colorado River, decent snowpacks reduced to a shrug in the Utah desert because of evaporation but also because plants need more water. Too, baked soil sops up water.

We can’t flip the switch on global warming, and it’s almost certain to worsen, the temperature rise doubling or tripling, as Colorado State University’s Brad Udall warns. He describes what is occurring as aridification. Unlike drought, it’s not temporary.

This brings us to another number for this Colorado River Basin math problem: 11 million acre-feet.

That’s the number cited last week at a University of Utah conference about future flows of the Colorado River. “The best climate scientists in the world say we will be lucky to have 11 million acre-feet,” said John Entsminger, general manager of the Southern Nevada Water Authority, the agency serving Las Vegas.

To recap this math problem, the Colorado River Compact assumed 20 million-acre feet, the reality has been 12.3 in the last two decades, and we’ll end up with 11 million-acre feet—or conceivably less.

“Every new use will have to be mitigated by someone, somewhere, using less water,” Entsminger added.

That’s not entirely right either. We all will have to use less water. Keep in mind that not one drop of the Colorado River gets to the Sea of Cortez.

Cinching of the water belt has been underway from Mexico to Colorado. It’s not happening as rapidly as needed, though. Consider the rapidly emerging walls of Glen Canyon and the dam that creates Lake Powell. Despite emergency releases from upstream reservoirs in Colorado and Utah last summer to bolster Powell, the water levels last week dipped below 3,525 feet.

Lake Powell storage in acre-feet. 1 acre-foot = 325,851 gallons. USBR.

That elevation is arbitrary but a loud warning that a further decline of 35 feet leaves Glen Canyon unable to generate electricity. Recent modeling by the U.S. Geological Survey shows a 25% risk. If —or perhaps when—that happens, municipalities and cooperative members who get power from Glen Canyon will still get electricity from elsewhere, but it will cost more. That includes Holy Cross Electric.

Long term, this worsening situation of subpar runoff in the Colorado River matters to well more than 90% of Colorado’s population. The Colorado River and its tributaries deliver half of Front Range water. Even the easterly flowing rivers in Colorado that pass through more distant, less citified places, Sterling and La Junta, carry water augmented by diversions from the Colorado River.

Much remains to be worked out. Within Colorado, agriculture uses 80% to 90% of all water. Farmers and ranchers who own the more senior water rights, not subject to compact limitations, have served emphatic notice that their water will not be the answer to the math problem.

Lees Ferry streamgage and cableway downstream on the Colorado River, Arizona. (Public domain.)

Another problem is the compact clause that puts the upper basin states—Colorado, Utah, New Mexico and Wyoming—on the hook for diminished flows. It says they “will not cause” the flows at Lee Ferry, just below Glen Canyon, to be depleted below 75 million acre-feet of water over a rolling 10-year average. The upper basin states cannot do this alone. The risk must be shared.

This sounds gloomy. That said, the seven basin states, Mexico, and the sovereign tribes who collectively own about 20% the basin’s water have yet to throw rocks at each other. They are talking. They just haven’t solved this math problem.

#Empire still without #water as leak detection efforts continue: Public updates at 10 a.m. March 28, 2022 and 6:30 p.m. March 29, 2022 at Town Hall — The #ClearCreek Courant

Empire as seen from Douglas Mountain. By Xnatedawgx – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=25798349

Click the link to read the article on the Clear Creek Courant website (Corinne Westeman):

Most Empire residents and businesses are still without water, as of March 25, 2022 as town officials continue to search for a suspected large leak in the town’s water infrastructure. Anyone who does have water service is under a boil warning, which will remain in place until water service is restored to the entire town and it has been tested, Mayor Wendy Koch said. According to Koch and Police Chief John Stein, most of the town’s infrastructure has been pressurized with gas to locate the suspected leak. Those efforts didn’t yield any major leaks, but several smaller issues were noted and are now being addressed, Koch said. Now, Empire is restoring water service to different sections of the town to see if that helps to locate the suspected leak.

Stein said Empire will be hosting public updates at 10 a.m. March 28 and 6:30 p.m. March 29 at Town Hall. The latter will include an opportunity for public comment, but the former is an informational meeting only…

An emergency declaration has been made to assist with resources and seeking funding, Stein stated. Colorado’s Water/Wastewater Agency Response has been activated and is assisting, and volunteers were scheduled to deliver two cases of bottled water to every housing unit on March 25…

Stein said that, thankfully, several municipalities have offered to help fix whatever the problem is. However, the town is “still in detection mode,” he said. Another piece of good news, Koch detailed, is that surface water levels are back up thanks to the warmer weather. Additionally, Koch and Stein stated, Empire is adding a new filtration system to its old well. The state health department approved the design on March 24, and crews will start work on March 28.

If all goes according to plan, Koch said the town might have water service mostly restored by April 1. However, she stressed that she couldn’t guarantee it.

#Drought news (March 28, 2022): #Denver’s no longer in a drought, but it’s still really dry. The majority of the state remains in at least moderate drought conditions — The Denver Post

Colorado Drought Monitor map March 22, 2022.

Click the link to read the article on the The Denver Post website (Conrad Swanson). Here’s an excerpt:

Climatologists no longer consider the Denver metro to be suffering from drought conditions, instead the area’s now considered “abnormally dry.” The change shows a significant improvement over conditions in December, during which Denver was considered to be swathed in an “extreme drought,” data collected by the National Drought Mitigation Center shows.

While the improvement around Denver is reflected this week around much of the rest of Colorado, more than 80% of the state’s land is still in what is considered to be a “moderate drought,” the data indicates. Climatologists repeatedly said this winter that the state needed consistent, above-average snowfall to recoup lost moisture and that didn’t happen. Other areas, like those around Grand Junction and most of Pitkin County are also now considered to be abnormally dry, the data shows. Swathes of extreme and “exceptional” drought still cover large portions of Colorado’s southern counties.

West Drought Monitor map March 22, 2022.

#NewMexico finalizes $1 million in restoration projects from #GoldKingMine spill — The Sante Fe New Mexican #AnimasRiver #SanJuanRiver

Click the link to read the article on the Sante Fe New Mexican website (Scott Weyland). Here’s an excerpt:

The $1 million in restoration work is part of the $11 million settlement New Mexico reached last year with Sunnyside Gold Corp. and its two parent companies…

The plan calls for:

  • San Juan County to build the Cedar Hill Boat Ramp on the Animas River.
  • The city of Farmington to build the Festival and Farmers Market Pavilion at Gateway Park.
  • The San Juan County Soil and Water Conservation District to implement a soil restoration project in San Juan Valley.
  • The Tse Daa Kaan Chapter of Navajo Nation to upgrade its irrigation system.
  • The other $10 million in the settlement covers environmental response costs and lost tax revenue, among other things.

    Bulkheads, like this one at the Red and Bonita Mine, help stop mine water discharges and allow engineers to monitor the mine pool. Credit: EPA.

    Sunnyside Gold oversaw construction of the bulkheads that led to mines filling with acidic water…

    Some money from the EPA settlement will go to northwestern New Mexico communities for agriculture and outdoor recreation, partly to ease the stigma the spill caused in that region, state officials said in a news release. It will cover some of New Mexico’s costs responding to the spill. And it will pay the state to restore and conserve river and land habitats, monitor water quality, and clean up pollution to protect drinking water.

    Ruedi Reservoir at lowest level in two decades: #Water managers waiting to see if spring #runoff is enough to fill depleted storage buckets — @AspenJournalism #FryingpanRiver #RoaringForkRiver #ColoradoRiver #COriver #aridification

    Ruedi Reservoir on the Fryingpan River as seen on March 24. The reservoir is at its lowest level in nearly two decades, but U.S. Bureau of Reclamation officials say if forecasts hold, it should still be able to fill in 2022. CREDIT: HEATHER SACKETT/ASPEN JOURNALISM

    Click the link to read the article on the Aspen Journalism website (Heather Sackett):

    Ruedi Reservoir is at about its lowest level of the year — and also of the past 19 years — according to numbers from the Bureau of Reclamation.

    As of Wednesday, the reservoir on the Fryingpan River contained 54,914 acre-feet of water and was about 54% full. And according to U.S. Bureau of Reclamation data, outflow is currently slightly more than inflow, meaning levels may not have bottomed out yet.

    The last time the level was this low was in the drought year of 2003 when Ruedi hit 46,117 acre-feet, according to Timothy Miller, a hydrologist with Reclamation, which operates the reservoir. Many reservoirs across the West are at their lowest levels of the year right before spring runoff starts, and water managers will start to see in the next month what this year will bring and whether it’s enough to fill depleted storage buckets.

    Despite the current low levels, Miller said forecasts show Ruedi should be able to fill this year — but just barely. The most recent forecast from the Colorado Basin River Forecast Center shows that spring inflow for Ruedi will be about 96% of average.

    “If we continue to get average precipitation, we should be able to fill by the skin of our teeth,” he said. “We won’t have any extra water. It’s going to be a tight fill.”

    In 2021, Ruedi, which has a capacity of about 102,000 acre-feet, was only about 80% full after spring runoff.

    Ruedi Reservoir was 54% full as of March 24, 2022 — its lowest level in nearly two decades.

    “April hole”

    Something that may influence if and how Ruedi fills this year is a phenomenon called the “April hole.” Agricultural irrigators downstream in the Grand Valley usually begin filling their ditches around April 1, and if irrigation ramps up faster than the snow melts in the high country, there may not be enough water to meet their demand.

    Grand Valley irrigators, with large senior water rights dating to 1912, can command the entire Colorado River and its tributaries in western Colorado by placing a call. This means water users with junior water rights have to stop taking water so that the Grand Valley irrigators can get their entire amount of water to which they are entitled. When these irrigators put a call on the river, known as the “Cameo call,” it can control all junior water rights upstream of their diversion at the roller dam in DeBeque Canyon.

    Water travels through a roller dam, generating power, then continues downstream. Roller Dam near Palisade. The Grand Valley Diversion Dam in DeBeque Canyon sends water from the Colorado River into the Grand Valley Project Canal. Rehabilitation of the structure could be one of the projects funded by the River District’s new Partnership Project Funding Program. Photo credit: Hutchinson Water Center

    The Cameo call doesn’t come in April of every year, but it did in 2021 and lasted for 16 days — the longest April hole ever. Dry soils and hot temperatures in 2020 and 2021, fueled by climate change and drought, robbed the river of flows and created conditions never before seen by water managers.

    “Last year was definitely the extreme,” said James Heath, Division 5 Engineer for the Colorado Division of Water Resources. “We never had a call in April last that long. The prior longest was in 2002, with five days of call.”

    Instead of curbing their water use when the Cameo call is on, some water users simply release water from Ruedi that they have bought and store there as part of an augmentation plan. The problem, Heath said, is that many of these water replacement plans counted on a call lasting at most seven days.

    “What we are finding is a lot of the plans were originally decreed for a worst-case call scenario of seven days in April,” he said. “Last year, they were diverting out of priority and injuring the downstream water rights.”

    Heath said his office is still figuring out how to address these shortfalls and analyze different entities’ augmentation plans. He said Ruedi had to release about 1,300 acre-feet of water last year to satisfy the Cameo call in April.

    The dam on a frozen Ruedi Reservoir as seen on March 24. Last year, an “April hole” where downstream irrigations demands outpaced snowmelt resulted in a Cameo call and extra releases from Ruedi. CREDIT: HEATHER SACKETT/ASPEN JOURNALISM

    Hydropower production

    A consequence of low levels in Ruedi is a reduced capacity to generate power at the hydroelectric plant, which is operated by the city of Aspen. Steve Hunter, utilities resource manager with the city, said the bottom line is this: the less water, the less power that is able to be produced. Hunter said if water levels fall below 7,700 feet elevation, utilities staff may decide to shut the unit off because the water pressure may not be generating much power. Ruedi was at 7,708.7 feet Wednesday. When Ruedi is full, the surface elevation is 7,766 feet above sea level.

    When hydropower production decreases, Hunter said Aspen fills its all-renewable portfolio by buying more wind power.

    “When hydro goes down, wind picks up the slack,” he said. “We are not in a terrible place right now. We are not Glen Canyon Dam.”

    Hunter was referring to water levels in Lake Powell, which last week dipped to their lowest ever, hitting a target elevation of 3,525 feet, just 35 feet above the minimum level needed to generate hydropower at the dam.

    “Hydropower across the board in the West is being affected by drought,” Hunter said. “This is crunch time, just watching what happens in the next month as we approach peak snow-water equivalent and see what the snowpack does.”

    Aspen Journalism covers water and rivers in collaboration with The Aspen Times. This story ran in the March 25 edition of The Aspen Times.