Day: March 16, 2024

As states butt heads over #ColoradoRiver plans, water experts gauge impacts to #Colorado — Fresh Water News #COriver #aridification

From left, J.B. Hamby, chair of the Colorado River Board of California, Tom Buschatzke, Arizona Department of Water Resources; Becky Mitchell, Colorado representative to the Upper Colorado River Commission. Hamby and Buschatzke acknowledged during this panel at the Colorado River Water Users Association annual conference that the lower basin must own the structural deficit, something the upper basin has been pushing for for years. CREDIT: TOM YULSMAN/WATER DESK, UNIVERSITY OF COLORADO, BOULDER

Click the link to read the article on the Fresh Water News website (Shannon Mullane):

March 13, 2024

Colorado’s water and reservoirs are in the thick of disagreements over Colorado River management in a drier future.

All seven Western states in the Colorado River Basin agree that climate change is exacerbating conditions in the basin, and water users need sustainable, predictable water management. They agree that the current rules, which expire in 2026, didn’t do enough to keep reservoirs from dropping to critically low levels. They even agree that water cuts need to happen.

But they’re at loggerheads over how to share the pain — and have been for years. Now, the Lower Basin officials have proposed a plan calling on all basin users, including Coloradans, to make sacrifices.

“This is not a problem that is caused by one sector, by one state, by one basin. It is a basinwide problem, and it requires a basinwide solution,” John Entsminger, Nevada’s top negotiator, said during a news conference March 6.

Basin officials are negotiating Colorado River management in order to create new interstate water sharing rules that will replace the current agreements, which were created in 2007. The overburdened river system provides water to seven Western states, two Mexican states and 30 Native American tribes.

Basin states released competing proposals March 6, outlining their ideas for releasing, storing and cutting back on water use.

The Upper Basin proposal — put forward by Colorado, New Mexico, Utah and Wyoming — only includes cuts to the Lower Basin’s water use, although the four states would continue developing voluntary conservation programs.

The Lower Basin alternative — from Arizona, California and Nevada — looks at the amount of water stored in seven federal reservoirs. When that storage falls below 38% of total reservoir capacity, all seven states would conserve water to cut their collective use by 3.9 million acre-feet. One acre-foot roughly equals the annual water use of two to three households.

That’s a no-go for Upper Basin states, where water supply fluctuates yearly because it primarily relies on mountain snowpack. In 2020, a particularly dry year, the Upper Basin used 4.5 million acre-feet — much less than its legal allotment of 7.5 million acre-feet. In 2021, another drought year, the states had to cut back further.

That’s without any additional water cuts, like those proposed by the Lower Basin.

“When we’re looking at those years, like 2021 when our uses in the Upper Basin were at 3.5 million acre-feet, that represents almost a 25% cut,” Commissioner Becky Mitchell, Colorado’s top negotiator, said. “To cut further in a year like that could wreck communities and economies.”

Colorado’s role in the Upper Basin plan

The Upper Basin proposal calls for few changes in the upstream states.

The Upper Basin would keep taking steps to ensure Lake Powell, located on the Utah-Arizona border, could make its required releases downstream, and to reduce Upper Basin water use through voluntary, temporary and compensated cuts, like the system conservation pilot program.

The rest of the proposal is meant to offer guidance to the Lower Basin, Mitchell said.

In the past, officials have changed how water is stored and released at lakes Mead and Powell based on the reservoirs’ elevations. The Upper Basin plan links operations more closely to each year’s available water storage, a high priority for Colorado officials.

In years when Lake Powell is less than 20% full, the Upper Basin states suggested releasing as little as 6 million acre-feet of water downstream. Upper Basin states are legally obligated to let at least 7.5 million acre-feet flow to Lower Basin states (plus some for Mexico) annually, as averaged over a rolling 10-year period.

If reservoir storage dropped to certain trigger levels, Lower Basin states would also cut up to 3.9 million acre-feet in a year.

The approach is designed to replenish depleted water storage in reservoirs, like Mead and Powell. These two enormous reservoirs — which function like savings banks for water users — drained to a third of their volume in the early 2020s, prompting a crisis response among officials and ramping up concerns about water availability in the future.

It would also protect Lake Powell’s ability to release water downstream according to water law, Mitchell said.

“That protects Colorado users. That protects all the Upper Basin states’ users,” Mitchell said. “The rebuilt storage protects all 40 million people — that’s the way that we protect all 40 million is to have a safety net.”

A call for widespread cuts

The Lower Basin officials say that the entire Colorado River Basin — including Colorado and the other Upper Basin states — must cut water use.

In their proposal, Lower Basin officials said they would take responsibility for the structural deficit, which refers to water losses from factors like evaporation, by cutting back on their water use by 1.5 million acre-feet in some years.

Credit: Upper Colorado River Commisstion

In years when the total storage in the system drops below 38%, the Lower Basin says the Upper Basin states need to help out so the basin as a whole can cut 3.9 million acre-feet.

If this plan had been in place since 1971, the states would have started taking cuts around 2000. For most of the past 24 years, the Lower Basin would have taken annual cuts of 1.5 million acre-feet. The Upper Basin would only have faced shortages in 2020 and 2021, according to Lower Basin officials.

“It’s very easy to craft an alternative that doesn’t require any sacrifice, but that’s not what the Lower Basin alternative does,” said JB Hamby, California’s top negotiator, during a March 6 news conference. “The Lower Basin is home to three-quarters of the Colorado River Basin’s population, most of the basin’s tribes, and the most productive farmland in the country. Our proposal requires adaptation and sacrifice by water users across the region.”

What would the Lower Basin option mean for Colorado?

Officials have released written plans, but it will take modeling out many different water supply scenarios to understand the impacts of each proposal, according to water experts.

But under the Lower Basin plan, Colorado could be on the hook for cutting its use by hundreds of thousands of acre-feet, said Colorado water expert Eric Kuhn.

In one hypothetical low-storage scenario, the Lower Basin would cut its use by 1.5 million acre-feet, then the two basins would each conserve an additional 1.2 million acre-feet, Kuhn said.

If Colorado took on a third of the Upper Basin’s obligation — and this is a big “if” — it would mean cutting water use by nearly 400,000 acre-feet.

“If Colorado ever agreed to absorb a certain percentage of the final … cuts, it’ll have a big impact on the state,” Kuhn said. “It’s not theoretical; it would be quite significant.”

For reference, all of the cities, towns and industries in Colorado use a combined total of about 380,000 acre-feet per year from multiple water sources, including the Colorado River, according to the 2023 Colorado Water Plan.

Mandated cuts could even send states into litigation, which is the worst outcome, said one Colorado official. Once the issue moves to the courts, state officials can’t talk to each other, and their future could be in the hands of U.S. Supreme Court justices who may not have expertise in the complex realm of Western water law.

“We’ll talk 1-to-1 cuts when they’re down to 4.5 million acre-feet,” said Steve Wolff, general manager of the Durango-based Southwestern Water Conservation District, referring to the average amount of water used by Upper Basin states. “When you’re still using twice as much as us, why should we agree to a 1-to-1 cut?”

Peter Ortego, general counsel for the Ute Mountain Ute Indian Tribe, said basin tribes that have made agreements to share in future shortages could be impacted. Most tribal nations have senior water rights, which get water first in dry years and should be protected from most water cuts, he said.

Environmental groups say more needs to be done to protect rivers and freshwater resources, which provide vital habitat for wildlife in the arid West.

In recent, very dry years, Colorado trout fisheries, like the Yampa River, have been shut down because of low flows and warmer water temperatures in mid-to-late summer. If modeling shows that federal or state plans would leave less water in the rivers, that would be concerning, said Jennifer Pitt, Colorado River Program director for the National Audubon Society.

Going forward, Pitt and other water experts will be watching for updates from the Bureau of Reclamation’s analysis. That’s when they’ll know more about possible impacts to Colorado.

Until then, Coloradans need to keep one thing in mind, Pitt said.

“This is not Colorado against the rest of the West. This is Colorado, part of a river basin that is shared,” she said. “All those parties need each other to get through some challenging conditions in the future.”

Map credit: AGU

The latest El Niño diagnostic discussion is hot off the presses from the #Climate Prediction Center

Click the link to read the discussion on the Climate Prediction Center website:

March 14, 2024

ENSO Alert System Status: El Niño Advisory / La Niña Watch

Synopsis:  A transition from El Niño to ENSO-neutral is likely by April-June 2024 (83% chance), with the odds of La Niña developing by June-August 2024 (62% chance).

During February 2024, sea surface temperature (SST) anomalies continued to weaken across most of the equatorial Pacific Ocean. In the last week, below-average SSTs emerged in a small region of the eastern equatorial Pacific Ocean (~100°W; [Fig. 1]). The weekly Niño indices weakened but remained positive, with the latest value in Niño-3.4 standing at 1.4°C [Fig. 2]. Area-averaged subsurface temperature anomalies were slightly negative [Fig. 3], reflecting the consequences of an upwelling Kelvin wave and associated below-average temperatures across the equatorial Pacific Ocean [Fig. 4]. Low-level winds were near average over most of the equatorial Pacific, while upper-level wind anomalies were easterly over the east-central Pacific. Convection was enhanced near the Date Line and was suppressed near Indonesia [Fig. 5]. Collectively, the coupled ocean-atmosphere system reflected a weakening El Niño.

The most recent IRI plume indicates a transition to ENSO-neutral during spring 2024, with La Niña potentially developing during summer 2024 [Fig. 6]. While different types of models suggest La Niña will develop, the forecast team favors the dynamical model guidance, which is slightly more accurate for forecasts made during this time of year. Even though forecasts made through the spring season tend to be less reliable, there is a historical tendency for La Niña to follow strong El Niño events. In summary, a transition from El Niño to ENSO-neutral is likely by April-June 2024 (83% chance), with the odds of La Niña developing by June-August 2024 (62% chance; [Fig. 7]).

How has Front Range snowstorm forecasting advanced since March 2003? — @ColoradoClimate Center

My son about to hit the rail March 2003 blizzard.

Click the link to read the article on the Colorado Climate Center website (Russ Schumacher):

March 13, 2024

For those who were on Colorado’s Front Range in 2003, the epic snowstorm in mid-March likely still holds a place in your memory. This was the biggest snowstorm on record at Fort Collins, with 32.2″ of snow in two days on March 18-19. Denver’s 32″ of snow is 2nd only to the 41.3″ in four days in December 1913. There were multiple reports of over 70″ of snow in the foothills around Nederland and Conifer.

The March 2003 storm was also known for very wet snow. Fort Collins received 5.29″ of liquid precipitation over three days, which is in the top-10 wettest 3-day periods and easily the wettest snowstorm. The roofs of multiple commercial buildings caved under the weight of the heavy, wet snow.

Snowfall totals in northern Colorado from the March 2003 snowstorm. Map produced by National Weather Service Boulder. Credit: Colorado Climate Center

At the time, the perception was that the March 2003 storm was very well forecast, far in advance of the storm. (State climatologist emeritus Nolan Doesken confirms this perception.) The forecasts of the March 2021 “Pi Day” storm also got plenty of attention at the time, and with another potentially big snowstorm on the way for the Front Range this week, let’s take a look at how far forecasting has come in the 21 years since the March 2003 storm.

Aerial photo of the Bed Bath and Beyond on College Ave in Fort Collins with its roof collapsed from the March 2003 snow. Original image source unknown; this image was posted at https://www.rcgroups.com/forums/showthread.php?111045-Collapsed-building-in-Fort-Collins

Predictions of the March 2003 storm

Compared to what’s available today, the information available to forecasters in 2003 was pretty limited. The US essentially ran two numerical weather prediction models: an earlier version of the Global Forecast System (GFS), and the Eta model (predecessor to today’s North American Mesoscale (NAM) model). Ensemble forecasting was still a relatively new concept and not in wide use (more on this in a bit). Reading through National Weather Service forecast discussions leading up to the storm, the guidance from these two models was clearly what forecasters were relying on. Forecasts from the GFS are archived and accessible, but I wasn’t able to find an archive of the Eta model output (except for shorter-range forecasts). Here’s what the GFS liquid precipitation forecasts looked like for the 5 days leading up to the storm, with the observations in the lower right.

NOAA GFS model precipitation forecasts for the 3-day period ending the morning of 20 March 2003, for forecasts nearing the storm (longer lead times in upper left to shorter in lower middle.) The lower right panel shows observations from the PRISM dataset (courtesy of the PRISM climate group, Oregon State University). Archived GFS forecasts obtained from NOAA/NCEI.

These actually don’t look very good. Part of that is the coarse resolution of the model that was available at the time, so details are washed out. But part of it is that the heaviest precipitation wasn’t really predicted in the right place! There’s a signal for substantial precipitation, but it jumps from southern Colorado to Wyoming and never really locks in very well on northern Colorado. There’s also nowhere near the over 6 inches of liquid precipitation (!) that fell in the Front Range foothills.

Fortunately, NWS forecasters are experts at what they do, and they use knowledge of meteorology rather than just what the models are showing. And this knowledge was critical in identifying what was likely to happen. Here are some quotes from the NWS area forecast discussions leading up to the storm:

Approximate time before snow startedSelected text from NWS area forecast discussion
~5 daysIF MODELS DO VERIFY…WE COULD SEE A SIGNIFICANT STORM ALONG THE FRONT RANGE EASTWARD INTO NORTHEASTERN COLORADO MONDAY NIGHT INTO TUESDAY. CONDITIONS MAY IMPROVE ON WEDNESDAY. AT THIS TIME WILL KEEP POPS AT A CHANCE AS WE ARE STILL OUT SOME 156 HOURS.
~4 daysBEST BET LOOKS LIKE THE BEST STUFF WILL BE SOUTH OF US…THOUGH IT COULD STILL BE CLOSE ENOUGH TO GET GOOD SNOW ALONG THE FOOTHILLS NEAR DENVER.
~3 daysNOW FOR THE TROUBLE. ETA SHOWS A PRETTY WELL ORGANIZED CYCLONE DEVELOPING OVER SERN CO SUN NIGHT AND PARKING THERE FOR ETERNITY… MEANWHILE CONSENSUS OF THE OTHER MEDIUM RANGE MODELS HAS BEEN A STRONGER AND SLOWER SOUTHERN SYSTEM…PERHAPS EVEN TOO FAR SOUTH TO BE GOOD FOR US.
~2 daysMODELS ARE COMING INTO BETTER AGREEMENT ON THE DEVELOPMENT OF A MAJOR WINTER STORM MON THROUGH WED…MODELS DEPICT FRIGHTFUL SNOW AMOUNTS…15 TO 20 INCHES FROM THE AVN ON THE PLAINS FROM MON NIGHT THROUGH WED NIGHT. ETA HAS HEAVIER AMOUNTS WITH 12 TO 18 INCHES ALONG THE FRONT RANGE BY TUE AFTERNOON IN THE MIDDLE OF THE EVENT.
~1.5 daysTHERE IS GREAT POTENTIAL IN THIS STORM TO PRODUCE THE BIGGEST PLAINS SNOWSTORM SINCE THE OCTOBER BLIZZARD OF 97…IF ALL THE PIECES COME TOGETHER AT THE RIGHT TIME…RIGHT PLACE…AND RIGHT INTENSITY.
~1 day CONFIDENCE INCREASING ON A BIG SNOW STORM… PERHAPS REALLY BIG…THE AVN GIVES STORM TOTALS OF 15 TO 20 INCHES FROM CHEYENNE TO DENVER AND OUT TO LIMON. THE ETA … SHOWS 35 TO 45 INCHES IN DENVER WITH 8 TO 20 INCHES ON THE MIDDLE PLAINS AND JUST AN INCH IN THE NE CORNER….FOOTHILLS WILL GO NUTS ON WED IF THE ETA IS RIGHT.
start of eventINGREDIENTS ARE ALL COMING TOGETHER FOR SIGNIFICANT SNOW EVENT WHICH WL CONT FOR THE NEXT COUPLE DAYS…FORECAST STORM TOTAL SNOW ACCUMULATIONS FROM THE MODELS ARE HOLDING STEADY…ETA HAS 30 TO 40 INCHES FOR DENVER…GFS IS HOLDING STEADY WITH 15 TO 20 INCHES…. ETA GENERATES A BAND OF 80 INCHES OF SNOW IN THE HIGHER FOOTHILLS… SNOW MODEL GIVES INCH PER HOUR RATES FROM NOW THROUGH WED NIGHT. THE 5 FOOT LIMIT IN THE FOOTHILLS DOES NOT APPEAR TO BE ENOUGH. I WILL TRY 3 TO 8 FEET BUT THERE COULD BE SOME PRIME SPOTS THAT GET EVEN MORE. I SUPPOSE THERES NO DIFFERENCE EXCEPT FOR THE RECORD BOOKS.
Select text from NWS Boulder Area Forecast Discussions leading up to the March 2003 snowstorm. Obtained from the Iowa Environmental Mesonet.

As of about 2 days before the start of the storm, this was a very accurate description of what would happen, especially for 2003 standards. But more than 3 days in advance, there wasn’t much useful information beyond the idea that a storm was possible.

We can compare the graphic above to a similar one for the March 2021 Pi Day storm. For that storm, the GFS forecasts were remarkably consistent from 5 days in advance to when the event started. They all had the heaviest precipitation along the northern Front Range and southern Wyoming, extending out into Nebraska, and that’s what happened. The primary issue with these model runs is that some of them over-predicted the precipitation. So even though there was uncertainty in the details, the fact that there would be a big storm on the northern Front Range was quite clear at least 5 days in advance, which is a big improvement over what was possible in March 2003.

Similar to the above figure, but for GFS model forecasts of precipitation for the March 2021 Pi Day storm. Credit: Colorado Climate Center

A big advance: ensemble forecasting

Today, a critical tool in the forecasting toolbox is “ensemble” forecasting, whereby many different model forecasts are made, using slight tweaks to the initial estimate of the state of the atmosphere, or different assumptions about processes like cloud microphysics, or both. This ideally provides a range of possible outcomes, and allows forecasters to highlight “worst case” and “best case” scenarios. Here’s an example of an ensemble “plume” for the big Pi Day storm in March 2021:

Plume diagram for accumulated precipitation at Fort Collins from NOAA’s Global Ensemble Forecast System. Each colored line represents a different model run, all initialized at 0000 UTC 9 March 2021, out to 10 days. The thick black line is the mean of the 31 different forecasts. The dashed line shows the total precipitation that was observed from this storm in 2021 (2.39″), which is close to the ensemble mean forecast. Available here for current forecasts. Credit: Colorado Climate Center

This forecast was made around 4 days in advance, and again, it’s pretty clear that a big storm is on the way. But was also still a wide range of possible outcomes — from lower-end amounts (around an inch of liquid) to some extreme amounts (5+ inches). The mean (thick black line) was a little over 2.5″ for this forecast, and turned out to be quite close to what happened (Fort Collins recorded 2.39″ of liquid in this storm.) This signal continued as the storm neared, and the NWS issued this remarkably good forecast early on March 12th (backed up by insightful discussions of the meteorology behind the forecast):

(left) Observed snow from the March 2021 “Pi Day” snowstorm (right) NWS snowfall forecast issued at 3:51am MST on March 12, 2021. Credit: Colorado Climate Center

Sure, you can find some details to quibble with (Fort Morgan got more snow than the forecast, while parts of El Paso County got less), but the overall pattern was right on. This level of detail also goes far beyond what was possible in March 2003. NWS now routinely provides the “best case” and “worst case” scenarios, along with probabilities of exceeding certain snow amounts.

Still really difficult: rain vs. snow, details, and bands

You might notice that I mostly showed model depictions of liquid precipitation rather than snowfall. Figuring out the changeover from rain to snow, and what the snow-liquid ratio will be, are big challenges that remain in snowfall forecasting. Think of it this way: on most days, you probably don’t care if the temperature forecast is off by a couple degrees. If the forecast is 70 and it ends up being 68 or 72, no big deal. But when those couple degrees surround 32F, it can be the difference between a huge snowstorm or a miserable cold rain. [ed. emphasis mine] The complex terrain in Colorado complicates this further, because temperature can change rapidly with small changes in elevation. This is one of the big questions about the incoming storm on the eastern plains: there’s been a slam-dunk signal for a lot of liquid for nearly a week, but will it be cold enough for significant snow to accumulate? We shall see…

National Weather Service snow total forecast for the March 13-15, 2024 snowstorm, issued at 2:06pm MDT on March 12, 2024. Some large ranges! From https://www.weather.gov/media/bou/DssPacket.pdf

Another big challenge is when the snow is arranged in “bands”. These bands can cause big snow totals in very localized areas, while nearby spots get next to nothing. One recent example was the 10+” of snow that fell around Greeley on February 9-10, 2024. These are really hard to predict, and when there is a “busted” forecast, it’s often because of these snowbands.

What’s also changed: dissemination of information

The other big change over the last 21 years is how information is communicated. TV meteorologists and newspapers still play an important role in getting the word out, but many people get their weather information from a smartphone app or social media. Most of us have internet-connected computers in our pockets, which makes it much easier to find credible forecast information, if you know where to look.1 But on the other hand, the potential for “hype” ahead of a potential big storm is much greater, as is the criticism that forecasters receive if the predicted totals aren’t right on. (Forecasters don’t ever seem to get equivalent praise for getting it right…)

The improvement in weather prediction over time has been called a “quiet revolution.” No single discovery or advance has led to these improvements, but instead the incremental increase in knowledge, data, and computing power. The forecasts of the March 2003 snowstorm by human forecasters were indeed very good for the time (the computer model output itself, maybe not so great.) But today, although snow forecasting remains difficult, it’s usually possible to see what’s coming a lot farther in advance, and with a lot greater detail.

For further reading

If interested in more reading on Front Range snowstorms:

My own story from March 2003: my girlfriend at the time (now wife) and I had been in Florida for spring break, flying back to Colorado the evening of March 17. Despite the good forecasts noted above, we had no idea about the incoming snowstorm, because people weren’t just on the internet all the time. That wouldn’t happen today! We made a harrowing drive back to Fort Collins just as rain was changing over to snow, but it turns out that if we hadn’t driven back that night we would’ve been stuck at the airport for multiple days.

Upper Gunnison River Water Conservancy District forms collective to cover expensive snow survey flights — The Gunnison Country Times #GunnisonRiver #ColoradoRiver #COriver #aridification

Gunnison River in Colorado. Source: Bureau of Reclamation via the Water Education Foundation

Click the link to read the article on the Gunnison Country Times website (Bella Biondi). Here’s an excerpt:

March 13, 2024

Although the Upper Gunnison has proven the value of ASO flights, the agency — as well as many other water districts in Colorado — cannot pay for the costly technology alone. This year, the district created an Upper Gunnison Basin ASO funding partnership, a growing collective of local agencies that will divide the cost of running flights. 

Link to the Colorado Airborne Snow Measurement Program website

“For the Western Slope, it’s incredibly important to be able to predict annual hydrology so that we can live within our means on the river,” said District General Manager Sonja Chavez. 

The annual cost of conducting snow surveys for the East and the Taylor River watersheds exceeds $300,000. These basins, which encompass roughly 570 square miles, are prioritized because they typically hold the most snow and generate the largest amount of water in the spring…After a $50,000 investment from the water district, the Gunnison County Electric Association, the Lawrence Berkeley National Laboratory, the Upper Colorado River Commission and the Colorado Water Conservation Board (CWCB) helped cover the rest. Chavez said she plans to expand the partnership next winter.

Lower #ColoradoRiver Mainstream Evaporation and Riparian Evapotranspiration Losses Report — Reclamation #COriver #aridification

Click the link to access the report on the Reclamation website. Here’s the introduction:

The Colorado River System provides essential water supplies to approximately 40 million people, nearly 5.5 million acres of agricultural lands, hydroelectric renewable power, recreational opportunities, habitat for ecological resources, and other benefits across the southwestern United States and northwestern Mexico (Reclamation, 2012). While the annual flow of the Colorado River and its tributaries varies considerably from year to year, the Colorado River System is currently experiencing prolonged drought and low runoff conditions accelerated by climate change that have led to historically low water levels in Lakes Powell and Mead (Reclamation, 2021). The period from 2000 through 2022 is the driest 23-year period in more than a century and one of the driest periods in the last 1,200 years (Meko et al., 2007).

On August 16, 2022, the Bureau of Reclamation (Reclamation) and Department of the Interior announced several administrative actions for consideration to improve and protect the long-term sustainability of the Colorado River System (Reclamation, 2022a). These actions were identified in the context of the low reservoir conditions as described in Reclamation’s Colorado River Basin August 2022 24-Month Study.

The administrative actions in the Lower Basin included reviewing and prioritizing additional administrative initiatives that would ensure maximum efficient and beneficial use of urban and agricultural water, and address evaporation, seepage, and other system losses in the Lower Basin. As part of that action, this report provides an overview of evaporation and riparian evapotranspiration (ET) losses along the lower Colorado River mainstream. The report presents methodologies that have been used to develop those datasets; however, it does not make recommendations on how to implement or account for system losses from the lower Colorado River mainstream. Data regarding seepage to groundwater were not included in this report. Seepage along the mainstream of the lower Colorado River is not considered to be a loss from the system as water entering the aquifer will re-emerge further downstream within the Colorado River.

Estimates of lower Colorado River mainstream evaporation and riparian ET losses provided in this report were divided into five reaches, as follows:

  • Reach 1: Lake Mead
  • Reach 2: Hoover Dam to Davis Dam
  • Reach 3: Davis Dam to Parker Dam
  • Reach 4: Parker Dam to Imperial Dam
  • Reach 5: Imperial Dam to the Northerly International Boundary (NIB) with Mexico

1 The Colorado River Basin natural flow record is available at https://www.usbr.gov/lc/region/g4000/NaturalFlow/provisional.html.
2 For more information on the 24-Month Study Projections, see https://www.usbr.gov/lc/region/g4000/riverops/24ms-projections.html.

Unique formal deal reached for middle #RioGrande irrigation district, state of #NewMexico: The Interstate Stream Commission said agreement a step in addressing a looming water crisis requiring an ‘all hands on deck’ approach to deliveries downstream — Source NM

The Rio Grande at Isleta Blvd. and Interstate 25 on Sept. 7, 2023. (Photo by Anna Padilla for Source New Mexico)

Click the link to read the article on the Source NM website (Danielle Prokop):

March 13, 2024

New Mexico and Albuquerque-based irrigation officials have signed off on a first-of-its-kind cooperative agreement for “emergency, short-term and long-term” management of the Rio Grande.

Last week, the Interstate Stream Commission voted unanimously to allow its staff to enter an agreement with the Middle Rio Grande Conservancy District, which was signed Monday evening after receiving approval from the irrigation’s board.

The deal will allow these governing bodies to better manage flood prevention, improve “water conveyance,”  meet interstate legal agreements and build species habitat for endangered animals in the Middle Rio Grande, said Hannah Riseley-White, the executive director for the Interstate Stream Commission.

“It exemplifies our commitment to each other to work together in solving and tackling these problems,” she told commissioners in the March 5 meeting.

The five-year agreement will allow for communication and coordination between the state and irrigation district officials and outline responsibilities in the partnership, according to a packet given to commission members.

The Interstate Stream Commission is a division of the New Mexico Office of the State Engineer, charged with the “broad powers” to protect, conserve, develop and investigate New Mexico surface waters – such as rivers, streams and lakes.

The Middle Rio Grande Conservancy District, based in Albuquerque, is the governmental body which oversees irrigation for land between Cochiti Dam to the Bosque Del Apache Wildlife Refuge. Irrigated lands in the district are ballparked between 55,000 to 58,000 acres with about 11,000 active irrigators, said Conservation Program Supervisor Casey Ish.

Top officials for the irrigation district and the state agency said the agreement puts an unofficial two-decade partnership to paper.

The state and district face colliding concerns of climate change causing more fires and floods in the region; difficulty in sending water downstream for legal agreements and a need to build habitats for endangered species, Riseley-White said.

As federal funds pour in from infrastructure and climate-adaptation projects, the agreement will help address difficult reaches in the irrigation district’s area, Jason Casuga, chief engineer and CEO for the irrigation district, told commissioners last week.

In a summary given to commissioners, the partnership is necessary to meet legal obligations to Texas and Mexico users downstream, made in treaties and a nearly 80-year old agreement.

“The looming water crisis is prompting an ‘all hands-on deck’ approach by water managers in the Rio Grande basin to ensure New Mexico can maintain water deliveries within the Middle Rio Grande under the Rio Grande Compact,” the summary said.

Concerns raised by Interstate Stream commissioners

Board members had questions for how the agreement might impact relationships with other irrigation districts and tribal governments of Cochiti, Santo Domingo, San Felipe, Santa Ana, Sandia and Isleta Pueblos.

At the March 5 meeting, board member Phoebe Suina (Cochiti), a hydrologist, asked if any of the six middle Rio Grande Pueblos were consulted, or going to be included formally in future project planning or agreements.

Riseley-White said the state’s intent would be engaging relevant parties, including tribes, on specific projects.

“I think those six Middle Rio Grande Pueblos are important partners for us in figuring out what this needs to look like, and it will be critical to engage with them effectively,” she said.

Casuga further responded that the projects would target “benefiting all middle Rio Grande users.”

“When we get into project specifics and the funding associated with those, that’s when I think we would engage individually with the constituents who would be affected by this,” he said.

Board member Greg Carrasco, a Las Cruces farmer and rancher, asked if this agreement impacts the state’s relationship with other irrigation districts.

Riesely-White replied that the agreement has no impact on other relationships.

State Engineer Mike Hamman addressed the commission, calling the agreement a “starting point” for the state to work with other irrigation districts, Pueblos and other water users to address “mutual interests” and leverage federal dollars.

Hamman noted upcoming settlements in adjudication for the six middle Rio Grande Pueblos’ water rights and the pending settlement agreement in the Rio Grande U.S. Supreme Court lawsuit between Texas and New Mexico, could operationally impact the Rio Grande and Rio Chama.

He said that meeting those legal agreements to ensure water in rivers flows to recipients poses a challenge to both entities, requiring a “symbiotic relationship” to turn it around.

“We’re in a compact-deficit situation drifting towards potential violation in theory,” Hamman said, referencing the Middle Rio Grande’s debit of about 25,000 acre feet owed to Elephant Butte Dam for users downstream in Texas and Mexico.

Hamman said both the irrigation district and the state were concerned about delays in construction on the El Vado Dam, and how that is impacting sending water downstream.

Before the vote, Suina urged soliciting Pueblos’ inclusion on upcoming projects, saying the land and water stewardship of the Pueblos has often been overlooked in the past century of water planning.

She noted that Pueblo governments have pushed back against assertions that the middle Rio Grande is “at the end of its life cycle,” saying that the river itself is a necessity.

“I want to encourage that engagement, encourage the collaboration, I see this [agreement] as a step towards that,” Suina said. “But even in that state, just not to forget our Pueblo communities.”

Suina voted yes, but appended her vote with a comment.

“I have confidence in director Riseley-White to have that Pueblo engagement that enables me to say yes to this,” she said.

Rio Grande and Pecos River basins. Map credit: By Kmusser – Own work, Elevation data from SRTM, drainage basin from GTOPO [1], U.S. stream from the National Atlas [2], all other features from Vector Map., CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=11218868

2023 Report on the Health of #Colorado’s Forests — Colorado State Forest Service

Choristoneura occidentalis, Western Spruce budworm. By Jeffrey J. Witcosky, USDA Forest Service – http://www.forestryimages.org/browse/detail.cfm?imgnum=1441043, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=7494807

Click the link to access the report on the Colorado State Forest Service website:

Forest Pests Continue to Spread in Colorado Despite Milder Year

Colorado experienced wetter, cooler conditions in 2023 compared to recent years. This was good for many species of trees in areas of Colorado suffering from prolonged drought, but trees will need several years of adequate moisture and lower temperatures to recover, regain their health and ward off attack from bark beetles and other forest pests. Populations of bark beetles and western spruce budworm remain high in forests and a milder year is not enough to reverse recent trends.

Western spruce budworm remains the most widespread forest pest in Colorado, according to aerial survey data from the Colorado State Forest Service and U.S. Forest Service Rocky Mountain Region. Data from the aerial survey also indicate that western balsam bark beetle remains the deadliest forest pest for the second year in a row, despite it impacting fewer acres of Colorado’s forests in 2023.

Scientists and water managers are keeping their eyes on a “nasty” layer of dust deposited in the #RoaringForkRiver watershed’s #snowpack during two windstorms in late February and early March — The #Aspen Daily News #ColoradoRiver #COriver #aridification 

Albedo effect

Click the link to read the article on The Aspen Daily News website (Austin Corona). Here’s an excerpt:

March 15, 2024

The storms (Feb. 26-27 and Mar. 2-3) were western Colorado’s first major dust event this year. Windstorms carrying dust from the arid Four Corners region commonly hit the Colorado Rockies in spring, depositing dark layers in the local snowpack. The dust often causes snow to melt faster, meaning there is less water available in local rivers and streams by late summer and fall. Rafting companies and recreators have less time to play, and some farmers and ranchers must stop irrigating earlier. Snow researchers say the combined event was relatively large and may have hit the Roaring Fork watershed harder than other areas. The dust has been visible on Aspen ski mountains, including at the bottom of this year’s FIS Alpine World Cup course on Ajax…

Jeff Derry — executive director of the Silverton-based Center for Snow and Avalanche Studies — said the event was widespread, depositing dust in an area spanning from the San Juan Mountains near Telluride to Rabbit Ears Pass near Steamboat Springs. Andrew Temple, a field assistant at CSAS, said McClure Pass south of Carbondale received more dust than any other site he visited for snow observation this week, including Park Cone east of Crested Butte and Spring Creek Pass south of Lake City…

In April, a dust storm arrived just as local snowpack was hitting its peak, meaning it remained high in the snow layers and affected almost the entire runoff process. Even with last year’s wet, cloudy spring conditions, Deems estimates the dust cut a month off the spring runoff season.

Westwide SNOTEL March 16, 2024 via the NRCS.