Navajo Dam operations update: Release = 700 CFS April 24, 2021 #ColoradoRiver #SanJuanRiver #COriver #aridification

San Juan River. Photo credit: USFWS

From email from Reclamation (Susan Novak Behery):

In response to decreasing flows in the critical habitat reach, the Bureau of Reclamation has scheduled an increase in the release from Navajo Dam from 600 cubic feet per second (cfs) to 700 cfs on Saturday, April 24th, starting at 0400 AM. Releases are made for the authorized purposes of the Navajo Unit, and to attempt to maintain a target base flow through the endangered fish critical habitat reach of the San Juan River (Farmington to Lake Powell).

The San Juan River Basin Recovery Implementation Program recommends a target base flow of between 500 cfs and 1,000 cfs through the critical habitat area. The target base flow is calculated as the weekly average of gaged flows throughout the critical habitat area from Farmington to Lake Powell.

Opinion: Our rivers are not plumbing — Gunnison Country Times

Map of the Gunnison River drainage basin in Colorado, USA. Made using public domain USGS data. By Shannon1 – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=69257550

From The Gunnison Country Times (Sam Liebl):

Near the tiny town of Red Cliff, three big cities conducted an experiment last fall. The Homestake Reservoir released a burst of water at the behest of the water utilities of Pueblo, Colorado Springs and Aurora. Their goal was simple: track a 1,600 acre-feet blob of water from the reservoir as it flowed to the Colorado state line.

The experiment’s results were unsettling. The subsequent report, released this month, is a reminder on this Earth Day that our Western Slope rivers — some of the most intensely managed and measured in the world — do not amount to plumbing. They are wild, complex and continue to baffle our models and controls.

Homestake Reservoir is one of the state’s many trans-mountain diversions. The man-made lake collects water from the Eagle River watershed. Pipes and tunnels send that water under the Continental Divide and into the Arkansas River near Leadville. Once in the Arkansas River, further diversions bring that water to the Front Range.

But water managers used Homestake to send the burst of water in the other direction, into the Colorado River via the Eagle River. They then carefully monitored gages to see if the water reached Utah, a tracking exercise that in the jargon of the field is called “water shepherding.”

But by the time the Homestake water reached the stateline, state engineers could not determine how much of the water completed the journey.

This conclusion should open our eyes to the uncertainty that climate change poses for the Gunnison Valley and for the rest of the Western Slope. If we can’t use our reservoirs to send water downstream with any kind of precision, our prospects of slaking the thirsts of downstream states look bleak.

he basis of much of our water management, and the reason for conducting the Homestake experiment, is the 1922 Colorado River Compact. The agreement among southwestern states requires that Colorado send a minimum amount of water downstream to Nevada, California and Arizona. If we fail to meet that target, federal reservoirs like Blue Mesa would be used to release more water. But we assumed in the 1950s and 60s, (when, to build Blue Mesa Reservoir, we destroyed thousands of acres of farmland, one of the world’s greatest trout fisheries, drowned the towns of Iola and Sapinero and wiped out half of the Gunnison sage-grouse’s best habitat) that we could get the water from point A to point B.

The Homestake experiment shows that we don’t have the ability to deliver a given amount of water downstream. We don’t know how we would guarantee a certain amount of water flowing downstream to Nevada, California and Arizona.

If, for instance, the Upper Gunnison River Basin was called upon to increase Colorado River flows downstream, it would be “extremely difficult to track or quantify” the delivery, said Frank Kugel, former General Manager of the Upper Gunnison River Water Conservancy District.

It would be a “mammoth task,” Kugel told me. The resulting higher river levels would lead to more water pouring through headgates and onto hay fields. Dry soils along the Gunnison and Taylor rivers would soak up some of the water. And then the three reservoirs and dams (Blue Mesa, Crystal, Morrow Point) in the Aspinall Unit would muddle the picture further. And that’s all before the Gunnison Tunnel would shunt hundreds of cubic feet per second into the Uncompahgre River Valley.

To just detect the delivery of water, much less to measure it, would require a very large release from the Upper Gunnison River Basin, Kugel told me.

Both Kugel, as well as Sonja Chavez, the current general manager at the Upper Gunnison River Water Conservancy District, told me that the difficulties of water shepherding contribute to their skepticism of “demand management” — a massive effort by Colorado water managers to determine how to best cut water use.

“The whole issue of shepherding is huge,” Chavez said. Demand management might sound good on paper, but the legal implications and the water shepherding implications throw doubt on the implementation of a statewide demand management program.

“The ability to track water that is conserved consumptive use all the way to the state line is really critical for the success of that program,” Colorado River District General Manager Andy Mueller told Aspen Journalism on the subject of the Homestake experiment. “And if you can’t track a slug of 1,600 acre-feet of water to the state line, how are you going to track the voluntary reduction in use of a small ditch on the West Slope that maybe they are saving 15 acre-feet?”

Water shepherding experiments will continue because the state has to figure out how to deliver more water downstream. Colorado has set its sights on storing 500,000 acre-feet of water in Lake Powell to protect against the increasingly likely scenario that too little water will flow to Nevada, California and Arizona. But, as shown in the Upper Gunnison River Water Conservancy District’s supply report for this week, that 500,000 acre-feet buffer may not be enough. Lake Powell will release about 8 million acre-feet this year. Only about 5 million acre-feet are expected to flow in.

“Throwing 500,000 acre feet down there will not do much if it stays hot and dry and if the flows do not materialize,” Chavez said.

Next time you drive by Blue Mesa Reservoir, this news may put its waters in a different light. We don’t know how to deliver water through rivers, but we do know how to dam them. And as Lake Powell is expected to fill to just 33% of capacity this year, our limited knowledge may not be enough.

Low #snowpack, exceptional #drought conditions “bad precursor for what is to come” — #Aspen Times #wildfire

Westwide SNOTEL basin-filled map April 23, 2021 via the NRCS.

From The Aspen Times (Jason Auslander):

With the snowpack and precipitation levels in Pitkin County below last year at this time, local officials are bracing for an active wildfire season this summer.

“We’re the only county in the northwest region (of the state) that did not deal with a significant wildfire last summer,” Valerie MacDonald, Pitkin County’s emergency manager, said Thursday. “We have no reason to believe our luck is going to hold. All the predictive services we use indicate that we’re going to have another bad wildfire season in Colorado.”

Currently, the snowpack in Pitkin County and most of the area west of the Continental Divide is at between 70% and 80% of the normal average, said Jeff Colton, a warning coordination meteorologist with the National Weather Service in Grand Junction. Last year, the snowpack at the end of February stood at 118% of normal.

In addition, precipitation this winter measured at the Aspen-Pitkin County airport is 3.27 inches of liquid compared with 3.45 inches last year at this time, he said. The average for this time of year is 4.69 inches.

Despite the larger than normal snowpack last year, it melted quickly and the monsoons never materialized, he said. Along with higher than normal temperatures, that led to about 2,300 wildfires in the Rocky Mountain region and more than 1 million acres burned, though those statistics are not yet available, Colton said…

Colorado Snowpack April 23, 2021 via the NRCS.

This year, the National Weather Service’s Climate Prediction Center is predicting that drought conditions will persist through June, traditionally the driest month of the year, he said. Also, the weather service is predicting a 65% chance that temperatures through June in Pitkin County will be above normal…

Colorado Drought Monitor April 20, 2021.

On the Western Slope, the snowpack isn’t melting as quickly this year as last, he said, while the monsoon season prediction this year is not as bad as last year…

MacDonald suggested going to http://www.pitkinwildfire.com — which features tips on how to protect property and people from wildfire in English and Spanish — for information on how to create defensible space and use fire resistant materials. Residents also should sign up for the Pitkin Alert system, which will keep residents informed of emergency situations, she said.