Aspinall Unit operations update: 550 CFS in the Black Canyon, diversions through the Gunnison Tunnel = 300 CFS

Sunrise Black Canyon via Bob Berwyn

From email from Reclamation Erik Knight:

Releases from the Aspinall Unit will be increased to 1050 cfs on Wednesday, March 25th. Releases are being adjusted to accommodate the change in diversions to the Gunnison Tunnel, which will occur on Thursday, March 26th. Snowpack in the Upper Gunnison Basin is currently at 106% of normal. The March 15th runoff forecast for Blue Mesa Reservoir predicts 78% of average for April-July inflows. Flows in the lower Gunnison River are currently above the baseflow target of 1050 cfs. River flows are expected to stay above the baseflow target for the foreseeable future.

Pursuant to the Aspinall Unit Operations Record of Decision (ROD), the baseflow target in the lower Gunnison River, as measured at the Whitewater gage, is 1050 cfs for January through March.

Currently, Gunnison Tunnel diversions are at 300 cfs and flows in the Gunnison River through the Black Canyon are around 400 cfs. After this release change Gunnison Tunnel diversions will be at 500 cfs and flows in the Gunnison River through the Black Canyon will be around 550 cfs. Current flow information is obtained from provisional data that may undergo revision subsequent to review.

Aspinall Unit operations update: March 1, 2020 runoff forecast for Blue Mesa Reservoir predicts 78% of average

Blue Mesa Reservoir, Curecanti National Recreation Area. Photo credit: Victoria Stauffenberg via Wikimedian Commons

From email from Reclamation (Erik Knight):

Releases from the Aspinall Unit will be increased to 700 cfs on Thursday, March 19th. Releases are being adjusted to accommodate the start of diversions to the Gunnison Tunnel and to lower river flows given the below average runoff forecast. Snowpack in the Upper Gunnison Basin is currently at 103% of normal. The March 1st runoff forecast for Blue Mesa Reservoir predicts 78% of average for April-July inflows. Flows in the lower Gunnison River are currently above the baseflow target of 1050 cfs. River flows are expected to stay above the baseflow target for the foreseeable future.

Pursuant to the Aspinall Unit Operations Record of Decision (ROD), the baseflow target in the lower Gunnison River, as measured at the Whitewater gage, is 1050 cfs for January through March.

Currently, there are no diversions into the Gunnison Tunnel and flows in the Gunnison River through the Black Canyon are around 600 cfs. After this release change Gunnison Tunnel diversions will be at 300 cfs and flows in the Gunnison River through the Black Canyon will be around 400 cfs. Current flow information is obtained from provisional data that may undergo revision subsequent to review.

#Snowpack news: #GunnisonRiver Basin SWE = 91% of normal

Gunnison River Basin High/Low graph March 12, 2020 via the NRCS.

From The Montrose Press (Michael Cox):

According to the figures from SNOTEL and the Colorado Natural Resources Conservation Service (NRCS) this week, the snowpack in the Southwestern Colorado mountains is nothing close to the 700% of normal we experienced last year, although it is well above the low mark set in 2018.

As of Tuesday this week, even with a relatively active snow season on Colorado, it turns out that the most intense snowpack is in the northern part of the state, while the San Juans and other more southern ranges did not fare as well.

There were 39 SNOTEL sites across northern Colorado that received above the 90th percentile of February precipitation on the period of record, with nine of these being the record high. Conversely, 24 SNOTEL sites in the southern half of the state were in the bottom 10th percentile with six sites observing record low precipitation…

As of this week the SNOTEL numbers for the Gunnison Basin are ranging somewhere between the 2018 low and the averages over the past couple of decades.

The basin watershed has an average of about 13 or 14 inches of snow water equivalent and rests at about 103 percent of normal, as opposed to even lower numbers in the Dolores River Basin…

The good news tends to be the level of the reservoirs, like Blue Mesa and Ridgway…

Following the trends of snowpack and precipitation, stream flow forecasts predict considerably higher values across Northern Colorado than in the southern half of the state, with respect to normal. On the low end the average of forecasts in the combined San Miguel, Dolores, Animas, and San Juan basins is for 64 percent of normal, followed closely by the Rio Grande at 68 percent.

The Gunnison is doing a little better with all forecast points averaging out to 72 percent of normal. The most plentiful forecasts in the state reside in the South Platte Basin with some exceeding 130 percent of average in the main stem headwaters. The Arkansas, Colorado, and combined Yampa and White basins are forecasted to have near normal runoff volumes with the basin-wide average of forecasts ranging from 96 to 106 percent of normal.

Aspinall Unit operations update: The February 15th runoff forecast for Blue Mesa Reservoir predicts 83% of average for April-July inflows

Aspinall Unit dams

From email from Reclamation (Erik Knight):

Releases from the Aspinall Unit will be decreased to 600 cfs on Wednesday, February 26th. Snowpack in the Upper Gunnison Basin is currently at 103% of normal. The February 15th runoff forecast for Blue Mesa Reservoir predicts 83% of average for April-July inflows. Flows in the lower Gunnison River are currently above the baseflow target of 1050 cfs. River flows are expected to stay above the baseflow target for the foreseeable future.

Pursuant to the Aspinall Unit Operations Record of Decision (ROD), the baseflow target in the lower Gunnison River, as measured at the Whitewater gage, is 1050 cfs for January through March.

Currently, there are no diversions into the Gunnison Tunnel and flows in the Gunnison River through the Black Canyon are around 800 cfs. After this release change Gunnison Tunnel diversions will still be at zero and flows in the Gunnison River through the Black Canyon will be around 600 cfs. Current flow information is obtained from provisional data that may undergo revision subsequent to review.

The February 2020 “Gunnison River Basin News” is hot off the presses

Click here to read the newsletter. Here’s an excerpt:

Attention K-12 teachers in the Gunnison River Basin – NEW financial assistance for water education now available (for example: bring your students to the Eureka Science Museum in Grand Junction). Please visit our website for more information.

The confluence of Henson Creek (left) and Lake Fork Gunnison River (right, against the wall) in Lake City, Colorado. By Jeffrey Beall – Own work, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=73852697

How big are the discrepancies with snowpack-measuring tech? — The Montrose Press #snowpack #runoff

San Juan Mountains March, 2016 photo credit Greg Hobbs.

From The Montrose Press (Michael Cox):

The primary tool currently in use to measure snowpack in the Western United States is SNOTEL. We all rely on the SNOTEL website to see what’s happening during winter in the Rockies. But, you may be surprised to learn that the SNOTEL (SNOw TELemetry) has been missing the mark in its automated reading of snow depth in the Western US. How do we know that? Because, there is a new tool – actually an old one, repurposed – that could enhance greatly the accuracy of the 732 SNOTEL stations currently being used for the critical purpose of measuring snowpack in the mountains to help water managers forecast the potential runoff.

The solo SNOTEL system was as good as it got for 50 years when it came to measuring snow in the mountains. The system of sensors that measure snow depth and the amount of water contained in the snow was put into use back in the 1970s. It has not been updated since then, although some stations were added in the 1980s. SNOTEL measures two primary parameters, snow depth and density. Density tells us how much water is in the snow. It does this by sensing the weight of the snow on something called a snow pillow. The pillow is about eight feet square and as the snow builds up, it gets weighed. That number and the depth at the station are reported to the system as what we call the snowpack.

SNOTEL actually functions pretty well up to a point. The biggest drawback with it is the minuscule sampling of a vast area of snow production. The 732 stations are spread out through the mountain snow regions of all the Western states, including Alaska. That area is 1.76 million square miles, of which about a third is mountainous and has snow pack. That means there is a SNOTEL station for every 800 square miles of mountain terrain. Some of the stations are not as accurate as they need to be because of location. Some terrain, where extraordinary snow accumulation occurs, such as the bottom of an avalanche chute, never get measured because they are below the altitude level where SNOTEL stations are located. The avalanche-prone San Juans may have much more snow than we ever knew.

Given the increasingly critical nature of determining even short term snow inventories, people like John Lhotak, an operations hydrologist with the Colorado River Basin Forecast Center, told a press meeting, “SNOTEL is the best network we have, but there are definitely shortcomings.”

Enter LIDAR. LIDAR is one of those pseudo-acronym things that the lab guys and bureaucrats love. This one stands for Light Detection and Ranging.

This map shows the snowpack depth of the Maroon Bells in spring 2019. The map was created with information from NASA’s Airborne Snow Observatory, which will help water managers make more accurate streamflow predictions. Jeffrey Deems/ASO, National Snow and Ice Data Center

Quite simply, if you flew over the mountains without snow on them and determined the height (compared to sea level), and then flew over and scanned them when the snow is in place, you would simply deduct the original snow-less height from the snow packed image and “voila!!!” you get the snow depth of the whole mountain almost to within centimeters.

Sounds simple enough, but the data crunching is mind numbing. All the data points from the ground-only image must be overlaid with the image taken with snow on the ground. The measurement points are chosen and then comes all the subtraction and interpolation. The people like Jeffrey Deems at the National Snow and Ice Center and Sam Tyler at Utah State University (and their teams) have developed the computer tools to breakdown the gigabytes of data collected to simple usable terms.

The whole concept was first tested in California’s Sierra Nevada Mountains eight years ago. The dry model of the mountains was made by flying at 20,000 feet in a straight back-and-forth pattern. After some storms passed the location, the team went back and flew the same pattern at the same altitude. The resulting 3D images were a precise measurement of the snow on the ground. Tyler’s team also did a test of the system near Logan, Utah, at about 8,000 feet…

The Airborne Snow Observatory (ASO) folks tell us, “We see it as moving from a sparse-point base network (with SNOTEL) to a system that can map the entire snow pack in a river basin,” Jeffrey Deems said, “It is really an enabling technology.”

In 2013 the ASO tested the system on selected sections of the Front Range, Gunnison Basin, Rio Grande Basin, and Uncompahgre watershed. Deems said, regarding the SNOTEL numbers, “We were missing a lot of the picture. We need to fix that.”

What the tests revealed was that in the Rio Grande Basin, for example, the forecasts were way off, reporting as much as 50% less snow and water than what was actually on the ground. That makes accurate forecasts and water use management for that basin impossible…

But the bean counters aren’t so sure. First of all, flying several thousand miles back and forth over the Colorado peaks costs a lot of money. The tab for flying for the new imagery on a regular basis could cost $400,000 a year or more, according to Frank Kugel, director of the Southwest Water Conservation District. Is the return on investment really there?

SNOTEL Site via the Natural Resources Conservation Service

Also, everyone in the water biz seems to agree that we will still need SNOTEL. It is currently the only tool for proofing the accuracy of the LIDAR images and vice versa. It is also the best tool for the density issue. For the time being, people like Deems think using SNOTEL in tandem with LIDAR is the right way to get the best measurements. Rather than replacing SNOTEL, Deems would opt for even more SNOTEL stations…

Deems said [February 6, 2020] that the cost of LIDAR seems justified when you consider the cost of a bad forecast. It is no secret that the low estimate on the Rio Grande in 2013 translated into millions of dollars of water misused after the forecast. Making the investment available for better measurements seems like a no brainer…

Meanwhile, the Colorado Water Conservation Board has already decided to invest $250K in 2021 for flights to measure the Gunnison Basin, of which the Uncompahgre River is a part.

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

First steps taken in developing Cow Creek pipeline and reservoir — the Watch

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 Watch (Tanya Ishikawa):

Ouray County is hoping to develop new and existing water rights on a major tributary of the Uncompahgre River, so water can be stored in a proposed reservoir and transported through a ditch or pipeline for temporary storage in Ridgway Reservoir. The county partnered with the Ouray County Water Users Association, a group representing ranchers with water rights, and Tri-County Water Conservancy District, the operator of Ridgway Reservoir and Dam, to apply for new and augmented water rights Dec. 30, 2019.

The three partners are jointly seeking the right to divert surface water from Cow Creek up to 20 cubic feet per second and store 25,349.15 acre feet, which is equal to 8.26 billion gallons, in a yet-to-be-built reservoir. The water rights application also requested the right to exchange up to 30 cubic feet per second of water from Cow Creek for water from other locations within Tri-County’s water rights holdings around Ouray County.

The water rights application was made after the completion of a water supply study commissioned by the Ouray County Stream Management & Planning Steering Committee, a group including the three partners and other local stakeholders that was organized as an effort to understand local water supply conditions after the droughts of 2012 and 2018.

“Our challenge is that during dry years the Uncompahgre Valley Water Users Association with its members’ senior rights puts a call on water from the Uncompahgre River (UVWUA), which means a lot of our users in Ouray County don’t have the water they need. This water rights application is essentially an augmentation plan, to alleviate the results of a call from UVWUA. It would help us add some water supplies where we don’t have them by retiming flows and releases, moving water and storing it in years when we have lots of water, and using it in years without water,” said Marti Whitmore, attorney for the Ouray County Water Users Association, who was formerly the attorney for the county and has long been involved in water rights law.

The plan is to take water from Cow Creek without impacting the water that belongs to current water rights holders. Beyond that basic premise, much about the proposed projects is yet to be determined. The exact location of the pipeline or ditch, as well as the design and management of the reservoir, still need to be researched and negotiated with various stakeholders, including private and public property owners.

The main use for the water rights would be to supplement irrigation of 100,300 acres of mostly hay pastures, but the water rights application also lists other prior uses as domestic, municipal, industrial and flood control, and new uses as storage, flow stabilization, augmentation, exchange, aquifer recharge, reuse, commercial, piscatorial, streamflow enhancement, aquatic life, and hydropower generation and augmentation.

The water storage is a right owned by Tri-County, which was approved sometime in the 1950s as Ram’s Horn Reservoir, and decreed to be located in the vicinity of Ramshorn Gulch and Ramshorn Ridge northwest of Courthouse Mountain in the Cimarron Range. The Ridgway Reservoir was selected as the preferred alternative, and the smaller reservoir was never developed.

The proposed reservoir is on Uncompahgre National Forest land, but not within the wilderness area. Though on public land, the reservoir would not be publicly accessible for any uses such as recreation due to a stipulation made during a previous water rights case about the project. The pipeline or ditch would be located somewhere north of the reservoir, connecting flow from a point on Cow Creek to the Ridgway Reservoir to the west.

The cost and funding for the projects had not been determined yet, Whitmore said.

While no timeline has been set for the projects, the partners hope to have the water rights application successfully completed in 2020, after which other steps in the process from design to funding and federal permitting will begin, she added…

Ken Lipton has been a member of the Ouray County Stream Management and Planning Steering Committee, as well as a local rancher and former board member of the Uncompahgre Watershed Partnership, a nonprofit with a purpose of protecting the watershed in the county.

“The projects are necessary to prevent total loss of irrigation and stock water during extreme drought,” he said. “The bottom line is a reduced chance that there will be calls on our ditches during extreme droughts. However, I don’t think this will totally guarantee that no calls will occur.”