A dry, dry year: Elkhead Reservoir offers drought insurance for fish, power, residents
November 19, 2018
CRAIG — For many Moffat County residents, Elkhead Reservoir is a fun place to play and fish during the summer months, but it also serves a very serious purpose in the world of water users. The reservoir stores up to 25,656 acre-feet of water, offering a sort of insurance policy against drought, for everything from residential water use to power plant operations to endangered fish populations in the Yampa River.
And, in dry, hot years like 2018, owners of Elkhead water were glad to have the backup.
"The reservoir served a good purpose for multiple reasons in Moffat County," said Jim Pokrandt, director of community affairs for the Colorado River District.
Both the Upper Colorado River Endangered Fish Recovery Program and Tri-State Generation & Transmission had to call on their water stored at Elkhead this year. They are among four major owners of water in the reservoir, which also includes the city of Craig and the river district. The city drew ample water from the Yampa and didn’t need Elkhead water this year.
The Fish Recovery Program owns 5,000 acre-feet of water, which it procured when the reservoir was expanded in 2006 in exchange for a $13.5 million contribution to the project. An acre-foot is enough to cover one acre, about the size of a football field, with one foot of water, or about 326,000 gallons.
The Recovery Program also has the option to lease an additional 2,000 acre-feet from the River District, bringing its total to 7,000 usable acre-feet of water.
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"It was an extraordinary and unique new year on the Yampa," said Don Anderson, in-stream flow coordinator for the Recovery Program. "Near the beginning of the irrigation season, we recognized that 5,000 acre-feet probably was not going to be enough to carry us through the season. … Things were just so dry."
The Recovery Program utilized every drop of its 7,000 acre-feet, releasing water into the Yampa beginning in late July — unusually early — and continuing until October.
With the prolonged summer drought, Yampa flows dropped to a precipitously low 38 cubic feet per second by early October in Maybell, where the United States Geological Survey operates a stream gauge. The Maybell gauge is used to determine how much water is making it downriver and how much to release from Elkhead. For comparison, the Recovery Program ordinarily aims to keep flows at 93 cfs or greater, Anderson said.
Drought poses some obvious challenges to native fish populations. Colorado pikeminnow can reach lengths of 2 to 3 feet, according to Tom Chart, director of the Recovery Program, and low flows in the river can make it difficult for them to swim.
"Just being able to maneuver from pool to pool is tough when it's only an inch or two deep," Chart said. "The temperatures can also be pretty stressful. With low flows, the water has a chance to warm up more."
Adding insult to injury, non-native fish populations, such as small-mouth bass, tend to thrive in drought years and prey on native fish.
Reservoirs exist to create a buffer against drought, but the Yampa River has very little storage capacity compared to most rivers in the Colorado River system. Though the Yampa accounts for nearly one fifth of the water that feeds into the Colorado River, reservoirs in the Yampa River drainage account for only 2-percent of the total storage in the state of Colorado, according to Kevin McBride, district manager for the Upper Yampa Water Conservancy District.
"The historical reason for creating a water conservancy district was to store water for drought and dry periods later in the year," McBride said. "So, when there's drought, it has more impact in an area, without a lot of reservoir storage."
The free-flowing nature of the Yampa River is what makes such good habitat for native fish, which are adapted to extreme flow conditions, Chart said.
"However, current municipal, industrial, and agricultural demand diminishes Yampa River summer flows and, therefore, increases the effects and frequency of the low summer flow conditions," he added.
The city of Craig draws all its municipal water from the Yampa, and Craig Station is a major industrial user in Moffat County. The power plant relies on Yampa River water to make steam, a key ingredient for generating power with coal.
According to a 2004 report on the Yampa River Basin, Craig Station historically draws an average of "15 to 16 cfs, with daily diversion rates of up to 45 cfs," from the Yampa. Tri-State, the operator and partial owner of Craig Station, declined to provide current figures about the plant's water use.
One cubic foot per second, or cfs, is equivalent to 646,320 gallons of water per day, or nearly two acre-feet. At 15 cfs, Craig Station would use about 9.7 million gallons from the river daily. For comparison, the city of Craig diverts about 6 cfs and treats about 4 million gallons of water per day during peak summer usage.
When river flows dropped too low this year, Tri-State called on its water in both Elkhead and Stagecoach reservoirs to keep the plant operational.
From Elkhead, it used 341 acre-feet of water, according to the River District, though it owns much more. Tri-State secured 2,500 acre-feet of water several years ago to add to its existing portion of an 8,408 acre-foot pool shared by owners of Craig Station Units 1 and 2, according to the River District. Additionally, Tri-state owns 4,000 acre-feet of storage in Yamcolo Reservoir and 7,000 acre-feet in Stagecoach, according to the 2004 Yampa River Basin report.
Tri-state would not divulge how much water it used from Stagecoach this year. According to historical data provided in the 2004 report, however, Craig Station's annual water use averaged more than 11,000 acre-feet per year between 1985 and 1991. Again, Tri-state declined to provide more recent data.
Decisions about how much water to release out of Elkhead are evaluated in a weekly phone call between the reservoir's partners and users, state officials, meteorologists, irrigators, and other stakeholders, all led by Anderson. Water levels in the reservoir dropped slightly lower than average this year, down to 12 feet instead of 14 — revealing more shoreline than some are used to seeing — but recreational use of the reservoir by fisherman and boaters wasn't significantly affected.
The reservoir collects water from a 205-square-mile basin and reliably recharges with spring runoff each year. Water managers worry about what would happen if drought persisted for several years, but so far, Elkhead has offered a measure of security to Moffat County's biggest water users.
This story has been updated to clarify that Tri-State secured the additional 2,500 acre-feet of water several years ago, not when the reservoir was expanded in 2006.
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