Wyoming waters Tour looks at Goshen water facilities
Torrington – On July 11, nearly 20 members of the Wyoming Water Association gathered in Torrington for the organization’s annual Summer Water Tour.
The day-long tour covered a variety of water facilities and structures in Goshen County and included visits to the Goshen Irrigation District, Guernsey Dam, Guernsey Silt Run, Grey Rocks Reservoir and others.
Construction on Guernsey Dam was completed in July of 1927. The 135-foot-tall structure is 560 feet long and created capacity of over 71,000 acre-feet of water in Guernsey Reservoir.
“Today, capacity is 45,612 acre-feet,” said Matt Wells of the Bureau of Reclamation. “That is because of siltation.”
All of the water that leaves Guernsey Reservoir is for irrigation.
“We don’t have flows for fish or anything else,” Wells said. “If we get demand for irrigation, we open the gate, but if there is no call for irrigation, no water leaves except for what seeps out.”
The reservoir feeds approximately 345,000 acres of irrigated ground in Wyoming and Nebraska.
The water leaving the reservoir also powers a hydroelectric power plant.
“There are two units in the power plant that produce 6.4 megawatts of power,” Wells explained. “That is a pretty small power plant by today’s standards.”
In comparison, the Glendo power plant, which was built in the 1950s, produces about 38 megawatts of power.
One particularly unique feature of the tour was the Silt Run, a practice that is very rare.
Wells commented, “The Silt Run is a unique deal. I don’t know of any other place that does it.”
Prior to the Silt Run becoming a necessity, water infrastructure was developed in Goshen County.
“The north canal of the irrigation districts was completed in 1915, and the south was finished around 1925,” Wells said. “For several years, they were just running water through here. The only dam on the system at the time was Pathfinder.”
As a result, a huge silt load was being deposited in the irrigation system.
“What they found was that there were huge silt loads coming down every spring,” he mentioned. “When they put Guernsey Dam in, that stopped the silt load because the silt filled the lake instead.”
At the same time, from 1927 to 1936, the canals were scouring, bank stability was being lost, and the seep below the canal was rising.
Wells noted, “It was starting to become a big problem.”
As a result, the Silt Run began in 1936.
With a reservoir that is silting in, Wells noted that the Silt Run alleviates challenges.
“The Silt Run is where we cut the releases out of Glendo and drop this lake very quickly for about four days until the reservoir turns into just a riverbed, basically,” Wells said.
During the Silt Run, the silt that has been deposited in Guernsey Reservoir over the year is sloughed down the river.
“The water gets churned up and carries silt down the canals,” he said. “It lines the canals and cleans out the reservoir.”
Usually, by the beginning to middle of July, the Silt Run begins.
“The tricky part of the silt run is getting the water back into Guernsey so we don’t lose our demand down below,” he continued. “It is stressful. We have an eight- to 10-hour lead time. We kick the water back in from above, and if we do it just right, we don’t lose any water down below.”
The Silt Run allows Bureau of Reclamation to flush the silt from Guernsey Reservoir without harming irrigators down below.
“Usually, July 10-11 we have Silt Run for two to three weeks, depending on what the irrigators ask for,” Wells said. “They did studies and decided that as a result of the run, banks stability was getting better and the seep wasn’t nearly as bad. It’s been a fixture ever since.”
Learn more about different elements of the Wyoming Water Association tour in a future article in the Roundup.
Saige Albert is managing editor of the Wyoming Livestock Roundup and can be reached at firstname.lastname@example.org.