Irrigation tunnel collapse update

The University of Nebraska’s CropWatch provided an update following a disruption to irrigation caused by a tunnel collapse in 2019. In July 2019, irrigation tunnel No. 2 on the Goshen/Gering-Fort Laramie main canal collapsed, which resulted in a washout of the supply canal south of Fort Laramie, Wyoming. This immediately ended water deliveries by Goshen and Gering-Fort Laramie districts for 44 days, during a critical growth period for crops. The loss of irrigation water affected 107,000 acres and many farmers’ yields were reduced as a result.

According to CropWatch, temporary repairs were made to Tunnels No. 1 and 2, and steel ribs were installed inside the tunnels to support the concrete tunnel walls. The temporary repairs allowed the irrigation districts to resume deliveries in 2020, but installation of the ribs restricted water flow to 80-85% of capacity of the tunnel.

“During the winter of 2020-21, metal sheeting was installed over the ribs to increase water flow through the tunnels. This increased the water flow through the tunnels to 97% of capacity in the summer of 2021,” reported CropWatch. “Water deliveries by the three major irrigation districts in the North Platte Valley (Goshen and Gering-Fort Laramie on the south side of the river, Pathfinder Irrigation District on the north) were near normal for the 2021 growing season.”

Storage water was utilized to meet the irrigation needs of growers, which left reservoirs in Wyoming and lower-than-average carryover at the end of the water year. To refill these reservoirs with spring runoff by the 2022 irrigation season, CropWatch notes that major snowfall events would be needed in the Snowy Range and Siera Madre mountains of north-central Colorado and south-central Wyoming this winter.