Update on 2019 tunnel collapse and canal washout — water flowing for 2020 growing season
July 17 will mark the one-year anniversary of an event that many irrigators in western Nebraska will not forget — the Goshen/Gering-Fort Laramie Irrigation Districts Tunnel No. 2 collapsed, causing a breach in the main canal that dried up water deliveries for irrigators on the south side of the North Platte River under these two districts.
The farmers lost water for 42 days during the critical crop growing time, affecting over 107,000 acres in the North Platte River Valley of Nebraska and Wyoming.
Temporary repairs to the three tunnels on the main canal had to be completed before water could be delivered this season. But the water is flowing to the farmers.
The repairs to Tunnels No. 1 and No. 2 have been completed with the installation of approximately 60 steel “ribs” or supports inside each of the tunnels along with some grouting. Permanent repairs to these two tunnels should be completed by the end of 2022, including the permeation grouting and removal of most of the steel “ribs” from both tunnels. The ribs in Tunnel No. 2 will remain in place near the collapse site. These two tunnels are located in Wyoming on the Goshen Irrigation District portion of the canal.
Permanent repairs to Tunnel No. 3 have been completed, including installation of the steel “ribs” and grouting. The only remaining repair item is the installation of cathodic protection for the steel ribs, a technique to control the corrosion of the ribs. This will take place at the end of the 2020 growing season. This tunnel is located in Nebraska on the Gering-Fort Laramie Irrigation District portion of the canal.
With the installation of the steel “ribs”, water flow through the tunnels has been reduced. Goshen Irrigation District estimates total water flow through Tunnels No. 1 and No. 2 will be reduced to 80-85 percent of full capacity. Water flow through these tunnels is approximately 1,200 cubic feet per second (cfs) or 19,020,000 gallons per minute.
Reduced water flow through these tunnels means reduced deliveries to Nebraska growers. The Gering/Fort Laramie Irrigation District is planning for their irrigators to receive only 75 percent of their normal allotment. By starting the irrigation water in the canal earlier and planning to run later in the season, it is hoped this will lessen demand during the peak water demand in July and August. When final repairs to Tunnels No. 1 and No. 2 are completed and the removal of most of the steel “ribs” is done, water flow volume should return to near normal.
Both irrigation districts are still seeking funding options to pay for the repairs.
Irrigators can find more information on irrigation water management and other helpful water management resources at https://cropwatch.unl.edu/corn/water.
Nebraska Extension and the University of Wyoming Extension are working together to share information and help growers in both states. A joint web page has been created so stakeholders can get information relating to the situation. The URL is go.unl.edu/canal,
For more information on the North Platte River and the irrigation projects in Nebraska and Wyoming, visit the slideshare presentation found at
Previous CropWatch stories and articles on the tunnel collapse, canal breach and related information are found at https://cropwatch.unl.edu/tags/canal-irrigation. ❖
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