Built in 1917 as part of the North Platte Project, the No. 2 Tunnel on the Goshen and Gering-Fort Laramie Main Canal collapsed on July 17, 2019, creating a subsequent gullying of the canal which continues to have catastrophic effects .
Estimates reach the bar of 200 million dollars of loss for the economy since the collapse. The damaged tunnels initially affected approximately 107,000 acres of water south of the North Platte River reaching both Nebraska and Wyoming. Gering-Fort Laramie Irrigation District Manager Rick Preston said the collapse had an estimated $60 million impact on the economy in 2019.
During the irrigation off-season following the collapse, temporary works were carried out to secure the stability of the tunnels with ribs. During the 2020 growing season, the irrigation district restored up to 75% of normal water flow. After the water was cut off, sheets were placed in the tunnels to improve flow over the support ribs, but only 88% of the water was delivered to the farms in the 2021 season.
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“So that year (2019) crop yields were down, farmers were just trying to survive and that cost keeps going up,” Preston said. “We then lost income every year because we didn’t have the same amount of water to deliver to the crops. So crop yields went down, farmers weren’t spending money. They were just trying to survive.
Scott Hort of the Gering-Fort Laramie District said engineers at global engineering firm HDR Inc. recommended adding tapered sheets before and after rib sections in the tunnels. Preston explained that the solution was suggested to reduce backflow of water as it encounters the rib sections.
“We’re trying to force the same amount of water through smaller openings, which impedes flow,” Preston said. “Now that water will have a smooth wall instead of hitting those shores and having to back up and around it.”
With water allocations likely for the upcoming season, they hope the recent adjustments will improve flow. Once the channel reaches its maximum throughput, they will be able to see if there are benefits to the last efforts.
HDR Inc. engineers were recruited in September 2021 to begin the arduous process of defining the permanent options for Tunnels No. 1 and 2. The two irrigation districts held a joint meeting and agreed on the option of replacement of the tunnel by sequential excavation. Hort said the rebuilding process will be the least invasive for the land surrounding the tunnels because it will stay within the existing footprint.
“It makes it easier, going back to the original expense of the system rather than going out and modding and changing it,” Preston said. “So you’re more likely to go to where the original work was done and redo it, than to mess around and everything else to modify it on a different scale.”
The existing tunnels will be rebored in manageable sections and relined to an effective diameter of 16 feet, two feet larger than they are now. It is estimated that the completion of the two tunnels will cost approximately $50 million.
Preston said the engineering firm will handle environmental assessments and permits as well as state and federal agency approvals and construction bids. Once this begins to take place, districts will have a clearer estimate of when the procedure will take place and whether the tunnels will be done at the same time or separately. Preston and Hort both pointed out that the paperwork process would be long and gave a better estimate of fall 2024, if everything fell into place quickly.
Adam Hoesing, an attorney with Simmons Olsen Law Firm, said the Gering-Fort Laramie District applied for ARPA relief funds as well as a $23 million Bureau of Reclamation loan to cover their 51% of estimated costs. Preston said applying for the 50-year loan would not be the most ideal situation. According to Hoesing, the funds for the tunnel replacement will most likely be a mix of the two sources and they will likely change the office loan request to a more manageable amount.
Final unicameral approval was given to LB 1014 last week and it is now awaiting Governor Pete Ricketts’ signature. LB 1014 allocates $23.5 million in ARPA aid to help fund canal repairs.
Preston and Hort said the entire Goshen and Gering-Fort Laramie irrigation system is aging and will need upgrades.
Nicole Heldt is a reporter for the Star-Herald and covers agriculture. She can be reached at 308-632-9044 or by email at [email protected]