By Gary Stone | Extension Water & Cropping Systems Educator / Jessica Groskopf | Extension Agricultural Economics Educator / John Thomas | Extension Water & Cropping Systems Educator / Xin Qiao | Irrigation & Water Management Specialist
The U.S. Bureau of Reclamation, in conjunction with the Goshen Irrigation District, Gering-Fort Laramie Irrigation District, and HDR Engineering, held public meetings on Jan. 8 at the Scotts Bluff County fairgrounds and on Jan. 9 at the Fort Laramie Community Center.
The public, stakeholders, and agencies were provided with information and are now encouraged to review the draft EA and provide comments at https://www.usbr.gov/gp/nepa/sopa.html or https://www.usbr.gov/gp/nepa/Draft%20EA_Fort%20Laramie%20Canal.pdf.
Comments and questions will be received from Jan. 7 through Feb. 7, 2025. Once the comment period is closed and all comments addressed, a Finding of No Significant Impact (FONS) will be prepared, closing the NEPA process.
If the EA goes well, Tunnels Nos. 1 and 2 rehabilitation is expected to occur over two consecutive non-irrigation seasons. Tentatively, Tunnel No. 2 will be replaced in fall 2025. Work on Tunnel No. 1 would begin in the fall of 2026, and construction would be completed in the spring of 2028.
The rehabilitation of the tunnels involves using a sequential excavation method (SEM). This method utilizes a special purpose-built digger shield excavator for the project. Excavation of the original fourteen-foot, horseshoe-shaped tunnel will begin at the exit end of the tunnel. The excavator will dig out small sections of the existing tunnel in four to five foot increments to a diameter of approximately 18 feet. The old tunnel material and surrounding substrate will be removed through the tunnel entrance. The newly excavated portion of the tunnel will be replaced with pre-cast, reinforced concrete sections bolted in place. The void between the outside of the new tunnel walls and the substrate will be filled with a special grout.
The concrete sections used to create the new tunnel are approximately four feet wide and 13 inches thick. When assembled, they will create a tunnel approximately 16 feet in diameter. These pre-cast concrete sections will be constructed at an environmentally controlled location and transported to the staging area and construction site as needed. The old tunnel and substrate are proposed to be disposed of by applying them to the canal roads.
Goshen Irrigation District and Gerin-Fort Laramie Irrigation District have received 44 million dollars in grants from Wyoming and Nebraska. The remaining balance, which will cover the project’s cost, will come from a low-interest, long-term grant from the U.S. Bureau of Reclamation. The irrigation districts are pursuing other grant sources to help cover the project’s cost.
Preliminary work can be completed before water deliveries are started in the spring of 2025. The preliminary work includes building access roads to the construction sites, installing power lines to serve the construction equipment during the tunnel replacement, and preliminary work on the entrance and exits of the tunnels.
A current update on the tunnel replacement will be presented at the 2025 Yonts Water Conference on April 9 at the Panhandle Research, Extension, and Education Center in Scottsbluff.
Complete background and history of the tunnel collapse and canal breach can be found on the CropWatch Canal Irrigation | CropWatch page.