Tribal One Completes Lake Ilo Dam Rehabilitation Dunn Center, ND

The U.S. Fish and Wildlife Service (USFWS) recently partnered with Tribal One to address critical seepage issues at Lake Ilo Dam, a high-hazard earthen dam located within a protected wildlife refuge. Following the discovery of seepage during a 2020 inspection and subsequent monitoring through 2022, USFWS secured funding in 2023 to execute essential safety repairs.

Tribal One delivered exceptional results, completing the most critical dam safety work in just 30 days—one-third of the original 90-day schedule—and finishing the entire project in 60 days. This accelerated timeline enabled USFWS to raise the lake’s pool elevation ahead of schedule, mitigating risk and restoring operational stability.

The scope of work included the installation of a deep trenched filter wall and blanket wall drain system to manage seepage from coal seams, as well as the installation of a diaphragm filter around the outlet works conduit. Tribal 1 also modified and inspected the gate structure, cleaned and inspected the spillway, and performed structural concrete repairs to ensure the dam’s long-term integrity.

The project presented several challenges that required innovative solutions. Time was a critical factor, and Tribal One’s strategic planning and efficient execution reduced the schedule by two-thirds. Public scrutiny added additional pressure, as the draining of the lake and delays in repairs had drawn significant attention, making flawless performance essential. Through value engineering and optimized sequencing, Tribal One generated $180,000 in cost savings, enabling USFWS to fund additional critical work. Furthermore, the team operated within a sensitive wildlife refuge, adhering to strict environmental and safety protocols and achieving a zero-incident safety record.

The project carried an initial value of $4.68 million and concluded at $5.3 million with options. Tribal One’s performance on this project underscores its ability to deliver complex, high-visibility infrastructure projects on time, within budget, and to the highest safety and environmental standards.