Water levels to lower on the Snake River at the City Plant facilities for underwater dam inspection

September 17, 2025

Tourists, residents, boaters, and outdoor enthusiasts are advised that water levels on the Snake River near the City Plant in Idaho Falls will be temporarily lowered starting the week of September 22 to allow for an underwater inspection of the hydroelectric facilities at the City Plant. The inspection is anticipated to last several days.

The inspection is an important part of the facility’s long-term maintenance and safety program and requires lowering the water on the falls to provide access to normally submerged structures.

What the Inspection Entails

The primary goal of this comprehensive inspection is to assess the current condition of the facility's concrete structures. Specialized inspection teams will be examining:

• The upstream face of the concrete dam, retaining walls, spillway, and powerhouse.
• The downstream face of the powerhouse structure.

The full scope of the work involves inspecting approximately 2,483 linear feet of structures, including the weir, retaining walls, spillway gates, dam face, and draft tube. This meticulous survey is designed to:

1. Detect any abnormalities or signs of deterioration that may exist in the concrete.
2. Provide a baseline assessment of the facility’s condition for future maintenance planning.

Water depths in the inspection areas currently range from 1 foot to 62 feet, necessitating the temporary draw-down to safely and effectively complete the work.

What to Expect

The lowering of the water level is expected to begin the week of September 22. The duration of the draw-down will be dependent on weather conditions and the time needed to complete the full inspection, but the public should anticipate lower water levels throughout that week and possibly into the following week. During this period, it is likely the iconic falls will stop flowing temprorarily.

Public Safety is Paramount: The public is urged to exercise extreme caution near the river and dam during this period. Lower water levels may expose slick banks, mudflats, and hidden hazards.

Idaho Falls Power thanks the public for its understanding as this essential work is carried out to ensure the continued safety and reliability of our community hydroelectric facilities.

Residents with specific questions are encouraged to contact our office at 208-612-8430.