Evaluation of Fish Bypass Channel Velocity and Depth Pertaining To Meeting Biological Criteria

The Lower Yellowstone Project is a U.S. Bureau of Reclamation (Reclamation) irrigation project located in eastern Montana and Western North Dakota. The project consists of a diversion dam, a headworks structure, canals and pumps. Entrainment of fish into the main canal, along with lack of fish passage, specifically for the listed Pallid sturgeon, led the U.S. Army Corps of Engineers (USACE), in collaboration with Reclamation, to design and construct a screened intake structure, bypass channel and new weir. The screened intake structure was completed in 2012. The new weir and bypass channel were completed in 2022. Bathymetric surveys and velocity and flow measurements were conducted five times between May and August 2022. Additionally, fish tracking via radio-telemetry was completed by Montana Fish, Wildlife & Parks throughout the year. This extended abstract will focus on changes to the bypass channel cross section due to scour of erodible materials, deposition of material in the bypass entrance and the impact to the biological criteria set to maximize the attraction to and use of the bypass channel by Pallid sturgeon and all aquatic species of the Yellowstone River. This abstract is a follow up to that presented during the 2015 SEDHYD conference, “Sediment Modeling on the Lower Yellowstone River at Intake Dam, Montana”, which presented modeling of the bypass channel during the design phase.