Pallid Sturgeons Make Their Way Through The Bypass Channel At Intake Diversion Dam

For the first time since the completion of the Intake Diversion Dam on the Yellowstone River, pallid sturgeons have successfully swam upstream on their own. This was made possible because of the newly constructed bypass channel.

The first pallid passed through the bypass channel on May 5. The fish was identified as "1997 HOPS" (male code 332). It had been hanging out at the Intake FAS boat ramp for a couple of days before passing through. 

"This is extremely encouraging, especially with the low flows on the Yellowstone River," said David Trimpe, Bureau of Reclamation Environmental specialist.

In the past, pallid sturgeon have attempted to migrate up the dam, but have been stopped by the rock field at the diversion dam. 

"They do not like turbulence or rocks and the diversion dam area is very violent, so the bypass provides a very smooth natural-like channel that routes around that."

The 2.1-mile-long channel was created as part of the Lower Yellowstone Intake Diversion Dam Fish Passage Project, a joint federal project between USACE and the U.S. Bureau of Reclamation. 

 The construction on the channel started in April 2019 and was completed on April 9, 2022. The project also includes a replacement diversion dam to facilitate irrigation diversions to the Lower Yellowstone Project which was completed by USACE in 2021.

The bypass channel was designed to help the sturgeon and other fish move freely up and downstream of the diversion, creating an area for natural recruitment of the pallid sturgeon.  

"The full intent is to get these fish further upstream so that they can spawn, and their young can float back down stream and mature and survive before they enter Lake Sacagawea on the Missouri River," added Trimpe. 

In 1990, the U.S. Fish and Wildlife Service under the Endangered Species Act listed pallid sturgeons as endangered.  

Trimpe hopes that the passage will increase the population of the species and facilitate natural recruitment. 

As of May 19, nine radio-tagged pallid sturgeons have successfully swam through the bypass channel. "In addition to the pallid sturgeons, we have seen paddlefish and the full gamut of native species on the Yellowstone River go through the bypass channel," said Trimpe. 

"Looking forward, we want to see natural recruitment on the Yellowstone River, and we want the bypass to continue to function and provide upstream and downstream passage." He said, "Hopefully that leads to putting the pallid in a much better position to survive long term."