KLAMATH FALLS, Ore. — Federal agencies are headed back to the drawing board on water management plans for the Klamath Project aimed at protecting several species of endangered fish.

The U.S. Bureau of Reclamation — which operates the 210,000-acre irrigation project in Southern Oregon and Northern California — spent months working with the National Marine Fisheries Service and U.S. Fish and Wildlife Service to mitigate potential harm to endangered sucker fish in Upper Klamath Lake, as well as threatened coho salmon in the lower Klamath River.

The result was two coordinated studies released in March, known collectively as the biological opinion, or BiOp.

However, the bureau now says it received “erroneous data” from an outside source during consultation, meaning it must scrap the plans and start over again.

Laura Williams, a spokeswoman for the Bureau of Reclamation Klamath Basin Area Office, said she could not go into detail about the faulty data, other than it did impact their modeling for how much water would be available annually from the Klamath Project for fish.

“We need to redo the modeling and rewrite the report reflecting the correct information,” Williams said.

The Klamath Project provides irrigation water for more than 1,200 family farms and ranches, feeding a $557 million agricultural economy across the basin. But water managers must also account for Lost River and shortnose suckers in Upper Klamath Lake, listed as endangered under the Endangered Species Act in 1988.

Southern Oregon and Northern California coastal coho salmon were listed as threatened in 1997.

The ESA requires plans to ensure the Klamath Project will not jeopardize the continued survival of the fish. The BiOp is updated periodically to account for changing conditions throughout the basin, outlining effects of the project on water availability and critical habitat.

Reclamation began consulting with the USFWS and National Marine Fisheries Service on Dec. 21, 2018 for the latest update, completed earlier this year on March 29. The BiOp was supposed to last for five years. Instead, it lasted just seven months.

“There was a lot of consultation between the services and us to put those (plans) together,” Williams said. “Now, because it’s been discovered that there was some erroneous material given to us, we will need to consider the correct information.”

The agencies will hope to have a new BiOp completed by March 31, 2020, ahead of the summer irrigation season.

Paul Simmons, executive director of the Klamath Water Users Association, said it remains to be seen what changes may come about in the revised BiOp.

“It’s more things to worry about, I guess,” Simmons said. “We always have the concern that the Klamath Project is the only knob in this system that gets turned to mitigate conditions (for fish).”

While Simmons said no one is happy about the latest development, it is a necessary step given the circumstances.

“I don’t believe Reclamation can do anything other than pick up and move ahead, and we’ve confirmed that to them already,” he said.

Both the KWUA and Klamath Irrigation District sued the Bureau of Reclamation following the release of the 2019 BiOp over water supplies for producers. The Yurok Tribe of Northern California, Pacific Coast Federation of Fishermen’s Associations and Institute for Fisheries Resources, meanwhile, sued the bureau seeking greater protections for fish.

Joseph James, chairman of the Yurok Tribe, said Klamath salmon stocks are “in an extremely fragile state.” The 2019 BiOp proved to be an “utter failure,” according to the tribe, due to artificially low flows that contributed to an outbreak of a fatal fish disease in the Klamath River near Iron Gate Dam.

“The Yurok people depend on the Klamath River’s salmon runs for survival and we should not have to bear the brunt of the agency’s poor decision-making,” James said in a press release. “BOR’s actions are an egregious mismanagement of critical public resources and the fishery that we as Yurok People hold sacred.”