Lake County to study impact of PG&E’s plan to remove Scott Dam

Lake County plans to spend $700,000 to study the potential consequences of removing the Potter Valley Scott Dam after getting a grant from the California Department of Fish and Wildlife.

The county’s study seeks to determine how decommissioning Scott Dam could affect the surrounding ecosystem, the Lake Pillsbury water supply, infrastructure, power, sediment and the county’s ability to fight fire.

“The grant was part of a conversation with CDFW we’ve been having for a while,” said Lake County Board of Supervisors chair Bruno Sabatier.

The county on May 2 put out its call for a company to do the study in response to Pacific Gas & Electric’s efforts to decommission its powerhouse in Potter Valley, which includes Scott and Cape Horn dams. The power company detailed its plans to tear down the dams, located on the Eel River, in November 2023.

Scott Dam was built in 1921 and, according to PG&E’s plan, is slated to come down before Cape Horn Dam and could come down in phases or in one season. Those plans still need final approval from the Federal Energy Regulation Commission.

Water supply, fire risk top list of main concerns

The Lake County Board of Supervisors worries that removing the dam puts the region’s water supply at risk during a time when the region teeters between drought and having ample water. According to a county news release, 600,000 Californians depend on releases from Lake Pillsbury and the Potter Valley Project for drinking and agricultural water for Potter Valley, Alexander Valley, Sanel Valley and Ukiah Valley.

The county worries that if Scott Dam were removed, the upper Eel River could be dry for significant portions of the year, making the area vulnerable when fire risk is the greatest. Lake Pillsbury has served as a natural fire barrier, stopping forward progress to the 2018 Mendocino Complex fire, which consumed more than 459,000 acres and the 2020 August Complex, the state’s first gigafire.

Lake County Supervisor Eddie Crandell, whose district includes Lake Pillsbury, said firefighters have reported that without Lake Pillsbury, the Mendocino Complex had enough energy to burn through to Upper Lake.

“If Lake Pillsbury wasn’t there, we’d be toast,” he said.

The Lake Pillsbury basin is home to four established communities of about a total of 300 single-family homes, including the Lake Pillsbury homesite tract, Lake Pillsbury Ranch, Ricefork and Westshore.

Environmental protections a high priority

The watershed above Scott Dam is roughly 289 square miles, accounting for a little more than 7 percent of the Eel River’s 3,971 square mile watershed. It forms Lake Pillsbury, the largest lake in the Mendocino National Forest, according to the US National Forest Service. The area is home to nesting bald eagles, migratory waterfowl and Tule Elk. Lake Pillsbury is also home to salmon populations, which continue to face decline, according to the National Oceanic and Atmospheric Administration.

Crandell recognizes the importance of salmon. He’s not against protecting the environment for the salmon, but believes that other options can be explored. “We can build a fish ladder and keep the dam for water for resiliency,” he said.

Crandell’s ultimate hope is for study to provide data that can offer a compromise to a project that feels like a done deal. “The dam is what it is. I know there are folks that are not happy and want the Eel to run the way it used to,” he said. “We just want PG&E to be accountable.”

The goal is to get an impartial report from a technical or environmental firm, says Crandell, whose district includes Lake Pillsbury.

“We’ve never had an equitable study,” Crandell said of the work performed by the Potter Valley Project ad-hoc commmittee, which was established by Congressman Jared Huffman in 2017 as a way to channel stakeholder feedback to federal officials.

Crandell said Lake County government officials often felt bulldozed by the ad-hoc committee and have been unable to get answers about how decommissioning the dam would affect the communities around Lake Pillsbury. For example, the committee published models of how different scenarios could affect water levels and salmon populations, but neither Crandell nor Sabatier have been able to see the data supporting those models.

“We’re looking to make the best decision based on data. It’s important to know,” Crandell said.

Amie Windsor is the Community Journalism Team Lead for the Press Democrat. She can be reached at amie.windsor@pressdemocrat.com or 707-521-5218.