Janet Pauli speaks on the PV Project on Tuesday
Janet Pauli will talk on the Potter Valley Project on Tuesday, Jan. 21 at 7 p.m. in the Ukiah City Council Chambers.
Janet Pauli will explain the components, history, and current challenges of The Potter Valley Project, a diversion of water from the Eel River to the Russian River through a tunnel in the mountains at the northern end of Potter Valley. Owned and operated by P.G.&E. for almost 100 years, this hydroelectric project supplies water for wildlife and people from Mendocino County through Marin County.
In 1905, Mr. W.W. Van Arsdale had a plan for the city of Ukiah and surrounding areas and their need for a reliable source of electrical power to replace a small coal-burning plant. Mr.Van Arsdale envisioned an electrical power plant that could be built at the north end of Potter Valley powered by water that would be diverted from the Eel River. The vision was inspired by his knowledge that the Eel River was an impressive 475 feet higher in elevation than the valley floor in Potter Valley. A simple exercise in physics, some knowledge of construction and financial backing was all he needed.
Eel River Power and Irrigation Company proceeded to build a small dam on the Eel River. Cape Horn Dam, a concrete gravity and earth filled structure, backed up the Eel River to form a small reservoir called Van Arsdale. This reservoir serves as the forebay for the diversion tunnel. From here, an 8 foot diameter tunnel, lined with redwood timbers, was dug over a mile long south through the mountain, finally opening into the north end of Potter Valley, where water flows through a penstock dropping over 450 vertical feet into the Potter Valley Powerhouse. As the project continued it required more capital investments and the Eel River Power and Irrigation Company was reorganized as the Snow Mountain Water and Power Company in 1906.
Work was stopped for a period of time after the great quake of 1906 when the crews were needed to help in San Francisco. Finally, April 1, 1908, the project began to produce power. The first two units in operation were each 2,000 kilovolt-ampere. In 1910 the power company added a 3,000 kva unit. In 1912 a second penstock was constructed. In 1917 a final 2,000 kva unit was installed and the total capacity of the powerhouse grew to 9,400 kva (9.4 megawatts).
The Potter Valley Powerhouse was a boon to the Ukiah area with only one small downfall. The powerhouse only ran at capacity after late fall rains and into spring because the Eel River, like most of our north coast rivers, naturally gets drier and drier as the late spring rains end and summer begins. In the summer, there was not enough water in the river to run the powerhouse! Early on, in 1908, a plan was studied to build a reservoir near Gravelly Valley, twelve miles upriver from Van Arsdale, to store winter runoff and release the stored water to produce power in the summer. The first attempt to build the dam was abandoned. However, Snow Mountain Water and Power Company began the application process for a power permit again in 1918. By 1920 they acquired a Department of Agriculture Power permit to build a dam. Construction of Scott Dam began right away in 1920. The Federal Power Commission (precursor to the Federal Energy Regulatory Commission (FERC) which now licenses the Project) granted a 50 year license for the project on April 15, 1922. Scott Dam was completed, and Lake Pillsbury began to fill, in 1922. Scott Dam and Lake Pillsbury were named after two of the principal investors in the project. In 1930 Pacific Gas and Electric Company (PG&E) acquired the Project from Snow Mountain Water and Power and assumed the license 1/.
The project also has an impact on salmon habitat in the Eel River. Historically, the Eel River contained the third largest run of salmonids in California, behind the Sacramento and Klamath Rivers, collectively totaling over a million fish returning annually. The Eel River is home to fall-run California Coast Chinook salmon, Southern Oregon Northern California coho salmon , winter-run and summer-run North California Coast steelhead , resident rainbow trout, anadromous coastal cutthroat trout, Pacific Lamprey and Green sturgeon. Of these populations, Chinook salmon, coho salmon and steelhead have all seen dramatic declines in historic populations and are currently listed as threatened under the federal Endangered Species Act 2/ .
In January of 2019, P.G.&E announced that it would not be seeking to relicense the project, essentially abandoning a project that affects over 600,000 people. Congressman Jared Huffman has spearheaded an Ad Hoc Committee composed of stakeholders in both the Eel River and Russian River watersheds to come up with a “two basin solution” that will improve fish passage and habitat on the Eel River and minimize or avoid adverse impacts to water supply reliability, fisheries, water quality, and recreation in both watersheds. Janet, chair of the Mendocino County Inland Water and Power Commission, is involved in this complicated planning process and she will bring us up to date. Click on the links for more information about the Potter Valley Project Licensing and the Inland Water and Power Commission.