Decades-old project to raise Lake Mendocino dam gets a boost

In early 2014, after fewer than 8 inches of rain had fallen in the upper reaches of the Russian River the previous year, Lake Mendocino dwindled to a third of its capacity, exposing acres of bare ground, and Mendocino County supervisors declared a drought emergency.

“How many times do we have to knock ourselves on the head before we get it?” then-Supervisor John Pinches asked during the board meeting. “Folks, we’ve got to come up with another water supply.”

The irony, in retrospect, is that a major addition to the reservoir near Ukiah - boosting its capacity by 25 billion gallons - had been planned by the Army Corps of Engineers more than 50 years ago. But with California in the midst of a five-year drought, the plan was gathering dust on the shelves of the federal dam-building agency.

A coalition of local agencies, including Mendocino County and the city of Ukiah, already had paid $617,000 toward a feasibility study that would determine if the benefits of raising Coyote Valley Dam by 36 feet justified the cost of about $320 million.

But without more money, Corps officials said in 2014 the study could not move forward.

Now, with the prospect of drought and hotter weather considered California’s “new normal” due to climate change, new hopes have arisen for the relief Pinches and others have sought: More water in Lake Mendocino to quench the needs of residents, farmers and fish along 75 miles of the Russian River from Redwood Valley to Healdsburg and contribute to the Sonoma County Water Agency’s deliveries to 600,000 customers in Sonoma and Marin counties.

Rep. Jared Huffman, D-San Rafael, got the Coyote Valley Dam project - in one 13-word sentence - on a list of feasibility studies for some 30 Corps projects from Alabama to Alaska to be expedited by the Secretary of the Army.

Tucked into the 122-page Water Resources Development Act of 2018, the list was approved two weeks ago on a lopsided 408-2 vote in the House and was forwarded to the Senate.

Since Congress no longer allows individual appropriations known as earmarks, Huffman said he was unable to include money in the measure, and much more is needed.

“It helps when Congress calls out specific projects for priority,” he said.

Huffman said he hopes to get Corps officials, Mendocino County representatives and his staff to work on finding the money.

“We need to get moving,” he said, acknowledging “there are all sorts of projects backlogged” at the Corps.

Janet Pauli, a Potter Valley rancher and irrigation district official, said she was grateful for Huffman’s legislation.

“It definitely helps us,” she said. “We have to get something from the federal government for this project.”

Just to revive the feasibility study will cost $400,000 and completing it will cost $5.5 million, with the Corps splitting both bills 50-50 with the Mendocino County coalition called the Inland Water and Power Commission.

The steep price of the study is due to dam seismic safety issues that must be addressed, Corps officials said.

Pauli, the commission chairwoman, said it would be “a stretch” coming up with the local share of nearly $3 million. She’s hoping for state assistance at a time when “water supply is the most important infrastructure improvement we can have.”

“Without water, we don’t have anything else,” Pauli said.

The commission is a joint powers authority consisting of the county, Ukiah, Redwood Valley County Water District, Potter Valley Irrigation District and the Russian River Flood Control District.

The cost of raising Lake Mendocino’s 160-foot earthen dam by 36 feet was last estimated in 2015 at more than $320 million, said Neil Hedgecock, the supervisory program manager in the Corps’ San Francisco District project management division.

But that’s years away, since the feasibility study will take four to five years, he said.

Huffman called that a “ridiculously long time frame.”

The history of the dam reaches back to a catastrophic flood in December 1937, when the turbulent Russian River spread about a mile wide over the Ukiah Valley. A year later, Congress authorized the Army Corps to assess flood control in Mendocino and Sonoma counties, and the agency hatched a three-phase plan.

First came Coyote Valley Dam, authorized by Congress in 1944 and built 14 years later on East Fork of the Russian River, impounding Lake Mendocino.

Phase Two was 319-foot Warm Springs Dam, which was completed by the Corps in 1983, creating Lake Sonoma northwest of Healdsburg.

Lake Sonoma, with a capacity of 381,000 acre-feet, is more than three times larger than Lake Mendocino’s 116,500 acre-feet. An acre-foot is about 326,000 gallons and an average California household uses up to one acre-foot of water a year.

Under phase three, Coyote Valley Dam was to be raised 36 feet, which would boost its capacity by about 77,000 acre-feet.

The Corps made allowances for it, engineering the initial dam to bear the addition, securing easements to prevent development of permanent structures on land that would be covered by the higher water and even setting aside soil for the dam raise, now covered by a vineyard.

But it never came, perhaps, Pauli suspects, because the two existing dams have, for the most part, controlled Russian River flooding over the past four decades.

Now, however, in the wake of the five-year drought that saw Lake Mendocino shrink to 36 percent of capacity, Pauli contends that water storage is the region’s most pressing need.

At the same 2014 meeting when Pinches spoke up, Mendocino County Supervisor Dan Hamburg said, “Nobody’s mentioned the elephant in the room, which is climate change. I’m afraid the new normal is low rainfall.”

Communities from Redwood Valley to Healdsburg depend on water from Lake Mendocino, including agriculture in Mendocino County. That farming, including wine grapes generates an economic impact of more than $700 million, according to a study by economist Robert Eyler.

Lake Mendocino also plays a critical role in providing water to sustain federally protected fish in the river’s upper reach, said David Manning, the Sonoma County Water Agency’s environmental resources manager.

Raising the dam might make it easier to support those fish, he said.

Grant Davis, the water agency general manager, said Lake Mendocino is “an important asset in our ability to deliver water supply to the entire region.”

Davis said he hopes the Mendocino coalition of agencies will move forward with the feasibility study and that Huffman can obtain funding for it.

“Very much incumbent on us to investigate the options for raising Coyote Valley Dam,” he said.

Asked if Sonoma County might become one of the financial partners, Davis said that would require a decision by the Board of Supervisors, who also are the Water Agency’s directors. The dam raise won’t come soon, Pauli said.

“We have a long way to go anyway,” she said.”It’s going to take 20 years to get this done.”

You can reach Staff Writer Guy Kovner at 707-521-5457 or guy.kovner@pressdemocrat.com. On Twitter @guykovner.