A new partnership between three organizations will explore options for raising the dam at Lake Mendocino to boost the water supply supporting agriculture and recreation.

State and local politicians, tribal officials and representatives from the U.S. Army Corps of Engineers met this past Friday at Lake Mendocino to formalize a cost-sharing agreement for the Coyote Valley Dam General Investigation Study.

According to the Mendocino County Inland Water and Power Commission, Lake Mendocino provides drinking water for over 650,000 people in Mendocino, Sonoma and Marin counties and plays a role in flood control.

The study, led by a partnership between the commission, the Lytton Rancheria and the Corps of Engineers will assess the prospects of greater water supply and potential federal interest in reducing flood risks.

The cost of the study is estimated at $3 million, with funding coming from federal sources secured by U.S. Rep. Jared Huffman, D-San Rafael, the Corps of Engineers, the commission and other potential partners.

The study will begin by evaluating water storage options in the watershed and explore upgrades to Coyote Valley Dam infrastructure. It will also examine ways to restore aquatic species, like the local salmon and steelhead population.

“We are going to look at a lot, and one of the most obvious options is a dam raise,” said Allison Conn, project manager for the San Francisco District of the Corps of Engineers. “Raising this dam to the originally authorized height would increase the conservation and the body of water that can be stored.”

Bringing clarity to a murky situation

Conn said the study will also explore how to make the water supply less “turbid,” meaning murky. She added that the study will investigate a different dam outlet, which refers to a location inside the dam that allows water to exit the reservoir.

“We will look for a different location of an outlet that would allow for cleaner water in the reservoir,” Conn said. She said that cleaner water will allow for a better environment for the native fish population. “The less turbid the water, the better for the fish.”

Huffman said the project will enhance a plan to improve water supply by coordinating transfers between the Eel and Russian rivers.

“We are going to be able to store more water and not have to dump it for flood control purposes. That will help people in the North Bay get through droughts better, and the fisheries in the Russian River will benefit.” Rep. Jared Huffman

“If this reservoir is enlarged, it’s going to work even better,” Huffman said in an interview. “We are going to be able to store more water and not have to dump it for flood control purposes. That will help people in the North Bay get through droughts better, and the fisheries in the Russian River will benefit.”

As PG&E moves ahead with plans to decommission the Potter Valley Project — a historic system that has transferred water from the Eel River to the Russian River for years — concerns about water supply are increasing among local politicians and residents.

For Ukiah City Councilmember and commission representative Mari Rodin, it’s more important than ever for regional and state agencies to adopt new approaches to water supply.

“The dam and the region’s entire water system must evolve,” said Rodin. “The climate is changing, the infrastructure is outdated, and PG&E’s exit means we need a new, coordinated approach.”