Sonoma pipeline favored over reservoir expansion

Minimal disturbance to environment, public cited

By Adrian Rodriguez

Marin Municipal Water District managers appear to be placing a controversial reservoir expansion proposal on the back burner.

District staff said Tuesday that constructing a pipeline to convey water from Sonoma County would be the most efficient way to boost supply with minimal disturbances to the environment and residents.

Staff said the plan to raise the Soulajule Reservoir in northwestern Marin would yield great water gains, and it offers the district flexibility and resilience. However, the loss of farmland and homes would be a big impact on the ranching community, staff said.

The board took no vote Tuesday, but members tended to agree.

“I wouldn’t take anything off, but in terms of focus in the short term, I believe that the conveyance has both regional and local impact, and I think there’s a lot that we can do there,” said board member Jed Smith.

“I’m comfortable with the direction you’re going and I look forward to the next steps,” Smith said.

A staff presentation provided an analysis of more than a dozen proposals of potential ways to bolster water supply and protect the county from drought.

In addition to cost, the staff analysis judged the projects on factors such as social and environmental effects, flexibility, resiliency, water quality, reliability and sustainability.

Paul Sellier, the district’s water resources manager, said the goal set by the “water supply road map,” a plan to build drought resiliency, was to construct a project in the short term that could add about 8,500 acre-feet of water. An acre-foot equals about 326,000 gallons.

Instead of planning just one project, or one effort, the district could take an integrated approach to meet that goal, Sellier said.

Water-saving efforts by customers amount to about 2,000 acre-feet of water a year, he said.

Additionally, the district is in the environmental review phase of a plan to reshape the Nicasio Reservoir. That project could add 3,000 acre-feet of storage, producing 750 acre-feet a year. The project would modify the spillway gates of the dam.

Sellier said there are a host of other district improvements adding up to about 1,000 acre-feet of water gains a year.

With those projects in mind, the new goal is a project yielding 4,750 acre-feet of storage, Sellier said.

The advantages of a pipeline project is that it could provide a good water yield, be constructed in phases and be functioning in as few as four years, Sellier said. The pipeline, which would feed into the Nicasio Reservoir, could also make it easier and more practical to consider reservoir storage expansion projects in the future, he said.

One of the reservoir projects being considered is the expansion of Kent Lake. The only way to do the construction, though, is to empty the lake. That would require deep planning and flawless execution because of a shortened construction season squeezed by environmental constraints, Sellier said.

If a new pipeline were in place, the district would have enough supply to offset the absence of Kent Lake during construction, Sellier said.

The pipeline project could be done in phases, with the first phase yielding about 3,800 acre-feet of water and costing around $168 million. The second phase would increase supply to 8,100 acre-feet and increase the total cost to $405 million, according to the district.

The Kent Lake expansion is expected to cost $519 million, compared to expanding Soulajule Reservoir, which would cost $484 million.

Desalination projects would range from $352 million to $520 million, with annual costs expected to range from $27 million to $51 million.

The analysis also looked at a range of recycled water options, with a potential project at Peacock Gap standing out as a viable contender. The project would cost about $28 million, but annual operations and maintenance would remain under $1 million.

Board member Diana Maier said she has been concerned about the Soulajule project because of permitting, environmental effects and inundating the farmland that many ranchers call home.

A chorus of Marin ranchers has been against expanding the reservoir, which they say would upend their livelihood. Multigenerational homes and ranches could be threatened by the footprint of a bigger dam, requiring the water district to acquire land, likely by eminent domain.

“I personally have big concerns about that, and concerns for what kind of a conflict that could create that might take many, many years to get over if we were to go that route,” Maier said, recommending that staff move forward with the pipeline proposal.

Board member Larry Russell said the Soulajule project would not only create conflict, but doesn’t seem practical. He said it would not capture the same watershed as the other reservoirs.

“I think that we need to trim out things like the Soulajule consideration altogether because of its impact and also because of the practicality,” Russell said.

West Marin ranchers urged officials to continue with the pipeline project and other ideas, but not the Soulajule option.

“I just think we need to remember that it will devastate the farmland and terminate all the operations,” said Annie Dolcini. “We need to remember the immense emotional stress that it will put on the families, to force them to leave their homes and their family history that’s been part of their land for hundreds of years.”

Board members said that although the pipeline project looks like the best short-term option to pursue next, they are still interested in projects to construct a desalination plant and to add more recycled water opportunities in the future.

Staff is expected to make a formal recommendation on a project at a board meeting next month.