The Marin City Water District has begun efforts to explore the new water source and study how it could help the county survive future droughts.
The study comes after 191,000 residents in the region and the central and southern Marin it serves face potential reservoir depletion after a two-year drought.
To prevent running out of water, the region scrambled to plan a $100 million emergency pipeline across the Richmond-San Rafael Bridge to draw water purchased from the Sacramento Valley by mid-2022.
But regional official Paul Sellier told a public seminar that heavy rains in late 2021 have nearly refilled the region’s reservoirs, allowing the region to take a step back from the emergency and dig deeper into new supply options this month. .
“We have more time to work on the water supply we have now, which will allow us to do this strategic water supply assessment,” Sellier said. “The outcome of the assessment will be a roadmap for achieving water resilience.”
A variety of options are available for evaluation, including bridge pipelines, also known as interties; desalination plants; building dams at reservoirs; expanding circulating water systems; and subterranean reservoirs in partnership with Sonoma Water.
The assessment will be conducted by the Jacobs Engineering Group in Texas. The company’s project manager, Armin Munevar, said the research will be divided into two main phases.
The first is to examine how the region’s two-year water supply is affected by future changes, such as increased demand, various drought scenarios and climate projections. The team will also run the same stress test against more water supplies in the area to see how they compare.
“What we’re trying to do is explore different futures, droughts, demands, policies, etc., and make sure the system is resilient taking into account these plausible futures,” Munevar said. “We’re not trying to predict a specific outcome.”
The study will then look at various new water sources and assess their cost, their resilience in future droughts, environmental impacts and social factors.
“We may find that some alternatives work best in combination with others,” Munevar said. “So we may have a process to develop a combination of alternatives.”
A second public workshop scheduled for May or June will provide an update on some of these efforts. In June and July, the study will review water sources and prepare a final report. The third public workshop will be held in July or August.
Taxpayers who attended the March 9 seminar raised a variety of questions and comments, from desalination options to the role of conservation to the impact of housing development.
“Could our potential interconnection link us to a future desalination plant in San Pablo Bay so we can draw nutrients from that source without needing our own desalination system?” Beryn Hammill asks school district jobs personnel.
Steve Isaacs asked if the board had established a water supply target that Jacobs Engineering Group wanted to achieve.
“Marin’s two years of water supply has been an acceptable strategy for the MMWD board, and it was a disaster,” Isaacs said.
The region’s general manager, Ben Horenstein, said the first part of the study would explore how much water the utility might want to get, rather than setting specific targets now.
“I don’t really see disaster,” Horenstein said. “What I’m seeing is a region responding to external changes in climate change in a similar way as we did in the late ’70s and early ’80s, when we experienced record droughts.”
Sellier said school districts can’t just randomly choose a number to store.
“It needs to have some foundation, and that’s what we’re trying to do with water supply assessments,” Sellier said.