Marin Municipal Water District directors are making diligent progress toward increasing the district’s water-storage capacity.

This strategy is in response to the crisis the district faced several years ago when back-to-back years of drought reduced the district’s supply to levels where MMWD officials warned of possibly running out of water — even with customers following strict conservation measures.

The crisis fueled voter frustration that led to a turnover of a majority of the district’s board.

Since then, the new majority has been making slow, steady progress toward increasing the district’s storage.

The process takes time and money.

Among the strategies the board is advancing is possibly increasing the capacity of Nicasio Reservoir, the district’s second-largest reservoir.

According to engineers’ estimates, modifying the reservoir’s spillway could add 3,000 acre feet to its maximum capacity — a roughly 13% increase.

The district says the improvement is part of its “roadmap” toward making MMWD’s supply more resilient to future prolonged droughts. The spillway is one of the near-term, lower-cost tasks on a roadmap of measures that, if completed, could nearly double MMWD’s capacity by 2035.

That “if,” however, is significant, as the project cost and potential environmental consequences may take some of the proposals off the table.

Other proposals, such as significant expansion of the capacity of some of the reservoirs, are a lot more expensive and more complex.

It has been nearly 50 years since the district constructed any large addition to its rain-driven water-supply network, building Soulajule Dam in 1979.

It has connected with the Lake Sonoma reservoir, importing water that comprises about 25% of the district’s supply and has twice explored — and shelved — plans to build a desalination plant.

The district’s next step for the Nicasio spillway plan is a $1.9 million study of potential environmental impacts of the Nicasio improvement, complying with state law.

That examination will include a fisheries study of Nicasio Creek, which runs from the reservoir to Lagunitas Creek, a focus of efforts to restore habitat for spawning coho salmon, a federally protected species.

Potential impacts on creeks are among the key environmental issues facing attempts to bolster the capacity for any of the district’s seven reservoirs, which collect and hold 75% of the district’s water supply.

A thorough analysis at the front end of the decision-making could save the district from costly and time-consuming legal entanglements later.

The roadmap also includes potential capacity-increasing improvements at Soulajule Reservoir, as well as Kent and Alpine lakes.

Plans to enlarge Soulajule, one of the lower-cost projects among the larger-capacity options, have already drawn protests from nearby ranchers who fear they could lose land, if not their homes.

The board is continuing to deepen its review of those options, but it is also taking the map one step at a time, initially focusing on “near-term” strategies.

That’s a sound and steady approach and the kind of progress voters said they wanted to see when, in 2022, they voted out two veteran directors. Essentially, voters called for a move away from the district’s primary reliance on conservation.

The board is moving forward, looking at short- and long-term options with the goal of increasing the district’s capacity and, together with the district’s longstanding work in conservation, provide greater protection from facing a repeat of the recent threat that its supply wouldn’t withstand a prolonged drought.