How Davis will determine its water future remains an open question.

In several weeks, voters will receive ballots for a special March 5 mail-in election on its joint Surface Water Project with Woodland.

The first ballots are expected to land in Davis mailboxes Feb. 4.

A yes vote on Measure I directs Davis to proceed with the multimillion-dollar project to provide surface water from the Sacramento River to Davis and Woodland to supplement what the cities pull from their aging wells in 2016.

Supporters say the 12 million gallons a day Davis would receive from the project would ensure the city has a clean, long-term water supply while saving millions of dollars by joining forces with Woodland to comply with state clean water requirements.

Woodland, facing state and federal clean water deadlines in 2016 and its own water quality issues, is moving ahead with its part of the plan.

But in Davis, the project has been a tougher sell.

The project had won the support of the City Council and the city's 10-member Water Advisory Committee.

Both panels are endorsing so-called plans for "conjunctive use" – water supplies combining surface and groundwater.

But the council was forced to delay a ballot measure asking for residents' support from November 2012 to this March.

Meanwhile, water committee members Marc Siegler, former Davis Mayor William Kopper and Michael Bartolic have reversed course since the committee's vote and now oppose the project and Measure I.

The measure's opponents say the plan, as much as $116 million before water purchase, operations and other costs, is too expensive and comes too soon after a crippling recession from which Davis and Yolo County are still emerging.

They also cite a dramatic hike in water rates in a city that already approved a series of voter-approved parcel taxes and other fees for schools and parks. They contend that the measure's supporters overstate concerns about the city's groundwater.

"I'm concerned for the folks who've lived in town a long time. You're going to see a doubling of rates for some," and even higher rates for other Davis water users, Siegler said.

Siegler says details of the Surface Water Project haven't been fully explained. He suspects the urgency to move the project forward is motivated by Woodland's shorter 2016 timeline. Davis' clean water deadlines arrive in 2020.

"Multiple sources of water is a good thing, but I don't see the absolute emergency," Siegler said. "We're making a huge decision. Why do we have to do it right this minute with the information we have?" Siegler said.

Instead, opponents said Davis should consider more effective ways to store and manage its water supply, revisit a water treatment and delivery plan with West Sacramento that city leaders mulled over the summer or plot a regional approach with Woodland, West Sacramento and the University of California, Davis.

Elaine Roberts Musser chairs the water advisory committee and is among those leading the effort to pass Measure I and keep the joint project on track.

Musser rejects opponents' claims ("Heard 'em all," she says).

"We looked at the cost of the project. There's a cost if we don't do anything. There's no way of telling how much that's going to cost," Musser said. "It's not just state fines. We may have to drill new wells or treat wells – if that's even feasible."

She said deteriorating wells and groundwater – and the costs of repairs – as well as the specter of state clean water penalties and the potential costs of standing pat or joining Woodland at a later date are reasons enough to support the measure to go forward with the water project.

"The (opponents') argument is that we need more time. It's a risk assessment," Musser said. "Suppose we don't do the Woodland project and Woodland goes it alone. What if we want to come back in two years? What will Woodland say? 'You can come in, but for a price.' "