Sonoma County government administrators have told members of the county’s largest labor union that they could be disciplined if they participate in a planned Feb. 28 strike and the walkout later is found to be unlawful by a state labor board.

The largest group of unionized Sonoma County government employees plans to strike next month to protest what it says is county inaction on a union proposal to save taxpayer money and several other issues it says amount to unfair labor practices.

A day after many of its signature overhaul proposals were rejected in a lopsided union vote, Sonoma County took action Tuesday to implement state-mandated changes to employee pensions. The changes, most of which do not require labor’s approval, affect mainly future hires and are expected to help curb rising taxpayer costs over the long run.

The largest union of Sonoma County government workers on Monday soundly rejected a proposed contract that would have cut their pensions and pay. Eighty-three percent of those workers, represented by Service Employees International Local 1021, who voted opposed the proposal.

Long-sought changes to curb Sonoma County’s public pension costs are included in a proposed labor contract that covers about half the county workforce and is up for approval by the Board of Supervisors Tuesday.

An interim appointment to one of Sonoma County government’s most embattled jobs — transportation and public works director — could go to two people under a proposal to be considered today by the county Board of Supervisors.

After spending a day digesting the details of Gov. Jerry Brown’s complex pension deal pending in the Legislature, local officials say it would impact not only future local public employees but thousands of current workers, too. By enacting ‘anti-spiking’ provisions for existing workers, requiring employees to pay half the cost of their pensions and shifting the landscape for labor negotiations, it is becoming clear that the governor’s plan goes beyond state employees and would have wide-ranging implications for local governments. Future employees would face caps on pensions and less generous pension formulas.

Santa Rosa today will consider spending up to $200,000 to study whether it makes sense to build a tunnel under the SMART rail line to help pedestrians and bicyclists go under the tracks at Jennings Avenue.

For the first time in four years, Sonoma County supervisors are set to consider a balanced budget Monday when they begin hearings on a spending plan for the upcoming fiscal year.

Janice Atkinson, Sonoma County’s clerk, recorder, assessor and registrar of voters, has announced her plans to retire this summer.