YAKIMA, Wash. — Defense Department workers in Washington state, including some in the Yakima area, would see their paychecks whacked by about 20 percent from late April through the end of September under a furlough plan announced Wednesday to help the Pentagon cope with budget cuts to take effect March 1.

The furloughs could affect some 16,200 civilian employees at Joint Base Lewis-McChord, a combined Army and Air Force installation. It would also hit some 16,000 Northwest civilian Navy employees, the majority of whom work in Washington.

Some of those employees work at the Army’s Yakima Training Center, which is part of Lewis-McChord. Between 550 and 600 people — military and civilian employees, as well as contractors — regularly work at the training center; about 120 of that number are directly assigned to the training center through Lewis-McChord, a spokesman said.

Jay Overton, internal-relations manager at Navy Region Northwest, which supports Navy operations in six states, told The Seattle Times it is unclear whether workers might take a day off each week, or whether some might take off larger chunks of time.

“We’ve known this has been a possibility for some weeks and have been getting the word out to employees,” Overton said. “But we still don’t know how this will play out.”

Nationwide, the Pentagon projects the furloughs will save about $4.8 billion.

In Washington state, the Defense Department estimates, it would save about $175 million and reduce annual spending on civilian-employee payrolls by about 9 percent, according to a document released Wednesday by the Pentagon.

Civilian employees carry out a multitude of tasks, among them teaching at base schools, maintaining aircraft and ships, providing medical care and working in programs aimed at reducing sexual assaults and suicides.

In a Pentagon briefing with reporters Wednesday, Acting Under Secretary of Defense Jessica Wright said furloughs will be applied in a “consistent and equitable” fashion” with only a few exceptions.

The automatic cuts — known as sequestration — were part of a 2011 budget agreement reached by Congress and President Obama. They were supposed to be a distasteful, across-the-board approach to reducing spending that would prod Republican and Democrats to come to a broader agreement on taxes and spending cuts.

Obama this week called for a plan that would involve spending cuts and increased revenues to avoid the sequestration. Congressional Republicans say they agreed to increased taxes in a deal reached in January and want any new budget agreement to focus on spending cuts.

If sequestration is allowed to proceed, in addition to furloughs, there will be plenty of other spending cuts hitting the military and other federal agencies.

For the military, the effects are expected to include reductions in training, contracting and — under a proposal announced earlier this year by the Navy — cancellation of the Blue Angels air show at Seattle’s Seafair this summer.

“We are doing everything possible to limit the worst effects on ... personnel but I regret that our flexibility within the law is extremely limited,” wrote Defense Secretary Leon Panetta, in a message sent Wednesday to department employees.

The Yakima Herald-Republic contributed to this report.