ROCKLAND, Maine — The RSU 13 school board voted Thursday night to consolidate the St. George and Rockland high schools, a decision designed to save money through staff reductions and by elimination of overlapping services.

The decision came three days after the state Department of Education notified the district, along with other school districts in the state, of reductions in state subsidy for 2010-11.

Starting in September 2011, Rockland and St. George eighth-and ninth-graders will go to what is the Georges Valley High School building. Tenth, 11th and 12th grades will be in the Rockland High School building.

The two high schools, which are less than five miles apart, house about 700 students altogether. In the next few years, Superintendent Judy Lucarelli said, the district is likely to lose about 100 high school students.

The plan being implemented was recommended by the RSU 13 High School Study Group, a committee charged with finding options for the futures of the towns’ schools.

As many as four teacher positions could be cut, in addition to nonteaching positions, according to Lucarelli. The plan would result in fewer but larger classes, enabling the district to eliminate overlapping positions.

“Both high schools have enough classes in math, English, social studies, science with fewer than 10 students that if we put the two together and combine the classes, you have classes with fewer than 20 students that can save a position in math, science, English, social studies,” she said. “That’s four fewer teachers.”

The salaries of 450 employees in the district make up about 80 percent of the RSU’s budget, Lucarelli said. Both teacher and nonteacher positions will be cut, according to Lucarelli, but she would not specify which positions or how many.

Lucarelli is choosing the positions now and will present them to the board in March. The board will vote on them at the April meeting.

School board member James Kalloch of Rockland voted for the measure to consolidate the high schools.

“You have a choice of raising taxes or changing education,” Kalloch said. “We can’t just put this on the back of citizens. A high school for 350 kids is not practical.”

Maintaining the current system, Kalloch said, would require a property tax hike of 8.5 to 9 percent.

“No one wants to do this,” he said. “I would love to be able to continue what we’re doing, but in today’s economy we can’t.”

Board member Josiah Wilson of Port Clyde voted against the reorganization of the schools.

“Quite frankly, I don’t like the idea of the kids traveling for 45 minutes,” Wilson said. “A kid from Cushing will have to go to one school in Cushing, in fourth grade he would be in Thomaston, then he would travel to another school and then high school. You’re talking about five transitions in the course of his schooling. It’s unacceptable.”

Wilson called the plan “rushed” and “ill-conceived” and said there is no proof the new model will save taxpayers money.

“You have to listen to the people, and the people clearly stated with all their e-mails and their output that they did not want this,” Wilson said. “If they were going to get this, they wanted us to take some time.”

The school district was hit financially twice this year.

The state budget chopped RSU 13’s subsidy from $5,207,000 to $3,848,000, according to Kalloch. In addition, the school district, after the separate school districts consolidated into the new regional school unit, had to give all money it had accumulated through the years back to the towns that paid in the money.

The districts that chose to consolidate were supposed to be rewarded with money taken from the school districts that refused to consolidate, according to Lucarelli, who fears that may not happen in the next two years.

“It could get worse,” she said of the tightening school budget.