The Anchorage School District unveiled on Monday a $563.6 million general fund budget for next year with a $15.3 million gap that would be mainly closed by eliminating 99 full-time classroom teacher positions.

District officials said layoffs would be unlikely, with attrition absorbing most of the job losses. The district has roughly 2,500 full-time classroom jobs, not counting those in special education.

"This budget will make us operate differently," said Superintendent Deena Bishop. "We must make changes to keep moving forward if we want to achieve success for all students."

Bishop presented the proposed budget to the Anchorage School Board on Monday. She said the administration crafted the general fund budget around the assumption that financial support for schools from the state would remain flat, as suggested in Gov. Bill Walker's budget proposal.

The proposed district budget was the first Bishop introduced as the Anchorage superintendent after years leading the Matanuska-Susitna Borough School District. She said the proposed Anchorage budget would spend $4 million in savings to save 40 teaching positions.

"This will allow us to ratchet down staffing reductions instead of taking the hit all at once," Bishop said.

While a loss of 99 teaching positions would likely affect some class sizes, Bishop said the district also expected to have about 270 fewer students next year to lessen the impact.

On top of the cut teaching positions, the budget also included much smaller reductions in the numbers school counselors, teacher assistants, assistant principals, safety and security specialists and administrators.

"Education as you know, is a people-intensive business," Bishop said. "Presently, 89 percent of our budget is in our people. We still have to turn the lights on and heat our buildings, therefore you can't get to $15 million without affecting people."

Heidi Embley, school district spokeswoman, said the annual churn of staff leaving the district  would account for most of the cuts, though employees in more specialized jobs that are eliminated could face layoffs. She said it was too early to know the precise effects.

Bishop said the administration also included additions in its budget, such as 48 full-time instructional coaches paid by grants, as well as the launch of "Capturing Kids' Hearts," a program that provides secondary school teachers with professional development on how to create high-achieving classrooms.

The proposed budget, from July 1, 2017, to June 30, 2018, represents a $3.3 million increase over the current year's adopted budget and about $8.4 million over the actual 2015-2016 budget.

The Anchorage School Board is scheduled to vote on the budget Feb. 21, and could revisit it again depending on how much state education funding goes through the Legislature. Bishop said the proposed budget was scalable should education funding increase or decrease.

Anchorage School Board President Tam Agosti-Gisler said she had just received the budget proposal Monday, and needed more time before issuing any recommendations. She praised the district's budget presentation as straight-forward and transparent, though, she added, that didn't lessen its impacts.

"There are cuts being made in many areas but the significant impact on the classroom is going to be felt," she said. "With a flat-funded budget, with increased costs, there is no other way."

Tom Klaameyer, vice president of the Anchorage Education Association, wrote in an email that the teachers union was "absolutely concerned" about the proposed district budget, as well as the impacts the fiscal uncertainty had on the entire state.

"While we believe a reduction in school personnel will have a direct impact on student learning, the Anchorage Education Association and its members remain committed to providing the best possible education in all of our classrooms, for each of our students," he wrote.