Two months after approving $125 million in budget cuts for Shelby County Schools, district leaders announced Thursday the layoffs of more than 500 educators due to shrinking enrollment and recent school closures.

The district began sending letters this month to an estimated 490 teachers notifying them that their contracts will not be renewed, as well as about 30 administrators, said Sheila Redick, the district’s director of human resources.

About half already have found new positions within the district, Redick said.

Shelby County Schools – which employs 14,500 people, including about 7,000 teachers – is one of the largest employers in Memphis and Shelby County. The school system is striving to adapt to shrinking enrollment and resources without impacting its school turnaround efforts. With one of the highest concentrations of underperforming schools in Tennessee, the district has become an incubator for change and is at the forefront of the state’s education improvement efforts.

“We are a district with declining enrollment and budget issues,” Redick said during a conference call with news reporters. “Every year we’re having to make tough decisions, and we try to keep as many of those decisions away from the classroom as possible.”

Employees have braced for the layoffs since April when the district’s Board of Education approved a scaled-down $974 million budget for the fiscal year beginning July 1. Roughly 80 percent of its budget goes towards personnel costs.

Student enrollment has steadily dwindled for decades in Memphis due to a declining economy and factory closings that turned bustling communities into aging and emptying neighborhoods. In the last three years, 19 schools have been closed, including three at the end of the 2014-15 school year. Siphoning off still more students, the state’s Achievement School District, tasked with turning around the state’s lowest-performing schools, has taken over 27 schools in Shelby County since 2012 and transitioned most to charter operators. With each student lost, Shelby County Schools loses per-pupil funding from the state.

Teacher layoffs have become an annual occurrence in Memphis as the district has sought to achieve balance amid all the changes.

Each year, the district works with displaced teachers to find other employment. Displaced teachers are entered into a pool of district candidates, but that does not guarantee a new position. Last year, however, 97 percent of the pool’s 800 teachers found new jobs, Redick said.

The district’s hiring practices have changed under policies implemented as part of a $90 million teacher improvement grant awarded in 2009 by the Bill & Melinda Gates Foundation to the former Memphis City Schools. The hiring process begins earlier in the summer than in previous years and, in the 2013-14 school year, the district introduced a “mutual consent” policy requiring teachers who are laid off or displaced to interview with the principal for open positions. The previous practice — of assigning displaced teachers to schools without input from the principal and teachers — had a negative effect on performance, Redick said.

The district also now uses staffing managers to assist principals in identifying the best matches for priority schools ranked academically in the state’s bottom 5 percent.

“We don’t limit sending our best teachers to the boutique schools,” said Redick, referring to the higher-performing schools. “We aim for equitable distribution.”

Redick said the district has hosted four hiring fairs and will host another one next week. She estimated that 350 positions remain open within the district.

Efforts to reach representatives of the Memphis Shelby County Education Association, the district’s largest teacher employee organization, were not immediately successful.