OTTAWA -- Ottawa's largest school board is exploring larger class sizes and combining grades in elementary schools to offset a drop in enrolment this school year.

The Ottawa Carleton District School Board is facing an estimated $24 million funding shortfall for the 2020-21 school year, and is now looking at eliminating 40 elementary classrooms and 13 secondary school teaching positions.

Enrolment in elementary schools is 1,700 below projections this fall, including 900 fewer students registered for kindergarten.

During a presentation to Trustees Tuesday evening, Superintendent of Human Resources Janice McCoy said the enrolment would result in 80 fewer classrooms in elementary schools, but the board received some funding to reduce class sizes. McCoy said the board still needs to reduce 40 elementary classes to cover the funding shortfall.

"Reorganizations will result in at least some students changing classes, including moving from straight grades to combined classes, and teachers being reassigned either within the school or to another school," said McCoy.

"Reorganizations are certainly more challenging this year given the pressure to keep in-person class sizes as low as possible, and within existing resources. When we look at our school reorganizations, it's apparent that's reorganizations would impact our in-person classes almost exclusively."

McCoy says staff are reviewing school organizations to identify places where a reorganization could take place without a "significant" impact on class sizes.

Enrolment in high schools is 183 students below projections. McCoy said from a staffing perspective, it means the system has 13 extra FTE positions.

"Adjustments to reconcile enrolment and staffing wound be actioned in the next quadmester, or, more likely, in the second semester at this point to avoid disruption of classes," said a report for the board.

Detailed information on enrolment and funding estimates will be presented to the OCDSB Board in December.