WESTFORD -- Fine-tuning its budget for fiscal 2015, the Nashoba Valley Technical School Committee voted last week to increase the minimum contribution of its member towns by $300,000.

The new amount is expected to be added to $12,241,899 in spending proposed for fiscal 2015 in a draft budget presented to the School Committee at a meeting Jan. 14.

That earlier draft represented an increase over the previous year of $619,657, an amount that is expected to rise slightly as a result of the committee's vote Tuesday.

The budget for 2014 was $11,572,242.

Driving the increase was a rising number of students who have chosen to attend the vocational school, necessitating addition to the budget of such items as the hiring of a new school psychologist at an annual salary of $83,340, an increase of $57,110 for software upgrades, $167,151 for instructional materials, $67,476 for a new guidance counselor, and $10,000 more for various student needs.

Other factors include the rising cost of health care due to changes imposed by the Affordable Care Act, upkeep of playing fields, and school supplies plus increases in utilities and contractual obligations.

But the main driver for the increased spending is Nashoba's rising popularity among local young people who continue to flock to its banners even as enrollment declines at some area public schools. For 2015, for instance, the school's student population is expected to increase by 30, with those from Chelmsford and Pepperell registering the most growth.

At the Jan. 28 special committee meeting, members were informed by Superintendent Judith Klimkiewicz that the shortfall in projected spending for fiscal came to $693,000. But voting reduced that figure to $300,000 after it was decided to take $200,000 from the district's Efficiencies & Deficiencies account and $193,000 from school choice funds to cover part of the expense.

Added to the budget only recently, and included in the $693,000 in spending, was $50,000 that the School Committee had previously voted to deposit in a new Other Post Employment Benefit irrevocable trust fund account.

Recommended by the district treasurer, the account was added as a new line item to the proposed budget earmarking money specifically for deposit in the fund which could not be used for anything other than retired employee health care. That amount will need to be accepted by Town Meeting when it considers the annual budget for approval.

Committee members were told that the district owed $11.3 million in such unfunded liabilities and though the district had been meeting its responsibilities on a pay-as-you-go basis, it was deemed best to assure such financial entities as the bond market that the district was serious about paying its bills.

Before the Jan. 28 voting, proposed minimum contributions for the district's member towns totaled $6,808,953: Ayer at $487,033 for a decrease of $29,695; Chelmsford at $2,229,779 for an increase of $257,724; Groton at $496,346 for an increase of $92,500; Littleton at $460,024 for a decrease of $156,535; Pepperell at $1,137,837 for an increase of $249,145; Shirley at $567,087 for an increase of $7,122; Townsend at $830,261 for an increase of $37,378; and Westford at $600,586 for an increase of $3,650.

Residents will have an opportunity for direct involvement in the budget process when a public hearing is held next month.

A final fiscal 2015 school budget will be prepared for discussion and voting by the School Committee on Feb. 4.

After that, residents will have the final say at Town Meetings held by the district's member towns beginning with Westford's scheduled for March 22.