AMHERST — New traffic patterns into and out of Fort River School will be in place in the coming weeks as a contractor undertakes initial site work for the new three-story elementary school to be built on the same site at 70 South East St.

Town officials announced Tuesday that Gagliarducci Construction of Springfield was awarded the low bid, at $2.25 million, for the “early site package” that had been estimated at $2.9 million. This work is the first phase of building the $97.5 million, 575-student K-5 elementary school immediately south of the existing school, on what are currently playing fields. Bids for general contractors will be issued by the town in June.

When Gagliarducci is on site, the existing southern entrance to the school, located closest to Belchertown Road and College Street, will be closed and converted to a construction-only entrance and exit, with all school traffic coming and going using the northern driveway closest to Main Street.

For Town Manager Paul Bockelman, the bidding, an important first step in construction, provided good news for the project. The low bid, among seven received, was $652,000 below estimates, reflecting a competitive bid process, he said. The bid was awarded after Anser Advisory, the town’s owner’s project manager, reviewed the company’s qualifications and checked references. Savings being realized from this will go toward the contingency account for other aspects of the project.

The scope of Gagliarducci’s contract includes fencing, erosion controls, stormwater management, roadwork, early site demolition, excavation and removal of topsoil and subsoil, installation of rammed aggregate piers as foundation support and placement of materials to compact the site of the new building.

The new school is to be completed by September 2026, and demolition of the existing Fort River School and other final site work will take place later that year. The net-zero energy building, using ground-source heat pumps and photovoltaic panels, will have a capacity of 575 students, with five classrooms for each of the six grades.

When it’s complete, both Wildwood School on Strong Street and Fort River will close, and Amherst’s sixth-grade students from the existing elementary schools, which also includes Crocker Farm School, will head to the Amherst Regional Middle School.

Town and school officials issued statements in support of the work about to begin.

“The news that the bid from a highly recommended, skilled contractor is well below the estimated budget bodes well for the entire project and will provide added funds for contingency as we move forward,” said District 1 Councilor Cathy Schoen, who has chaired the Elementary School Building Committee.