HATFIELD — An historic dam on School Street, where the rushing water in the Mill River forms a waterfall providing the sights and sounds for guests at the Old Mill Inn, is being examined for possible removal.

With a $250,000 grant from the Executive Office of Energy and Environmental Affairs’ Dam and Seawall program, the Connecticut River Conservancy is beginning both the study and the engineering work associated with exploring whether the D.F. Riley Grist Mill Dam can be taken down.

On Saturday from 11 a.m. to 2 p.m., representatives from the Greenfield nonprofit organization are holding an open house at the 87 School St. inn that will include participation from the engineering team and the dam owners.

Becky Budd, restoration program manager for the Connecticut River Conservancy, wrote in an email that the project team is working toward full removal of the dam, though is just starting data collection that will inform the engineering design approach, part of a long process that includes permitting and implementation.

“If all goes smoothly, we are hoping to go to construction in 2028,” Budd said.

The State Office of Dam Safety has ordered the privately owned dam be removed or replaced due to its current condition, which is classified as poor, meaning it has deficiencies. The dam has also been identified by the National Inventory of Dams as at risk of failing.

The open house will also be an opportunity for residents and others to share their perspectives on the dam and its great historical and ecological importance.

While the watershed group is taking a lead, town officials and residents are expected to have a role in the direction taken on removal. The dam was built as part of the 10,000-square-foot grist mill in 1880-1881 on the site of the Shattuck Gun Factory. In recent years, suites at the boutique inn have faced the waterfall.

A dam has been at the site since 1661. It is the only standing dam on the mainstream Mill River, blocking fish from accessing valuable upstream habitat. According to the watershed group, the dam removal will benefit migratory species such as American shad and sea lamprey, and improve the overall ecological health of the river system, as well as its resilience to climate change.

Those on hand will include the engineering team and dam owners. Those interested in attending should RSVP to Budd at rbudd@ctriver.org.

Refreshments will be offered and parking is at both the Old Mill Inn and at Mill River Storage, 10 Prospect Court.

Scott Merzbach can be reached at smerzbach@gazettenet.com.