Staff from the state Department of Conservation and Recreation and the US Department of Agriculture’s Natural Resources Conservation Service will be holding a public meeting to details plans for upgrading Hop Brook Dam from 7 to 9 p.m. Thursday in the selectmen’s meeting room in Town Hall, 63 Main St. The staff members will also answer questions about the proposal. Officials have said the dam is structurally sound, but development around it has generated higher amounts of runoff than it was designed to handle. They say the upgrade will provide better flood protection and help maintain the town’s wetlands and open space. The state agency, which owns the dam, has requested federal funding for the project.