CANTON – Officials planning the construction of a nearly $700,000 dam on Whitney Brook provided details of the project and answered residents’ questions at a public hearing Tuesday.

Forty people attended the hearing, which was required as part of the $500,000 Community Development Block Grant received for the work. Dam Advisory Committee Chairman Malcolm Ray presided over the hearing.

The dam will replace one the town took by eminent domain in 2008 after its owner failed to make repairs and the state declared it unsafe. The dam regulates the water level in nearly 2-mile long Lake Anasagunticook, which lies in Canton and Hartford.

Committee Secretary Judy Hamilton showed posters detailing the estimated $651,575 remaining cost of the project, a sum that includes the grant. So far, $42,658 has been spent on the project.

Lake Anasagunticook Association President Biff Atwater announced the kickoff of the Let’s Give a Dam Together fundraising campaign.

Civil engineer Kevin Cooley of Kleinschmidt Consultants, designers of the dam, said the Maine Emergency Management Agency was concerned that the 100-year- old dam and the built-up left bank of Whitney Brook were unsafe.

He showed drawings of the new dam, which is upstream from the old one where the brook is much wider. The design incorporates two gates which will normally control the water level in the lake.

Four-foot-high flashboards made of two-inch thick planks supported by iron rods will top the remaining 50 feet of the dam. Cooley said the flashboards are designed to break when topped by more than 2 feet of flowing water.

Sue Gammon was concerned what would happen downstream if the flashboards broke, in part, because she has been landscaping and building paths in the Androscoggin River floodplain below the dam.

The town bought out homes in the floodplain after a major flood in 2003 and is turning the area into a park.

It was suggested that Kleinschmidt consider adding more gates to the dam to reduce the likelihood that the flash boards will break.

Gammon also expressed the need for a minimum flow down the brook. She said that the prior absentee landlord let the brook dry up, leaving fish stranded in small pools.

Ray said the Canton Water District would be responsible for controlling the dam. He expressed confidence that all interested parties could work out an acceptable water control plan that meet their needs.

Brian Beneski explained the environmental assessment of the site, which once contained a tannery.

Maine Department of Inland Fisheries and Wildlife Chief Planner Leon Bucher discussed the possibility of constructing a public boat ramp on the site. He said if there was one the department would stock the lake.

Amy Landry of Androscoggin Valley Council of Governments, administrator for the grant, said there will be adequate comment periods over the next few months as AVCOG prepares the environmental impact statements.