The town of Darien will move forward with a project this fall to rebuild the Upper Gorham Pond dam, dredge thousands of cubic yards of road sand, and install a fish ladder to help herring migrate more easily, officials said.

The primary focus of the project will be the restoration of the aging dam, including equipping it with weir boards to help manage the flow of the Goodwives River during times of peak flow and will take about eight weeks to complete this fall, according to John Lundeen, president of the Friends of Gorham Pond.

Payment for the project will come from about $650,000 in funding split between state grants, town funding and private donations, Lundeen said.

The planned portion of the project to happen this fall will only deal with part of the anticipated need to dredge the pond above the dam, where silt is causing the dam to overflow during storms, Lundeen said. The silt also impedes on migrating fish, he said.

“It (the silting) has gradually been getting worse over the 30 years I’ve been here,” Lundeen said. “I don’t remember when upper Gorham Pond it truly looked like a pond.”

The Friends of Gorham Pond, a group of residents interested in restoring the pond, will continue to raise money for future projects to dredge silt from the Goodwives River, which Lundeen said could total 60,000 cubic square feet of silt or more.

The group helped finance the installation of a fish ladder on the Ring’s End Dam about a decade ago on the Goodwives River, Lundeen said.

The cost of the contract is expected to include the price of getting rid of the dredged sand, which is too contaminated by state standards to be used to fill beaches but could probably be re-purposed by a commercial contractor.

“It is dirty enough that it can’t be used willy-nilly as fill, but clean enough that commercial haulers will find places it can be used,” Lundeen said.

The project is notable not only for its environmental benefits, but because of the tenacity and dedication of the Friends of Gorham Pond for both fundraising and cultivating a partnership with the state to get the work done, First Selectman Jayme Stevenson said.

“The community benefits in the larger sense, but the folks around Gorham Pond are the most direct beneficiaries of the work,” Stevenson said. “It has been over a decade (the Friends of Gorham Pond) have been working and to see everybody’s labor come to fruition this fall is very exciting.”