Doble said the construction will start this summer when the Maine Department of Transportation picks the lowest bidder. The lowest bid is expected to be about $1.4 million.
The expansion will go through Chamberlain Bridge and come out by Veteran's Park on Penobscot Street.
Doble said the expansion plans have been in the works since 2000.
The project will also include fixing the brick walkway and lighting fixtures on Center Street, which city officials hope will pull people to local businesses.
"I think it's going to bring a lot more people walking along and seeing how beautiful this is," said Renee Doble, talking about the current walkway along the river. "I don't know if a lot of people even know about the Children's Garden that we have on the Brewer Riverwalk that already exists, which is so pretty."
Doble added that the Brewer Riverwalk has free wifi along the route and police surveillance.
She said the city will pay for about 20 percent of the costs, and a federal grant will take care of the rest.
The expansion should be done by October.