It was a long time coming, but work has started on the newest affordable-housing development in the Valley. On Friday, MidPen Housing, the Foster City based nonprofit developer, and the county held a ceremonial groundbreaking on the 6.4-acre site at 17310 Sonoma Highway.

Some three-dozen county officials and invited guests heard the history of the project, and saw renderings of what it will look like when it’s finished.

Phase I, which is under construction, will have 60 one-, two- and three-bedroom low-income family apartments when it opens some time late in the fall of 2016. And Phase II will have 40 low-income one-bedroom apartments for seniors.

There will also be a community garden, a shared playground with the Sonoma Charter School and an easement for the Central Sonoma Valley Trail.

There will also be a 6,400-square-foot commercial building called Vailetti Square.

Kathleen Kane, the head of the county’s Community Development Commission, said the initial loan to build low-income housing on the site was made almost 10 years ago by the then Springs Redevelopment Agency, which has since been dissolved. She said the county has $2.6 million in loans plus rental subsidies in the project.

“It’s been a long time coming,” Kane said. “And I look forward to coming back for the grand opening.”

Kane was one of a number of speakers that included 1st District Supervisor Susan Gorin, Jan Lindenthal, MidPen’s vice president of real estate development, Merle Malakoff with CitiBank, Tim McCann of Wells Fargo, Kevin Kassabaum with the Sonoma Charter School and Scott Johnson, the project manager.

Johnson also introduced Celestina Vailetti, whose family owned the property where the project is going up, and whose family is developing a commercial aspect in conjunction with the affordable housing.

Johnson pointed out that the senior units are going to be called Celestina Gardens in honor of Mrs. Vailetti.

“The Vailetti Family Trust has been a real treat to partner with,” Johnson said.

Currently, the site is being graded, and utilities, both wet and dry, will follow.

MidPen is also working with the county to coordinate with its Highway 12 sidewalks and streetlights project that is also under construction.

While construction has started, it’ll be some time next year before the nonprofit starts accepting any applications for the units.

Johnson said MidPen does have an interest list with about 60 people on it already who will receive formal applications when they become available.

Earlier, Johnson said he anticipates that MidPen will hold some community meetings probably in February with the outreach being launched in March. And applications will be accepted in April and May for the June lottery.

He expects the demand will be greater than the number of units being constructed, so there will be a lottery.