TAMPA — In what a high-rise developer is calling “a big stamp of validation for downtown,” Publix Super Markets confirmed Tuesday it will open a grocery store in the Channel District.

Plans call for a 38,000-square-foot store, slightly smaller than a typical 45,000 square-foot Publix, in retail space alongside the Channel Club project at East Twiggs Street and North Meridian Avenue.

The Channel Club will be a 21-story high-rise with 323 rental apartments and a parking garage at 1115 E. Twiggs St. The Publix will be at street level with a parking garage on the roof. A building permit was filed with the city on Tuesday.

“Publix is excited about the opportunity to serve the Channel District community. We are diligently working with our developer, Mercury Advisors, the city and the mayor to make this project a reality,” Publix spokesman Brian West said in an email. “While there is still work to be done, including final contracts and the permitting process, we are confident that all parties want to see the successful completion of this project.”

Ken Stoltenberg, a principal at Mercury Advisors, and other developers have tried in vain for years to lure a grocer to downtown or Channelside.

“This is really the last big piece to put in place to make the Channel District a truly urban, walking neighborhood,” said Stoltenberg. “Now, you can live there, work there, and get all the services you need and not have to get into your car ... I think it’s a big stamp of validation for downtown.”

Publix has a store on the western edge of downtown at 243 Bayshore Boulevard, but had declined to add a second. Stoltenberg estimated he’d been turned down 16 times by various grocers he’s pitched.

But he had a staunch ally in Tampa Mayor Bob Buckhorn, who described himself as the “chief prodder, cheerleader and bureaucracy-mover” on the issue.

“I think Tampa’s becoming the city we always hoped we would be,” Buckhorn said. “The addition of a grocery store downtown just validates that.”

The Channel Club project was previously known as Martin at Meridian. It joins two other Mercury projects, the condominium towers Grand Central at Kennedy, directly across Madison Street, and a future high-end condo development, The DelVillar, planned for 858 Channelside Drive.

The 23-story SkyHouse Channelside apartment tower held its grand opening in the summer on 12th Street between East Washington and East Whiting streets, a couple blocks from the new Publix.

Meanwhile, residential structures are included in the massive redevelopment plans of Strategic Property Partners, the team of Tampa Bay Lightning owner Jeff Vinik and Bill Gates’ Cascade Investment, and Port Tampa Bay. Both are master-planning more than 40 acres each in the Channelside and downtown areas.

Developers have announced or speculated about as many as 16 high- or mid-rise residential complexes in the downtown vicinity, which could more than double the number of housing units to nearly 12,000.

That’s obviously a lot of inventory to fill. Stoltenberg said that would be an issue if there was normal residential construction since the housing crash of 2008, but there has been virtually none built downtown between 2008 and 2013.

“We’ve had a backlog where you’ve had no supply,” he said. “I think we’re just getting back to where we should have been.”

Publix declines to share proprietary metrics that indicate an area can support a new store. “We want our stores to be convenient for our customers,” West said. “This location would provide more convenience.”

The Bayshore store will remain open, he said.

Construction on Channel Club and the new Publix store is expected to begin in early 2016 with completion in 2017.