A $1.8 million upgrade at the Erie Basin Marina will see a second floor added to the Hatch Restaurant and construction of a free-standing clam bar and ice cream gazebo, Mayor Byron W. Brown announced Sunday during a noon groundbreaking ceremony.

“The Hatch is bursting at the seams,” said Brown. “Believe it or not, the Hatch Restaurant draws a million visitors a year, even more than Canalside, where we expect 750,000 this season. It’s important to note that the Hatch is the most popular destination on Buffalo’s waterfront.”

The Hatch Restaurant, at 329 Erie St., has been a summer destination for residents, boaters and visitors since 1974. It opened Wednesday for the 2013 season with hours from 7 a.m. to 10 p.m. daily.

The cost of the new ice cream gazebo and clam shack, which will have adult beverage service, is estimated at $640,000. Funding for the project, Brown said, is available in the city’s capital improvement budget.

“This is a go project,” said Brown. “Construction has already started on the clam bar, and we expect it to be completed in July.”

A temporary ice cream shop has been built for use until the new gazebo is complete, according to Michael Wolasz, operations director of the Hatch.

“Ice cream is one of our hot sellers,” said Wolasz, “and we didn’t want to lose that service for our customers.”

Nearby, sisters Annelise and Elizabeth Coe sat in a patio of the Hatch eating ice cream with their father, Ethan, of Lancaster, and his friend Debbie Oberg.

Coe, who works as a financial consultant downtown, said he often visits the Hatch for lunch. In recalling the long noontime food lines at the Hatch, Coe said he is looking forward to this summer’s expanded service.

Work on the second-floor addition to the Hatch will begin this fall after the restaurant closes for the season. It will include a wrap-around walkway and will greatly improve sightlines for visitors, said Public Works Commissioner Steven Stepniak. That project should be complete by spring 2014.

“When the patio was designed a couple years back, it was designed to carry the weight of a second floor,” said Donald J. Poleto, operations engineer for the City of Buffalo. “Because of its proximity to the lake, any building down here feels the full brunt of any winter storm.”

The patio at the Hatch is 70 feet by 90 feet, said Wolasz, who took over the restaurant from Statler City developer Mark Croce in 2001.

In 2012, the Brown administration spent $930,000 on improvements at the Erie Basin Marina. Those improvements included a $400,000 boardwalk, handicap-accessible restrooms and security gates for boaters. The city also oversaw beach construction, sidewalk paving and installation of security lighting and picnic tables.

Since 2006, the city has invested more than $2.9 million at the marina.