Businesses are scrambling to change their plans for the Fourth of July after learning that Macy’s has changed the layout for its barges on the East River this year, depriving some of the city’s favorite fireworks viewing spots.

Bars and restaurants in lower Manhattan neighborhoods, like Battery Park and the South Street Seaport, and in Brooklyn Heights will be left out of the colorful festivities, as Macy’s this year will center all five of its barges in the East River between 24th and 41st streets. And it’s wreaked havoc on businesses that were counting on the extra traffic or have had to cancel events and refund customers who’ve already bought tickets, they said.

“Honestly, we were a little bit taken aback, like, ‘Wait, this is not happening,’ ” said Ilinca Munteanu, general manager of the Watermark Bar, located in the South Street Seaport.

The change in barge locations came as a last-minute surprise to the bar, which had already started selling tickets for its Freedom Fest. In the past few years, tickets have gone for at least $149, including a barbecue buffet, drink specials and a view of the fireworks.

The bar had to refund tickets and apologize to its patrons after realizing their main show had sailed ship, Munteanu said. She’s now scrambling for an alternative event for the holiday — Independence Day is one of the bar’s most profitable events.

“We’ve had so many calls, and people were a little bit upset that their favorite fireworks viewing spot wasn’t going to work,” she said. “But, it is what it is, and we’ll adapt to it.”

Industry Kitchen, another Seaport bar boasting unobstructed views of the river, also had to cancel its Fourth of July bash due to the lack of pyrotechnics. Last year, the bar charged a minimum of $119 per person for their July Fourth open bar. A spokeswoman for the eatery confirmed the event’s cancellation but declined to comment further.

A spokesman for Macy’s said several factors contribute to how the company chooses the locations for its barges each year, “including show design, size/scale of the pyrotechnics used, safety requirements, accessible public viewing locations and available city resources.” This will be the largest display in nearly two decades, according to Macy’s.

On the other side of the river, Brooklyn Bridge Park, another prime viewing spot that runs about a mile through Brooklyn Heights, will be left in the dark. Some neighborhood businesses boomed on the holiday when the fireworks show moved to the East River in 2014, after five years on the Hudson, but owners don’t expect to see that this year.

“It will be a normal Tuesday night at best,” said Jason Furlani, 47, general manager of the Roebling Inn bar on Atlantic Avenue. “I think we’ll stay open, but we don’t expect the same volume.”

The Brooklyn Bridge Park Conservancy is already warning visitors that they shouldn’t expect to see the show from its shores this holiday, posting a notice on its website that the fireworks won’t be visible.

But Henry’s End bar and restaurant manager Mark Lahm, 58, said people will likely come anyway. When the show was on the west side, people still came to watch the light from the explosions reflecting off the clouds, he said.

“People come because of the vantage point, because they think they can see it,” he said. “They still have a good time.”

Lahm still expects a lull in business: The bar is 50 to 70 percent more crowded than normal when the fireworks are visible from Brooklyn Heights, and that number should drop to only 30 to 50 percent, he said.

Furlani is disappointed, but said he’s accepted that there’s not much he can do about the loss of traffic.

“Sure, it would be great to have that business, but at the same time things like that are completely out of our control. You just kind of have to roll with it,” he said. “But hopefully we have a nice crowd and people enjoy the Fourth.”

Scott Stamford, owner of Brooklyn’s Michelin-star waterfront River Café, said the restaurant is not doing anything special for the Fourth this year. Last year, the restaurant, which sits right under the Brooklyn Bridge, served a special July Fourth prix fixe dinner, but ended up having to cancel its 8 p.m. dinner service due street closures, Stamford said.

“The problem is, when the fireworks are visible, the police pretty much seal off the streets after 7 p.m. So we can only do one seating,” he said. “We’re happy when they’re here, and we understand when they’re not.”