More than 1,500 Chicago Police Officers will work overtime or on adjusted schedules this weekend — 100 of them patrolling parks and the lakefront — hoping to prevent yet another July Fourth holiday in Chicago from turning into a bloodbath.

The Chicago Fire Department will deploy two additional rescue boats — the water equivalent of an advanced life support ambulance. One will be dedicated to the Chicago River and the city’s wildly popular downtown Riverwalk.

“The weather is now warm. But the lake is still cold. And the lake current is strong. People should be especially careful about diving into the water. Don’t be fooled by the warm weather. The lake is tough. And if you’re not a strong swimmer, you put yourself at risk,” Mayor Lori Lightfoot said.

Last year, 1,500 additional police officers hit the streets during the long holiday weekend. Even so, seven people were wounded from 1 a.m. to 11:30 p.m. on July 4 alone. Ten people were killed and 58 shot over an extended holiday weekend that ran from July 3 through July 9, Chicago police spokesman Anthony Guglielmi said.

The year before, the Independence Day weekend was a bloodbath, with 14 people killed and 87 wounded across Chicago.

In 2016, 66 people were shot, four fatally, over a Fourth of July weekend that was one day shorter than the year before. It was Chicago’s lowest death toll for a July Fourth weekend in nearly a decade.

Lightfoot and Chicago Police Supt. Eddie Johnson outlined this year’s security plans—including 40 additional officers assigned to the mass transit unit—during an afternoon news conference at Milton Lee Olive Park near Navy Pier.

It’s the CPD’s second big test under Lightfoot.

After “flooding the zone” over Memorial Day weekend by putting 1,200 more police officers on the streets and partnering with dozens of religious leaders — and touting more than 100 events and youth programs as alternative activities — Lightfoot came away with results tragically similar to previous years.

Seven were killed, same as last year. And 34 were wounded, two more than last year.

After the following weekend was even worse — with 10 dead and 52 wounded — Lightfoot started what she’s calling “Accountability Monday.”

That’s when she summons top brass to the mayor’s office to hash out the violence from the previous weekend.

On Wednesday, Johnson pointed to the “all hands-on-deck” decision by faith leaders in the Austin district to hold a “positive loitering” event to take back their streets and to the decision by local liquor store owners to close early on the Fourth of July.

“I cannot tell you how huge that is,” he said.

Johnson also acknowledged that CPD learned a thing or two from Memorial Day weekend that guided its planning for this weekend.

“One of the things that we just have to get better at is watching pop-up parties. They pop up all over the city. Those things can go from fifteen people to 200 in ten minutes,” he said.

“All around the city, there’s target areas that are always potentially flash points. So, we’ll be monitoring those areas real tightly. ... One of the things we’re gonna do a bit differently — we have a lot more undercover officers out here this time than we did” over Memorial Day weekend.

Lightfoot has acknowledged pushing Johnson and his team to have a “sense of urgency” about reducing summer violence. If they don’t, she says, they’re in the wrong line of work.

She wants them to use all the data analytics and other tools at their disposal to implement a winning crime-fighting strategy.

On Wednesday, with Johnson at her side, Lightfoot was asked to weigh in on the superintendent’s job performance. Was he doing well enough to keep his $260,044-a-year job?

“He’s doing good. I have a great deal of respect for the superintendent. ... You’re putting him on front street right here,” the mayor said with a smile.

“The thing I appreciate most about the superintendent is, he is very straightforward and candid about the strengths, about the progress. But he’s also very candid about the other opportunities. ... He’s not satisfied. I’m not satisfied — until we really, significantly, structurally change the violent crime in the city. He’s pushing himself and his leadership team.”

Lightfoot reiterated that one of those “opportunities” for improvement is the city’s dismal, but mildly improved homicide clearance rate.

“We’re not where we need to be. That’s not any secret,” she said.