The vision for the new water park at the Mall of America features colorful swirling slides, a wave pool, a lazy river and a retractable roof.

Members of the Sustainability Commission in Bloomington see something else: high water and energy use that conflicts with the city’s goals to fight climate change.

The City Council approved the use of public financing for the $373 million Mystery Cove project, along with the project’s basic terms and conditions, in April. But that approval of the water park plan, which had already been scaled back, came despite the Bloomington Sustainability Commission’s apprehension.

The commission had sent a letter to city officials outlining members’ “significant concerns” with the park, including a reminder that the city declared a climate emergency in 2022 and adopted an Energy Action Plan that calls for a 75% reduction in greenhouse gas emissions by 2035.

“A water park is a major energy user and a major water user. We can’t get past that,” said Angie Begosh, chair of the commission. “We need to be doing everything we can to curb our energy use and our resource use.”

But Triple Five Group, the mall’s owners, say updated plans will already reduce electricity use due to a smaller footprint and retractable roof feature. The Canadian company can’t commit to additional sustainability certifications, officials said, because building standards for “green” water parks don’t yet exist.

Triple Five also can’t quantify how much energy the new plans will save because the project is just entering the engineering phase, said Kurt Hagen, senior vice president of development for Triple Five at the Mall of America.

Even so, Hagen said, “It is our goal that this become the most sustainable water park in the country.”

Plans for a water park date back to before the mall was even built, said Bloomington Mayor Tim Busse, noting that other Triple Five malls, including the West Edmonton Mall in Alberta, have water parks.

“There’s always been the goal for Triple Five and the Mall of America to diversify [offerings] so they don’t fall into the ‘retail only’ trap,” Busse said, adding that a 50/50 mix of retail and entertainment is ideal.

Despite several significant pushes over the years, the water park — slated for a parking lot near IKEA north of the mall — has never materialized.

The latest iteration is about 30% smaller than previous plans to reduce costs. It would include a 220,000-square-foot building with one wave pool instead of two, accommodate 3,000 people and incorporate 30 different rides and slides, said Holly Masek, Bloomington’s port authority administrator.

A retractable roof that opens to reduce heat and humidity inside, decreasing the need for air conditioning, is “part of the ‘wow’ factor that will make this project different,” Masek said.

Masek said she believes there’s enough demand for the park even with the Great Wolf Lodge water park and hotel nearby.

“I honestly think there is room in this market for both,” she said, citing the many water parks at Wisconsin Dells. “As these entertainment features start to grow … I think we will see a cluster effect.”

The project will use $160 million in tax-increment financing, some of which will dry up if it’s not used by December 2025.

“We really need to move this project forward at an accelerated pace or this funding will no longer be available,” she said.

The Sustainability Commission’s letter said the city should ensure that a project with that much public financing “aligns with the city’s values” as the time to address climate change dwindles.

The group, which has an advisory role, also wrote a second letter to city officials casting doubt on whether the retractable roof, to be manufactured by a Canadian company called OpenAire, would work as Triple Five officials have said, achieving 30% energy savings. Commissioners noted that the energy reduction estimate was from a case study of a small, 6,000-square-foot pool with a retractable roof in Massachusetts.

Begosh said the group doesn’t want the roof to be the only sustainable element.

The commission suggested broader goals, such as having the building achieve LEED Silver certification — or another similar standard — plus the addition of $5 million in features like natural landscaping, sustainable materials and energy-efficient equipment. If those standards can’t be achieved, the commission said the developer should spend $7.5 million on landscaping and other other efficient features.

Hagen of Triple Five said he’s met with the council that certifies LEED projects. They want to create a new LEED category for water parks, he said, adding that Mystery Cove could then be the first certified water park in the U.S.

Other water parks in the U.S. already feature retractable roofs, Hagen said, and he’s “very confident” that the roof will reduce energy consumption.

Busse said that while he appreciated the commission’s input, he didn’t think it was fair for it to suggest specific criteria for making the project “green” when the city doesn’t have any official guidelines. Establishing broad criteria for buildings across the city is “probably work we need to do as we move forward,” he said.