The next major venture for the Mall of America could be a massive indoor water park costing up to $200 million, and owned and financed by the city of Bloomington.

But before the first waves begin rolling, city officials say they want to make sure they're not putting taxpayers at risk.

"We want to minimize any risk and see to it that if we do move forward on this, we have really high probability insurance of success," Bloomington Mayor Gene Winstead said.

The mall's ownership group, Triple Five, made its pitch for the water park Tuesday to the city's Port Authority. City officials decided they will conduct their own feasibility study on the water park and ways to finance it, Winstead said.

The indoor water park would be just one part of a proposed eastern expansion of the mall, which also could include hotels and sports and performance spaces, according to a city memo.

The water park, estimated to cost between $150 million and $250 million, would be one of the largest in North America at 225,000 square feet. It would be open to the public, unlike the smaller one at Great Wolf Lodge that opened in December just a short walking distance from the mall.

Officials stressed Wednesday that the city is nowhere close to approving the water park. Port Authority Administrator Schane Rudlang said that the project "is in the extremely early stages," while Winstead called Tuesday's meeting a "very preliminary conversation."

"Sure, there's an interest, but there needs to be a lot more known," he said.

The city memo underscores the speculative nature of the project. It says that Triple Five had considered private financing but ultimately decided against it, because interest rates would likely create higher payments on the debt than the park's revenue could support.

Instead, Bloomington would borrow money at rates below what's available to private entities, according to the memo. Park revenue would go toward operating and management costs and pay back the project debt.

Triple Five would lease the land to the city and be hired by the city to operate it. If revenue doesn't cover costs, the city could levy unused sales taxes as a funding source. These taxes, according to the memo, cannot be used to pay for a privately owned park.

Triple Five estimates Bloomington could get a potential $1 million to $2 million in annual profits from the park. That money could also be used for mall improvements.

Council Member Patrick Martin, who represents the district where the mall is located, expressed concern about the proposed public-private partnership.

"The mall seems pretty confident about the financing options or models they have put together," he said. "It's a huge opportunity, but on the flip side of that I think we need to be realistic of potential hurdles or complicating factors."

Winstead said the water park would be an amenity in Bloomington's South Loop district and that it might even draw competition from other major parks, such as those found in the Wisconsin Dells.

"It's a fun and interesting project that I believe could be complementary to the mall," the mayor said.

In a statement, Mall of America officials said that they "continue to explore opportunities with the city of Bloomington to determine the best way to continue growing and developing Mall of America and its surrounding properties to remain a vital worldwide destination. We are in the preliminary stage of exploring possibilities together."

Triple Five has contemplated building a water park at the mall for years, according to city officials.

The memo uses the water park at Triple Five's West Edmonton Mall in Edmonton, Alberta, as a model for what they would like to see at the Mall of America. It points out that the West Edmonton park has slides, a large wave pool that hosts evening beach parties and surfing leagues.

West Edmonton's water park "brings in over 500,000 users annually and adds to the vibrancy" of the mall, the memo says.

American Dream Meadowlands, a Triple Five mall expected to open next year in East Rutherford, N.J., will have a water park paid for in part by a $1.2 billion bond subsidy.

The Mall of America water park could have a major "international brand" involved such as DreamWorks or Nickelodeon, which already is the brand for the mall's indoor amusement park, according to the memo.

The plot of land being eyed for the water park is now a surface parking lot owned by Triple Five, bordered by 24th and 28th avenues, Old Shakopee Road and E. 82nd Street, Rudlang said.

Port Authority members recommended that the city send several representatives to the West Edmonton water park as part of its analysis of Triple Five's proposal. Rudlang said that such a trip is on hold as the city continues to do its homework.