PROVO, Utah (AP) — A group determined to tackle pollution at Utah Lake has proposed building an island city to help stymie toxic algae blooms that plague the water.

The group Arches Utah Lake said it envisions an island city that could house up to 500,000 people, KSL-TV reported .

The group's project manager, Todd Parker, said the project's $6.4 billion price tag would be covered by private funding.

The group said it wants to dredge the lake and use its own sand to build the city, but would first need approval from Utah lawmakers.

The group would rehabilitate the lake before building 10 to 15 years later, Parker said.

The project would include 76 miles (122 kilometers) of restored shoreline, plus 190 miles (306 kilometers) of new shoreline and nine marinas, he said.

"I hope that there's excitement about participating in the restoration of the lake," Parker said. "That's what it's going to take."

The proposed islands would mirror Utah's iconic Delicate Arch in Arches National Park to offer a place for floating ice to pile up without damaging the shore and surrounding area, Parker said.

The plan could also help guard against potentially toxic algal blooms and E. coli and called for removing invasive grasses and nonnative carp, he said.

The proposal came almost a year after lawmakers approved a symbolic resolution to encourage aggressive treatment for Utah's largest freshwater lake.

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Information from: KSL-TV, http://www.ksl.com/