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

KSL-TV reports that the group Arches Utah Lake envisions an island city that could house up to 500,000 people.

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

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

Parker says the group would rehabilitate the lake before building 10 to 15 years later.

He says the project would include 76 miles (122 kilometers) of restored shoreline, plus 190 miles (306 kilometers) of new shoreline and nine marinas.