Paul Schwiep, a Miami attorney who represents Waterkeeper, acknowledged EPA’s latitude was limited under a Clean Water Act primarily intended to prevent pollution. But he argues the agency also can invoke broader “public interest” authority.

Albert Slap, a Key Biscayne attorney also representing the group, said the county and EPA were ignoring their own initiatives encouraging climate “resilient” construction.

“They talk the talk,’’ he said, “but when they have to walk the walk and spend money on climate change, they deny it.’’

With the county already under orders from state regulators to phase out the practice of pumping partially treated waste off shore by 2027, they also argue that would sharply reduce the economic advantage of coastal plants. But Yoder said Miami-Dade intends to ask Florida lawmakers for leeway and has plans to convert Virginia Key to deep-well disposal underground if necessary.

Leonard Berry, director of FAU’s Center for Environmental Studies, said the plan lacked enough information to make an informed choice between renovation or building inland.

“We need that cost benefit analysis to know for sure,’’ he said. “That’s the issue.”

The scientists aren’t alone in their concerns. In a letter last week, Nathanial Reed, vice chairman of the Everglades Foundation and an influential former state and federal environmental official, urged the EPA not to rubber stamp a “defective plan.’’ Key Biscayne Mayor Frank Kaplan, in a letter last month to County Mayor Carlos Gimenez, asked for a “more thoughtful long-term engineering, environmental and economic evaluation” of plans to rehab Virginia Key.

“We’re not demanding they move it. We didn’t even ask that,’’ Kaplan said. “We just want answers.’’

Miami Herald Staff Writer Charles Rabin contributed to this story.

Interactive: Explore map that shows sea-level rise projections in Miami-Dade