A long delayed, controversial plan to build an underground hydroelectric power plant near the Stone Arch Bridge in Minneapoliswill go before the public again Tuesday, with a significant change.

Several previous proposals have not gotten past the Minneapolis Park and Recreation Board, which has owned the land near the bridge where Crown Hydro LLC wants to install water intakes, below-ground turbines and tunnels to carry water away.

But the latest proposal would move the project 150 feet east, toward the Mississippi River itself, onto U.S. Army Corps of Engineers land.

That doesn't mean it's ready to be built, though. The Army Corps has indicated to the Federal Energy Regulatory Commission (FERC), which is the approving agency, that it has a range of concerns about the potential impact of the project on the lock and dam itself, and on boaters.

Nan Bischoff, FERC's coordinator for the U.S. Army Corps of Engineers' St. Paul District, noted that the power plant would have to shut down whenever the lock — which is sometimes filled or drained for a single canoe passing up or downstream — is letting a boat through. That would have to be part of any agreement approving the power plant, she said.

The Park Board continues to hold a lever, said Commissioner Liz Wielinski, in the form of a permanent easement through the land above where the project's outlet pipes would be located.

Crown Hydro submitted a preliminary application for a federal license in 1991 and received it in 1999. The FERC has told the company that its new proposal is so significantly different that it requires extensive overhaul.

The company's informational meeting Tuesday is part of that process. It's scheduled for 3:30 p.m. in Pohlad Hall at the Central Library, 300 Nicollet Mall.

Since Crown Hydro's first proposal, the riverfront area along downtown has been transformed from hung-over industrial land to a spectacular urban showcase of housing and entertainment as well as historic and recreational amenities. In the past, critics of the Crown Hydro proposal have said it could jeopardize the central riverfront area and that taking more water from the river could dry up the falls during hot summers.

Another hydroelectric generator was built in recent years just downstream at the Lower St. Anthony Lock and Dam. Wielinski noted that it does not use tunnels. There are currently about 30 hydropower generators on rivers in Minnesota, operated by utilities, cities, counties and private companies such as paper mills.