IOWA CITY – Developers of a $180 million indoor rain forest said Wednesday they have narrowed their list of possible locations to four cities.

Board members of The Environmental Project announced that Pella, Grinnell, Tiffin and Riverside made the final cut of cities vying to host the ambitious tourist attraction.

Initial plans were to build the rain forest in Coralville, but developers began looking elsewhere when negotiations with the city on a land deal broke down last year.

“We were thrilled with the interest shown by these communities and the quality of their proposals – it speaks directly to the potential that many Iowans see in this national project,” said former Governor Robert D. Ray, chairman of The Environmental Project board of directors.

The project is the idea of Des Moines businessman Ted Townsend, whose group hopes to combine a 4 1/2-acre indoor rain forest with a one-million gallon aquarium, restored prairie project and educational classrooms.

Project officials have estimated it would attract up to 1.5 million visitors each year from around the world and inject $187 million annually into the state economy.

Each of the proposals offered a unique flavor, officials said.

For example, the proposal from Pella incorporated the rain forest into a bigger development project proposed on the shore of Lake Red Rock. DLM Land Developers, of Des Moines, is proposing to build condominiums, an indoor water park and retail and hotel space next to a golf course.

“We are gratified to have been chosen,” said Eric Woolson, spokesman for DML Land Developers. “Now the real work begins to put together the financial numbers The Environmental Project is looking for and begin making the case that Pella is the best location for it.”

Riverside’s proposal would make the rain forest neighbors with a casino now under construction.

In Tiffin, the rain forest would accompany a 200-acre commercial and residential development close to Interstate 80.

David Oman, executive director of The Environmental Project, said each of the communities would have to contribute up to $25 million in financing toward the project.

Oman said the board hopes to make its final selection in May, begin construction later this year and open doors in 2009.

Besides the breakdown in talks with Coralville, the project has been stalled by a lack of private contributions. Organizers have raised about $90 million.