The club calls the wetland "a natural resource and community asset," but also says that it‚s also one of the few remaining undeveloped parcels in Chanhassen, a town to the southwest of Minneapolis. Leaving it in a natural state has been a priority of Chanhassen's citizens and public officials, as well as the state, according to Sierra Club officials.

The Sierra Club recently unveiled the "Citizen's Guide To Endangered Green Space" this week, an 88-page guide that highlights special open space and natural areas across the Twin Cities that are in danger of being lost to urban sprawl and development. Other "endangered" green spaces in the metropolitan area it identifies are Springbrook Nature Center and Rum River Nature Area in Anoka County; the Big Woods in Wayzata; and River's Edge in St. Paul Park.

"Seminary Fen is one battle we thought we had won," says Sharell Benson, a Sierra Club volunteer who led the Endangered Green Space project. "But with development pressures in the Twin Cities and rising land prices it's been tough to save open space."