Let It Crumble: When No Infrastructure Is Best

It took a "whop on the side of the head called Katrina," Galloway said, for leaders to come to grips with the long-term problems created by many old structures.

By that time the Corps -- better known for its concrete rivers and dams -- was already looking for more environmentally friendly ways to do its job, Galloway said.

"If you look back over the last decade, there has been a shift towards more ecological restoration," Galloway told Discovery News. "Some people have called it the 'greening' of the Corps."

Now it is becoming more common to find not only the Corps, but local agencies, too, forming partnerships to deal with defunct infrastructure, Galloway said. He cites, for example, cases in New England where rivers are blocked by century-old mill dams or aged, inefficient hydroelectric dams.

Energy producers and environmentalists have come together in some cases to remove a dam on one river to restore salmon habitat, while at the same time replacing or upgrading a defunct hydroelectric plant on another.

"So you see new partnerships," said Galloway.

Out With the Old

There are, however, less clear-cut cases.

"Decommissioning aging infrastructure offers some intriguing and potentially cost-effective environmental restoration opportunities," said biologist Margaret Palmer of the University of Maryland at College Park. "However, depending on the type of infrastructure and its location, it is not without controversy -- even among scientists."

Removing unused or under-used roads, breeching certain levees and converting old military bases to wildlife refuges are "no-brainers," Palmer said. Science shows clear benefits for wildlife and human safety by removing these structures, she said.

"We have less data on dam removal but certainly a number of examples of great benefits," she said. A more controversial matter is whether it's worthwhile to remove old oil platforms from the sea -- which have sometimes been used as artificial reefs.

"Fishery benefits of disposing of defunct oil platforms are not something that has been supported by strong science," Palmer said. There is no clear evidence that fish are actually reproducing more at the platforms.

"Perhaps this paper will help stimulate some interesting work to evaluate this," she said.

Related Links:

Larry O'Hanlon's blog: Earth Matters

National Infrastructure Improvement Act

National Infrastructure Protection Plan