Highlights

Dams: How Industrial Age Technology is Costing Us

Thousands of dams—many more than a century old—block the natural flow of our rivers.

That’s well past the productive lifespan of many of these structures. Beginning in the 18th century, dams were built to power mills producing cloth, flour, and other goods. With the mills gone, the dams no longer play the role they once did.

But after all these years, the dams are still impacting the rivers. Millions of fish that migrate annually between the ocean and rivers can’t get to their native spawning grounds, contributing to drastic reductions in the populations. This affects the entire ecosystem since they are important prey for other animals, both on land and at sea.

Dams that “breach” (rupture) also pose a significant threat to human life and property.  To prevent this, dams require regular maintenance, which can be costly. A 2009 report by the Association of State Dam Safety Officials estimates that at least $16 billion is needed to rehabilitate the nation’s most critically degraded dams.

Northeastern states, in particular, are grappling with the need to address these issues. Massachusetts, for example, is “sitting on hundreds of potential time bombs waiting to go off,” according the Boston Society of Civil Engineers.  In 2006, one Connecticut storm resulted in 20 dam failures.

Removing dams can be a boon to fish and a relief to local residents. After heavy rains in 2005, officials recognized that the 180 year-old Whittenton Pond Dam in Massachusetts was in danger of failing—which would have sent a 6-foot wall of water through the nearby town of Taunton. Residents were evacuated and National Guard troops stationed in the town. 

NOAA is providing funding and technical guidance to remove the Whittenton Pond Dam as well as two other nearby dams that pose a threat to residents and block fish passage. This project will help to restore access to prime habitat for important fish species.

The NOAA Restoration Center has conducted hundreds of other dam removals in the last 15 years, opening thousands of stream miles for fish to access upstream habitat.

Posted July 10, 2012