"CONCORD, Mass. -- The dozens of public works officials, municipal engineers, conservation agents and others who crowded into a meeting room here one recent morning needed help. Property in their towns was flooding, they said. Culverts were clogged. Septic tanks were being overwhelmed.

'We have a huge problem,' said David Pavlik, an engineer for the town of Lexington, where dams built by beavers have sent water flooding into the town's sanitary sewers. 'We trapped them,' he said. 'We breached their dam. Nothing works. We are looking for long-term solutions.'

Mary Hansen, a conservation agent from Maynard, said it starkly: 'There are beavers everywhere.'

Laura Hajduk, a biologist with the state's Division of Fisheries and Wildlife, had little to offer them. When beavers are trapped, others move in to replace them. And, she said, you can breach a beaver dam, but 'I guarantee you that within 24 hours if the beavers are still there it will be repaired. Beavers are the ultimate ecosystem engineers.'

That was not what Mr. Pavlik was hoping to hear."

Cornelia Dean reports for New York Times June 8, 2009. [2]