LONGMONT — City employees on Tuesday morning started removing a beaver dam that stretched across the St. Vrain River just west of South Pratt Parkway and slowed water flow in the area.
Workers used a backhoe to push the dam’s twigs, branches and willows off to the northern edge of the ditch’s embankment. Jim Engel, water utilities supervisor for the city, said the materials will be removed by a hydraulic excavator today and taken to a compost heap.
The dam will be removed because it slowed water flow and posed a flood risk, Engel said.
“It held up the water approximately 3 feet higher behind the dam,” he said.
Tuesday was the first time employees had to remove a dam in that stretch of the St. Vrain River, Engel said. It’s the second time the city has had to remove a beaver dam in the past five years, he added. In 2007, a dam at Oligarchy Ditch was removed.
David Hollingsworth, senior civil engineer for the city’s public works and water utilities department, said water that backs up behind a beaver dam can cause flooding and property damage.
“It’s more of a preventative measure, because we’ve got, in general, about an average snowpack up in the mountains,” Hollingsworth said. “What we have to do is be prepared, because when the snowpack melts, then it’s too late to do anything.”
Not all dams are removed
The city removes dams only if they block more than 20 percent of the water flow, which was the case with this dam, Hollingsworth said.
“If (dams) aren’t causing us any problems, we don’t do anything,” he said.
An alternative would be to install a pipe that runs through the dam to allow water to flow, Hollingsworth said. The beaver dam in this case was too large for that, he said, but the city may use the technique in the future.
Beavers allowed to stay
Dan Wolford, manager of Parks, Open Space and Forestry for Longmont, said the city has no plans to trap or relocate the beavers but will monitor the situation to see whether further measures are necessary.
“These little guys are pretty tenacious, so if you’re not persistent, they’ll be right back building them again,” he said.
Wolford said the dam removal did not disrupt the beavers’ lodge, a separate shelter with an underwater entrance, which is on an embankment about 50 feet west of where the dam was.
“Beaver management, like any other wildlife management, can be a challenge, and we try to work with the understanding that we’re trying to mutually cohabit with the wildlife,” he said.
City employees had to use a front-end loader to get the backhoe out of the ditch after moving the dam. The backhoe was stuck on the muddy embankment for a little less than two hours while workers tried to pull it out.
“It was classic,” said Roger Serrett, who works across the street. “Man moves dam. Man gets stuck when he goes to get out.”
