Dams are key to successful ponds

Thursday, April 7, 2016

The key to a good pond is keeping aquatic growth controlled, a healthy population of fish and a high quality of water. Are we forgetting something?

“We tend to focus on the water and the fishing but pond dams need our attention too,” said Marley Beem, Oklahoma State University Cooperative Extension aquaculture specialist. “Dams fail because people either don’t understand how they work or they just forget about them.”

A dam failure is at best expensive and at worst, disastrous, when roads, homes and other structures are in the path of the flood. To avoid these costly events, Beem offers a reminder of the three main enemies of pond dams that require attention. The first being burrowing animals, such as muskrats, beaver or pocket gophers.

“A gopher burrow may look minor but you need to take steps to eliminate the pest and properly fill the burrow as soon as it’s noticed,” said Beem. “Even a small burrow is enough to get water flowing through the dam and it’s all downhill from there.”

The burrows can interconnect or be dug very close to each other, greatly weakening the structure. The second threat to a dam is one many people have a misconception about. Oftentimes, trees are thought to strengthen a dam, but the roots can become a serious threat.

“Tree roots loosen the compacted soil of the dam and provide pathways along which water can begin to move through the dam,” said Beem. “When a large tree dies or blows over, the roots decay leaving a network of small tunnels that often lead to dam failure.”

The final of the three dam killers is erosion of the slopes, top or auxillary spillway. These areas should be refilled with compacted soil and revegetated. Caution should be used in dam reconstruction.

“Seek engineering help whenever in doubt about the safety of a dam,” Beem said. “An earthen dam can look massive and solid but there are millions of pounds of water pushing against it looking for any weakness.”

Beem recommends walking the faces of your dam at least once a year to be able to catch problems before it is too late. For more information on keeping a pond in good shape condition, visit osufacts.okstate.edu and search for Fact Sheet NREM-9212.

“If all of these steps are followed, you will be doing yourself a great favor by protecting the useful life of your dam and pond,” he said.