In order for these pipe systems to work, they must be designed so that a beaver cannot detect the flow of water into the pipe. The Flexible Pond Leveler works by surrounding the submerged intake of the pipe with a large cylinder of fencing to prevent the beavers from getting close enough to the intake to detect water movement. As a result, the beavers do not try to clog the pipe, and maintenance is rarely needed. Usually a pond depth of at least three feet is required for the Flexible Pond Leveler to function properly.
The height of the pipe in the dam determines the pond level (see diagram). Water will flow through the pipe unless the pond level drops below the peak of the pipe. The pipe is set in the dam at the desired pond level, and can be adjusted up or down if desired.
Flexible Pond Leveler TM Diagram
Flexible Pond Leveler pipes do not need to be sized like culverts to handle catastrophic storm events because heavy storm runoff will simply flow over the top of the dam. Following the storm the pipe will return the pond to the normal level. Some mild pond fluctuations are possible following very wet periods, but since the dam height is controlled by the pipe the pond size remains controlled at a safe level.
When installing a pipe system it is very important to lower a pond only enough to protect human interests. The more a pond is lowered the more likely it is beavers will build a new dam downstream to render the pipe ineffective. Lowering a beaver pond by up to one vertical foot is generally not a problem.
Whenever a pond must be lowered by more than a foot, a single round of trapping may be necessary prior to the flow device installation. When new beavers without the memory of the higher water level relocate to this area they are more likely to tolerate the smaller pond so repeat trapping will not be needed. Most Flexible Pond Leveler TM failures are due to new downstream damming in response to a dramatic lowering of the water level.