Flow device

Flow devices are relatively cost-effective, low-maintenance solutions that regulate the water level of beaver dams and keep culverts open.

[4] The most common beaver-related flooding issues that people encounter are caused by blocked road culverts or freestanding beaver dams.

The beneficial effects of beavers on stream flow, riparian habitat, salmon and trout, and wetland creation can be sustained with application of these inexpensive technologies, which require little maintenance.

This caused widespread environmental damage including the drying up of many streams and rivers formerly sustained by the high water tables associated with beaver dams.

This led to the return of numerous birds, steelhead trout (Oncorhynchus mykiss), river otter (Lontra canadensis) in 2008, and mink (Neogale vison) in 2009.

[9][10] In 1952, the concept of installing perforated pipes in dams was introduced to control water levels at the Northeastern Wildlife Conference as a solution for problem beaver ponds.

[12] In 1978, the New York State Department of Environmental Conservation began designing and testing various culvert protection devices, of which the T-culvert guard was the most effective and cost-beneficial.

[17] A 2006 study by the Virginia Department of Transportation found that for every $1 spent on flow-device installation relative to historical preventive maintenance, road repairs, and beaver population control activities, $8 was saved, for a return on investment of nearly 8:1.

A beaver swimming along the outside of the fence enclosure is unable to hear or feel the flow of water into the pipe and cannot reach it to block it.

The Beaver Deceiver (a trapezoidal shaped culvert fence) was invented by Skip Lisle in the 1990s while working for the Penobscot Indian Nation in Maine.