Attempt to manage after-effects of beaver impounding activities in drainage systems: one trial assay

Abstract

When there is a high population density of beavers, they readily occupy open drains. By impounding these drains, the animals also dam up the subsurface drainage systems that empty into them. This paper provides the results from a trial conducted in a beaver-obstructed stretch of the open drain, Žiedupis, and its environs in the Nevėžis River basin in Lithuania. Studies were carried out on the functioning of pond drains installed in beaver dams, the behaviour of beavers in reacting to the lowered water levels, the condition of the tile drain pipes operating under damming, and the hydrological conditions of the soils drained by these drains. The trial was conducted in soils with a light texture. The weather conditions were generally rather drier than average. It was found that pond drains were able to maintain water in ponds at the desirable levels that benefit the functioning of subsurface drainage systems. However, they did not prevent beavers from building new dams, and did not encourage the animals to abandon the beaver site. Possible reasons for beaver expansion into open drains, as well as ways to avoid or mitigate the harm from their damming of drainage systems, are also discussed in the paper.