Nature census takers, while surveying the condition of freshwater habitats, have recorded signs of beaver activity – felled trees, beaver burrows, lodges and dams – in 60% of the river sections surveyed.

Beaver dams, which have the most negative impact on river flow, are found in a quarter of Latvia's rivers, with the highest number of dams recorded on the Vilce in the Zemgale region.

Various types of obstructions, including large piles of fallen trees and beaver dams, alter the hydrological regime of a river, promote overgrowth, impede water flow and hinder the river's primary function – the transport of substances and energy. This is a significant problem in Latvia's small and medium-sized rivers, as their currents lack the strength to allow the rivers to cleanse themselves.