It is also an important winter roosting place for many birds, especially geese. The construction of the Nove Mlyny reservoirs on the Dyje River (1976-1989), intended to provide flood retention and a possibility to enhance low flow during droughts, changed the character of the river below the reservoir, and, besides other changes, reduced spring floods of the neighbouring flood-plain. The most negative impact of river regulation works is nowadays the dredging of the riverbed, causing disconnection of the river-floodplain system, decrease of the water table, and potentially threatening groundwater sources.