The Site is a typical well-developed estuary where three small rivers converge, forming a system of sheltered brackish lagoons and extensive intertidal mudflats with wet meadows. Salinity varies from freshwater to brackish and finally salt water. A total of 250 different bird species have been recorded. The high biological production, extensive beds of aquatic vegetation, and invertebrate populations support large numbers of migrating birds and numerous wintering swans, geese, ducks and waders. Particularly high numbers of birds gather here during the autumn migration, with regular counts of several hundred whooper swans and various ducks and waders. Several waterbird species as well as the otter Lutra lutra breed at the Site. Human activities include agriculture, recreation and research. Birdwatching takes place throughout the year and there is a viewing facility. The further expansion of agricultural activities, abandonment of traditional management practices and infrastructural development could pose threats to the Site.