In Antarctica there is a plenty of freshwater reservoirs. Numerous rivers and streams exist due to snow and rainfall, or flow down from the Central Antarctic glacier. Many of them exist temporarily, only during the time of intensive snow thawing in spring and in summer. In lowlands and on plains extensive marshes exist. Also there is a lot of small glacial and thermokarst lakes in Antarctica. In winter the majority of freshwater reservoirs freezes down to bottom.