The river flows into the Dnieper through the Kremenchuk Reservoir, with which it forms a large delta with numerous islands, on which rare kinds of birds live. An important tributary is the Uday, smaller ones being Orzhytsya, Sliporid, Romen and Tern.
The river's name evokes slow or muddy waters considering the words it is related to: Lithuanian/Latviansulà "birch sap", Old Prussiansulo "curdled milk", Norwegian dialectal saula "dirt", Sanskritsúrā "spiritous liquor", and Avestanhurā "intoxicating drink, kumis".[5] Another etymology of the hydronymSula is the Turkicsuly, 'filled with water, wet'.[6]