What's the noun for river? Here's the word you're looking for.
river
A large and often winding stream which drains a land mass, carrying water down from higher areas to a lower point, ending at an ocean or in an inland sea.
“Although no longer standing, the brick riverside palace was a favourite of the Tudors and it became Elizabeth's most favourite out-of-town Residence when she was Queen.”
“It is preparing the construction of its own production plant in the riverport town Ruse on the banks of the Danube River.”
“In La Paragua, a small riverport where the dead men and their families lived, the walls are covered with angry graffiti calling for an end to the army's policing of the area.”
“There is concern over the future of five FPI draggers based in Riverport.”