Downstream

In the direction that a river or other watercourse normally flows.

Downstream is generally towards the lower reaches or mouth, while upstream is towards the source. The terms describe the watercourse’s normal geographical direction and are useful when identifying banks, traffic direction and the relative position of features.

In tidal rivers, the instantaneous current can run upstream on the flood tide even though the geographical downstream direction remains unchanged. Directions based on stream or tide should therefore be stated clearly when confusion is possible.