BOATsmart! Base de connaissances du Canada 

An upstream direction means you are travelling against the current. In many places, the direction of the current is determined by consensus or by the tide. Although not always the case, often you’ll find that water flows from north to south–this means that if you’re going north, you will likely be heading upstream. To help you determine the direction of water flow, use the following tips:

• If you’re entering a channel from the sea, you are considered to be travelling ‘upstream’
• You can refer to a marine chart to identify the upstream direction of travel