How Can You Determine The Direction Of A River's Flow?

Observing Natural Features

When navigating near a river, observe the direction of its tributaries, the alignment of its banks, and the type of vegetation growing on each side. A river’s tributaries typically flow in the same direction as the main river, and the vegetation on the upstream side of a bend is usually thicker and more dense due to the slowed water velocity. For example, if a tributary is flowing into the river from the north, the river is likely flowing south.

Using a Compass

A compass is an essential tool for determining the direction of a river’s flow. By taking a bearing on a landmark or a distinctive feature upstream, you can use the compass to determine the direction of the river’s flow. Additionally, if you know the magnetic declination for your location, you can adjust the compass reading to account for this variation. For instance, if you’re in an area with a +10° magnetic declination, you would add 10° to your compass reading to get the true direction.

Identifying Water Level Changes

Changes in water level can also indicate the direction of a river’s flow. Look for areas where the water level is higher on one side of the river than the other. This is typically an indication that the river is flowing from the higher side to the lower side. For example, if the water level is higher on the east side of the river, the river is likely flowing west. Additionally, observe the direction of any rapids or waterfalls, as these features typically indicate the direction of the river’s flow.