The base level of a river is the lowest elevation to which it may erode.

Question

Quizplus · Accepted Answer

The base level of a river is the level below which erosion cannot occur. This may be due to the presence of an impermeable layer of rock or sediment, or to the fact that the river is flowing into a larger body of water such as the ocean. At the base level, the river has reached its lowest elevation and can no longer erode its channel any further. Any additional energy that the river may have would be used to transport sediment downstream rather than eroding the channel.

The Base Level of a River Is the Lowest Elevation