Definitions for "Downcutting"
When a stream channel deepens over time.
The process in which water flowing through a channel cuts into the substrate and deepens the channel relative to its surroundings.
Downcutting, also called erosional downcutting or downward erosion is a geological process that deepens the channel of a stream or valley by removing material from the stream's bed or the valley's floor. How fast downcutting occurs depends on the stream's base level, which is the lowest point to which the stream can erode. Sea level is the ultimate base level, but many streams have a higher "temporary" base level because they empty into another body of water that is above sea level or encounter bedrock that resists erosion.