Why does a streams base level affect how it down cuts it's channel?

A stream's base level is the lowest point to which it can erode its channel, typically the level of a lake, river, or ocean. When the base level drops, a stream can cut down more deeply into its channel, increasing its gradient and potentially leading to features like waterfalls or canyons. Conversely, if the base level rises, the stream may have less energy to erode and can begin to deposit sediment, leading to a more meandering channel. Thus, the base level plays a crucial role in determining the stream's erosional power and channel morphology.