What factors can act as Local (Temporary) Base Levels?

Local (Temporary) Base Levels are defined by features that can temporarily halt or slow the process of erosion by a stream or river, thus influencing the local landscape and sediment deposition patterns.

Lakes, resistant rock layers, and tributary rivers serve as excellent examples of temporary base levels. When a river encounters a lake, the water's velocity decreases significantly, allowing sediments to deposit and altering the downstream river's dynamics. Similarly, when a river flows over a resistant rock layer, it can create a waterfall or a rapid where the elevation change causes the water to drop, creating a local base level. Tributary rivers can also create temporary base levels as they flow into a larger river; the junction can cause changes in water flow and sediment deposition due to differences in water saturation and velocity.

Understanding these features reveals why they are categorized as local temporary base levels, as they can influence the erosional and depositional processes occurring within a river's watershed intermittently, as opposed to more permanent features like the sea level, which represents a global and stable base level.