GEOG 141 Lecture Notes - Lecture 17: Turbulence, Savings Account, Headward Erosion
15 Mar 2018
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Document Summary
As we move down a drainage basin, the watershed increases. Lag time means top of basin feels impact from rain faster than bottom. Streamlength stream of a river is adjusted to geology in a river: sediment and amount of water. Dynamic equilibrium: at any given point, things are moving: over longer time, there is a balance. Stream develops a graded profile over time: grade gets smoother over time. Steep slope more erosion and flattens with time. Low slope more deposition steeped relative to downstream reaches. The level at which the river cannot erode: ocean is the base level for all rivers. Rivers can have multiple, local base levels: lakes, reservoirs. Tectonic activity can change local base: if sea level drops, it changes local base. Incision/entrenchment of river into its own floodplain. Reaches new equilibrium and creates a new floodplain: then it does it all along. Alluvial terraces of roughly the same elevation form as a result.
