GEOG M107 Lecture Notes - Lecture 3: Gully, Surface Runoff, Stream Bed
Document Summary
Aim of lecture: this lecture outlines difficulty in defining and understanding geologic rates of erosion. Erosion varies remarkably in space and time. Variation in climates across space and time. Depends on climate, vegetation, slope, and material. Raindrops detach particles on surface; there becomes a surface flow and it transports loosen sediment. Overland flow: surface runoff precipitation intensity exceeds soil infiltration. Water concentrates into streamlets, moves downhill; energy can erode tiny channels. Rills = smaller, can be parallel to each other and crop rows. Headwater; channels that don"t flow often; larger than rills; amphitheater shape. Actively erode w/o vegetation, inactive erosion when vegetated. Occurs because of seepage and piping, eroding material internally before collapsing. Stream erosion: as stream meanders, a lot of energy on the bends cut the bank and then a great deal of erosion and sediment deposit on inside of bend (less energy here) Floodplain erosion: can be scoured during floods; new channels can be formed.
