Earth Sciences 1022A/B Lecture Notes - Lecture 7: Point Bar, Distributary, Abrasive Blasting
19 Oct 2015
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Earth sciences 1022a lecture brief 6 nov 14. Streamflow: stream erodes, transports according to its velocity and channel shape gradient - slope of stream channel over its length; cross-sectional shape determines how much of the channel contacts water, slowing it down; rougher, more friction. High gradient streams water falls discharge - volume of water flowing through the stream"s cross- section per second; if discharge increases, stream usually gets wider, deeper, and faster downstream. Streams erode, transport, and deposit simultaneously over their lengths. Erosion - by abrasion using particles in transport as cutting tools to scour channel walls (like sandblasting) and in circular eddies to cut potholes into the channel floor. Deposition - occurs when stream can no longer carry its load and particles fall to the bed; can form a channel deposit of sand and gravel in bars, or floodplain deposit of mud beyond the channel.
