EARTHSC 2GG3 Lecture 2: Rivers and Flooding
14 Jan 2016
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Document Summary
The way in which streams pick up and deposit sediment determines pattern of channel, determines the way channel moves over time and the type of characteristic flooding for type of stream. Braided streams are less common and straight streams are rare. Bedrock streams occur in mountainous areas of solid rock. A thalweg is a deep and highest-velocity part of a stream. Streams preferentially erode outside of the meander bends. Sediment is deposited as a point bar along the inside of a bend. Braided streams do not meander, instead form broad, multi-channel paths. They are overloaded with sediment that is deposited in islands between small channels. They are promoted by dry climate with little vegetation protecting slopes from erosion. They are characterized by eroding banks, a steep gradient, and an abundant stream bedload. The highest hazard area is at the apex of the fan, where the flow concentrates.
