river landforms - braiding
TRANSCRIPT
Landform:Location:
River Braiding
Lower course – usually close to the delta/mouth (Can be found upstream)
Direction of water flow
Gravel bars
Older floodplain deposits
Abandoned channelsActive sand-
filled channel
Floodplain
Channel bars
Main characteristics1. Small islands or eyots of deposited material within the channel.2. A network of small intertwining channels converge and diverge
around the eyots.3. At times of high discharge, braided streams carry a large load of
coarse material.4. Braiding is a characteristic of streams with a variable discharge
Appearance:
Braided rivers are basically rivers that have multiple channels & islands of sediment in between those channels. They occur in rivers with high slopes and also in areas where the river channel banks are made up of easily erodible rock (carbonate rock) or areas of high sediment load where discharge rate varies (e.g. glacial melt water rivers)
Formation / Processes:
Braiding occurs when a high velocity rivers carry large amounts of sand or small stones downriver and where it slows down as it passes through wide valleys this allows the sediment to settle on the riverbed. Over time the levels of sediment will rise and cause the river to flow a decreasing velocity. Eventually the river will become blocked by the sediment build up, this causes it to overflow and form new channels.As the river finds a new way down towards its mouth it will repeat the process many times which causes the braided channel shape.
ExamplesRakaia RiverCanterburyNew Zealand
Son-Kul RiverTien Shan Mtns
Kyrgyzstan