BRAIDED CHANNELS

By the end of this presentation you should: 1.Know where braided channels are found. 2.What is a braided channel. 3.How braided channels are formed. 4.Why braiding occurs. 5.Look at diagrams and photographs that explain the braiding process.

IntroductionA channel that consists of a network of

smaller channels separated by small and often temporary islands called “braid bars” or “eyots”.

Deposition process is regularly occurring in braided river channels.

Source: Oxfordictionary.com

A type of stream made up of many small interconnecting channels, separated by small islands of deposited material, known as eyots.

EYOTS

Braided channels occurs in rivers with high slope when, threshold level of sediment load or slope is reached, any slope over this threshold creates a braided stream. This occurs due to rapid evaporation and infiltration after

period of heavy rainfall, it can lead to deposition of sediment load.

Braiding is caused by fluctuations in discharge levels, low river velocity and also by the stream or river losing.

Capacity- optimum load which can be carried.Competence- the maximum size or weight of the load which can be carried. Braided streams occur in areas where the transported load contains a high amount of coarse material such as sands and stones

Source: Wikipedia

Why Braided Channels occur?

How are braided channels formed?

1 )When the rain is heavy the streams start moving in a higher velocity.

2) The high velocity carries large amounts of sand and small stones.

3)The water flow slows down in sections passing through wide valleys with little downward slope allowing sediment to settle on the river bed.

4) The sediment starts to block the stream of water, causing lower velocity.

5) Until enough sediment settles on the bed forming “sandbanks” or “shoals” that block the stream.

6) The steam overflows it’s banks forming new channels.

7) The stream is split into many streams causing the braided channel shape.

8) The streams meet up again at a certain point only to split apart again.

Source: Freeonlinedictionary.com

How does braided channels look like?

It is consisted of small islands or eyots of deposited material within the channel.

It is a network of small intertwining channels coverage and diverged around the eyots.

Sources: Braidedchannels.com

(Braided river at junction of Gakona and Copper River, Alaska)

Examples of braided channels:

-The Rakaia river in Canterbury , New Zealand.

- Naren river in Poland and Belarus.

- Tagliaments in Northeaster Italy.

- Platte river in central and western Nebraska United States.

- The yellow river in china.

The Rakaia river in Canterbury New Zealand