Delta

Where can you find delta?

Mouth of river

What is a delta? A flat depositional plain formed at

the river mouth

Types of delta

Arcuate delta Triangular in shape E.g. river Nile, Egypt, Africa.

The Nile Delta

Satellite Image

Bird’s foot delta Look like a bird’s foot E.g. river Mississippi, U.S.A, North

America.

Mississippi Delta

Satellite image

Estuarine delta No particular shape E.g. river Amazon, Brazil, South

America.

Estaurine delta

Satellite image of

Amazon river mouth

Examples from China

A

B

C

AHuang He Satellite imageArcuate d

elta

Satellite image

Chang Jiang delta p. 48

B

Estaurine delta

Shanghai

C. Zhu Jiang Delta

Estaurine delta

Satellite image

Discussion What are the uses of delta to man?

Explain your answer. Quote examples.

What are the favourable conditions for the formation of delta? (Think in terms of the river characteristics and the coastal environment……)

The uses of delta …..

And many more ….

Conditions favouring the formation of delta

Characteristics of the river

River carries a large load There are few or no lakes along the

river

Characteristics of the coastal environment

Sheltered bay Weak tides and waves Removal of sediment is slower than

deposition Gentle offshore slope Shallow sea Presence of vegetation

Formation of delta When a river bring down a large

amount of sediment River reaches the sea, it slows down Particles group into larger and

heavier particles (flocculation process)

When sediment is deposited faster than it can be removed, delta is formed

Exercises Complete the worksheet Homework – Nam Chung River,

p.55-56