2.4 What happens to all the sand, shingle and clay

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• Leerjaar 2

2.4 What happens to all the sand, shingle and clay?

River from the source to the mouth

Higher reaches

Middle reaches

Lower reaches

Delta

Sediment

	Higher reaches	Middle reaches	Lower reaches
Relief	A lot	Transition from high to low	Plain, little relief
Flow rate	High	Average	Slow
Process	Erosion	Erosion and Sedimentation	Sedimentation
Sediment	Coarse material	Coarse sand and gravel	Fine sand and clay

1. The upper reaches: high in the mountains, where the river originates. Due to the large difference in height, the river flows quickly and the erosive force is great.

 

2. The middle course: the middle part where the river runs through a valley where it has cut into itself.

3. The lower reaches: close to the mouth where the river flows through a river plain. The current speed is low and this increases sedimentation.

River Valley

Glacier Valley

The bigger picture

A

Upper reaches

B

Middle reaches

C

Lower reaches

Delta

How do you recognize a delta?

-A piece of land that extends into the sea.

-The river branches into several channels.

-It has a shape of a triangle.

Rivers flow into the sea in different ways:

Delta: coast that is being formed when more material is deposited at the mouth of a river than is discharged into the sea by the current.

Estuary: wide river estuary, often in the shape of a funnel (trechter), which has been scoured by ebb and flow currents 

(take a look in your wb).

Some of the sand that ends up in the sea ultimately forms the dunes.

Meander river erosion/sedimentation

Inside bend, slow current and sedimentation

Outside bend, fast current and erosion

Write a brief summary of the heading Sedimentary Rock