LESSON OUTCOMES:

W hat: Understand the main processes that cause a river to meander

How: By stimulating a physical model to explain how erosion and deposition effect the shape of a rivers course.

Why: So I can create an annotated diagram of key features in the middle course of a river

CONNECT: HOW DID THE RIVER GET TO LOOK LIKE THIS

SHAPE? WRITE A THEORY TO EXPLAIN YOUR IDEA.

http://www.bbc.co.uk/northernireland/f

orteachers/water/river/ft_cl_water_

river_journey.shtml

• Watch the 2 video

clips about the

features found in the

middle course of

river.

• Come up with 3

ways that the middle

course is different to

the upper course.

ACTIVATE: HOW DOES THE RIVERS JOURNEY CHANGE AS

IT MOVES FROM THE UPPER TO MIDDLE COURSE?

ACTIVATE: WHAT IS A RIVER MEANDER AND OX

BOW LAKE?

Q. What is a Meander? A. A bend in a river

What is an Oxbow lake and how do they

form?

Meander neck becomes

smaller

new course of

the river

oxbow lake

When the river

floods it breaks

through the thin

meander neck and

the river takes the

easier, straight

course. This leaves

the meander loop

‘cut off’ as an oxbow

lake. Over time, the

oxbow lake will

become colonised

by vegetation.

Oxbow lakes

DEMONSTRATE: HOW IS DEPOSITION AND

EROSION RESPONSIBLE FOR THE SHAPE OF A

MEANDER? Task 1:

Create virtual meander in class room to show how the rivers energy

changes.

http://www.bbc.co.uk/schools/gcsebitesize/geography/riverswater/river_

landformsrev2.shtml

Task 2:

a. Draw diagram D pg.105 to demonstrate how a river meanders.

b. Annotate your diagram by adding the number code of key terms and

definitions into the appropriate places.

Task 3:

a. Complete the diagram on your worksheet to show how ox bow lakes

form.

b. Fill in the missing words to show that you can explain the processes

that cause an ox bow lake to form.

REFLECT: SELF ASSESS YOUR PROGRESS

TODAY!

1. As the outer banks of a meander continue to be eroded through processes such as

hydraulic action the neck of the meander becomes narrow and narrower.

2. Eventually due to the narrowing of the neck, the two outer bends meet and the river

cuts through the neck of the meander. The water now takes its shortest route rather

than flowing around the bend.

3. Deposition gradually seals off the old meander bend forming a new straighter river

channel.

4. Due to deposition the old meander bend is left isolated from the main channel as an

ox-bow lake.

5. Over time this feature may fill up with sediment and may gradually dry up (except for

periods of heavy rain). When the water dries up, the feature left behind is known as a

meander scar

I got …./10

Understanding of meanders …../5 Understanding of ox bow lakes …./5

Enjoyed learning …../5 Any other comments: ………

HOMEWORK: CAN YOU APPLY WHAT YOU HAVE LEARNT

TODAY TO LABEL AND ANNOTATE A PHOTOGRAPH OF

RIVER FEATURES?

This is a transferable skill required for the exam!

Label and annotate this photograph to show how these feature are formed.