Transportation
TRACTION
SALTATION
Particles of rock are dissolved in the water
and carried along without being seen.
Large boulders and rocks are ‘rolled’ along
the bed of the river.
SUSPENSION
Smaller pebbles and stones are ‘bounced’
along the bed of the river.
SOLUTION
Smaller particles of silt and sand are held
within the water and transported along in the
flow of water.
Erosion
ABRASION
The sheer force of the water removed material
from the bed and banks of the river.
CORROSION
Material is rubbing against the bed and banks of
the river wearing them away.
ATTRITION
Some rock such as calcium carbonate dissolve in
the water if it is slightly acidic.
HYDRAULIC
ACTION
The load itself being carried, bang into each
other and break up and become smaller and
smaller.
River Processes
EROSION
The wearing away and removal
of rocks by the action of water,
wind or ice
TRANSPORTATION
The movement of sediment
along the river’s course
DEPOSITION
The putting down of material
by the river
Meanders & Ox Bow Lakes
LO: To explain how a river
meander forms and develops into
an oxbow lake.
All of you will be able to describe
the processes that form a meander
Most of you will be able to describe
how a meander becomes an oxbow
lake
Some of you will be able to explain
why meanders and oxbow lakes
form.
The Plenary
C-D Must be able to describe the process that
leads to the formation of meanders.
A*-B Must be able to explain the process that
leads to the formation of river meanders.
Geogingo
Choose five words from the following
Hydraulic
action
waterfall
store
transfer
evapotranspiration
Freeze thaw
transportation
abrasion
deposition
V shaped
valley
infiltration
attrition
Surface run off
River Tees Upper Course
River Tees Middle Course
We are going to look at a land
processes that takes place in
the middle stages of a river.
We are going to look at a
Meanders.
Water in a meander bend
Water in a meander does not all travel at the same
speed. The fastest and most powerful water
travels around the outside of the bend.
Think about being in the back or
a car when going round the corner…
Or being on a rollercoaster
and being thrown to one side
of the carriage.
Meanders
As the course of a river reaches its middle stages it flows
over flatter land. Lateral (sideways) erosion happens
because of fast moving water on the outside of meanders.
Meanders constantly change their shape and position.
Where is there more erosion? Why?
Where is there more deposition? Why?
B
A
Draw a river in your book. It should be about a 1/3
of a page high and as wide as your page.
Make sure it has bends it in like this one:
Using a different colour mark on your river the route of
the fastest water.
Where the red line hits the banks – it erodes material.
In the areas of the river the water is travelling slower, the
water has less energy and so deposits the eroded
material.
6. Add to your diagram where deposition and
erosion are taking place
Video
Deposition
= Lateral Erosion
= Deposition
Lateral Erosion
Deposition
Meander = a bend in a river
River cliff deposition
river beach
lateral erosion
undercutting
slowest current fastest current
Oxbow lakes
Meanders
3.
1.What is a meander?
2.What sort of land do they form
on? Flat or steep?
3.Which side of a meander erodes
the banks? Why?
4. Explain the formation of an
oxbow lake
new course
of the river
oxbow lake
Meander neck
becomes smaller
When the river floods it
breaks through the thin
meander neck and the river
takes the easier, straight
course.
This cuts off the meander
loop leaving an oxbow lake.
Over time, the oxbow lake
gets filled in and overgrown.
Explain the formation of an oxbow lake