KEY WORDS and TERMS:
Erosion
Transport
Deposition
River basin
Tributary
Source
Mouth
Confluence
Watershed
Waterfall
Meander
Gorge
Levee
Flood plain
Flood Management
Drainage basin
Long profile
Oxbox lake
Upper, middle and lower course
The River System
Moving water has energy. The faster it moves the more
energy it has. Rivers have energy, and they can wear things
down, move things and carry them along as they flow. We
call this the work of the river. The faster a river flows, the
more energy it has and the more work it can do.
Streams and rivers alter the landscape by redistributing
material through the three processes of erosion,
transportation and deposition.
The river erodes mud, soil and other material from places, transports it down
stream and deposits somewhere else. This changes the shape of the landscape.
Creating meanders and oxbow lakes
In this picture, soil and mud is being eroded from various
points on the bank. It’s being transported in the direction of
the white arrows and deposited downstream (the sandy
patches). This is changing the course of the river
This picture shows the same river many many years later, the
erosion and deposition have created such a deep meander
that it has nearly formed a circle
Eventually, the river erodes so much that it cuts off part of
the meander and creates an oxbow lake
Waterfalls
Falling water and rock
particles wear away soft rock
The hard rock is undercut as
erosion continues
Hard rock collapses and if moved
by the flow. The waterfall moves backwards
Erosion continues and the waterfall
continues to move upstream
leaving a gorge of recession
The River System - Tasks
1. Draw the 3 stages that create an oxbow lake in the boxes below and use the
given labels to help explain what is going on.
Erosion, Transport ,
Deposition
Meander, Continuing Erosion,
Continuing deposition
Oxbow lake, New river
course
2. Draw a sketch of the first stage of a waterfall forming and label it using the
labels provided
Waterfall
Soft Rock
Hard Rock
Plunge Pool
River
3. Over time which bit of the waterfall erodes first?
………………………………………………………………………………………………………………………
4. Eventually, the waterfall will move, but which way (circle one)?
Upstream
Downstream
River Courses
A river flows through a piece of land called a ‘River Basin’. The river basin is all the
land that is drained of water by a river and the streams that flow into it. Below are
some of the features you will find in a river basin.
This is the Long Profile of a river – in 3 sections which each have their own features.
UPPER COURSE – The course is a steep slope
The start of a river is its source, which could be melting snow or ice, a spring
(water bubbling out of the ground), a lake or a bog. The source of a river is usually
in upland areas such as mountains or hills.
Small streams flow downhill from the source and join other
streams until they form the main river of a river system. The
streams are the tributaries of the main river. In upland areas,
water in streams and rivers is very
fast-flowing, cutting and eroding the
land to form valleys, and features such as waterfalls.
MIDDLE COURSE – The course is less sloping than before
Where two streams join, or a stream joins a river, this is called a
confluence.
When the ground becomes flatter, the river slows down and starts
to swing from side to side, this is called
meandering. The large bends it makes are
called meanders.
Sometimes, these large bends become cut off from the main
river, and ox bow lakes are formed.
LOWER COURSE – The course is slightly sloping or practically flat
The river widens and starts to cross a flood plain. This is a wide, flat area
either side of the river. It is used for flooding.
The end of a river, where it flows into the sea or sometimes a lake, is called its
mouth.
The area where the river meets the sea (the tidal part of the
river) is called the estuary.
A delta may be formed near the mouth of the
river, if the land is very flat and the river is
very slow-flowing and carrying a lot of sediment.
Drainage Basin & Watershed
The drainage basin is the area drained by
a river. The watershed is the edge of this
basin, and can be made by a line joining
all the highest points in the basement.
We all live inside the watershed of a river.
River Courses - Tasks
1. What is the name for the beginning of the river?
………………………………………………………………………………………………………………
2. Where does the water come from at the start of a river – name 2 places?
………………………………………………………………………………………………………………
………………………………………………………………………………………………………………
3. Put these features in the order you’d expect to find them in a river:
SOURCE
…………………………
MOUTH
FLOOD PLAIN
WATERFALL
MEANDER
………..……………… ………………………… ……………………………. ………………………….
4. Match the letter to the feature
Mouth
Source
Gorge
Meander
Waterfall
Tributary
5. A confluence is a
i.
ii.
iii.
A small river that feeds into a big river
The join of two rivers
A type of valley formed by erosion
6. Which river feature does this picture show:
i.
ii.
iii.
A tributary
A delta
A mouth
7. Ring the features that can happen at the end of a river:
Delta
Meander
Plunge pool
Mouth
Tributary
Lake
Estuary
Confluence
8. TRUE OR FALSE
i.
The drainage basin of a river is the bit at the end with a grill over it
ii.
The drainage basin of a river is the area of land that drains into the river
iii.
The edge of the basin is called a watershed
iv.
The watershed can be worked out by connecting the lowest points of the basin
v.
Only people who live on hills live inside a river watershed
vi.
Everywhere is inside the watershed of a river