River Processes Lab
Follow a river from source to sea. Learn how it erodes, transports and deposits material, and how those processes carve waterfalls, meanders, ox-bow lakes and floodplains.
Put it to work, not just to memory
Free and interactive, so you are arguing with the material rather than rereading it.
Start revising freeWhat you'll cover
From source to sea
A river is a landscape machine. As it flows from the hills to the sea it erodes the land, transports the material, and deposits it again downstream. This lab follows those three processes and shows how they carve waterfalls, meanders, ox-bow lakes and floodplains along the way.
River process words
Three processes and one landform underpin the topic:
Match each erosion process to what it does
- Hydraulic action
- Abrasion
- Attrition
- Solution
- The force of water pushes into cracks in the bank
- Rocks carried by the river scrape the bed and banks
- Rocks knock together and become smaller and rounder
- Soluble rock is slowly dissolved by the water
How is material moved?
Which of these is a way a river TRANSPORTS its material?
- Saltation: bouncing pebbles along the bed
- Hydraulic action: water forcing into cracks
- Abrasion: rocks scraping the banks
- Deposition: dropping material when slow
One river, three courses
A river changes character from source to mouth: - Upper course: steep and fast in floods; erodes downwards; V-shaped valleys and waterfalls - Middle course: gentler; the valley widens; meanders begin - Lower course: slow and full; deposits material; floodplains, levees and deltas Erosion dominates upstream; deposition dominates downstream.
Which are erosion?
Select the TWO processes that are types of EROSION.
- Hydraulic action
- Attrition
- Saltation
- Deposition
Upper versus lower course
The two ends of a river look and behave very differently.
Name that landform
A river flows over a band of hard rock and drops steeply onto softer rock below. What landform is this?
- A waterfall
- A meander
- A floodplain
- A levee
Put it together
A river shapes the land as it flows. In the _____ course it cuts down to form a V-shaped _____. Rocks are worn smaller by _____. In the lower course the river _____ material to build a _____.
How a waterfall forms
Put the stages of waterfall formation into the correct order.
- A band of hard rock lies over softer rock
- The soft rock is eroded faster, undercutting the hard rock
- The hard rock is left as an overhang
- The unsupported overhang collapses
- The waterfall retreats upstream, leaving a gorge
Match each landform to how it forms
- Ox-bow lake
- Gorge
- Levee
- Delta
- A meander is cut off when its neck is breached
- Left behind as a waterfall retreats upstream
- Built from sediment dropped at the banks in floods
- Sediment deposited where a river meets the sea
In the field
Three observations along a river. Identify the process or landform each time.
- Pebbles in the river knock together and become smaller and rounder over time. Which process is this?
- The river reaches flat ground, slows down and drops its load of sediment. Which process is this?
- A large meander loop is finally cut off, leaving a curved lake beside the main channel. What has formed?
Explain a landform
Explain how a waterfall and its gorge are formed. Refer to the erosion processes in the correct order.
- Describe the rock layers (hard rock over softer rock)
- Explain how erosion undercuts the hard rock, naming a process such as hydraulic action or abrasion
- Describe how the overhang collapses
- Explain how the waterfall retreats upstream to leave a gorge
Landforms are a sequence
Top answers explain landforms as a sequence of processes, not just a label. For a waterfall: hard rock over soft, the soft rock eroded by hydraulic action and abrasion, the overhang collapsing, and the fall retreating to leave a gorge. Always link process to place on the long profile: erosion and V-shaped valleys upstream, deposition and floodplains downstream. Sequence the processes, link them to the course - top band.