1. Drainage Basins

2. Definitions
Drainage basin: An area of land drained by a single river. Also called the catchment area of a river.
Watershed: The dividing line between two drainage basins.
Drainage Density: The total length of streams / area of basin.

3. Drainage Basins Source Watershed Confluence point – where
tributary meets main river
Tributary
Main river
Catchment Area

4. Drainage Basins Write a definition of the major features of a river
Watershed, source, tributary, confluence, mouth
You must also be able to explain the drainage basin system with
reference to:
Inputs
Outputs
Transfers
Stores

5. Hydrosphere: River Basins

9. Types of Drainage Patterns

10. Stream Order

12. Write the questions and answers:
The drainage basin
What is the area drained by a river called?
What is the line around this that encircles the whole system?
Stream ordering
Draw a diagram to show stream ordering and explain what it is used to show.
Drainage density
Write out the formula for working out drainage density of a river system.
What factors can affect the drainage density of an area?
What major risk does a high drainage density exacerbate?

13. Hydrosphere Drainage basin as a system
Explain why the river system is an open system.
Make a copy of Fig 3.5 p.41, ensuring to colour code in the key.
What is evapotranspiration?
What is interception?
Name the different ways in which water can be transferred through the system.
What is groundwater and how can it be stored?
Why is baseflow important to stream and rivers during the dry weather?
Describe 2 ways in which runoff occurs.

14. Flows and storm hydrographs
Make a list of the factors that can have a bearing on the discharge of a river.
Define the term discharge.
What is a hydrograph and how and where is the data for it’s construction collected?
Make a copy of fig 3.8.
What is lag time?
Why does it happen?
What can be said about the base flow lag time?
Why is this?
If this rising limb of the graph is steep, what does this mean?
Why do you think that the recessional limb falls less steeply than the rising limb?
What will happen if the bankful discharge level is exceeded?
What becomes the source of water in a river after the storm flow has finished?