Water On The Land Flashcards
What is a drainage basin?
The area of land drained by a river
What is the source of the river?
The beginning or start of the river
What is a watershed?
The edge of highland surrounding the drainage basin, marking the boundary between two drainage basins
What is a confluence?
The point at which two rivers or streams join
What is a tributary?
A stream or smaller river which joins a larger stream or river
What is the mouth of the river?
The point where the river comes to an end (usually when it comes to the sea)
What is a load in a river?
Gravel, sand and pebbles being dragged along by the current of the river
What is a rivers cross profile?
A slice across the river
What is a rivers long profile?
A slice through the river from source to mouth
What is solution transportation?
Minerals are dissolved in the water and carried along the in a solution
What is suspension transportation?
Light materials are carried along in the water
What is saltation transportation?
Small pebbles and stones bounce along the river bed
What is traction transportation?
Large boulders and rocks are rolled along the river bed
What is deposition?
When a river loses energy, it will drop or deposit some of the material it was carrying
Where is deposition most common and what can that form?
Nearer the mouth of the river, deposition can form deltas (landform) in and around the river
What is hydraulic action erosion?
The rivers force causes trapped air in the rocked crevices, splitting the rocks when the pressure builds up and wearing away the bank as a result
What is abrasion erosion?
Rocks carried along the river wear down the river banks
What is attrition erosion?
Rocks being carried by the river smash against each other, wearing them down into smaller smoother rock particles
What is solution erosion?
Soluble particles are dissolved into the river
How are V-shaped valleys formed?
The water flowing quickly down steep slopes will perform vertical erosion which cuts down towards the river bed and carves steep sided valleys in the upper course of the river
What is the upper course of the rivers features?
V shaped valleys Interlocking spurs Rapids Waterfalls Gorges
What is the middle course of the rivers features?
Wider, shallower valleys
Meanders
Oxbow lakes
What is the lower course of the rivers features?
Wide, flat bottom valleys
Floodplains
Deltas
How are meanders formed?
Lateral erosion widens the river channel, which makes the water flow faster which means more lateral erosion. All this eroding causes great horseshoe like bends called meanders.
The erosion takes place on the outside, meanwhile on the inside of the bend (where the current is slower) materials are deposited.
How are oxbow lakes formed?
A meanders horseshoe shape becomes tighter and tighter at the open end over time because of the erosion and deposition. When they become very close and the river breaks through on each side, breaking away from the main stream, an oxbow lake is formed
What is river discharge measured in?
Cumecs (cubic metres per second)
What factors could aid flooding?
Steep downwards slopes next to the channel
Lack of vegetation
Impermeable rock (flows fast of rock because it cannot percolate)
Sewers and drains add to the waters flow
What is the advantage to flooding?
Alluvium deposited to make the soil very fertile
What are the hard engineering options?
Dam construction
River engineering
What are the soft engineering options?
Afforestation
Flood management (allow some flooding to prevent other)
Planning
What are levees and how are they formed?
The current pushes sediment aside (attrition erosion) forming natural levees (walls) made of sediment and silt which regulate water levels
What does a hydro-graph show? Explain further
Rainfall/precipitation (bar graph) discharge (line graph)
The peak precipitation is before the peak discharge and the time taken imbetween is called the lag time because it takes the rain time to reach the river
