Freshwater Flashcards
What are the stores and flows of the hydrological cycle?
Flows
- Precipitation - Evaporation - Transpiration - Surface flow - Groundwater
Stores
- Lakes - Ice - Clouds - Snow - Oceans
Is the hydrological cycle an open or a closed system?
The hydrological cycle is a closed system
What are the stores and flows of the drainage basin?
Stores
- River
- Soil
- Rock
Flows
- Interception
- Infiltration
- Surface runoff
- Throughflow
- Percolation
- Groundwater flow
What are the inputs and outputs of the drainage basin?
Inputs
- precipitation
Outputs
- evapotranspiration
- River run-off
Define the term ‘Drainage Basin’
A drainage basin includes all the area that is drained by a river and its tributaries
Define the term ‘Water Shed’
Drainage basins are divided by watersheds which are imaginary lines that separate neighbouring basins.
What is an aquifer?
Aquifers are permeable rocks (eg sandstone and limestone) where the water moves very slowly and acts as a natural regulator in the hydrological cycle.
What is the cryosphere?
The cryosphere is the snow and ice environment. Up to 66% of the world’s fresh water is in the form of ice and snow.
What factors affect the drainage basin?
Geology:
- The permeability of the rocks
- Impermeable rock decreases percolation which will probably increase throughflow
Land Use:
- A lot of vegetation means more interception so potentially less infiltration
- In cities with tarmac, there is less infiltration and more surface runoff which has an increased flooding risk
Precipitation:
- More rainfall, more chance of flooding but it depends on geology and land use
- More snow, more water is stored as snow and ice, less chance of flooding as it is frozen but when it melts, there is more chance of surface runoff
Relief:
- Steep slopes reduce the amount of infiltration and increase surface runoff which can increase the chances of flooding
What are the 4 types of erosion?
- hydraulic action
- abrasion
- attrition
- solution
What are the 4 types of transportation?
- traction
- saltation
- solution
- suspension
What is traction?
Traction is where large boulders roll along the bed
What is saltation?
Saltation they will bounce along the river bed
What is suspension?
Suspension is where small and fine particles float along in the river
What is solution? (transportation)
Solution is where small particles dissolve in the water
What is discharge?
Discharge is the volume of water passing a given point over a certain period of time.
Discharge is normally expressed as cubic metres per second (cumecs)
Which type of flow causes more erosion in a river?
Turbulent flow
Turbulent flow is more likely to happen. There is a corkscrew motion that happens within the channel. This motion is called helicoidal flow. The turbulent movement affects the banks and the bed which causes more erosion
What is laminar flow?
Laminar flow is where there are no obstructions. The river will always take the path of least resistance. Water tends to move in a series of sheets.
It is common in groundwater and in glaciers, but not in rivers, although it can occur in the lower course of a river. The conditions for laminar flow are: - Shallow channels - Smooth, straight channels - Low velocities
Velocity and Friction - the effect?
The effect of friction is to create an uneven distribution of velocity in a stream. Water closest to the bed and banks travels the slowest, while water nearest the centre travels fastest. The highest velocity is thus mid-stream about a third of the way down
What is the most efficient stream shape?
Semi-circular