Rivers🌊 Flashcards
Water/hydrological cycle
A natural system where water is in constant movement above, on or below the surface of the earth, always changing from water vapour (gas) to liquid into ice (solid)
Drainage basin
The area of land drained by a river and its tributaries
Drainage basin system -imputs
When water is introduced or put into the system
Drainage basin system- stores
When water is kept within the system and not moved through it.
Drainage basin system- transfers
Process or flows within the system, where water is moved from one place to another.
Drainage basin system - outputs
When the water is carried through the river and back into the sea or water leaving the system.
Evapotranspiration
Loss of water from soil/ leaves/ plants by evaporation.
Example of input
Precipitation
Example of stores
Interception (from veg), soil moisture, ground water, surface storage.
Example of transfers
Surface run off/over land flow, infiltration, through flow, percolation, ground water fall.
Example of outputs
River discharge,evaporation.
Percolation meaning
Downward movement of water through soil by gravity.
Infiltration meaning
Downward movement of water into the soil from the surface.
Characteristics of a drainage basin
97% of water on earth is stored in the seas and oceans. 2% is stored in icecaps and glaciers. 0.3% is freshwater on the surface of the earth as part of the drainage basin system.
Features of drainage basin - drainage basin
The area of land drained by a river and its tributaries.
Features of drainage basin - watershed
The boundary separating two drainage basins.
Features of drainage basin - source
The start of the river.
Features of drainage basin - tributary
A smaller river flowing into the main river channel.
Features of drainage basin - confluence
Where two rivers meet.
Features of drainage basin - river mouth
The end of a river, where the river meets the sea.
Load definition
The sediment carried by a river.
Gradient definition
The slope over which the river loses height.
Depth definition
The distance from the surface of a river to the river bed.
Width definition
The measurements from one river back to the other across a channel.
Discharge definition
The amount of water in a river which is passing a certain point in a certain time, (measured in cubic meters per second).
Erosion definition
The wearing away of the landscape by the action of ice, water and wind.
Abrasion definition
The grinding of rock fragments carried by a river against the bed and banks of the river.
Attrition definition
Transported particles hit against each other making the particles smaller and more rounded.
Hydraulic action definition
Erosion caused by force of moving water. It undercuts riverbanks on the outside of meanders and forces air into the exposed cracks in rocks in waterfalls.
Solution definition
The process by which water (in the river or sea) reads chemically with soluble minerals in the rocks and dissolves them.
Transportation definition
The movement of material across the earths surface.
Solution definition - transportation
Soluble materials dissolve in the water and are carried in solution. This chemical change affects rocks such as limestone and chalk.
Suspension definition
Transportation of the smallest load eg. fine sand and clay which is held up continually within river (or sea water).
Saltation definition
The bouncing of medium sized load (small pebbles and stones) along the river bed.
Traction definition
The rolling of boulders and pebbles along the river bed. (This requires a lot of energy)
Deposition definition
When the velocity of the river is reduced, the energy decreases, the water can no longer erode or transport material. Instead the load of dropped starting with the largest (heaviest) particles.
When is deposition likely
-River enters a lake or the sea slowing its flow.
-The river floods onto its floodplain, where it flows very slowly.
-There is an area of shallow water flowing the river flow.
- The load is increased suddenly eg after a landslide.
