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Geography Glossary 2
Geography Key Words and Definitions Rivers Topic
Question | Answer |
---|---|
Evaporation | A transfer of water from the Earth’s surface to the atmosphere where it changes from a liquid to a gas |
Condensation | A transfer of water vapour back into water droplets due to cooling |
Transpiration | A transfer of water from vegetation to the atmosphere |
Precipitation | Water transferred from the atmosphere to the Earth’s surface as snow, sleet or rain |
Overland flow | Water transfer over the land’s surface – the quickest route to the river. Also called ‘Surface Run-off’ |
Infiltration | Water moving vertically into the soil AT THE SURFACE |
Through flow | Water moving sideways through airspaces in the soil (the second fastest route to the river) |
Percolation | Water travelling vertically down through the soil or rock |
Groundwater flow | Water travelling sideways through permeable rock. (the slowest route to the river) |
Streamflow | The transfer of water in river channels |
Hydrological Cycle | The natural circulation of water. The cycle is a natural system of ‘stores & transfers’ |
Lag response | A slower rise in discharge, long lag time & lower discharge; perhaps due to permeable rock or gentle slopes |
Flash response | This response shows a steep increase in discharge, a short lag time & a high peak discharge. This can be caused by impermeable soils, deforestation or urbanisation |
Lag time | The time between peak rainfall and peak discharge |
Hydrograph | Shows the changes in discharge over time following a period of rainfall |
Watershed | The dividing line between two drainage basins |
Tributary | A small river feeding into the major river |
Source | The start of a river |
Mouth | Where the river meets the sea |
Impermeable | A surface that does not allow water to soak through |
Drainage basin | The area drained by a river & its tributaries |
Discharge | The volume of water in the river flowing past a certain point at a certain time |
Confluence | Where two rivers meet |
Gradient | The degree of steepness - can be seen on the long profile of a river |
Suspended load | The material moved along by the river |
Saltation | Smaller fragments carried in the flow of a river |
Bedload | Larger fragments rolled along the river bed |
Traction | Fragments bouncing along the river bed |
Solution | Dissolved minerals carried in the water |
Lateral erosion | Erosion of the sides of the valley |
Vertical erosion | Downward erosion of the river bed |