14 terms

Rivers Key Terms

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Hydraulic action
the sheer force of the moving water against the banks can cause air to be trapped in cracks and crevices. The pressure wekens the banks and gradually wears it away.
Abrasion
rocks carried along by the river scrape, scour and rub along the bed and banks and wear down the river like sandpaper
Attrition
rocks being carried by the river smash together and break into smaller, smoother particles
Solution (erosion)
minerals in the rocks are dissolved by weak acids in the river water. Particularly in rocks like chalk and limestone, soluble particles are dissolved into the river water
Traction
large stones and boulders are rolled along the river bed by water moving downstream. Mainly when there is high discharge and therefore high energy levels.
Saltation
Small pebbles and stones are bounced along the river bed. As these particles land they dislodge other particles causing further saltation
Suspension
Fine light materials, sand and silt, are carried along in the flow of the water. This gives rivers their brown appearance
Solution (transportation)
Minerals are dissolved in the water and carried along in solution
Deposition
When the river puts down its load due to lack of energy
Watershed
Is the dividing line which separates two adjacent drainage basins/catchment areas
Mouth
Zips the end point of the river where it enters the sea or a lake.
Tributary
Is the name given to a smaller river joining a bigger river.
Confluence
Is the point where a tributary meets the main river.
Source
Is the place where the river begins, usually in an upland area