River

• Precipitation


  Any source of moisture reaching the ground e.g. rain, snow, hail or sleet.
• Source


  The starting point of a river.
• River basin/drainage basin


  The area of land drained by a river and its tributaries.
• Watershed


  The boundary that separates one drainage basin from the next. It is usually on high ground.
• Confluence


  The point where two rivers join.
• Channel


  The river flows in this.
• Tributary


  Smaller rivers that join the main one.
• Mouth


  The end of a river. Rivers flow into the sea or a lake at the end of its journey
• Erosion


  Material is broken off and picked up. As a river gets further down its course, vertical erosion becomes less important and lateral erosion (sideways) takes over.
• Hydraulic Action


  Erosion where the sheer force of the river against the bed and banks breaks up the rock.
• Abrasion


  Erosion where pebbles and sand get flung against the river bed and banks, scraping and scouring it away.
• Attrition


  Erosion where the rocks and pebbles get flung against each other wearing each other away.
• Solution


  Erosion where the water in the channel can dissolve some material.
• Transport


  The movement of eroded material
• Solution


  Minerals such as limestone are dissolved in the water.
• Saltation


  Smaller pebbles are bounced along the river bed.
• Suspension


  Finer particles are carried along in the flow.
• Traction


  The rolling of larger boulders and pebbles along the river bed.
• Long profile of a river

  The gradient of a river, from its source and its mouth.
• Cross profile of a river

  The side to side cross-section of a river channel and/or valley.
• Discharge


  The quantity of water that passes a given point of a river within a given period of time (e.g. the quantity of water in a river).
• Interlocking spurs


  A series of ridges projecting out on alternate sides of a valley and around which a river winds its source. Made of hard rock, they are more resistant to the erosion of the river.
• Waterfalls


  A sudden descent of a river over a vertical or very steep slope in its bed. It forms when a river meets a band of softer rock after flowing over an area of more resistant rock.
• Gorges


  A narrow steep sided valley formed when a waterfall retreats upstream.
• Meanders


  A pronounced bend in a river.
• Slip off slope


  The gentle slope on the inside of a meander bend formed by deposition due to slower flowing water.
• River cliff


  The steep bank on the outside of a meander bend formed by erosion due to fast flowing water.
• Oxbow lakes


  An arc-shaped lake which has been cut off from a meandering river.
• Leeves


  A levee is a ridge of sediment deposited naturally alongside a river by overflowing water, which then acts as a barrier to keep normal flow of the river in the channel. It can be built by people as a flood prevention strategy.
• Flood


  Occurs when river discharge exceeds river channel capacity and water spills out of the channel onto the floodplain and other areas.
• Flood Plain


  The large area of flat land either side of a river that is prone to flooding. They form due to both erosion and deposition.
• Estuary


  Found in the lower course, an estuary is the tidal part of a river where the chanel widens out as it reaches the sea
• Flood risk


  The predicted frequency of floods in an area.
• Interception


  Water being prevented from reaching the ground by trees or grass.
• Surface runoff


  Water flowing on top of the ground.
• Infiltration


  Water sinking into soil/rock from the ground (aka going underground).
• Groundwater


  Water stored in rock.
• Transpiration


  Water lost from vegetation.
• Evaporation


  Water lost from the ground.
• Throughflow


  Water flowing through the soil layer just below the ground.