rivers

• Water Cycle


  The continuous circulation of water between land, sea and air
• Drainage basin


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


  The boundary of a drainage basin, it is often a ridge of high land
• Source


  The starting point of a river, it may be a lake, glacier or marsh
• Tributary


  A stream which flows into a larger river
• Confluence


  The point at which a tributary joins the main river
• River Mouth


  The end of a river where it meets the sea, ocean or a lake
• River Discharge


  The amount of water in a river which is passing a certain point in a certain time. It is measured in CUMECS (cubic metres per second)
• Interception


  The process whereby precipitation is prevented from falling onto the ground by plants. It slows run-off and reduces the risk of flash flooding.
• Groundwater


  Water which is stored in saturated rock
• Surface run off / overland flow


  Water moving over the surface of the ground
• Infiltration


  Movement of water into the soil from the surface
• Throughflow


  Water flowing through the soil layer parallel to the surface
• Percolation


  The movement of water downwards from the soil into the bedrock below
• Groundwater flow

  Water which is moving through the bedrock below
• Precipitation


  Any moisture falling from the sky (rain, hail, sleet, snow)
• Erosion


  Wearing away of the landscape by the action of ice, water, wind.
• Attrition


  The process of erosion where transported particles hit against each other making the particles smaller and more rounded.
• Abrasion (Corrasion)


  The grinding of rock fragments carried by a river along the banks of the river.
• Hydraulic Action


  A form of erosion caused by the force of moving water undercutting the riverbanks on the outside of meanders and forces air into cracks in the exposed rocks in waterfalls.
• Solution (Corrosion)


  The process by which water (river or sea) reacts chemically with soluble minerals in rocks and dissolves them.
• Suspension


  The transportation of the smallest load eg. fine sand or clay, held up by the water.
• Saltation


  The bouncing of medium size rocks along the river/sea bed.
• Traction


  The rolling of large rocks along a river/sea bed.
• Deposition


  The dropping of material on the earth's surface
• Flooding


  A temporary covering of the Earth's surface which is normally dry
• Hard engineering


  A strategy to control a natural hazard which does not blend into the environment
• Levees


  Raised river banks allowing the river to hold more water
• Embankments


  Walls built on the side of the river allowing it to hold more water
• Soft engineering


  A strategy to control a natural hazard which does blend into the environment so is often sustainable
• Washlands


  Areas of land that water is allowed to wash into during a flood.
• Afforestation


  The planting of trees (trees increase intercept, store water and reduce runoff). They can reduce the risk of flooding
• Land use zoning


  Divided areas of the floodplain according to flood risk, then choosing an appropriate type of land use for the land. e.g. residential, farmland etc.
• Somerset Levels

  Case study for the physical and human causes of flooding within the UK
• Mississippi River


  Case study for a river management scheme from outside the UK
• Evapotranspiration


  The process by which water is transferred from the land to the atmosphere by evaporation from the land and ocean surface and transpiration from plants.
• Gradient


  The gradient of a river is a measure of how steeply it loses height.
• Load


  The material carried in a river.
• Transportation


  How rivers move material. There are four different ways.
• River landforms


  Created by the processes of erosion and deposition in a river. These change with distance downstream.