Hydrological cycle and flooding

Subdecks (4)

Cards (43)

  • rivers form part of the water cycle - they are a downward flow of water, under the force of gravity
  • rivers shape the land through erosion, transportation and deposition - these create distinct landforms
  • in the upper course, vertical erosion creates waterfalls and v-shaped valleys
  • in the middle and lower courses, lateral erosion creates meander bends, oxbow lakes and deltas
  • the hydrological cycle, or water cycle, shows the movement of water between the atmosphere, land and oceans
    • energy from the Sun heats the surface of the Earth
    • water is evaporated from oceans, rivers, lakes
    • the warm, moist air rises because it is less dense
    • condensation occurs when water vapour is turned back into water droplets as it cools down
    • precipitation occurs as water droplets get bigger and heavier they begin to fall
    • surface runoff is water that flows on the surface of the ground
    • infiltration is when this water moves into the soil and rock layers below the surface
    • through flow is water that flows downhill within the soil
    • groundwater flow is water that flows downhill within rock layers under the soil
  • evapotranspiration - water moves from the land surface to the atmosphere via evaporation and transpiration
  • percolation - movement and filtering of fluids through porous materials
  • Waterfalls and rapids are found in the upper course. These form when rivers flow over hard and soft rock. Vertical erosion wears away soft rock, forming rapids and waterfalls
  • V-shaped valleys are found in the upper course. Vertical erosion lowers the level of the river channel. The bank either side are unsupported and so fall into the wate, leaving behind a v-shaped valley
  • Floodplains are found in the middle course - these are are flat areas of land either side of a river channel
  • there are many physical and human causes of river flooding, including heavy rainfall, steep surfaces and urbanisation
  • consequences of flooding include damage to property, loss of power and deaths
  • the impacts of flooding are often more severe in LICs
  • river floods can be managed using hard and soft engineering strategies - hard engineering strategies aim to control natural processes and soft engineering strategies work alongside natural processes
  • hard engineering: man made structures or approaches to reduce floodig
  • soft engineering: natural approaches to flood prevention
  • What is discharge
    The amount of water in a sea, lake, river
  • What is lag time

    Time between peak rainfall and peak discharge
  • What type of graph is used to show flooding
    A flood hydrograph