5.3 water budgets

• what is a water budget


  annual balance of inputs (precipitation) and outputs (evapotranspiration) of the drainage basin, which affects soil snd water availability
• what does the water budget impact

  soil and water availability
• explain the importance of water budgets on a global scale

  determines how much water is available for human use
• explain the importance of water budgets on a local scale

  determines soil water availability which is important to farmers as they can use irrigation for crops when requires
• what month does the UKs water year start and why


  October

  because this is where precipitation exceeds potential evapotranspiration, thus soil moisture is recharged
• what are the two variables in a water budget

  precipitation and potential evapotranspiration
• what happens when precipitation exceeds potential evapotranspiration

  soil moisture recharged
• what months does evapotranspiration exceed precipitation

  April to September (soil utilisation)
• what happens from the months April to September

  soil utilisation
• what happens in July

  soil moisture store used up so irrigation must be used
• what is effective rainfall

  The amount of precipitation remaining after evaporation
• what is recharge


  precipitation after a period of drought
• what is a river regime


  The annual pattern of discharge in a river
• what physical factors affect a river regime

  -soil/geology/topography as these affect surface run off

  -amount of precipitation

  -climate as this influences meltwater and evaporation
• why does climate affect the rivers regime

  affects amount of meltwater and evaporation
• what are the two types of river regime

  simple and complex
• what is a simple river regime


  river experiences seasonally high discharge followed by low discharge
• what type of rivers typically have a simple regime

  meltwater rivers (eg) Yukon, Alaska
• what is a complex regime


  river experiences the effects of many seasonal events as it runs through various climates, also can be impacted by human intervention (eg) dams
• what is the input for the Yukon river

  meltwater
• what is the impact of receding glaciers

  causing meltwater rivers to disappear
• at what rate is the glacier in Alaska (that feeds the Yukon river) thinning

  10 metres per year
• what is the glacier called that feeds the Yukon river

  Grand plateau glacier
• explain the simple regime of the Yukon river


  high flow in spring/ summer as meltwater, so high seasonable variability
• does the Yukon river have high or low seasonal variability

  high
• what are the main influences on the Yukon river

  temperatures / climate
• explain the regime of the Amazon river in Brazil


  higher flow in wetter season and lower flow in dryer season, but constant rainfall all year around so moderate seasonal variability
• describe the seasonal variability of the Yukon river

  moderate
• what are the major influences of the Yukon river


  -hydroelectric dams so human intervention

  -rainforest climate
• what type of storm hydrographic is associated with a small, circular drainage basin

  flashy river, so steeper hydropgraph
• what type of storm hydrographic is associated with a rectangular/larger drainage basin

  flat river, so shallower hydrograph
• what % of water does a deciduous forest in summer in the uk intercept

  60%