EQ1

• Stores are stocks of water in places where water is held (ocean).
• Fluxes are the measurement of the rate of flow between the stores.
• Processes are physical factors which drive the fluxes of water between stores.
• Hydrological cycle is a closed system. No water is added or removed from the budget.
• The closed cycle in the hydrological cycle is driven by solar and gravitational potential energy.
• There are 3 states of matter and stores:

  • In the last ice age more water was held in the Cryosphere (solid).
  • Climate warming reverses water being held in a solid.
  • Humans are now building water storages (reservoir) to increase water security.
• The ocean is the worlds largest water store holding 96.9% of water.
• Atnosphere is the smallest water store. Water is harder to evapourate to get into the atnosphere and also hard to stay in atnosphere due to gravity (only stays there for 10 days).
• Residence column shows that water stores arent distributed evenly across the globe and not always fresh water.
• Water stores in residence column (fresh water)

  • 1% River
  • 1% Living organisms
  • 8% Atnosphere
  • 38% Soil Moisture
  • 52% Lakes
• Most of our fresh water is from small sources.
• 69% of fresh water supplies are locked in snowflakes, ice sheets, ice caps and glaciers.
• 30% of fresh water is held in ground water and is very deep, inaccsessible.
• 1% of fresh water is easily acsessible for human usage.
• Blue water is visible water, suhc as lakes and rivers.
• Green water is 'invisible water' stored such as water stored in vegetation.
• Residence times

  • Oceans 3.6k years
  • Icecaps 15k years
  • Ground water 10k years
  • Rivers and lakes 2 weeks - 10 years
  • Soil moisture 2-50 weeks
  • Atmospheric moisture 10 days
• Fossil Water in Sahara Desert

  • Thought to be non renewable but recent research shows it is recharging 1.4 cubic kilometers rainfall anually- 2mm rise.
  • 2003-2010 annual recharge 4.4 cublic kilometers.
  • NASA did GRACE (gravity recovery and climate experiment) shows that 60% if annual take issnt being replenished.
• Antartica Hydrological Cycle

  • Ice caps melting anual rise of 3mm annually
  • Reducing ice means more freshwater wildlife
• Rainfall and Drainage Basins

  • Level of precipitation has a direct impact of discharge
  • Type of precepitation acts as a temporary store (ice)
  • Seasonality (mediteranian) have impact on physical processes
  • Distribution of precipitation in a basin (may stretch over many climatic zones)
• Variability in Rainfall

  • Secular varibility: happens over long term
  • Periodic varibility: happens in annual, seasonal or daily basis
  • Stochastic Varibility: results from random factors (thunderstorms)
• The nature of soil surface and structure is important, compact surfaces inhibit inflitration.
• The rate of infiltration depends on the amount of water already in the soil as surface or overland flow will take place when soil is saturated.
• Slope angle is significant. Very steep slopes encourage overland run off, shallow slopes promote infiltration.
• Infiltration capacity decreases with time through a period of rainfall untill more or less constant value is achieved.
• The type, amount and seasonal changes in vegetation cover are important factors. Infiltration is more significant with land covered in forests.
• Soil texture influences porosity. Sandy soils have a higher infiltration capacity than clays.
• Percolines are lines of concerntrated water flow between soil horizons to the river channel.
• Albedo is the measure of proportion of incoming solar radiation that is reflected by the surface back to atnosphere and space.
• Evapotranspiration is the combined effect of evapouration and transpiration.
• Channel storage is the storage of water in streams or rivers.
• Potential Evapotranspiration is water loss that would occur if there was an unlimited supply of water in soil used by vegetation.
• Overland flow is the surface run off due to rapidity of reaching the channel. Type of flow is primary agent of soil erosion as sediment is removed by a range of erosive processes.
• Throughflow is the very slow transfer of percolated water through pourous rocks. Vital componant in maintaining steady level of channel flow in verying weather conditions.
• Percolation is the deep transfer of water into permable rocks.
• Saturated overland flow takes place in river once water from 3 transfer processes reaches it.
• Groundwater flow is a much slower transfer process, resulting from upeards movement of the water table in evapouration zone. After the sucsession of winter storms the water table rises to the surface at the base of hillsides, leading to saturated overland flow making major contributions to channel flow.
• Channel flow is the transfer of water down a slope through soil via natural pipes and percolines. Happens rapidly in pourous soils.
• Relief can impact the amount of precipitation and slopes effect surface run off.
• Climate influences the type and amount of precipitation overall, amount of evapouration and vegetation type.