Definitions

• What does a systems approach study in hydrology?

  It studies hydrological phenomena by looking at the balance of inputs and outputs.
• What are stores in the context of hydrology?

  Stores are reservoirs where water is held, such as the oceans.
• What are fluxes in hydrology?

  Fluxes are the rate of flow between the stores.
• What are processes in the hydrological cycle?

  Processes are the physical mechanisms that drive the fluxes of water between the stores.
• What is the cryosphere?

  The cryosphere includes areas of the Earth where water is frozen into snow or ice.
• What is blue water in the hydrological cycle?

  Blue water is water stored in rivers, streams, lakes, and groundwater in liquid form.
• What is green water?

  Green water is water stored in the soil and vegetation.
• What is precipitation?


  Precipitation is the movement of water in any form from the atmosphere to the ground.
• What is evaporation?


  Evaporation is the change in state of water from a liquid to a gas.
• What is residence time in hydrology?

  Residence time is the average time a water molecule will spend in a reservoir or store.
• What is fossil water?

  Fossil water is ancient, deep groundwater from former pluvial periods.
• What is transpiration?


  Transpiration is the diffusion of water from vegetation into the atmosphere.
• What is groundwater flow?

  Groundwater flow is the slow transfer of percolated water underground through pervious or porous rocks.
• What is a catchment?

  A catchment is the area of land drained by a river and its tributaries.
• What is a watershed?

  A watershed is the highland that divides and separates waters flowing to different rivers.
• What is condensation?


  Condensation is the change from a gas to a liquid, such as when water vapor changes into water droplets.
• What is the dew point?


  The dew point is the temperature at which dew forms; it measures atmospheric moisture.
• What is convectional rainfall?

  Convectional rainfall is often associated with intense thunderstorms in areas with ground heating.
• What is cyclonic rainfall?

  Cyclonic rainfall is a period of sustained, moderately intensive rain associated with depressions.
• What is orographic rainfall?

  Orographic rainfall is concentrated on the windward slopes and summits of mountains.
• What is interception loss?

  Interception loss is water retained by plant surfaces that is later evaporated or absorbed by vegetation.
• What is throughfall?


  Throughfall is when rainfall persists or is relatively intense, causing water to drop from leaves and branches.
• What is stem flow?


  Stem flow is when water trickles along twigs and branches and then down the trunk.
• What is infiltration?


  Infiltration is the movement of water from the ground surface into the soil.
• What is infiltration capacity?

  Infiltration capacity is the maximum rate at which rain can be absorbed by a soil.
• What is surface run-off?

  Surface run-off is the movement of water unconfined by a channel across the surface of the ground.
• What is throughflow?


  Throughflow is the lateral transfer of water down slope through the soil via natural pipes and percolines.
• What are percolines?


  Percolines are lines of concentrated water flow between soil horizons to the river channel.
• What is percolation?


  Percolation is the transfer of water from the surface or from the soil into the bedrock beneath.
• What is saturated overland flow?


  Saturated overland flow is the upward movement of the water table into the evaporation zone.
• What is albedo?


  Albedo is a measure of the proportion of incoming solar radiation that is reflected by the surface.
• What is evapotranspiration (EVT)?

  Evapotranspiration (EVT) is the combined effect of evaporation and transpiration.
• What is channel flow?


  Channel flow is the flow of water in streams or rivers.
• What is channel storage?

  Channel storage is the storage of water in streams or rivers.
• What is potential evapotranspiration (PEVT)?

  Potential evapotranspiration (PEVT) is the water loss that would occur if there was an unlimited supply of water in the soil.
• What is deforestation?


  Deforestation is the cutting down and removal of all or most of the trees in a forested area.
• What is afforestation?

  Afforestation is the planting of trees in an area that has not been forested in recent times.
• What is a river regime?


  A river regime is the annual variation in discharge or flow of a river at a particular point.
• What is the rising limb in a storm hydrograph?

  The rising limb is the part of a storm hydrograph in which the discharge starts to rise.
• What is peak discharge?

  Peak discharge is the time when the river reaches its highest flow.