the water cycle Flashcards
what human factors can affect hydrograph shape?
- urbanisation
- agriculture/farmland
- channelisation
- dams/ hard engineering
- deforestation
- aforestation
how can agriculture/farming affect hydrograph shape?
- farm machinery can compact soil so its impermeable resulting in a flash hydrograph
- after harvest = flash
- before harvest = flat
what physical factors can affect hydrograph shape?
- number of tributaries
- relief
- vegetation cover
- geology
- rainfall amount
- size + shape of catchment area
when may there be a flash hydrograph?
- thunderstorms
- urban areas
when may there be a flat hydrograph?
- forest areas
- chalk area
how is rain formed ?
- air rises
- air cools
- condensation
- rain falls
when will there be relief rain?
when a mountain causes the air to rise, resulting in rainfall
when will there be frontal rain?
when warm air meets cold dense air
when will there be convectional rain?
when hot temperatures cause the air to rise
why is the global hydrological cycle a closed system?
the amount of water within the system stays the same, it is transferred between different stores
what are examples of stores in the drainage basin system?
- groundwater
- vegetation
- soil
what are examples of outputs in the drainage basin system?
- river flow into the sea
- evaporation
- evapotranspiration
what is an example of inputs into the drainage basin system?
- precipitation
what are examples of flows in the drainage basin system?
- infiltration
- percolation
- surface run-off
- through flow
- groundwater flow
define afforestation
planting trees on land that has never had a forest
define agricultural drought
a rainfall deficiency from meteorological drought leading to deficiency in soil moisture, affecting plant growth and yields.
define aquifers
a permeable or porous rock which stores water
define base flow
the normal day-to-day discharge of a river
define blue water
water stored in rivers, streams, lakes and groundwater in liquid form
define catchment area
the area of land drained by a river and its tributaries
- drainage basin
Define closed system
A sequence of linked processes with a transfer of energy, but not matter, between the parts of the system
Define condensation.
The change from a gas to a liquid?
Define cryosphere
areas of the earth where water was frozen into snow ice.
Define deforestation.
The cutting down removal of all or most trees in a forested area.
define desalination.
The process of converting salt water to fresh water suitable for human consumption and industry.
Define desertification.
Land degradation in arid, semi arid and dry, subhumid areas resulting from various factors including climatic variations and human activities.
Define dew point.
The temperature at which Dew forms.
Define drought.
An extended period of deficient rainfall relative to the statistical outrage for a region measured over a very long period of time.
Define economic waters scarcity.
when water resources are available, but there is insufficient human institutional and financial capital to access the water in order to meet demand.
Define eutrophication.
Excessive richness of nutrients in a lake or other body of water frequently. due to runoff from farming land, which causes a dense growth of plant life and death of animal life from a lack of oxygen.
Define evaporation.
The change in the state of water from a liquid to a gas.
Define Evapotranspiration.
The combined effect of evaporation and transpiration.
Define falling limb.
The pot of a storm hydrograph in which the discharge starts to decrease and returns base flow.
Define famine drought.
A humanitarian crisis in which the widespread failure of agricultural systems needs to food shortages and famines with several social, economic and environmental impacts.
Define flash flood.
A flood with an exceptionally short lag time, often minutes or hours.
Define fossil water.
Ancient deep groundwater from former wetter periods.
Define green water.
Water stored in the soil and vegetation.
Define groundwater flow.
The slow transfer of percolated water underground through porous rock.
Define hard engineering
The use of man-made artificial structures to manage flooding or water supply.
Define hydrological drought.
Associated with reduced stream flow and groundwater levels, which decreases because of reduced inputs of precipitation and continued high rates of evaporation, regarding reduced storage in lakes and reservoirs.
Define infiltration.
The movement of water from the ground surface into the soil.
Define intertropical convergence zone.
A concentration of warm air that produces rainfall as part of a global circulation system. It moves N and S across the equator seasonally. Small shifts and location can cause drought.
Define meteorological drought.
Defined by shortfalls and precipitation as a result of short term variability or longer term trends, which decrease the duration of the drive.
Define Monsoon
A seasonal change in the direction of prevailing winds of a region causing wet and dry seasons in many subtropical areas.
Define peak discharge.
, the time when the river reaches its highest flow.
Define percolation
The transfer of water from the surface or from the soil into the bedrock beneath.
Define potential evaporation.
The water lost that would occur if there was no limited supply of water in the soil for use by vegetation.
Define precipitation.
The movement of water in any forms from the atmosphere to the ground.
Define residence time.
The average time a water molecule will spend in a reservoir or store
Define rising limb
The part of the storm hydrograph in which the discharge starts to a rise.
Define River regime.
The annual variation in discharge or flow of the river at a particular point or gauging station, usually measured in tumax.
Define saltwater encroachment.
The movement assault water into fractured water aquifers due to sea level rise, Storm surges and/ or human abstraction of groundwater, which lowers the water table.
Define stores.
Reservoirs by water held such as the oceans.
Define storm hydrograph.
Shows changes in a rivers discharge at a given point on a river over a short period of time.
Define surface runoff.
The movement of water that is unconfined by a channel across the surface of the ground, also known as overland flow.
Define surface water flooding.
Flooding that occurs when intense rainfall has insufficient time to infiltrate the soil, so flows over land.
Define thermohaline circulation.
The global system of surface and deep water ocean currents is driven by temperature and salinity differences between areas of oceans.
Define through fall.
This is when the rainfall possess or is relatively intense, and the water drops from the leaves twigs, needles, etc.
Define through flow
Water moving sideways through the soil downslope under the influence of gravity.