Water EQ1 Flashcards
what is an example of a closed system
a global hydrological cycle
what is the global hydrological cycle
circulation of water around the earth
what are the two powers which drive the global hydrological cycle
- solar energy - as a form of heat
2. gravitational energy - causes rivers to flow downhill and precipitation to fall to the ground
what is a store?
reservoirs where water is held
what are the 4 main stores in the global hydrological cycle?
- oceans
- glaciers
- surface runoff
- atmosphere
what are flows?
transfers of water from one store to another
what are the 4 main flows in the global hydrological cycle?
- precipitation
- evaporation
- transpiration
- vapour transport
what are fluxes?
the rates of flow between stores
where do the greatest fluxes occur?
in the oceans
what is the global water budget?
all the water that is held in the stores and flows of the global hydrological cycle
what is a residence time?
average time a molecule of water will spend in one of the stores
what percentage of all water is freshwater?
2.5%
what percentage of freshwater is easily accessible surface freshwater?
1%
what two water stores are non renewable?
cryosphere and fossil water (ancient deep groundwater from wetter periods)
what are the main stores of easily accessible surface freshwater?
lakes and soil moisture
what is an example of a open system?
drainage basin
what is a drainage basin?
subsystem within the global hydrological cycle, it has external inputs and outputs. they vary in size as the inputs vary overtime therefore the amount of water varies as well
what is the main input in a drainage basin?
precipitation
characteristics of precipitation which impacts a drainage basin?
- form - rain, snow, hail
- amount -this will affect the amount of water in a drainage basin and fluxes
- intensity - the greater the intensity, the greater the likelihood of flooding
- seasonality - drainage basin system operating at different flow levels at different time of the year
- distribution - where tributaries start in different climate zones
what are the 7 flows in transferring water into the drainage system?
- interception = retention of water by plants and soils which is absorbed by vegetation
- infiltration = process by which water soaks into or is absorbed by the soil
- percolation = similar to infiltration, but a deeper transfer of water into permeable rocks
- through flow = the lateral transfer of water down slope through the soil
- groundwater flow = the very slow transfer of percolated water through previous or porous rocks
- surface runoff - movement of water that is unconfined by a channel across the surface of the ground
- river/channel flow = takes over as soon as the water enters a river or stream
what are the three main outputs of a drainage basin?
- evaporation - moisture is lost directly into the atmosphere
- transpiration - biological process by which water is lost from plants through minute pores and transferred to the atmosphere
- channel flow - into a larger drainage basin
what are the human factors affecting a drainage basin???
- river management
- deforestation
- changing land use - agriculture
- changing land use - urbanisation
what is a storm hydrograph?
a graph showing changes in the discharge of a river over a short period of time. It shows the rate flow (discharge) versus time past a specific point
what are the two types of hydrograph?
- flashy hydrograph with a short lag time and high peak
2. flat hydrograph with a low peak
what type of factors is a flashy hydrograph influenced by?
human factors such as:
- deforestation
- urbanisation
- agricultural use
what type of factors is a flat hydrograph influenced by?
physical factors
what is a water budget/ balance?
balance between precipitation, evaporation and run off. it is a tool to assess the current status and trends in water resources availability in an area or over a period of time
what is the equation for precipitation?
p=Q+E +_S
precipitation = runoff + evapotranspiration +_ storage in the soil, aquifers or reservoirs
define river regime
annual variation in the discharge or flow of a river at a particular point measured in cummec
what is soil moisture surplus?
precipitation is greater then evapotranspiration
what is soil moisture utilisation?
as temperature increases, the rate of
evaporation will increase, the soil uses the
moisture gained during its surplus
what is soil moisture recharge?
when evapotranspiration exceeds precipitation and as a result the soil will regain moisture and reduce it’s deficit
what is soil moisture deficit?
Despite evaporation decreasing, there isn’t
enough precipitation to provide for vegetation
use of water loss
what is a names example of a drainage basin?
Amazon
name 3 factors affecting the characteristics of a river regime?
▪ Channel capacity of the river
▪ Area and relief of the drainage basin
▪ Volume, pattern and intensity of precipitation
▪ Climate
▪ Geology of the soil (affecting the input of groundwater)
▪ Anthropogenic (human) activities, such as building dams or terracing the land.
how is deforestation affecting the amazon drainage basin?
- provokes irreparable damage in the amazon water cycle
- the retention of humidity of the soil decreases which facilitates the the evaporation of water from the soil
