The water/ hydrological cycle EQ1 Flashcards
what is the most common water store
oceans (97.5%)
what is the most common freshwater store
ice caps and glaciers (69%)
what is the most common accessible surface freshwater
lakes (52%)
what two water stores are non-renewable
fossil water(untapped ancient stores off fresh water)and the cryosphere
whats the cryosphere
frozen snow or ice
whats fossil water
ancient deep underground water from the geological past
why does a drainage basin vary in the amount of water it holds
because its an open system with inputs and outputs, these inputs may vary with time
what is a drainage basin
an area of land that is drained by a river and its tributaries, sometimes referred to as a river catchment. The boundary of a drainage basin is defined by the watershed.
what 5 characteristics have a significant impact on the drainage cycle
-form- rain snow or hail- entry of snow into a drainage system would be delayed
-amount-
-intensity- higher intensity= more likely to flood
-seasonality- different flow levels at different times of the year
-distribution- some tributaries may start in diff climate zones
what are the 7 flows important in transferring precipitation into a drainage network
-interception
-infiltration
-percolation
-throughflow
-groundwater flow
-surface runoff
-river/channel flow
what are the 3 types of precipitation
orographic
frontal
convectional
define the flow: interception
when vegetation takes up water
define the flow: infiltration
where water is absorbed/ taken in via the soil. water enters the topsoil and may move into the soil and rock below.
define the flow: percolation
a deep transfer of water into rocks (downwards seepage)
define the flow: throughflow
the lateral transfer of water downslope through the soil
define the flow: groundwater flow
Water contained within the soil and underlying rocks, and derived mainly from the percolation of rainwater and meltwater. (Very slow transfer of percolated water through porous rock)
define the flow: surface runoff
movement of water across the surface of the ground (also known as overland flow)
define the flow: river/ channel flow
the flow once water enters a stream/ river; the flow is confined within a river
what are the 3 main outputs of a drainage basin
-evaporation- ( moisture lost directly into the atmosphere)
-transpiration- ( the loss of water vapour from plants)
-discharge- movement of water into the sea, lake or another larger drainage basin ( also know as channel flow))
What are the 5 physical factors affecting drainage basins
-climate
-soils
-geology
-relief
-vegetation
how does the physical factor of climate affect drainage basins
- has a role in influencing the type and amount of precipitation overall and the amount of evaporation- climate also influences vegetation type
how does the physical factor of soils affect drainage basins
soils determine the amount of infiltration and throughflow and indirectly the type of vegetation
how does the physical factor of geology affect drainage basins
geology can impact on subsurface processes such as percolation and groundwater flow (and therefore impact aquifers) Indirectly, geology affects soil formation.
how does the physical factor of relief affect drainage basins
relief can impact the amount of precipitation. slopes affect the amount of runoff
how does the physical factor of vegetation affect drainage basins
the presence or absence of vegetation ahs a major impact on amount of interception, infiltration and occurrence of overland flow, as well on transpiration rates.
What are the 4 human factors affecting drainage basins
-river management
-deforestation
-changing land use ( agriculture)
- changing land use ( urbanisation)
How does the human factor of river management affect drainage basins
-construction of storage reservoirs holds back river flows
-abstraction of water for domestic and industrial use reduces river flows
-abstraction of groundwater for irrigation lowers water tables
How does the human factor of deforestation affect drainage basins
-clearance of trees reduces evapotranspiration, but increases surface runoff*
How does the human factor of changing land use (agriculture) affect drainage basins
-(arable to pastoral)- compaction of soil by livestock increases overland flow
-(pastoral to arable)- ploughing increases infiltration by loosening and aerating the soil
What does an open system receive?
Inputs from and transfers outputs of energy and matter to other systems.
Why is a hydrological cycle a closed system?
Because all the water is continually circulated through the stores and there is a constant amount of water in the system. The system does not change because there are no gains from or losses to other systems.
What is the global circulation of water driven by?
Solar energy and gravitational potential energy.
How does solar energy drive the cycle?
Global circulation of water is heated by the sun, water on the Earth’s surface evaporates into the atmosphere, while water is also drawn from the soil by plants and evaporated from leaves and stems by the process of evapotranspiration.
What happens when humid air rises?
Condensation occurs at the cooler temperatures, forming clouds, and this eventually leads to precipitation and water is returned back to the land and oceans on the Earth’s surface.
On land, what is gravitational potential energy converted to?
Kinetic energy as the water moves through the system by plant interception, or over land as surface runoff. Water also flows through the soil by processes of infiltration and throughflow.
What happens when water flows through soil by the processes of infiltration or throughflow?
Here it may be stored as soil moisture, or if the bedrock is permeable or porous, will percolate into the rock where it’s stored as groundwater. Some of this water will return to the oceans via streams and rivers
As the global hydrological system is a closed system of interlinked processes, what does this mean for the amount of global water?
It is finite and constant.
What does gravitational potential energy do in the hydrological cycle?
Causes rivers to flow downhill and precipitation to fall to the ground. Keeps water moving through the system in a sequence of inputs, outputs, stores and flows
What happens when more evaporation occurs as the climate warms?
- Increases moisture levels in the air
- Therefore greater condensation and precipitation.
What are the four main water stores?
- oceans
- cryosphere
- surface runoff (land based stores such as lakes and rivers)
- the atmosphere
define annual fluxes
the movement of water between stores over the course of the year
What are fluxes?
The rates of flow between stores.
Where do the greatest fluxes occur?
Over the oceans.
What is the second largest freshwater store?
groundwater (30% of global freshwater)
Less than 1% of freshwater is stored where?
In the biosphere ( vegetation and soil moisture)
In the system of inputs, outputs, stores and flows, what are the 5 𝘀𝘁𝗼𝗿𝗲𝘀 in this system?
- interception storage
- surface storage
- soil moisture storage
- groundwater storage
- channel storage
About ____ of the Earth’s surface is water-covered.
71%
What’s the problem with glaciers being the largest freshwater store?
They’re predicted to melt, so could be a problem.
Is there more water stored in the soil or in the atmosphere/rivers?
More water stored in the soil!
What are flows also referred to as?
Transfers.
Define 𝘃𝗲𝗴𝗲𝘁𝗮𝘁𝗶𝗼𝗻 𝘀𝘁𝗼𝗿𝗮𝗴𝗲
Any moisture taken up by vegetation and held within plants.
Define 𝘀𝘂𝗿𝗳𝗮𝗰𝗲 𝘀𝘁𝗼𝗿𝗮𝗴𝗲
Any surface water in lakes, ponds, puddles.
Define 𝗴𝗿𝗼𝘂𝗻𝗱𝘄𝗮𝘁𝗲𝗿 𝘀𝘁𝗼𝗿𝗮𝗴𝗲
Water held within permeable rocks (also known as an aquifer)
Define 𝗰𝗵𝗮𝗻𝗻𝗲𝗹 𝘀𝘁𝗼𝗿𝗮𝗴𝗲
Water held in rivers and streams.
Define 𝗯𝗮𝘀𝗲 𝗳𝗹𝗼𝘄 (groundwater flow)
Slow-moving water that seeps into a river channel.