The water cycle and water insecurity Flashcards
Aquifer?
A permeable or porous rock which stores water
Channel flow?
The water flowing in a rivulet, stream or river contained within the banks
Closed system?
A sequence of linked processes with a transfer of energy but not matter between parts of the system
Cryosphere?
Describes the set of all locations on earth where water is found in solid form, including areas of snow, sea ice, glaciers, permafrost, ice sheets and icebergs
Deficit?
Where a resource is less than the necessary amount
Drainage basin?
The area of land drained by a river and it’s tributaries. Drainage basins are separated by a ridge of high land called the watershed
Economic water scarcity?
Occurs when water resources are available but there is insufficient capital to access the water to meet demand
Evapotranspiration?
Combined loss of water to the atmosphere via the processes of evaporation and transpiration
Flux?
The flow or flowing of a liquid
Fossil water?
Water that has been contained and undisturbed for millennial. There is no significant recharge therefore it is a non-renewable resource.
Global water budget?
The amount of water transferred and stored in the earths hydrological cycle each year.
Hard engineering?
Often hi-tech and high-cost engineering schemes such as dams or Thames barrier
Hydrological drought?
Occurs when there is insufficient soil moisture to meet the needs of vegetation at a particular time
Infiltration?
The movement of water vertically downwards via spaces (pores) in the soil.
Interception?
The process by which raindrops are prevented from called onto the ground via leaves, branches, twigs of vegetation.
Monsoon?
A seasonal prevailing wind which causes wet and dry seasons in many sub-tropical areas
Open system?
A sequence of linked processes with inputs and outputs, including transfers of energy and matter to and from other systems.
Orographic?
Relating to mountains, orographic uplift if when the uplift of an air mass, because of orographic obstruction, causes the cooling of air mass. If enough cooling takes place, condensation can occur and form into orographic precipitation.
Percolation?
A process similar to infiltration but travelling through rock surfaces towards the water table.
Permafrost?
Zone of permanently frozen water found in high latitude soils and sediments
Permeability?
The ability of a substance to allow another to pass through it, especially porous rock, sediment or soil to transmit fluid through pores and cracks
Physical water scarcity?
Occurs when there’s physical lack of available freshwater resources to meet demand due to over-abstraction by agriculture, industry and domestic activity
Porosity?
A surface that allows water to pass through it, such as sand
Precipitation?
Any form of water falling from the sky
Relief?
The range of topographic elevation within a specific area
Resilience?
Ability to recover/adjust easily to an event or change
River regime?
The pattern of river discharge over a year; usually there are seasonal variations
Runoff?
Water (from rain, snowmelt etc) that flows over the land surface; can be due to soil saturation
Saltwater encroachment?
Where saline water beings to find it’s way into fresh water aquifers, especially near coastal aquifers which run low, allowing salt water to see back in and cause contamination
Saturated overland flow?
Occurs when the soil becomes saturated, and any additional precipitation causes runoff
Storm hydrograph?
Shows changes in a rivers’ discharge at a given point on a river over a short period of time (usually before, during and after a storm)
Water budget?
The annual balance between inputs (precipitation) and outputs (evapotranspiration and channel flow) at a place
Water security?
The capacity of a population to safeguard sustainable access to adequate quantity’s of acceptable quality water.
Water stress?
When demand for water exceeds the available amount during a certain period. Renewable water resources are between 1000 and 1700m
What is a closed system?
A system that does not allow a transfer of matter in or out of the system
Inputs of hydrological cycle?
Ocean precipitation
Land precipitation
Stores of hydrological cycle?
Ice Ocean Soil moisture Groundwater Rivers, lakes Land Vegetation
Flows/processes of hydrological cycle?
Ocean to land water vapour transport
Surface flow
Ground water flow
Outputs of hydrological cycle?
Ocean evaporation
Evaporation, transpiration
What type of system is the hydrological cycle?
A renewable one: no new water can enter the system and no new water can be lost
What is the water circulation in the hydrological driven by?
Solar energy- suns heat causes evaporation and transpiration
Gravitational potential energy- water accelerates under gravity causing it to flow
Why is fossil water considered non-renewable?
Will require significant amount of energy to obtain
Taken out of the store and not replaced
Of the fresh water present, where is most of it?
Locked up or bellow surface as ground water
Where is 68% of water found?
In icecaps or glaciers
Where is 30% of water found?
Groundwater
What does ITCZ stand for?
Inter tropical convergence zone
What type of pressure can be found at the equator?
Low pressure
What type of pressure can be found at the tropics?
High pressure
What type of pressure can be found at the polar regions?
High pressure
How many cells of circulating air are there?
Six
Why is the sun most intense at the equator?
Suns rays are most concentrated here
What does intense solar radiation result in?
Rising air
What type of rainfall can be found at the equator?
Convectional rainfall
What type of system is the drainage basin?
An open system within the closed global hydrological cycle
What is the definition of a drainage basin?
An area of land drained by a river and its tributaries with a boundary, usually composing of hills and mountains
What are the 5 main stores in the drainage basin?
Channel storage Groundwater storage Surface storage Soil moisture storage Interception storage
What is the main input in the drainage basin?
Precipitation
What are the 7 main flows in the drainage basin?
Throughfall Stemflow Surface runnoff Infiltration Groundwater flow Percolation Channel flow
What are the 3 physical factors that affect the drainage basin INPUTS?
Seasonality
Variability (long term changes to climate)
Latitude
What is interception?
Process by which raindrops are prevented from falling directly onto ground surface by a layer of vegetation
What is Infiltration?
The movement of water vertically downwards through pores in soil
What is Surface runoff?
Water flows overland, rather than permeating deeper levels of the ground.
What is Throughflow?
A down slope movement under the influence of gravity towards a stream or river through the soil
What is Percolation?
Water moves from the ground or soil into porous rock or rock fractures. The rate is dependent on the fractures that may be present + the permeability of the rock
What is groundwater flow?
The gravitational transfer of water through porous rock, under the influence of gravity. Water can sometimes become trapped within these deep layers of bedrock, resulting in aquifers.
What is infiltration capacity?
Is the maximum rate at which the soil can absorb precipitation
What is soil capacity affected by?
Soil composition
Previous precipitation
Type and amount of vegetation
Relief of land
What is the primary transfer of water to river channels?
Surface runoff
What are the 6 physical factors affecting drainage basin FLOWS?
Interception Infiltration Surface run off Through flow Percolation Groundwater flow
What are the two physical factors affecting drainage basin OUTPUTS?
Evaporation
Transpiration
What is transpiration?
A biological process where water is lost to atmosphere via pores of plants (stomata).
What is transpiration affected by?
Seasonality
Vegetation
Moisture content
What is evaporation also dependent on?
Volume and surface area of the water body
Vegetation cover
Colour of surface beneath the water
What are the 3 rainfall types?
Conventional
Frontal/cyclonic
Relief/orographic
Conventional rainfall?
Often a daily occurrence. Morning heat warms the ground in turn heats low level moisture which evaporates and rises. It cools and condenses to form rain. Very common in tropical climates.
Frontal/cyclonic rainfall?
Where two air masses meet, a wedge can occur of hot air within cold air (a depression). At the front, warm moist air is forced to rise above the cold air mass, causing the water moisture within it to cool and condense
Relief/orographic rainfall?
When warm moist air meets land of high relief, the air masses are forced to rise above the hill to continue travelling. As it rises, air masses cools and the moisture in it hun it condenses to form clouds and rainfall.
What are the 6 human (anthropogenic) factors that disrupt the drainage basin system?
Cloud seeding Urbanisation Change in lane use Deforestation Dan construction Ground water abstraction
Over abstraction?
When water is taken from aquifers, ground water levels fall. If the amount of water taken is greater that the amount it water falling it is called over abstraction
Groundwater abstraction?
When water us taken out faster than it is replaced (from aquifers), causing reduced ground are flow and a lower water table
Dan construction?
Dams reduce downstream river flow and discharge, increased surface stores thus means more evaporation
Cloud seeding?
This is in an attempt to change the amount of precipitation by dispersing substances into the air that serve as cloud condensation nuclei
Urbanisation?
Creates impermeable surfaces that reduces infiltration and increases surface runoff and through flow via artificial drains: river discharge increases as a result
What are 4 impacts on drainage basin due to reservoir construction?
Reduce river flow bellow the, leading to loss of vegetation
They abstract water from the drainage basin
Salinity levels can rise as water evaporates
In tropics, mats of floating plants on water surface makes evapotranspiration rates 6x higher than in open water
Water budget equation?
Precipitation= channel discharge + evapotranspiration + change in water storage
5 ways in which the Amazon forests can effect the hydrological cycle?
Risks to wildlife
Risks indigenous tribal communities
Precipitation can arrive in bursts causing floods
Affect water supplies of Brazilian cities
Winds blowing over uneven forest canopy creates turbulence, which allows atmosphere to absorb moisture
What does the water budget give a direct comparison to?
Natural water supply and demand- can identify a positive water balance and when there is a drought risk
What are the 6 characteristics on a soil moisture budget graph show?
Soil moisture surplus Soil moisture utilisation Maximum annual temp Soil deficiency Soil moisture recharge Field capacity
Soil moisture surplus
Precipitation is greater than evaporation thus meaning the soils moisture increases
Soil moisture utilisation
As temp increases, so does evaporation. The soil uses the moisture gained during its surplus, used up by plants etc
Maximum annual temp
The point of maximum evaporation= highest risk of drought. Soil moisture is now used up. Precipitation likely to be used up, no run off, river levels will fall