Water Cycle Flashcards
What is a flow/ transfer?
Elements moving around the system
What is an input?
The addition of matter and/or energy into a system
What is a store/component?
Elements being stored in the system
What are elements?
The things that make up the system
What are attributes?
The perceived characteristics of various elements
What are relationships?
Association which occur between elements and attributes
What is an isolated system?
No interactions outside the system boundaryNo input or output of energy or matter
What is a closed system?
There are no inputs or outputs of the system. Matter is confined to the system, but energy may enter or exit.
What is a open system?
Where matter and energy can be transferred from the system across the boundary into the surrounding environment
What is dynamic equilibrium?
When there is a balance between inputs and outputs of the system
What is positive feedback?
Where the effects of an actions are amplified or multiplied
What is negative feedback?
where the effects of an action are nullified
What is cascading system?
A chain of systems
What is a model?
A way of simplifying or representing a complex reality
What is a System?
A model which helps explain relationships within a unit. It consists of a number of components all linked together
What is a cycle?
A continuous system
Percentage of ocean water?
97%
Percentage of fresh water?
3%
How much of the fresh water is Cryospheric?
79%
How much of fresh water is Groundwater?
20%
What percentage of water is surface water?
1%
How much of surface water is lakes?
52%
how much of surface water is atmospheric water vapour?
8%
How much of surface water is in living organisms?
1%
How much of surface water is in rivers?
1%
How much of surface water is in soil moisture?
38%
What formation is the cryosphere found in?Exceptions…
Linear formation( North and South Pole) EXCEPTIONS: Himalayas and west coastlines of south America
Where are the majority of ice caps found?
South Pole
How much ice is in the south pole?
30 million km3- 15x amount in Greenland
How much groundwater in all continents?
5 million km3
How much groundwater in Asia?
7.8 million km3
How much grounwater in Europe and Austraila?
1.2-1.6 million km3
Where are a majority of lakes found?
a linear formation along the Tropic of Cancer
Where are lakes quite common?
Canada and North America
Where are less lakes found?
areas of little precipitation
Where are drainage basins found?
a linear formation especially along the Tropic of Cancer and the Tropic of Capricorn
Evapouration
Water turns straight to water vapour
Sublimation
Ice turns directly to water vapour
Ablation
Loss of ice through evapouration or melting
Accumulation
Water freezing into ice
Calving
The sudden falling away of ice from glacier
Deposition
Water vapour turning directly into ice
What is latent heat?
Heat required to convert a solid to a liquid, a solid to gas or liquid to gas without a chnage in temperature
What is a glacier?
A slow moving mass or river of ice formed by the accumulation and compaction of snow
What is permafrost?
A thick sublayer of ice that remains below 0 degrees C for two or more consecutive years
What are ice caps?
A covering of ice on land smaller than 50,000 km2
What is sea ice?
Ice that forms on the ocean’s surface, especially during winter and the fall
What is an Iceberg?
A large floating mass of ice detached from a glacier or ice sheet and carried out to sea
What is an Ice sheet?
A layer of ice covering an extensive area of land, bigger than 50,000 km2
what is a Ice shelf?
A floating sheet of ice permanently attached to a land mass
How does the magnitude of water stores vary over time and space? Space: The Hadley Cell
- The Equator is the hottest part of the Earth so is where most evaporation occurs.
- Low pressure rises into the Troposphere it cools and condenses at Dew point.
- Precipitation therefore occurs above the Equator.
- At the Tropopause, the air is pushed in the direction of either of the tropics.
- This cools the air and it becomes denser, sinking over the Tropics (High pressure).
- As the cool air sinks it is met by the warm air from the Earth’s surface and it warms itself.
- Therefore, condensation cannot occur and therefore there is less precipitation over both the Tropic of Cancer and the Tropic of Cancer.
- This warm air is then pushed by the trade winds back towards the Intertropical Convergence Zone above the Equator.
- Alternatively, instead of going to the ITCZ the air can go towards the poles.
- Here it is met by a cold air front and warm air rises and cools (Low pressure).
- The water vapour condenses and falls as rain.
- This is why we get lots of rain in Britain because this happens above us at 60 degrees Parallel North.
How does the magnitude of water stores vary over time and space? Space: Frontal rainfall
- Rain bearing wind approaches coastal areas of high relief and this air travels up the windward side.
- As the air is forced higher by the shape of the land it cools and the water vapour condenses.
- Precipitation then occurs above this high relief e.g Fort William in the Highlands of Scotland gets 1500 mm of rain.
- When the air goes down the other side of the orographic landscape it sinks and warms.
- Therefore, no condensation can occur and therefore there is less precipitation in the area known as the rain shadow.
- For instance, Grimsby situated East of the Pennines gets less rainfall.
How does the magnitude of water stores vary over time and space? Time: Seasonal shifts of the ITCZ
- Seasonal shifts of the ITCZ when the Earth Tilts 23 degrees.
- When the ITCZ moves north and the sun is overhead in the northern hemisphere, the band of rain moves north from the Equator and the opposite direction when the the ITCZ moves south.
How does the magnitude of water stores vary over time and space? Time: Different geological time periods
- In the Quaternary Period sea levels were 120 m lower than they are currently. Ice covered large areas on the continents.
Drainage basin
An area of land drained by a river and its tributaries.
Watershed
The edge of a drainage basin signified by a ridge.
Confluence
Where two rivers meet
Tributary
A mini river which feeds the main river
Precipitation
Water falling in it’s many forms such as rain, hail, snow, sleet…
Interception
Precipitation that does not reach the soil is intercepted by the leaves and branches of vegetation.
Stemflow
The movement of intercepted water to the soil through the vegetation stem.
Throughfall
Precipitation reaching the ground by dripping off leaves and branches.
Evapotranspiration
The transfer of water into the atmosphere through evaporation and transpiration of plant leaves.
Overland flow
Water flowing horizontally across the surface of the land when surface storage has become saturated.
Runoff
All the water which reaches the river channel and eventually flows out of the drainage basin.
Channel flow
The movement of water within the river channel.
Infiltration
Water entering the ground.
Percolation
The downward movement of water within the rocks below the surface.
Throughflow
The movement of water downslope through the subsoil due to gravity.
Groundwater flow
The gradual movement of water under the water table.
Inputs into the drainage basin?
Precipitation
Flows/ transfers into the drainage basin?
- Interception
- Throughfall
- Stemflow
- Infiltration
- Percolation
- Groundwater flow
- Runoff
- Channel flow
- Throughflow
Stores and Components into the drainage basin?
- Vegetation storage
- Surface storage
- Groundwater storage
Outputs of the drainage basin?
Evapotranspiration
What is the water balance?
The balance between inputs and outputs of water.
What are the two components on the soil moisture budget graph?
Precipitation and Potential evapotranspiration.
Precipitation is like adding money to a bank account, while Potential evapotranspiration is like spending your bank account savings.
What is recharge?
When the soil reaches its field capacity when precipitation is higher than potential evapotranspiration
What is water surplus?
When the soil is over and above its field capacity. When precipitation is higher than potential evapotranspiration, the soil moisture becomes saturated.
What is Soil Moisture Utilisation?
When Potential evapotranspiration is greater than Precipitation, so plants use the existing soil moisture supplies up.
What is Water deficit?
When Potential evapotranspiration is greater than precipitation and there is no more water left in the ground e.g drought conditions.
What is Water stress?
The annual water supply is less than 1700m3 E.g India and South Africa.
What is water scarcity?
the annual water supply is below 1000m3 E.g Egypt and Tunisia.
What is Physical water scarcity?
When more than 75% of river flows are used.
What is Economic water scarcity?
When human and financial factors limit water use to less than 25% of river flows.
What is a river regime?
The variability in its discharge throughout the course of a year in response to: - Precipitation (Amount, Seasonality and Type)- Temperature (Levels of evapotranspiration due to plant growth) - Water abstraction, Dams (Flattening the regime) and drainage basin characteristics.
What are the human and Physical factors affecting runoff?
Small or large amounts of rain High or low rates of evaporation Forest and woodland or lack of vegetation Large or small drainage basinDeep or thin soils Good or poor agricultural practices Low or high intensity rainfall Soft or hard ground Rural or urban land use Permeable or Impermeable soil Few or lots of lakes Low or high drainage density Permeable or impermeable rocks Low or high antecedent moisture conditions Slow or fast snow meltGentle or steep slopes Elongated or circular drainage basin shape
Why does the water cycle change over time? - RegimeTemperate climate
- There is a steady discharge throughout the year due to the consistent levels of precipitation. - Lower discharge in the Summer because there is less precipitation and more evapotranspiration. - Higher discharge in the Autumn and Winter because the ground becomes saturated (so no further infiltration can occur) and there are no leaves on deciduous trees for interception.
Why does the water cycle change over time? - RegimeMediterranean climate:
- Flashy hydrograph at the start of the year due to the dry ground from the previous summer (not allowing infiltration to occur).- Also, increased precipitation during this time plays a part.- Lower hydrograph during the summer due to decreased rainfall and higher rates of evapotranspiration.
Why does the water cycle change over time? - RegimeMountain Climate:
- Peak discharge during Summer because the mountain peak snow is melts in the warmer temperatures.- This causes more runoff towards the river.- The discharge is lower for the rest of the year because the water is frozen in the ice.
Why does the water cycle change over time? - RegimeEquatorial Climate:
- Two peaks during the year - one around April and one in October. - This is because the Hadley cell shifts over the Equator during the year. - This changes the weather systems and causes greater precipitation at two points in the year.
Why does the water cycle change over time? - RegimeHumid Tropical climate:
- Higher discharge around March and April because the area is experiencing the wet season. - Decrease in discharge from August to November (Where it almost flatlines) because this is the dry season.
How do human practices impact on the water cycle? Soil drainage
- Underground tubes positioned around 1m below the surface help drain excess water away. - Holes in the tubes or “Tiles” allow the water to seep in and be carried away, lowering the water table.
Strengths of soil drainage
- Can improve the soil structure and enables roots to grow further and deeper.- Increased activity of microorganisms leads to the breakdown of organic matter making humus and nutrients. - Increased aeration (Airing) of soils warms them and leads to the increased likelihood of germination. This helps improve the yield of crops.
Weakness of soil drainage
- Increased throughflow in soil increases the likelihood of flooding.- Dry topsoil due to lowered water table is vulnerable to erosion e.g East Anglian arable fields. - Nitrate loss as water drains away leading to Eutrophication of local water sources.
How do human practices impact on the water cycle? Land use change - Deforestation
- Decreased evapotranspiration as trees are replaced with plants with smaller leaves and roots.- Increased overland flow due to lack of vegetation and therefore a lack of interception. This could lead to a flashy hydrograph and an increased likelihood of flooding. - The lack of interception due to the lack of vegetation means water leaves the system. It is not recycled back into the system like it normally is as water leaves in the river channel. There is less water available for precipitation within the system.
How do human practices impact on the water cycle? Water Abstraction:
This occurs when demand for water exceeds the amount available. This is often due to little precipitation occurring in an area with high population density or areas of high agricultural / industrial activity.Across much of the Mediterranean e.g Italy, Spain and Turkey groundwater is the main source of fresh water. Tourists in these areas increase the demand for water further. Water abstraction is carried out to meet demand, but this leads to lowering water tables. In coastal areas Saline intrusion becomes an increasing problem. When the water tables get lower than the sea level, seawater seeps into the groundwater and mixes with the freshwater. As a result it is no longer suitable for domestic use. In Malta, they have had to make desalination plants to treat the water, so it is suitable to drink and to use domestically.
