The Water Cycle and Water
Insecurity
Whole A-level topic content including case studies, definitions and in depth explanations made
for Edexcel specification
,Key terms
1. Hydrological drought = the effects of periods of precipitation shortfalls on surface or subsurface water supply
2. Meteorological drought = when dry weather patterns dominate an area
3. Agricultural Drought = It happens when there isn’t enough rainfall, and moisture in soils to support crop production or
farming
4. Famine = Extreme scarcity of food
5. CMI (Crop Moisture Index) = It gives the short-term or current status of purely agricultural drought or moisture surplus
and can change rapidly from week to week Only used in the US
6. ENSO – El Niño Southern Oscillation = Is an irregularly periodic variation in winds and sea surface temperatures over
the tropical eastern Pacific Ocean, affecting the climate of much of the tropics and subtropics
7. El Niño and La Niña = El Niño refers to a warming of the ocean surface or above-average sea surface temperatures in
the central and eastern tropical Pacific Ocean. La Niña refers to a periodic cooling of the ocean's surface temperatures
in the central and east-central equatorial Pacific
8. Overcultivation = The act or an instance of cultivating something excessively especially: the act or practice of cultivating
land to an excessive degree in the growing of crops so that soil quality is degraded and productivity is reduced.
9. Peak Discharge = The peak rate of discharge or peak rate of runoff
10. Desertification = The process by which natural or human causes reduce the biological productivity of drylands
11. Eutrophication = Excessive richness of nutrients in a lake or other body of water, frequently due to the runoff from the
land, which causes a dense growth of plant life and death of animal life due to lack of oxygen. The decay of algae takes
in even more oxygen starving the body of water.
,Enquiry question 1
, 5.1 The global hydrological cycle
A system is any set of interrelated components that are connected Global water budget = annual balanc
together to form a working whole, characterised by inputs, stores, fluxes and the size of water stores (oc
processes (flows) and outputs atmosphere, biosphere, cryosphere,
- Closed system = when there is transfer of energy but not matter groundwater and surface water
between the system and its surroundings- the hydrological cycle as - The water stores have different re
there are no gains or losses to other systems times but the constant circulation,
- Open system = received inputs from and transfers outputs of variable speeds, means water is ge
energy and matter to other systems considered renewable
HOWEVER
Hydrological cycle: - Fossil water isn’t, its water that ha
- Driven by solar energy; heated by the sun contained in a undisturbed places
- Water on earth evaporates into the atmosphere while water is also (groundwater in an aquifer) for a m
drawn from the soil by plants and evaporated from leaves and longer
stems through evapotranspiration - In regions, such as Sahara, fossil w
- When humid air rises It condenses at cooler temperatures forming these aquifers may be extracted fo
clouds = precipitation and water returned to land and oceans use (agriculture, industry, consum
- On land, GPE is converted to kinetic energy as water moves there s no significant recharge = n
through the system by plant interception or surface run off renewable
- Water also flows through soil by infiltration and throughflow where
it can be stored as soil moisture or, if the rock is permeable or
porous, will percolate into the rock and store as groundwater
Insecurity
Whole A-level topic content including case studies, definitions and in depth explanations made
for Edexcel specification
,Key terms
1. Hydrological drought = the effects of periods of precipitation shortfalls on surface or subsurface water supply
2. Meteorological drought = when dry weather patterns dominate an area
3. Agricultural Drought = It happens when there isn’t enough rainfall, and moisture in soils to support crop production or
farming
4. Famine = Extreme scarcity of food
5. CMI (Crop Moisture Index) = It gives the short-term or current status of purely agricultural drought or moisture surplus
and can change rapidly from week to week Only used in the US
6. ENSO – El Niño Southern Oscillation = Is an irregularly periodic variation in winds and sea surface temperatures over
the tropical eastern Pacific Ocean, affecting the climate of much of the tropics and subtropics
7. El Niño and La Niña = El Niño refers to a warming of the ocean surface or above-average sea surface temperatures in
the central and eastern tropical Pacific Ocean. La Niña refers to a periodic cooling of the ocean's surface temperatures
in the central and east-central equatorial Pacific
8. Overcultivation = The act or an instance of cultivating something excessively especially: the act or practice of cultivating
land to an excessive degree in the growing of crops so that soil quality is degraded and productivity is reduced.
9. Peak Discharge = The peak rate of discharge or peak rate of runoff
10. Desertification = The process by which natural or human causes reduce the biological productivity of drylands
11. Eutrophication = Excessive richness of nutrients in a lake or other body of water, frequently due to the runoff from the
land, which causes a dense growth of plant life and death of animal life due to lack of oxygen. The decay of algae takes
in even more oxygen starving the body of water.
,Enquiry question 1
, 5.1 The global hydrological cycle
A system is any set of interrelated components that are connected Global water budget = annual balanc
together to form a working whole, characterised by inputs, stores, fluxes and the size of water stores (oc
processes (flows) and outputs atmosphere, biosphere, cryosphere,
- Closed system = when there is transfer of energy but not matter groundwater and surface water
between the system and its surroundings- the hydrological cycle as - The water stores have different re
there are no gains or losses to other systems times but the constant circulation,
- Open system = received inputs from and transfers outputs of variable speeds, means water is ge
energy and matter to other systems considered renewable
HOWEVER
Hydrological cycle: - Fossil water isn’t, its water that ha
- Driven by solar energy; heated by the sun contained in a undisturbed places
- Water on earth evaporates into the atmosphere while water is also (groundwater in an aquifer) for a m
drawn from the soil by plants and evaporated from leaves and longer
stems through evapotranspiration - In regions, such as Sahara, fossil w
- When humid air rises It condenses at cooler temperatures forming these aquifers may be extracted fo
clouds = precipitation and water returned to land and oceans use (agriculture, industry, consum
- On land, GPE is converted to kinetic energy as water moves there s no significant recharge = n
through the system by plant interception or surface run off renewable
- Water also flows through soil by infiltration and throughflow where
it can be stored as soil moisture or, if the rock is permeable or
porous, will percolate into the rock and store as groundwater
