Geography notes Section A: Physical environments
Chapter1: River environments
1.1 The hydrological cycle-a closed system
The flow of water is a giant closed system→ there is a fixed amount of water.
No external inputs and outputs
Forms of water:
The hydrological cycle →rain →snow
Stores and flows →hail →sleet
Stores: areas on sea, land and atmosphere where water is received hold&
released
The atmosphere
• water exists as water vapour or as mini droplets in the clouds
The land
• Water is stored in rivers, lakes and reservoirs
• Stored in vegetation.
• It is stored below ground in the bedrock (ground water → aquifer).in
liquid form. solid form: snow and ice → e.g ice sheets, glaciers
The sea
• over 95% of Earth’s water is stored in the sea
,Geography notes Section A: Physical environments
Flows (transfers)
Evaporation
→ Starts with evaporation →heating of the sun. Sea store→ atmosphere.
→ Water→ vapour
Transpiration
→ Plants take up liquid from the soil → transform it to water vapour.
Evapotranspiration
→ Loss of moisture from the ground due to:
direct evaporation from water bodies and the soil
transpiration from plants.
Condensation
→ When water vapour→ liquid. In form of water droplets and appears as
clouds.
Precipitation
→ The transfers of water in any form, from the atmosphere→ the land or
sea surface.
Overland flow
→ Precipitation that hits the ground and enters streams, rivers or lakes
due to gravity → run off (when soil is saturated)
Infiltration (through the soil) Percolation (through permeable rocks)
→ Transfer of water through the soil (Infiltration) and through
permeable rocks (percolation) into the aquifer or groundwater store.
→ When soil spaces are full, soil becomes saturated.
Throughflow & Groundwater flow
→ Happens between the ground surface and top of the groundwater
store. Due to gravity, water moves slowly through the soil until it reach
a steam or river (a store)
→ In the rocks of the aquifer and is the underground transfer of water to
rivers, lakes and the sea.
, Geography notes Section A: Physical environments
1.2 Drainage basins and their features
The difference between the hydrological cycle and the
drainage basin.
• A drainage is an open system meaning that there are external inputs
and outputs in the cycle.
• The amount of water can vary = amount does not remain the same
(amount of water is unstable) → it is an open system.
• The hydrological cycle is a close system no external inputs and outputs
(≠drainage basin).
The amount of water in the hydrological cycle is remains exactly
the same (amount of water is stable).
Chapter1: River environments
1.1 The hydrological cycle-a closed system
The flow of water is a giant closed system→ there is a fixed amount of water.
No external inputs and outputs
Forms of water:
The hydrological cycle →rain →snow
Stores and flows →hail →sleet
Stores: areas on sea, land and atmosphere where water is received hold&
released
The atmosphere
• water exists as water vapour or as mini droplets in the clouds
The land
• Water is stored in rivers, lakes and reservoirs
• Stored in vegetation.
• It is stored below ground in the bedrock (ground water → aquifer).in
liquid form. solid form: snow and ice → e.g ice sheets, glaciers
The sea
• over 95% of Earth’s water is stored in the sea
,Geography notes Section A: Physical environments
Flows (transfers)
Evaporation
→ Starts with evaporation →heating of the sun. Sea store→ atmosphere.
→ Water→ vapour
Transpiration
→ Plants take up liquid from the soil → transform it to water vapour.
Evapotranspiration
→ Loss of moisture from the ground due to:
direct evaporation from water bodies and the soil
transpiration from plants.
Condensation
→ When water vapour→ liquid. In form of water droplets and appears as
clouds.
Precipitation
→ The transfers of water in any form, from the atmosphere→ the land or
sea surface.
Overland flow
→ Precipitation that hits the ground and enters streams, rivers or lakes
due to gravity → run off (when soil is saturated)
Infiltration (through the soil) Percolation (through permeable rocks)
→ Transfer of water through the soil (Infiltration) and through
permeable rocks (percolation) into the aquifer or groundwater store.
→ When soil spaces are full, soil becomes saturated.
Throughflow & Groundwater flow
→ Happens between the ground surface and top of the groundwater
store. Due to gravity, water moves slowly through the soil until it reach
a steam or river (a store)
→ In the rocks of the aquifer and is the underground transfer of water to
rivers, lakes and the sea.
, Geography notes Section A: Physical environments
1.2 Drainage basins and their features
The difference between the hydrological cycle and the
drainage basin.
• A drainage is an open system meaning that there are external inputs
and outputs in the cycle.
• The amount of water can vary = amount does not remain the same
(amount of water is unstable) → it is an open system.
• The hydrological cycle is a close system no external inputs and outputs
(≠drainage basin).
The amount of water in the hydrological cycle is remains exactly
the same (amount of water is stable).
