1.0 Introduction to river environments Flashcards
Fluvial
A term applied to the action of rivers and streams
Fluvial Geomorphology
The study of processes and landforms resulting from river erosion, transport and deposition
What is the Global Hydrological Cycle?
The continual circulation of water between the Earth’s surface and the atmosphere.
What kind of system is the GHC and why?
Closed system- It doesn’t have any external inputs or outputs; water circulates through a number of stores
How does water move between stores in the GHC?
Movement between stores comes through inputs and outputs in a series of flows/ transfers and fluxes/ processes
How does water move through the cycle (in what form?)
Water moves through the cycle in all 3 forms
Explain why the GHC is a closed system (short answer)
Water on the Earth’s surface or in its atmosphere isn’t lost into space neither is it added to from outside of the atmosphere.
How much water is within the system?
A finite amount
Since there is a continuous cycle of water, what are the major stores it flows between?
Oceans, atmosphere, biosphere, land surface & groundwater store
What is the circulation in the GHC driven by?
-Solar energy (evapotranspiration)
-Gravitational potential energy
-Infiltration, percolation, throughflow, groundwater flow
Residence time within key stores
Vastly different
What is the significance of variations in solar energy input (polar vs rainforest) and geomorphology or landscapes?
Local/ regional variation in operation of system between different climatic zones and drainage basins
What is fossil / paleo water?
Untapped ancient stores or freshwater exist in the polar regions and below many deserts.
How much freshwater does Kenya’s Lotikipi Aquifer contain?
Estimated 200 billion cubic metres of freshwater
Define ‘residence time’
Storage times of the world’s main water stores/ resources
Residence time of oceans
4000 years
Describe the hydrology of The Cryosphere (Polar Regions)
Seasonal thaws bring increased surface saturation and thinning permafrost. If this thaw becomes continuous, water flows away and is lost which is known as Cryosphere loss
Describe the hydrology of The Cryosphere (Polar Regions)
Seasonal thaws bring increased surface saturation and thinning permafrost. If this thaw becomes continuous, water flows away and is lost which is known as Cryosphere loss
Describe the hydrology of Tropical Rainforests
Permanently dense forest produces high rates of evapotranspiration, with water returning to the surface as precipitation that feeds large rivers such as the Amazon
Identify the key factors to t influence the operation of the Hydrological Cycle in Polar Regions
Low temperatures - high % of water held in ice
Low evapotranspiration
Low annual precipitation
Seasonal change- freeze/thaw
Limited vegetation
Permafrost - impermeable
Identify the key factors to t influence the operation of the Hydrological Cycle in Tropical Rainforests
High temps - high evapotranspiration
High annual precipitation
Limited seasonal change (year round heat/rain)
Vast vegetation coverage- interception and storage- little water reaches ground or infiltrates
What is a drainage system an example of?
An open system which is a subsystem within the closed system if the GHC
Drainage Basin
Has stores , flows and processes (like closed system) but inputs/ outputs are added from outside the system and transfer to other drainage basins
Where do inputs come from within an open system?
Precipitation
Where do outputs include in an open system?
Evapotranspiration or river discharge into other drainage basins, lakes or coastal environment -> the ocean store
Within the GHC and drainage basin subsystems, what can the interaction between human and physical environments result in conditions lead to?
Water surplus (river flooding)
Water deficit (drought)
