Water Cycle Flashcards
Define system
Something that is made of different components that work together in a interconnected way to perform some function
What is a closed system
Only energy can pass in and out
Store
Places where water is held
Flow
Process that moves water from one store to another
Flux
Flow with a known quantity of water
Largest stores of water
1)oceans
2) glaciers
3) ground water
What are residency times
The average amount of time a water molecule will stay in a store.
Longest residency times =Ice caps
Shortest residency times =biospheric water
Drainage basin
Looks at a hydrological system at a smaller scale.Classed as an open system
Watershed
Boundary of a drainage basin
Factors affecting drainage basins
C=climate
S=size
R=relief
V=vegetation
G=Geology
H=humans
Pro graphic rainfall
Caused by the relief of the land forcing the water vapour to rise and cool
Conventional rainfall
Caused by the heating of the earth’s surface leading to more buoyant parcels of humid air rising
Frontal rainfall
Caused by Warner air masses rising above denser, colder air masses
How do humans distrust a drainage basin
Farming
Deforestation
Dams (eg Aswan dam)
Agriculture
Hydroelectric power
Impacts of deforestation on the hydrological system
1) reducer tree cover increase surface run off leading to more flood prone rivers
2)less interception meaning less water goes back up ( results in dry climate)
3)degrades soils -degraded soil can’t hold water
Positive feedback mechanism for deforestation
-Trees are cleared
-less interception and evapotranspiration
-less rain falls
- trees are stressed and begin to die
-increase forest fires because it’s drier
What does a river regime show
Shows river flow over a period of one year
Two types of river regime and the differences between them
Simple -shows high and low flow representing the climate
Complex -bigger scale with multiple climate zone not just high and low flow time of the year
What does a water budget show
Mean monthly precipitation and potential evapotranspiration
What are sustainable drainage systems , give examples
- collection of water management strategies
-green roof tops : vegetation cover planted which provides a waterproof membrane
-detention basins : delay storm run off for a few hours
-permeable pavements : delay run off by using gaps between pavements slabs
Factors influencing shape of a hydrograph
-relief(steep gradient)
-impermeable rock
- vegetation
-urbanisation
-Basin shape (circular or longer )
Two types of a hydrographi
Flashy
Flat
Factors influencing a flashy hydrograph
-high peak discharge/ short lag time
- heavy rainfall (orographic/ conventional )
-Impermeable rock
-impermeable soils
-circular basin shape
-no vegetation
-steep gradient
-pre existing water in the soil
- human activity
Factors influencing a flat hydrograph
-low peak discharge/long lag time
-frontall rainfall
-permeable rock
- permeable soils
-Flat gradient
-Longer basin shape
-vegetation
-no pre existing water in the soil
-less human activity
What is PDSI
Palmer Drought severity index
What measurements can be taken to monitor and record droughts
-amount of rainfall
-soil moisture
-river flow
-demand
-extraction rates
-temperatures
-soil moisture
4 types of droughts
1) meteological
2)hydrological
3) Agricultural
4) famine
Meteorological drought
Defined by shortfalls in precipitation.Becoming more common as recent trends are of decreased rainfall totals and decreased duration and predictability of the rainy season
Hydrological drought
Associated with reduced stream flow and groundwater levels due to decrease In precipitation but high rates of evaporation. Reduces storage in lakes and reservoirs often marked right poorer water quality and salinisation
Agricultural drought
Rainfall deficiency from meteorogical drought leads to deficiency of soil moisture and soil water availability which has knock on effect on plant growth and reduces biomass
Famine droughts
Humanitarian crisis in which the widespread failure of agricultural systems leads to food shortages and famines with severe social, economic and environmental impacts
What causes droughts
Physical :
Location
Climate change
Continentality
Heatwaves
Late monsoon seasons
El Niño / La Niña
Human:
High demand
Deforestation
Pollution
Climate change
Soil degradation
