Water Cycle Knowledge Flashcards
Stages of the global hydrological cycle
1) solar energy from sun evaporates water
2) water-> water vapour as it rises and cools in the atmosphere, forming clouds through condensation
3) water droplets collect and when heavy, clouds bursts
4) GPE-> KE as water falls and moves trough the sysem by plant nterception and SRO
5)some water is infiltrated through soil, some percolate trough porous,permeable rock
What is the global water budget
Distribution and movement of water within the earths hydrosphere, water is constantly cycled through different stores and reservoirs via processes like evaporation
Is water considered to be renewable
It is generally considered a renewable resource because it is continuously replenished through the hydrological cycle
However, its renew ability depends on the specific context and time scale
Examples of renewable and non renewable water sources
Renewable- freshwater sources e.g. rivers
Non relabel- deep aquifers e.g. ogallala aquifer takes thousands of years to recharge
Therefore, a water’s classification as renewable or non renewable depends on its source, rate of replenishment and human consumption patterns.
What is residence time and how can it limit human water use
Average amount of time water spends in a specific reservoir within he hydrological cycle and how quickly it can be replenished ad sustainably used
What is short residence time and how can it affect human usage
Waters in rivers have SRT, meaning that it is readily available but highly dependent on seasonal and climatic variations e.g. droughts can quickly deplete water availability
What is LRT and how can it affect human water usage
Water stored in deep aquifers and takes thousands of years to recharge ( centuries to millennia)
E.g. water locked in glaciers and ice sheets (cryosphere), Antarctica,has LRT. Melting glaciers due to CC provide temporary water for down stream rivers but cannot sustain long term water needs cuz ice takes thousands of yrs to regenerate -> poses challenge for regions, South Asia, where millions rely on glacier fed river, Ganges
Why is understanding residence times important
Understanding these time frames is essential for managing water resources effectively, particularly in a world facing increasing water stress and CC
How does orographic rainfall (input), affect drainage basin
Moist air is forced to rise over a mountain/elevated terrain, air rises, it cools due to temps decreasing at higher altitudes ( adiabatic cooling), condensed to form clouds, precipitation occurs on the windward side of mountain, air descends on leewards side, experiences drier conditions to create rain shadow(drier regions) , Andes Mountain in SAmerica created a rain shadow called the are atacama desert
Another example, mawsynram India highest annual rain as moist air from Bay of Bengal forces to rise over khasi hill (467inches of rain)
How does frontal rain (input) affect drainage basin
2 air masses of different temperatures and densities meet at a front. Warm air rises over cold air mass because it is less dense, rises, cools, condenses, clouds…. E.g. mid latitude regions, UK where warm air created from Atlantic meets cooler polar air creating cyclonic system w heavy rain
How does convectional rain (input) affect drainage basin’
Earth’s surface heats up due to intense solar radiation, causing warm air to rise,cools,condense…… forming towering cumulonimbus clouds= heavy rain e.g. tropical regions Amazon where high temps and humidity Create daily thunderstorms
However for these inputs….
These types of rainfall differ based on their cause and location
Most rainfall areas
Tropical zones
Intertropical convergence zones belt of low pressure near equator where trade winds from north and south hempisphere converge e.g. monsoons in South Asia
During the summer, the ITCZ shifts northwards over South Asia intensify monsoon as it brings over warm waters from Indian Ocean
Countries like India and Bangladesh experice severe monsoon due to high rainfall, location in relation to the ITCZ And low lying topography
Causing Ganges river to overflow, detrimental as many rely on the Ganges river for water
Least rainfall areas
High pressure systems (anticyclone); descending dry air that inhibits cloud formation and precipitation e.g. Sahara and atacama desert chile at around 30 latitude, 1mm of rain ancually due to its location in a rainsheadow and presence o cold ocean currents
Continentality; regions distance from large bodies of water, have low precipitation as they lack moisture e.g. Central Asia , semi arid due to its distance from moisture sources e.g. Indian Ocean
How do flows and transfers affect drainage basin
Determine how fast and volume of water moving thru a system
How does permeability affect drainage basin
Porous rock (limestone), allows water to infiltrate rapidly, leading to greater storage in groundwater and slower transfers via through flow or groundwater flow
How does vegetation affect drainage basin
Dense vegetation intercept rain , decrease SRO, facilitates evapotranspiration, retiurning water to the atmosphere and decreasing volume moving through basin
How does temperature affect evapotranspiration (EVT)
Increase temp=higher EVT as it provides more energy for the evaporation of water and transpiration of plants e.g. in tropical climates
How does strong winds affect EVT
They enhance movement of water vapour from surface
How does vegetation affect EVT
Forested areas have higher EVT as large leaf surfaces promote faster rate of transpiration cuz more water is released into the atmosphere through stomata
How do humans affect drainage basin through deforestation
Deforestation=less vegetation, meaning there is a reduced water uptake by plants and less moisture returning to the atmosphere
Abundance of tree roots weaken soil structure, increasing SRO and accelerating overland flow ( use thus term whenever u mention SRO) e.g. amazon logging increases overland flow, decreases regional rainfall thru lower transpiration rates
How does urbanisation affect drainage basin
Replacement of natural surfaces w/ impermeable material, concrete, no infiltration, rapid SRO as overland flow into drainage basin e,g, expansion of cities Houston USA increases flooding due to hurricane Harvey 2017
Explain a physical case of drought
The subtropical high pressure zone interrupts the intertropical convergence zone which is a belt of low pressure.
The SHPZ prevents cloud formation and lead to persistent dry conditions
The ITCZ moves north and south seasonally bringing in rainfall to tropical regions.
However, the SHPZ acts as a barrier,preventing the ITCZ from moving further into drier regions e.g. Atacama desert( driest in world), is kept dry due to the persistent high pressure zone
How is the subtropical high pressure formed?
Plays a major role in disrupting ITCZ
Created when the Hadley cell causes warm air to rise at he ITCZ near the equator and at high pressure, air descends at 30º which causes high pressure preventing cloud formation, leading to persistent dry conditions
How does the mismanagement of rivers using hard engineering systems cause river flooding/surplus
Construction of artificial levees designed to contain rivers can fail under extreme conditions,leading to flooding.
2005 hurricane Katrina, where levee breaches in New Orleans allowed for huge inundation of large parts of the city
Similarly, dams which alter a rivers natural path can disrupt its low, and if mismanaged sudden water releases can trigger downstream flooding
2010 Indus River floods in Pakistan where excessive dam releases contributed to widespread devastation.
However, hard engineering isn’t applicable to all countries, whereas urbanisation is happening at fast rates across the continents due to globalisation
Physical cause of water surplus
In colder regions, snow and ice accumulate during winter and melt in spring,turn water locked in glaciers and ice sheets (cyrsphere), LRT into SRT, heat causes ice to thaw and melt, causing large volumes of meltwater to enter rivers and lakes at a rate too fast for drainage system to handle—> Canada Russia , spring snowmelt floods can be severe.
Additionally, ice jams in the river can block the flow of the river, causing it to back up and flood surrounding areas
However, human induced climate change can exacerbate snowmelt and ice thawing, dictating the speed and magnitude of it.
How have the regreening in the Sahel, Niger, combat desertification
Deployed farmer managed natural regeneration (FMNR), to restore millions of trees and shrubs
Involves protecting and nurturing tree stumps to allow natural growth rather than planting new trees from scratch
Helps increase crop yields leading to better agricultural productivity and more moisture returning to the atmosphere
Overall, the fact that the Sahel is heavily reliant on agriculture which leads to an overfarming culture, means that they will continue to farm which can lead to more land desertification which will be harder to replenish through just regreening strategies.
How does salt water encroachment cause water insecurity
Human induced CC can lead to thermal expansion OR STORM SURGES and KING TIDES, where the intense heat causes the ocean’s water to heat up causing the volume of water to increase and expand.
This leads to increased coastal flooding posing threats to low lying atolls like Tuvalu.
Coastal flooding causes an overflow of seawater to contaminate freshwater aquifers and contaminate drinking water supplies leading to more saltwater intrusion.
