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6.1 Water Sources (The use and availability of freshwater (Used…
6.1 Water Sources
The use and availability of freshwater
Virtual water: it is used for other products. Not for consumption.
Virtual water footprint: the amount of virtual water used by an individual or an entity like a society or population
Makes a large part of our water footprint (3 largest in India, USA, China)
Used unsustainably
damages global health due to pollution
Pollutants, using water supplies faster than they can be replenished
Threats to food production and energy
Less ecosystem services and habitat degradation
Hydrologic cycle is disrupted due to pollutants and water being used faster than it can replenish
2.5% of Earth's water is freshwater (groundwater is 30.1% and glaciers/ice caps are 68.6% of that 2.5%)
Recycled thru water cycle
Groundwater is the biggest source of drinkable freshwater
High Use= Freshwater scarcity stress
Aquifires and Groundwater
Groundwater is the freshwater located underground, and the top of this collection is called water table
Aquifers: underground layer of water-bearing permeable rock
Unconfined and confined aquifer
UNCONFINED: water seeps directly from the ground surface CONFINED: impermeable rock layer exists that prevents water from entering directly. Instead, water enters from other confined aquifers where the layer does not exist.
Depletion of aquifers
Problems
poverty
Sinkholes
saltwater seep
Solutions
use water sustainably
stop growing crops that require lots of water in dry environments
Most aquifers are recharged naturally by precipitation, lakes, rivers, or streams. They take hundreds/thousands of years to fill to their current levels.
Increasing Freshwater Availability
Desalination
Lots of waste salt means increased salinity in other water habitats
very expensive and few cities can afford it
chemicals can kill marine organisms
Distillation to leave salt & Reverse Osmosis to leave out other impurities
Water Transfer / Aqueducts
This means less water for the original habitat from where it was taken
Water evaporates so they aren't as effective
Degrades ecosystems
Dams
Cons
causes sediment accumulation
river loses water downstream and floods upstream
Not useful for long
Floods can destroy terrestrial habitats
Pros
Provides a freshwater supply
Hydroelectric power
Helps control floods
Reducing Freshwater Use
Sustainable use in agriculture
We can see drip irrigation, polycultures, less thirsty crops, irrigating at night.
reduce waste water from homes and industries