Lecture 3 Global Freshwater Use and the Hydrologic Cycle Flashcards
What makes up Earth’s Water?
97% Ocean water
3% Freshwater
How much of fresh water is accessible?
less than 1% is accessible
less than 1% is ground water
2.15% ice and glaciers
Where is ground water stored?
Ground water is stored as aquifers.
Aquifers: geologic formations that contain pore spaces in soil or fractures in bedrock. only accessible by drilling
What makes up surface water?
snow and land ice (glaciers, ice sheets, ice caps) lakes, ponds
What is a watershed?
an area of land where all water falls on it and drains to a common outlet
Where does Vancouver get its water from
Capilano, Seymour, Coquitlam
What is freshwater and how is it replenished?
Fresh water is a renewable source and its replenished via the hydrological cycle
What are flows/fluxes?
when water moves between stores through various processes
What are stores/pools/reservoirs?
Parts of Earth system where water is stored
Renewable source does not equal…
not infinite, have to know and manage all fluxes output =input
The world’s water cycle consists of:
precipitation, evaporation, transpiration, and run off
Which water resource stays in its natural store the longest?
Ground water (2 weeks to 10,000 years)
Why is fresh water a planetary boundary?
It’s being consumed at a faster rate than replenished. Reductions in freshwater availability
Ways humans cause water to stop flowing
Water abstractions
Water storage
Land modification
Climate change
What are the control variable and planetary boundary for freshwater?
control variable:
max amount of consumptive freshwater use
boundary: 4000 km/year
basin: fresh water withdrawal as % of monthly river flow
