Lecture 17: Freshwater Resources

Question 1

What affects water availability?

Answer 1

• reservoir residence time
• temporal availability
• spatial availability
• proximity to human need

Question 2

What is renewable vs non-renewable freshwater

Answer 2

renewable = short residence time (water is always renewed) and significant withdrawals don’t cause depletion

non-renewable = long residence time where withdrawing water causes depletion

Question 3

How do temporal and spatial availability affect freshwater accessibility

Answer 3

temporal: not all freshwater is accessible all year (rainy vs dry seasons)
spatial: some areas have far more rainfall than others (rainforests vs deserts)

Question 4

What is green water vs blue water?

Answer 4

Green water = held in biological life
blue water = held in abiotic reservoirs

Question 5

What is water availability vs accessibility?

Answer 5

availability = how much water is available for potential use
accessibility = how much water can actually be used (eg economically, politically…)

Question 6

what is the relationship between available terrestrial water, precipitation, evapotranspiration and runoff?

Answer 6

Terrestrial renewable freshwater = precipitation over land = green water (evapotransp water) + blue water (runoff to sea)

Question 7

What are the classifications of water usgae?

Answer 7

W for survival: drinking, cooking, hygiene
W for economic purposes: agriculture, industry
Environmental w: support ecosystems & species

Question 8

What causes issues with water for survival availability?

Answer 8

2.2 billion do not have safe drinking water at home: distribution issues and infrastructure issues

Question 9

How does a lack of environmental freshwater affect salinity at interfaces?

Answer 9

Where freshwater used to hold back salt water, saltwater intrusion now occurs which is fatal to freshwater species