1.2 - Capturing Flow Flashcards
What is stress?
the annual supply of water per person falls below 1700m^3
what is water scarcity and the two types?
when the annual water supply drops below 1000m^3 per person. The two types are physical - demand is greater than the supply, and economic - where people can’t afford the water even if it’s available.
What’s the mass balance change formula?
Mass balance change = Water in - Water out
What physical factors affect the distribution of water? pg 34-35 Philip Allan
Climate, near the equator- high levels of precipitation while some tropical areas suffer from drought. River Systems- store large quantities of water and transfer across continents. The amazon accounts for 20% of all the river water entering the world’s oceans, and finally Geology, if land is impermeable, then the water will remain as surface runoff creating a high drainage density.
What are Aquifers?
Aquifers such as chalk and porous sandstones can store vast quantities of water underground- a body of permeable rock which can contain or transmit groundwater.
Why is water a finite resource in terms of the supply?
the world’s oceans account for 97.5% of the global water store. the rest is fresh water and almost 80% of that is trapped in ice snow and permafrost.
what amount of the world’s population is short of water?
1/3, by 2025 it could reach 45%
What human factors affect water supply?
Agriculture, Industry, Domestic use
What percentage of the world’s freshwater supply is used within agriculture?
69%
What are the two main sources of our water supply?
Surface Water - Rivers, lakes and reservoirs
Aquifers - they are the sole source of drinking water for about a quarter of the world’s population. Over abstraction is causing the dwindling of supplies, falling water tables and sea water contamination
How much of the Ogallala aquifer was used by 1960 and then 2010?
Only 3%, however by 2010 30% was used.
When does the consumption of the Ogallala aquifer peak?
2025, it isn’t sustainable for future generations.
What actions could be taken to prevent it from running out too soon?
Cutting back on water usage, Better technology to ensure efficiency and reduced pumping
What is the water table?
upper level of an underground surface in which the soil or rocks are permanently saturated with water.
Withdrawals from the Aquifer are essentially water from how long ago? which era?
Ice age, maybe even earlier
