EV1005 - L9 Groundwater Resources Flashcards
(32 cards)
How much of earths surface is covered by water? (%)
75%
How much of the human body is made up of water? (%)
65%
Of all the fresh water on earth, where is most of it? (2) and how much is easily accessible? (1)
Water is held in ground water (30.8%) and ice (68.9%). Rivers and lakes only make up 0.3% of fresh water resources
What amount of m^3 available per capita defines the area to be water STRESSED?
1700m^3 available per capita
What amount of m^3 available per capita defines an area to be water SCARCE?
1000m^3 available per capita
True of False? Water sources are often close by to large populations
False. For example, nearly 50% of the worlds lakes are at high altitudes in Canada
How much of the world’s population lives in countries that are water stressed? (/)
Approx one third (33%)
Where does the majority of fresh water get used?
Agriculture uses aprox 70 times more water that what is used for drinking water and other domestic purposes
According to UNESCO in 2000, agriculture accounted for what percentage of fresh water use?
Approx 67%
How is water supply linked with food security?
If water supply decreases, droughts can occur and this decreases crop yields.
Why is ground water use in agriculture more common than surface water in arid regions?
Because it is arid and there is little surface water
in populations living in arid regions, how much of their water supply comes from groundwater? (%)
20%
How does vegetation help groundwater recharge?
Water doesn’t dun off and is infiltrated instesad
How does vegetation hinder groundwater recharge?
The plants use the water up and so less water is held in the soil
Is this very high, high or low porosity?
Low porosity cemented sandstone
Is this very high, high or low porosity?
High porosity sandstone
Is this very high, high or low porosity?
Very high porosity mudstone
Is this high, low or very low permeability?
Low permeability cemented sandstone
Is this high, low or very low permeability?
High permeability sandstone
Is this high, low or very low permeability?
Very low permeability mudstone
Define permeability
The capacity of the material to transmit fluid
What is an aquifer?
Rocks that have high enough porosity and permeability to alow water to be withdrawn
What is an aquitard?
Rocks that dont have high enough porosity and permeability to alow water to be withdrawn
What is an aquiclude?
Impemeable beds of rock that surround permeable, water stransmitting beds
