Water Systems Flashcards
What is most of the water on earth?
Salt water
What percentage of the earth’s water is salt water?
97
What percentage of the earth’s water is fresh water?
2.6
What percentage of the earth’s water is in ice caps?
67
What percentage of the earth’s water is ground water?
30
Is water a renewable resource?
It depends on where it is stored. In oceans, no, in rivers, yes.
What drives the water cycle?
Gravity and solar radiation
What are water transfers?
Advection Flooding Surface run off Infiltration Stream flow and current
What are water cycle transformations?
Evotranspiration
Condensation
Freezing
Storages of water?
Oceans Soil Groundwater Lakes Rivers and streams Atmosphere Glaciers and ice caps
What are human impacts on the water cycle?
Withdrawals
Discharges
Changing the speed of water flow
Diverting rivers
What are withdrawals of water?
for domestic use, irrigation and industry
What are discharges of water?
Adding pollutants to the water
How can humans change the speed of water?
- Building roads and channelling rivers underground
- Canalizing
- With dams
What is canalizing?
Straightening large sections of rivers in concrete channels
Why would humans divert rivers?
To avoid flood damage rivers are diverted from important areas.
Some are also diverted towards dams to improve storage.
What are examples of major changes caused by humans?
The aral sea
The ganges basin
What happened in the aral sea?
irrigation decreased river flow into the sea which lowered the sea level. It decreased by 90%.
What are surface currents?
currents moved by the wind
What are deep water currents?
caused by differences in water density
How does density in sea water work?
warm water can hold less salt than cold water so its less dense and rises. The cold water sinks. When warm water rises, cold water has to come up and replace it. When cold water rises, warm water has to go down and replace is. Thus, water circulates.
How can ocean currents effect climates?
Since water has a higher heat capacity than land, water masses heat up and cool down more slowly than landmasses. Land closer to seas therefore has a mild climate with moderate winters and cool summers.
