Term
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Definition
- Keep us alive
- Moderates our climates
- Sculps the land
- Remove and dilutes wastes and pollutants
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Term
| Only ____ of the earths water supply is available to us as liquid freshwater |
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Definition
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Term
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Definition
- Precipitation infiltrates the ground
- It is stored in soil and rock (aquafer)
- some water evaporates into the air
- the rest runs of (surface runoff) into bodies of water
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Term
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Definition
- We use greater than 50% of worlds reliable runoff and could be using 70-90%
- 70% of the water we take out of rivers, lakes and aquafers is not returned
- Irrigation uses 70%, Industries 20% and residences use 10%
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Term
| ___% of the worlds population lives in river basins that do not have enough freshwater |
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Definition
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Term
| Many parts of the world are experiencing: |
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Definition
- Rivers running dry
- Lakes and Seas shrinking
- Falling water tables from over-pumped aquafers
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Term
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Definition
| There is a controversey over whether water supplies should be owned and managed by the Government or by private corps. |
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Term
| European based water companies aim to control ___ of US water supplies by buying up water companies and entering into agreements with cities to manage water supplies. |
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Definition
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Term
| Cities are outbidding ________ for water supplies from rivers and aquafers |
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Definition
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Term
| Countries are importing _____ as a way to reduce their water use. |
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Definition
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Term
| More crops are being used to produce____. |
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Definition
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Term
| If we need water, our options are: |
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Definition
- Get more from aquafers and rivers
- De-salinate ocean water
- Waste less water
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Term
| Most aquifers are renewable unless, |
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Definition
| Water is removed faster than it is replenished or it becomes contaminated |
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Term
| Advantages of withdrawing groundwater: |
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Definition
- useful for drinking and irrigation
- available year round
- exists almost everywhere
- renewable if not overpumped or contaminated
- No evaporation losses
- Costs little to extract
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Term
Disadvantages to withdrawing groundwater:
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Definition
- Aquafer depletion from over pumping
- sinking of land from overpumping
- polluted aquafers for decades or longer
- saltwater intrusion into drinking water
- as aquafers become depleted, deeper wells cost more
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Term
| Benefits of large dams and reservoirs: |
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Definition
- provides water for year round irrigation and cropland
- provides water for drinking
- resevoir for recreational uses
- production of cheap electricity
- reduces downstram flooding
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Term
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Definition
- Flooded land above dam can destroy cropland and forests, displace people
- Large losses of water through evaporation
- Cropland and estuaries downstream deprived of nutrient rich silt
- Dams pose risk of failure
- Migration and spawning of fish
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Term
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Definition
Too many dams and water withdrawals cause most water to never reach the ocean
- 14 major dams, resevoirs and canals
- Water used mostly in desert areas
- provides electricity for 30 million people (1/10 of US population)
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Term
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Definition
There is a debate as to whether the advantages of the woulds largest dam will outweigh the disadvantages.
- it will be 2km long (1.24 miles)
- the electric output will be that of 18 large coal burning plants
- it will be able to facilitate ship travel to reduce transportation costs
- dam will displace 1.2 million people
- dam is built over seismic fault and already has small cracks
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Term
| Transferring water can make unproductive areas more productive but can cause _________. |
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Definition
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Term
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Definition
- promotes investment, jobs and a strong economy
- encourages unsustainable use of water where water is not naturally supplied.
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Term
| Removing salt from water is: |
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Definition
- costly
- produces large amounts of saltwater waste
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Term
| 2 methods to desalinate water: |
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Definition
- Distillation- heating saltwater until it evaporates
- Reverse Osmosis- uses high pressure to force saltwater through a membrane filter
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Term
| Other options to desalinate water: |
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Definition
- Seeding clouds to promote rainfall
- Towing ice bergs
- Dragging huge bags filled with freshwater
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Term
| What is wrong with the other ways to desalinate water? |
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Definition
| They are too costly and will produce insignificant amounts of water. |
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Term
| We waste about ___ of the water we use, but we can cut it down to ___. |
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Definition
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Term
| ____ of the water people use throughout the world is lost through evaporations, leaks and other losses. |
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Definition
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Term
| Water is _____ through government subsidies. |
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Definition
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Term
| The lack of government subsidies for improving the efficiancy of water use contributes to: |
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Definition
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Term
| ___ of the worlds irrigation water is wasted |
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Definition
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Term
| Improved techniques could but world irrigation waste to ___. |
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Definition
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Term
| Some suggest that we should ____ the price of water while providing ____ rates for the poor. |
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Definition
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Term
| We must simply _____ our freshwater and use it wisely |
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Definition
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Term
| Effects of too much water: |
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Definition
- Heavy rain, snow melt, removal of vegetation and destruction of wetlands cause flooding.
- Floodplains help probide natural flood and erosion control (we develop these areas)
- develpment and other human activities have contributed to deaths.
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