Methods of water supply Flashcards
Water scarcity
The lack of fresh water resources to meet the standard or demand
Potable water
Water that is safe to drink or use in food preparation
Black water
Waste water that contains human waste and is unsafe
Grey water
The relatively clean waste water generated from households. Can be used for agriculture
What is a dam?
A barrier that holds back water
What are dams used for?
To save water, manage water and prevent the flow if excess water into specific regions
What is a reservoir?
A reservoir is an artificial lake primarily used for storing water
What are wells and boreholes?
A well or boreholeis a means of tapping into various types of aquifers, gaining access to groundwater. It is sunk directly down to the water table
What is a water table?
The highest level of underground water
What are aquifers?
An underground layer of water-bearing perbiable rocks
Difference between a well and a borehole
Boreholes are drilled by machine and are relatively small in diameter, while dams are relatively large in diameter and often sunk by hand.
What is desalination?
The process of removing salt and other minerals to create fresh, drinkable water
Where is desalination used?
In the Middle East and places where sea water is plentiful but there isn’t enough fresh water
What desalination technique do most plants use?
Disilling sea water by boiling it using energy from waste gases produced by oil wells
Why will desalinated water always be more expensive than water from conventional sources
The sea water will have to undergoconventional filter treatment to remove impurities such as microbes
What is a disadvantage of desalination plants?
They are expensive and do not offer a viable solution to the poorest countries unless costs can be drastically reduced
Advantages of desalination
It doesn’t affect the water levels in rivers, and could mean that controversial plans for new reservoirs could be shelved
What is cloud seeding?
A technique used to increase rainfall in an area
Advantage of cloud seeding
Can be used directly over an agricultural area where rainwater is required immediately
What is rainwater harvesting?
The collection and storage of rainwater that runs off from rooftops and gutters
What can harvested rainwater be stored in ?
Water butts and tanks
Why are households encouraged to carry out rainwater harvesting?
In ensures they take less from the piped public supply
Where is rainwater harvesting more common
In LEDCs and rural areas as not everyone can access the piped public supply
What measures are now in place for large-scale users of water?
Water pricing and granting licenses to use certain amounts of water from the public supply
What is water license exchange?
When the surplus of the water entitled to a license holder is sold
Example of a major dam in the world
The Kariba dam in Zimbabwe
