4. Water World

Question 1

What is the hydrological cycle?

Answer 1

The hydrological cycle regulates water supply and links the atmosphere, biosphere and lithosphere.

Question 2

What is the lithosphere

Answer 2

the rigid outer part of the earth, consisting of the crust and upper mantle.

Question 3

What are the hydrological processes?

Answer 3

• evaporation
• condensation
• precipitation

Question 4

what is overland flow/run-off

Answer 4

rain falls onto the ground and flows on the surface to rivers and lakes

Question 5

what is through flow

Answer 5

rainwater soaks into the soil (infiltration) and flows slowly through it to rivers

Question 6

what is groundwater flow?

Answer 6

rainwater soaks into rocks below the soil. it moves slowly through the air spaces (pores) or flows along cracks and joints

Question 7

why may water supplies be unreliable?

Answer 7

• there may be distinct wet and dry seasons
• weather cycles can occur, so an area may get between 3 or 5 dry years followed by the same number of wet years
• there is evidence of global warming and a continuing rise in temperatures

Question 8

what are the possible effects of climate change on water supplies in Asia:

Answer 8

Countries such as China, India and Vietnam depend on the water that comes from melting glaciers in the Himalayas.
Short term impacts:
A warmer climate would increase glacier melt in the Himalayas leading to seasonal stress of agriculture.
Long term impacts:
A warmer climate may melt the Himalayan glaciers leading to severely reduced water supplies

Question 9

What are the causes of river pollution and how does this threaten the hydrological cycle?

Answer 9

• untreated sewage pumped into rivers can lead to serious diseases such as cholera and typhoid
• fertilisers, pesticides and herbicides from intensive agriculture can poison wildlife and affect water quality
• chemicals from factories can poison wildlife and affect water quality
• plastic bags do not decay and other waste which does not decay can kill wildlife, block water pipes and affect water quality

Question 10

how can river pollution be managed?

Answer 10

• sewage is treated before it can be pumped into rivers
• use of fertilisers and chemicals on the land is regulated to reduce pollution
• factories get rid of their waste products, such as chemicals, before they return water to the river. In the UK, the Environment Agency imposes heavy fines on any factory which does not do this
• plastic and other waste is sent to recycling centres rather than being dumped in rivers