Water World

Question 1

What is the hydrosphere?

Answer 1

The hydrosphere consists of all the water on the planet, in seas, oceans, rivers and lakes, in soil and rocks, in living things and in the atmosphere.

Question 2

In what three states does water exist on the earth’s surface and in the atmosphere?

Answer 2

1) As a liquid - water
2) As a solid - ice
3) As a gas - water vapour

Question 3

What is the hydrological cycle in general terms?

Answer 3

It is a closed system, water is constantly cycled, none is added or lost.

Question 4

What are the stores in the global water cycle? (4)

Answer 4

Lakes, oceans, soil and rocks underground.

Question 5

Water in the water cycle flows between stores via which four main transfers?

Answer 5

1) Runoff (overland flow)
2) Infiltration
3) Throughflow
4) Groundwater flow

Question 6

Sometimes the flow of water between stores involves a change of state, what processes may this involve?

Answer 6

1) Evaporation - Heat energy can change liquid water into a gas, water vapour.
2) Condensation - Air can only hold so much water vapour before it becomes saturated, as air cools water vapour turns back into a liquid, condensation.
3) Freezing - water can freeze to solid ice as the temperature cools, or melt back to liquid as it cools.

Question 7

Outline the main stages in the hydrological cycle. (6)

Answer 7

1) Evaporation from oceans and lakes, and evapotranspiration from water surfaces and plants.
2) Transfer of water vapour by winds
3) Condensation of water vapour to form clouds.
4) Precipitation when clouds become saturated.
5) Some precipitation runs off over the surface.
6) Infiltration and groundwater flow.

Question 8

How is the biosphere involved in the water cycle?

Explain all three ways.

Answer 8

1) In the biosphere trees intercept precipitation, an over half of it is then evaporated and transpired without ever reaching the ground.
2) If there is a storm or rainfall is very heavy then the precipitation gradually drips form the leaves and stems and makes its way into the river system.
3) Precipitation infiltrates into the soil, where it flows downhill as throughflow or if the rock is permeable into the ground to be stored as groundwater.

Question 9

In general terms what is the role of the biosphere and lithosphere in the water cycle?

Answer 9

The biosphere and lithosphere help to regulate the water cycle.

Question 10

What is the biosphere?

What is the lithosphere?

Answer 10

The biosphere is the part of the earth and atmosphere in which living organisms exist.
The lithosphere is the outer layers of the Earth’s surface, the crust and upper mantle.

Question 11

What is evapotranspiration?

Answer 11

This is the combine process of Evaporation where water changes from a liquid to a gas due to the heat of the sun and Transpiration the movement of water through a plant and its loss into the atmosphere as water vapour.

Question 12

Give three reasons why water supplies are unreliable.

Answer 12

1) There may be distinct wet and dry seasons, e.g. the Sahel.
2) Weather cycles can occur, so an area may get 3 or 5 dry years followed by the same number of wet years. e.g. the Sahel had a series of dry years
3) Global warming and continuing rising temperatures

Question 13

Give four causes of river pollution.

Answer 13

1) Untreated sewage pumped into rivers can lead to serious diseases such as cholera and typhoid.
2) Fertilisers, pesticides and herbicides from intensive agriculture can poison wildlife and affect water quality.
3) Chemicals from factories can poison wildlife and affect water quality.
4) Plastic bags and other waste which does not decay can kill wildlife, block water pipes and affect water quality.

Question 14

Give four ways in which river pollution can be managed.

Answer 14

1) Sewage is treated before it can be pumped into rivers.
2) Use of fertilisers an chemicals on the land is regulated to reduce pollution.
3) Factories get rid of 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.
4) Plastic and other waste is sent to recycling centres rather than dumped in rivers.

Question 15

Give four facts about large-scale water management.

Answer 15

1) These schemes are expensive
2) They cover large areas
3) They are organised by local or national governments
4) They usually consist of dams and reservoirs being created.

Question 16

In what three main ways can humans intervene in the water cycle?

Answer 16

1) Overabstraction
2) Resevoir building
3) Deforestation

Question 17

What is overabstraction?

Give one case study and explain the five main impacts of overabstraction.

Answer 17

This is where too much water is being taken from the river, lake or water source.
Thames Valley, South England
1) Dramatic decrease in river flow 
2) Tributaries dried up
3) Ecosystem damaged
4) Droughts
5) Falling water table

Question 18

How does resevoir building interfere with the water cycle?
Detail three main problems.
Give two benefits.

Answer 18

It adds a new store to the hydrological cycle but brings problems.
Problems:
1) Loss of land, villages and farmland
2) Diseases - stagnant water - mosquitos
3) Vegetation drowned releases methane - greenhouse gas
Benefits:
1) Increased water supply
2) Recreation - fishing, sailing, walking and wildlife

Question 19

How does deforestation interfere with the hydrological cycle? Give 5 impacts.

Answer 19

1) There are fewer trees which means less evapotranspiration, less green water recycled means less rain.
2) Soil left exposed to sun and rain
3) Less nutrients in soil
4) Less interception means greater flood risk
5) Raindrops wash out the finer soil, leaving coarse heavy surface.

Question 20

Give benefits and disadvantages to large scale water management such as dams.

Named case study of large-scale management.

Answer 20

Benefits:
1) Resevoirs are good for recreational use such as fishing
2) Reservoirs create a habitat for water birds
3) Hydro-electric power is important for industry
4) Increased water supply
Disadvantages:
1) Loss of farmland/villages/cultural sites
2) People have to be relocated
3) Spread of disease - stagnant water
4) Interferes with fish migration

Three-gorges dam

Question 21

What is intermediate technology?

Answer 21

A scheme that meets the needs of the local people and the environment in which they live, the scheme should enable local people to maintain and operate the scheme within their technical ability. They are able to run it when the NGO has left.

Question 22

What is an NGO?

What do they do?

Answer 22

Non-governmental organisation such as Water Aid.

They often develop small scale, sustainable solutions to local problems in developing countries.

Question 23

Name three different types of intermediate technology.

Answer 23

1) Rainwater harvesting
2) Hand-dug/tube wells
3) Gravity-fed pipe schemes

Question 24

Give a named example of where intermediate technology has been put too good use.

What has been the effect of the technology?

Answer 24

Dhaka, Bangladesh
Old Zhimkhana, a slum community built on the site of a disused railway - Six deep tube wells were built.

They save people time and energy in collecting water, the water supply is also safer families no longer have to worry about waterborne diseases. People run the facilities themselves and the project has helped them to move out of poverty.

Question 25

What is a tube well?

Answer 25

Tube wells are built where the water table is too deep to be reached by a hand-dug well.

Question 26

Water shortage case study.
Where is this place?
Why is there water shortage here? (2)

Answer 26

The Sahel, it is a narrow belt of semi-arid land immediately south of the sahara desert.

1) Rain falls in only one or two months of the year and the rainy season is often variable, since 1970 rainfall has more often than not been below average.
2) Sometimes the rain comes in torrential downpours and there is lots of surface run-off which causes flooding, in other years the rains fail and there is prolonged drought.
3) Rapidly growing population puts stress on failing food supplies.

Question 27

What are the impacts of drought in the Sahel? (3)

Answer 27

1) Seasonal rivers and water holes dry up and the water table falls.
2) Devastating effects on nomads and subsistence farmers who rely on rain.
3) Grasses die and over grazing by animals causes soil erosion and desertification.

Question 28

Water pollution case study.
What happened?
What has Coca Cola done since the drought?

Answer 28

Coca Cola and the Plachimada Aquifer
Coca Cola used water from the the Aquifer to make their beverages which lead to prolonged drought in the area.

Coca Cola has since helped the people of Plachimada survive the drought by driving tankers of fresh water into the village.