U1- Water World

Question 1

Define hydrosphere.

Answer 1

All the water on or close to the Earth’s surface.

97% is in seas and oceans.

Question 2

What major water stores are there apart from the hydrosphere?

Answer 2

• Glaciers and snow cover.
• Groundwater.
• Lakes and rivers.

Question 3

Describe the evaporation process as part of the hydrological cycle.

Answer 3

Water evaporates from the seas and off ground surface. This process depends on temperature- the higher the temperature the more evaporation takes place.

Question 4

Describe the transpiration and evapotranspiration processes as part of the hydrological cycle.

Answer 4

Plants ‘breathe out’ water but also lose it by evaporation (evapotranspiration) from surfaces such as leaves.

Question 5

Describe the condensation process as part of the hydrological cycle.

Answer 5

Water vapour condenses into clouds.

At low level, fog and mist may be produced.

Question 6

Describe the precipitation process as part of the hydrological cycle.

Answer 6

Water is released by clouds in precipitation.

When the conditions are right, water droplets in clouds become water drops or snowflakes and gravity does the rest.

Question 7

Describe the surface runoff process as part of the hydrological cycle.

Answer 7

When precipitation reaches the ground, if the ground is saturated with water or too compact to allow water to infiltrate, it can run off the surface into rivers.

Question 8

Describe the groundwater flow process as part of the hydrological cycle.

Answer 8

When precipitation reaches the ground it can soak into the ground (infiltration) and moves downhill under the surface as groundwater flow.

Question 9

Briefly describe the three natural reasons why water supply may vary.

Answer 9

• Seasonal variations➡️Some climates have distinct wet and dry seasons.
• Longer natural cycles➡️Natural weather cycles bring clusters of drier or wetter years.
• Climate change➡️Year-on-year temperature rises may cause unreliable rainfall.

Question 10

Describe the Australian water supply case study.

1. What?
2. Explain why.
3. Impacts.

Answer 10

1. Since 1990 rainfall has fallen by 75% on long term average.
2. Naturally arid continent but climate change and over use of water by agriculture and industry has worsened this.
3. Wheat crop yields have fallen, increasing food prices.

Local ecosystems are suffering.

Question 11

Why might demand for water increase?

Answer 11

• Increased population.
• Increased farming and industry.
• Increased wealth means more people to use washing machines, etc.

Question 12

What is the impact with each of these sources of water pollution?

1. Toxic waste from mines.
2. Plant fertilisers.
3. Radioactive waste.
4. Human excrement.

Answer 12

1. Toxic pollution in rivers makes conditions poisonous for wildlife.
2. Causes eutrophication which kills off animals by depriving them by oxygen.
3. Nuclear waste can remain dangerous for thousands of years and storing it deep in ground is risky in case it leaks.
4. Human excrement in rivers causes cholera.

Question 13

How can deforestation reduce water supply?

Answer 13

Without trees, surface runoff increases and infiltration decreases so groundwater levels fall and rivers flow more seasonally.

Major floods can increase because interception by trees is reduced.

Question 14

What happened to the Aral Sea?

Answer 14

Located in Central Asia, the water was redirected to irrigate land to grow cotton crops.

Pesticides and chemicals used contaminated the Aral Sea, and wind-blown salt and fertiliser chemicals may have caused health problems.

Most animal life in and around Aral Sea died as sea’s volume dropped, only 4 of 38 fish species were left.

Question 15

Give some costs and benefits of the Hoover Dam and lake Mead, USA.

Answer 15

A- Lake Mead supplies Las Vegas and other cities/farms with water.

A- Water supply is clean, low cost and reliable.

A- Lake is popular place for recreation and fishing.

A- Can be used to generate electricity (2 gigawatts).

D- Cost $850 million to build.

D- Mexico’s water supply has been reduced as a result.

Question 16

Give some costs and benefits of the Three Gorges Dam, China.

Answer 16

A- Prevents seasonal flooding.

A- Generates 22.5 gigawatts of clean electricity.

A- Water supply is made reliable.

D- Cost $26 billion to build.

D- Over 1 million people relocated.

D- Many ancient monuments flooded.

D- Some animals like Chinese river dolphin have become extinct.

Question 17

What are bottom-up projects?

Answer 17

Bottom-up projects are controlled by the local community, using intermediate technology and accessible materials so it can be maintained locally.

Question 18

Describe how rainwater harvesters are used as small scale water management projects.

Answer 18

Gutters collect rainwater.

Clay tank (which takes 3 days to make) stores water.

Local people make taps and dig collection pit.

Question 19

The water system is a closed system.

What does this mean?

Answer 19

This means that the amount involved never changes, nothing is added and nothing is lost.

This means there is a finite amount of water on the Earth which is recycled through a number of processes.

Question 20

Many areas of the world are experiencing aridity.

Explain why this is happening (4marks).

Answer 20

Increasing temperatures (1) due to climate change increase evaporation (2), reducing water stores (3). Climate change also results in less predictable rainfall (4).

Question 21

Briefly define the hydrological cycle.

Answer 21

A water recycling mechanism, in which water circulates via the biosphere, lithosphere and back to atmosphere.

Question 22

How is/does water stored/flow?

Answer 22

• Interception by vegetation.
• Surface runoff.
• Groundwater flow.
• Infiltration and percolation.

Question 23

Describe two ways in which climate change could impact on water supples (4 marks).

Answer 23

In places where water is already naturally scarce for all or part of the year, the people and ecosystems in these areas could become seriously threatened. For example in Australia due to lack of water supplies due to reduced rainfall, winemakers could be forced out of business.

Also, in places in the Tibetan Plateau that rely on the Himalayan glaciers which feed into the major rivers in China, India and Vietnam climate change will lead to permanent melting of the glaciers- and ultimately the disappearance of the Himalayan glaciers which would cause billions of people to experience severly reduced water supplies because they rely on the seasonal melting and accumalating ice on the glaciers.

Question 24

How have TNCs threatened water supplies?

Answer 24

e. g: Coca Cola plant in the drought-prone Indian state of Kerala.
- Wells used by villages dried up because the Coca Cola plant was depleting ground water stores, Coca Cola was also accused of dumping waste between 1999 and 2004.
- Coca Cola had to pay compensation for agricultural losses, health problems and pollution caused.

Question 25

How can urbanisation disrupt the hydrological cycle?

Answer 25

Urbanisation leads to increased flooding because the soil is covered by tarmac and concrete. As a result, the rainwater travels quicker to the nearest river.

Question 26

Describe how the hydrological cycle links the biosphere, atmosphere and lithosphere (4 marks).

Answer 26

The atmosphere handles the clouds and rain. Precipitation from the atmosphere falls onto unvegetated ground which is part of the lithosphere, which is where water is stored in aquifers and on land as ice.

Plant root uptake links the lithosphere and biosphere which is the living parts (plants and animals) of the Earth. Then water evaporates off leaves back into the atmosphere.

Rain from the atmosphere falls on leaves in the biosphere. The water droplets fall off the leaves to the ground which is part of the lithosphere. Water evaporates into the atmosphere off ground surface.

Question 27

Label this hydrological cycle.

Answer 27

1) Evapotranspiration.
2) Condensation.
3) Precipitation.
4) Infiltration.
5) Groundwater flow.
6) Surface runoff.
7) -
8) Evaporation.

Question 28

Describe lined wells as a water management project in LEDCs.

Answer 28

Hand-dug wells which are lined with concrete rings to avoid sewage contaminating the well and a concrete cover slab should also be placed over the well when it’s not in use.

Question 29

Describe hand pumps as a water management project in LEDCs.

Answer 29

Raising water from the ground using a pump is preferable to using a bucket and rope and is a more efficient method. There is less chance of the water becoming contaminted by mud and dirty hands.

Question 30

Describe rain barrels as a water management project in LEDCs.

Answer 30

Roof gutters can be arranged so that rainwater flows into storage barrels. The best barrels contain a purification system. The rainwater soaks through filters which help to remove solids and various impurities.