The difference between natural disasters and natural hazards  (Page 3/3)

a) the causes

the consequences

c) possible solutions for disastrous droughts.

Assessment

Memorandum

Activity 1:

1. Approximately 60%
2. North-Western Cape and the Karoo.

1. The area lies far from the rainy eastern coast where hot, humid air flows into the country. As the hot, humid air is blown westwards, rain falls in the mountainous eastern areas, so that most of the humidity never reaches the western part of the country.

2. The West coast borders on the Atlantic Ocean where the cold Benguela Current flows, and there are relatively few mountains. Consequently the air does not move upwards (only hot air moves upwards, especially in mountainous areas), so that condensation cannot take place.

3. Evaporation (from the soil, plants and dams) is high in the dry western areas.

c) The eastern parts of South Africa

The East coast borders on the Indian Ocean where the warm Mozambique Current flows. Consequently the temperature of the air over the water also rises, condensation takes place and clouds are formed. These clouds are then blown towards the land, bringing rain to the areas bordering the ocean. The eastern side of the Drakensberg will therefore receive more rain because of its orthographical character. To the west of the Drakensberg the rain will decrease in a westerly direction, as the air becomes drier. Also the humid air is only blown beyond the mountains during summer, because of the higher levels of condensation (air containing more water is lighter).

d) 1. Building dams for water conservation.

2 Desalination of water.

3. Digging boreholes and erecting windmills.

4. Installing pipelines to lay on water.

5. Careful management of the soil and sensible, suitable farming methods.

6. Controlling soil erosion.

7. Planting trees and other crops.

8. Sowing drought resistant seed.

• Human behaviour should change radically and everybody should become environment-conscious.

Activity 2:

1. Africa, South Africa, India, China and Australia.
2. Add own ideas to existing list.
3. Human activities such as:

• Overgrazing of land;
• Overcultivation of soil;
• Felling of trees and the complete deforestation of areas;
• Demands by the population in overpopulated areas; poor irrigation causing salination and/or calcification of the soil, aggravates the effects of droughts. (The salt found in the soil rises to the surface due to an increase in the water table as a result of irrigation.)

The total effect of these human activities causes productive land to change into, arid, infertile areas. These conditions are often aggravated by droughts.

Activity 3:

Learners do their own research on any past drought in our country. Think for instance on the drought experienced by the South-western Cape in 2004/2005.

Write an essay under the following headings:

1. Causes

b) Effects

c) Possible solutions