Now that you have completed this study session, you can assess how well you have achieved its Learning Outcomes by answering these questions.
Place the following phrases alongside the appropriate water source:
quality can change with location and season; difficult to treat if contaminated; usually requires treatment; free of charge; can be easily polluted by industry and agriculture; likely to be free from pathogenic bacteria; can be polluted by bird droppings; can often have a high mineral content.
Suppose that inhabitants of a village obtain water from a spring. What advice would you give to the users about the prevention of contaminants entering the spring?
The users of the spring should be advised to:
- avoid open defecation around the spring
- not construct latrines above the spring because of the danger of contaminating the groundwater
- use latrines properly
- keep animals away from the spring.
Look at Figure 3.16, which shows a hand pump over a well. What would you recommend should be done to improve protection of this water source?
There should be a raised, smooth-sloping area around the pump for user safety and also so that any surface water or spillage runs off. The rock wall should be increased in height and a gate installed so that no animals can get near the pump and contaminate the area.
Which of the following statements is false in relation to the development of a new water source? In each case explain why it is incorrect.
- The water source has to be reasonably close to the consumers of the water.
- Its environmental impact has to be ascertained.
- The effect of the seasons has to be considered.
- The quality of the raw water is immaterial, since modern treatment techniques can render it safe for drinking.
- The long-term viability of the source is important.
4 is false. It is better to find a water source that is of good quality so that minimal treatment is required. This will keep costs low.
List the factors that make a water source ideal to use.
The following are important factors for an ideal water source:
- capable of providing a supply that satisfies the anticipated demand and, in the case of groundwater, the rate of extraction not exceeding the rate of replenishment
- good water quality
- near to the consumers
- economical to use
- abstraction having minimal environmental impact.