Corrosion in water supply pipelines: Identify the correct effects caused by the corrosion of a pipe used in civil engineering water distribution systems.

Introduction / Context:
Corrosion of pipes is one of the most important issues in water supply engineering. It affects not only the structural integrity of the pipe but also the quality of water supplied to consumers. This question checks understanding of the different impacts of corrosion on water supply systems.

Given Data / Assumptions:

• Pipes under consideration are metallic, typically cast iron or steel.
• Corrosion occurs due to chemical, electrochemical, and biological reactions.
• Effects must be evaluated in terms of lifespan, carrying capacity, and water quality (colour and odour).

Concept / Approach:
Corrosion reduces the wall thickness of pipes, thereby shortening service life. It also causes scaling and deposits inside pipes, reducing carrying capacity. Corroded surfaces release iron oxides and other particles, imparting colour and metallic taste or odour to the water.

Step-by-Step Solution:

Verification / Alternative check:
Engineers often use protective coatings, cathodic protection, or non-metallic pipes to avoid these combined issues. This confirms the multi-faceted nature of corrosion damage.

Why Other Options Are Wrong:

• Reduces life span: Correct, but incomplete.
• Reduces carrying capacity: Correct, but incomplete.
• Adds colour: Correct, but incomplete.
• Adds odour: Correct, but incomplete.

Common Pitfalls:

• Assuming corrosion only affects structural strength, ignoring water quality.
• Believing plastic pipes are also prone to corrosion (they are not, though they may suffer other issues).
• Overlooking secondary effects such as leakage and contamination risks.

Final Answer:
All the above