Population forecasting in civil engineering: The shape of the population growth curve commonly observed in demographic studies is identified as which of the following?
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AS-shaped curve
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BParabolic curve
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CCircular curve
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DStraight line
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ENone of these
Answer
Correct Answer: S-shaped curve
Explanation
Introduction / Context:Population forecasting is essential for civil engineering projects, particularly in water supply, sanitation, and urban planning. The growth of population often follows a mathematical pattern that can be represented graphically.
Given Data / Assumptions:
- Population grows slowly initially.
- Then growth accelerates rapidly.
- Finally, it slows down and stabilizes.
Concept / Approach:The population growth curve is generally represented by a logistic function. It begins as slow growth, then accelerates, and eventually stabilizes due to limiting factors such as resources and space. This results in an S-shaped (sigmoidal) curve.
Step-by-Step Solution:
1. Early stage: population grows slowly (lag phase).2. Middle stage: exponential growth occurs (steep rise).3. Final stage: limiting factors cause stabilization (plateau).Verification / Alternative check:This is consistent with logistic growth theory in biology and demography, which civil engineers adapt for long-term planning.
Why Other Options Are Wrong:
- Parabolic curve: Represents quadratic relations, not realistic for long-term population.
- Circular curve: Not meaningful in this context.
- Straight line: Represents arithmetic growth, unrealistic for actual populations.
- None of these: Wrong because S-shaped is the correct established answer.
Common Pitfalls:
- Confusing exponential growth with logistic growth; the latter accounts for limitations.
- Believing all cities grow indefinitely, ignoring saturation effects.
Final Answer:S-shaped curve