Classification of water sources Which of the following is correctly classified as a <em>surface water</em> source for a water-supply project?
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AWell
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BSprings
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CArtesian well
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DRain (runoff collected in rivers/lakes/reservoirs)
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EInfiltration gallery
Answer
Correct Answer: Rain (runoff collected in rivers/lakes/reservoirs)
Explanation
Introduction / Context:Water sources are broadly categorized into surface water and groundwater. Proper classification affects treatment design and yield analysis.
Given Data / Assumptions:
- Surface water is water present on the land surface (rivers, lakes, reservoirs) principally from precipitation and runoff.
- Groundwater is water stored in aquifers and accessed through wells/springs/galleries.
Concept / Approach:Rainfall is the driver of surface runoff that fills rivers and lakes; thus, the resource captured in reservoirs is surface water. Wells and springs access subsurface flows and are groundwater sources.
Step-by-Step Solution:
Identify which option clearly represents surface water: rain-derived runoff in rivers/lakes/reservoirs.Recognize that wells, artesian wells, springs, infiltration galleries are groundwater abstractions.Verification / Alternative check:Design standards treat surface water as more variable in turbidity and pathogen load, requiring full conventional treatment.
Why Other Options Are Wrong:
- (a) and (c) wells draw groundwater.
- (b) springs discharge groundwater at the surface but are classified as groundwater source types.
- (e) infiltration galleries induce riverbank filtration but are groundwater works.
Common Pitfalls:Confusing the origin point (surface appearance) with classification; springs emerge at the surface but are groundwater-fed.
Final Answer:Rain (runoff collected in rivers/lakes/reservoirs)