Maintaining self-cleansing velocity within sewer systems ensures___________________?
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Answer: D. Neither silting nor scouring occurs at bottom
Explanation
Maintaining self-cleansing velocity within sewer systems prevents the accumulation of sediment deposits and the erosion of pipe material. Proper hydraulic design ensures that neither silting nor scouring occurs during normal daily flow fluctuations. Keeping velocity within the correct design parameters protects infrastructure integrity over its long operational lifespan. Civil engineers calculate minimum gradient requirements to achieve self-cleansing velocities for sanitary and storm sewers. Silting happens when flow velocity drops too low, causing suspended particles to settle at the bottom of pipes. Scouring occurs when flow velocity is excessively high, causing abrasive materials to wear away the interior pipe walls.
Option A is incorrect because silting specifically describes unwanted sediment accumulation caused by inadequate flow velocities. Option B is wrong because scouring represents pipe erosion caused by excessively fast and turbulent fluid movement. Option C is invalid because a properly maintained system prevents both destructive extremes rather than causing them simultaneously.
- Subject
- Engineering
- Category
- Civil Engineering
- Topic
- —
- Difficulty
- medium
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