The discharge capacity of an irrigation channel is governed by ____________________?
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Answer: B. Channel dimensions
Explanation
The discharge capacity of an open channel is primarily determined by its cross-sectional dimensions, bed slope, and roughness. Flow equations like Manning formula demonstrate that cross-sectional area and hydraulic radius dictate carrying capacity. Engineers size channel dimensions carefully to convey peak irrigation demands without overflowing canal banks. Open channel flow velocity depends on gravitational driving forces balanced against boundary friction resistance. Channel dimensions include bed width, side slopes, and full supply depth parameters specified in design manuals. Roughness coefficients account for channel lining materials, weed growth, and sediment deposition impacts.
Proper channel dimensioning ensures that irrigation water reaches all designated agricultural command areas reliably. Undimensioned canals can lead to severe water shortages downstream or expensive over-excavation construction costs. Maintenance dredging restores original channel dimensions when silt accumulation reduces discharge capacity. Silt grade, charge and slope influence sediment transport rather than acting as the primary geometric discharge governors. Sediment size affects channel regime stability, but cross-sectional dimensions are the direct structural capacity determinants. Silt amount and bed slope affect sediment load management rather than defining the total volumetric discharge capacity.
- Subject
- Agriculture
- Category
- Agriculture
- Topic
- —
- Difficulty
- medium
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