11th International Drainage Symposium August 30-September 2, 2022 Des Moines, Iowa

1. Choice of Pipe Material Influences
Drain Spacing and System Cost
Ehsan Ghane
Assistant Professor and Extension Specialist
@MSUEhsanGhane

2. Effective Radius (Re) of a Drain Pipe
• Effective radius is the radius of an imaginary pipe with a completely
open wall
–Effective radius accounts for entrance head loss
• Dierickx (1999): Analytical Eq.
• Re is used
–DRAINMOD and RZWQM2
–Estimate drain spacing with Hooghoudt
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3. Rows of Perforations
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Sand-Slot Pipe
Regular-Perf Pipe

5. Two Pipe Choices: Drain Sedimentation Issue
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6. Pipe Manufacturers
• ADS (Michigan plant)
• Baughman Tile (Ohio)
• Fratco (Indiana)
• Haviland Drainage (Ohio)
• Prinsco (Minnesota)
• Springfield Plastics (Illinois)
• Timewell Drainage (Illinois)
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7. Effective Radius (Re) of Pipe (Rows of Perforation)
• 4-inch, 4-row regular-perf pipe
–Re = 0.3 to 0.9 cm (average 0.6 cm)
• 4-inch, 8-row regular-perf pipe
–Re = 1.9 cm
• Most important: Rows
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8. Effective Radius (Re) of Pipe
• 4-inch, 4-row regular-perf pipe
–Re = 0.3 to 0.9 cm (average 0.6 cm)
• 4-inch, sock-wrapped pipe
–Re = 5.9 cm
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9. Sand-Tank Experiment
• 4-row sand-slot pipe, 8-row sand-slot pipe
• Regular-perf pipe wrapped with knitted-sock envelope

10. Experiment Setup
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11. With Drain Sedimentation:
A Sock-Wrapped Pipe Has The Highest Drain Inflow
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Drain inflow of a sock-wrapped
pipe is 29% higher than the 4-row
sand-slot pipe, when installed at
30-ft spacing and 2.5-ft depth

12. A Sock-Wrapped Pipe Allows For a Wider Drain Spacing
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13. Which pipe properties increase water
entry into the pipe?

14. Myth: Higher Water Inlet Area, Higher Drain Inflow
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15. Greater Subdivision of Openings Reduces Convergence
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16. Take-Home Messages
• Perforation shape and pattern affects Re
• Most Important: Number of perforation rows
–8-row is much better than 4-row, for same price
• Second most important: Slot length
–Longer, narrower slots are better than shorter, wider slots
• Slot width has minimal effect
• With drain sedimentation, sock-wrapped pipe is fastest
• Without drain sedimentation, 8-row reg-perf pipe is fastest
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Length
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18. 43
3-Row Regular-Perf with Sock
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19. Water Passed Through The Sock From All Directions
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