1. Validation of the new B2B Bankless Channel Irrigation System model
Michael Grabham, R. Soppe,
J. Hornbuckle, R. Smith and S. Raine

2. Outline System overview Hydraulic challenges B2B model
Bay-scale comparison
Whole field simulations
Conclusions

3. System Overview

4. System overview

5. System overview

10. Why the system is being considered
Advantages
Labour savings
Can be automated
Machine efficiency
Expanded cropping options

11. Hydraulic challenges

12. Hydraulic challenges Variable inflow rates Variable bay sizes
Bay to bay hydraulic interaction

13. Hydraulic challenges Variable inflow rates
Volume balance approach used to determine surface storage and infiltrated volume
Variable discharge complicates calculations

14. Hydraulic challenges
Flow rate
Time

15. Hydraulic challenges Variable bay sizes 60:100:40 bay ratios
Surface storage volume accumulation
Interconnecting pipe size selection
Drainage water minimisation

16. Hydraulic challenges

17. Hydraulic challenges

18. Hydraulic challenges Bay to bay hydraulic interaction
Calculate the available volumes
Calculate inflow rates
Select adequate bay dimensions
Select adequate pipe sizes

19. B2B model

20. B2B model Current simulation models Single dimension Variable inflow
Recession phase limitations
Assume free flowing drainage

21. B2B model Clemmens’ (2007) surface irrigation design approach
Volume balance principles
Spreadsheet based
Simultaneously solves for advance and inlet depth
Uses fixed inflow

22. B2B model
Darcy Weisbach equation

23. Darcy Weisbach equation
B2B model
Clemmens’ Approach
Darcy Weisbach equation

24. B2B model Model features Infiltration parameters
Bay or furrow inflow rates
Manning n selection
σy pre-defined
Level furrow or bankless accommodated
Target infiltration depth
Up to nine bays can be simulated
Several irrigation termination options
Completion of advance
After set delay
After target infiltration depth achieved

25. Bay scale comparison

26. B2B – Bay Scale Discharge Errors from Measured winSRFR = 65%
SISCO = 65%
B2B = 18%

27. B2B – Bay Scale
Advance and recession

28. B2B – Bay Scale
Infiltrated depth

29. B2B – Bay Scale Simulation discrepancies
Attributed to model assumptions
Level water surface
Friction ignored
Infiltration during recession

30. Field simulations

31. B2B – Field Scale
Advance and recession
Bay 1
Bay 3
Bay 2

32. B2B – Field Scale
Depth

33. B2B – Field Scale
Inlet hydrographs

34. B2B – Field Scale
Inlet cumulative hydrographs

35. Conclusions Novel approach taking into account bay-to-bay interaction
Enables simulation of multiple bay systems
Discrepancies with known causes

36. Acknowledgements CRC IF Postgraduate scholarship
IAL and CRC IF Travel Fund grant
CSIRO Land and Water, Griffith
USQ, Toowoomba

37. Acknowledgements