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Irrigation Water Conveyance

Irrigation Water Conveyance. After completing this session the student will be aware of the features of irrigation water conveyance systems and how they may affect on farm water management. Conveyance System Requirements.

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Irrigation Water Conveyance

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  1. Irrigation Water Conveyance After completing this session the student will be aware of the features of irrigation water conveyance systems and how they may affect on farm water management.

  2. Conveyance System Requirements • Deliver water to every part of the irrigated area at a rate and elevation that permits proper operation of the application system; • Be compatible with the application equipment; • Convey the water as economically, efficiently and safely as possible; and • Be accessible for Operation and Maintenance. JEA 7-12-05

  3. On Farm Conveyance System JEA 7-12-05

  4. Conveyance System Schematic JEA 7-12-05

  5. Conveyance Efficiency “In the Western States, an estimated one-third to one-half of the water diverted for irrigation is lost between the source and point of use” NRCS NEH Part 623, Chapter 2, Irrigation Water Requirements JEA 7-12-05

  6. Conveyance Losses • Operational spills • Seepage • Consumptive Use by vegetation & evaporation • Leakage around structures JEA 7-12-05

  7. Source to Farm65% - 95% Farm to Field70% - 90% Source to Field30% - 65% Typical Conveyance Efficiencies JEA 7-12-05

  8. Distribution Efficiency Study 1988-1990, Riverton Unit - Wind River Project, USBOR, (72,000 acres) JEA 7-12-05

  9. Conveyance System Components • Open Channels • Pipelines • Conveyance Structures • Diversions & Pumps • Headgates, Wasteways, Division Boxes, Turnouts … • Water Measurement Devices • Check & Grade Control Structures • Flumes, Siphons & Culverts JEA 7-12-05

  10. Diversion Dam or Pumps They should: • Provide the Required Flow Rate • Provide the Required Elevation or Pressure • Perform Properly over the entire Irrigation Season • Accommodate Fish or Other Resource Concerns • Perform without Excessive Operation & Maintenance • And if they don’t: • Plan repairs, replacement; or • Develop an IWM strategy to deal with the constraint. JEA 7-12-05

  11. Diversion Dam JEA 7-12-05

  12. Diversion Dam JEA 7-12-05

  13. Diversion Dam JEA 7-12-05

  14. Headgates, Turnouts & Other Ditch Structures They should: • Provide the required flow rate & elevation or pressure • Screen excessive or undesirable debris • Accommodate expected sedimentation • Provide opportunity for water measurement • Perform without excessive Operation & Maintenance • And if they don’t: • Plan repairs, replacement; or • Develop IWM strategy to deal with the constraint. JEA 7-12-05

  15. Headgates & Turnouts JEA 7-12-05

  16. Headgates & Turnouts JEA 7-12-05

  17. Headgates, Turnouts & Other Structures JEA 7-12-05

  18. Headgates, Turnouts & Other Structures JEA 7-12-05

  19. Headgates, Turnouts & Other Ditch Structures JEA 7-12-05

  20. Other Ditch Structures JEA 7-12-05

  21. Other Ditch Structures JEA 7-12-05

  22. Other Ditch Structures JEA 7-12-05

  23. Other Ditch Structures JEA 7-12-05

  24. Canals & Ditches They should: • Have capacity for the required flow rate • Screen excessive or undesirable debris • Accommodate expected sedimentation • Limit Losses to an acceptable amount • Perform without excessive Operation & Maintenance • And if they don’t: • Plan repairs, replacement; or • Develop IWM strategy to deal with the constraint. JEA 7-12-05

  25. Canals & Ditches Features: • Used for main canal, laterals & on farm transport • Open channel, gravity flow • Water surface controls the delivery elevation • Natural earth or lined channels JEA 7-12-05

  26. Canals & Ditches JEA 7-12-05

  27. Canals & Ditches JEA 7-12-05

  28. Canals & Ditches Benefits: • Accommodate small to large flows • May accommodate large debris • Many alternatives for water measurement • Low to moderate construction cost (unlined) • Intercept runoff & groundwater • May provide some storage capacity • May support some riparian functions JEA 7-12-05

  29. Canals & Ditches Disadvantages: • Must have adequate slope • May require checks & grade control structures • Prone to operation waste (up to 50% pass through) • Seepage, vegetative & evaporation losses • Seepage may damage adjacent land & property • May occupy a large area & require crossing structures JEA 7-12-05

  30. Canals & Ditches Disadvantages: cont. • May provide source of weed seed • Susceptible to erosion, sedimentation, flood damage, & rodents • Higher maintenance than pipelines • Poor maintenance reduces capacity • Can be a safety concern JEA 7-12-05

  31. Canals & Ditches JEA 7-12-05

  32. Seepage Loss0.2 – 6 ft3/ft2/day Typical Unlined Canal/Ditch Losses Loss to Ditch-side Vegetation0.5% - 1% per mile Loss to Ditch Evaporation~ <0.5% per mile JEA 7-12-05

  33. Ditch Canal Lining Alternatives JEA 7-12-05

  34. Ditch Canal Lining Alternatives • Traditional Canal Linings ($1 to $10 / sq ft) • Compacted Clay • Concrete Lining • Buried Geomembrane • Exposed Geomembranes • Concrete Covered Geomembranes • Spray-applied Membranes • Reduce seepage loss by 90 – 95% • Service life 20 to 50 years. JEA 7-12-05

  35. Ditch Canal Lining Alternatives PAM Canal Treatment • Cost ~ $.005 to $0.02 / sq ft • May reduce seepage lossby 30% – 50% • May require annual treatment • Doesn’t work in all situations JEA 7-12-05

  36. Pipelines They should: • Deliver the required flow at the required elevation/pressure • Provide opportunity for water measurement • Perform without excessive operation & maintenance • And if they don’t: • Plan needed maintenance, replacement; or • Develop IWM strategy to deal with the constraints JEA 7-12-05

  37. Pipelines Features: • Gravity or Pressure Flow • Available head / pressure controls delivery elevation • Above ground or underground installations • PVC, PE, Concrete, Steel & Aluminum materials JEA 7-12-05

  38. Pipelines Benefits: • Less dependent on topography than ditches • Greater flow control = less operational waste • Very small water losses (0.01 – 0.15 ft3/ft2) • Little to no loss of land use • Eliminate weed seed production • Less susceptible to environmental damage • Typically fewer maintenance & safety concerns JEA 7-12-05

  39. Pipelines JEA 7-12-05

  40. Pipelines JEA 7-12-05

  41. Pipelines JEA 7-12-05

  42. Pipelines JEA 7-12-05

  43. Pipelines JEA 7-12-05

  44. Pipelines Disadvantages: • Moderate to high cost compared to unlined ditch • Not feasible for large flows • Must screen out debris and prevent sedimentation • Fewer and more expensive alternatives for water measurement • Provides no riparian function values JEA 7-12-05

  45. Pipelines JEA 7-12-05

  46. Summary “No irrigation system is worth a hill of beans if the water is not available to the crop at the time that the plants require it” Questions? JEA 7-12-05

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