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CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
CT4410: Requirement and delivery
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CT4410: Requirement and delivery

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  • 1. Irrigation: crops and water delivery Irrigation and Drainage CT4410 Maurits Ertsen 1 Water Resources Management
  • 2. Nevada Irrigation DistrictDecember 14, 2011 2
  • 3. Nevada Irrigation DistrictDecember 14, 2011 3
  • 4. A little history of NIDDecember 14, 2011 4
  • 5. Transforming a ditch for mines to aditch for irrigation• High canals• Continuous flow• Reservoirs• Water measurement in NIDDecember 14, 2011 5
  • 6. The system December 14, 2011 6
  • 7. Water measurement • The miners inch • Amount of water flowing through a surface of one square inch with a head of six inches. • How many liters per second?? December 14, 2011 7
  • 8. Controlling the canal• What if a farmer does not needs his water?• How to keep the constant head? December 14, 2011 8
  • 9. December 14, 2011 9
  • 10. December 14, 2011 10
  • 11. December 14, 2011 11
  • 12. Water requirements• How to determine water requirements?• How to predict water demand? December 14, 2011 12
  • 13. Design problemWhat cropping pattern do you take?How correct is the ET calculation?How correct is the ET and rainfall for the entire area?How would you take into account “real” soil processes? In other words: how to take into account heterogeneity? Lankford (2004) discusses this. How to use remotely sensed ET in DESIGN ??December 14, 2011 13
  • 14. How to irrigate crops?• Pressurized systemDecember 14, 2011 14
  • 15. Blue beans Start 1/1 Crop Growth stage Length coefficient Root depth Days Meter Initial 90 0.5 2 Development 90 >> Mid 90 1.2 2 Late 95 0.8 2 365 1.4 1.2Crop water 1requirement Crop coefficient 0.8calculation: 0.6example 0.4 0.2 December 14, 2011 15 0 0 50 100 150 200 250 300 350 400 Days
  • 16. Climate Rain ETo mm/stage mm/day Remarks: Initial 90 5 Assuming all rain is effective Development 65 6 Mid 40 7 Simplifying development stage Late 80 5 Significant numbers?? CRW mm/day Rain Eto kc Etg Etn Initial 1.00 5 0.5 2.5 1.50 Development 0.72 6 0.85 5.1 4.38 Mid 0.44 7 1.2 8.4 7.96 Late 0.84 5 0.8 4 3.16 December 14, 2011 16
  • 17. How to distribute that? Flow for a farm of one hectare mm/day m3/s l/s Continuous 8 0.0009259 1 Continuous during day 8 0.0018519 2 Every week for 10 hours 8 0.0155556 16 Every week for 1 hour 8 0.1555556 156 Every month for 1 hour 8 0.6666667 6671. Suppose I have 10 farms, how much should my canal carry?2. Suppose I have 1200 l/s, how many farms can irrigate at the same time?3. In case 2, how large would my surface area per canal become? December 14, 2011 17
  • 18. Your assignment1. Calculate total water demand for a 1000 hectare area in the NID over a year.2. Describe how this water would be supplied within the NID water delivery philosophy.3. Calculate required canal flows at the intake for this 1000 hectare area.4. Design the canal and outlets for this area, assuming that 20 farmers with each 50 hectares take water. Assume the canal being 10 kilometers long, with farm intakes evenly spread on one side. December 14, 2011 18
  • 19. Example information Trees 35% of total area Start 1/4 Growth stage Length Crop coefficient Root depth Days Meter Initial 140 0.9 2 Development 30 >> Mid 150 0.95 2 Late 45 0.9 2 365 C r o p c oe f f i c i e n t T r e e s 1.20 1.00 0.80 0.60 0.40 0.20 Kc 0.00 0 December 14, 2011 50 100 150 200 250 300 19350 Days
  • 20. December 14, 2011 20
  • 21. First, a little warning: physical realityneededDecember 14, 2011 21
  • 22. December 14, 2011 22
  • 23. December 14, 2011 23
  • 24. December 14, 2011 24
  • 25. December 14, 2011 25
  • 26. What did I do? Water requirements 10 8 6 4 2 0 -2 -4 -6 mm/day -8 1 31 61 91 121 151 181 211 241 271 301 331 361 days ET crops Rain ET net December 14, 2011 26
  • 27. Water need in l/s and miners inches/farm 80 60 40 20 0 -20 -40 -60 -80-100 December 14, 2011 27 1 31 61 91 121 151 181 211 241 271 301 331 361 Flow in l/s/10 Miners inch per farm
  • 28. So why start per April 1??• What if a farmer is an early vegetable grower?• What if it does not rain in April?• What if … ?And the canal? I know I will have fluctuating flows and that there is a need to maintain the same water level. So, one uniform flow calculation will not suffice. And I probably need some kind of water level control, and perhaps some spills.December 14, 2011 28
  • 29. Canal calculationNot that straightforward designing a fitting canal and structures canal AB L 10000 Q increases: Q decreases: H control 0.64 canal AB canal AB y 0.64 L 10000 L 10000 H control 0.71 H control 0.47 A 2.97 y 0.71 y 0.47 Q 0.66 A 3.34 A 2.10 m 1 Q 0.8 Q 0.4 v 0.22 m 1 m 1 v 0.24 v 0.19 R 0.51 R 0.56 R 0.39 s 0.0001 s 0.0001 s 0.0001 k 35 k 35 k 35 b 4 b 4 b 4 n 5.6 n 8.5 n 6.3 December 14, 2011 29
  • 30. Canal calculation So probably we need water level controls somewhere. Weirs? Spills? How many? Dimensions? December 14, 2011 30
  • 31. December 14, 2011 31
  • 32. And what if I have farmers with onlyfuit and vegetables???? 8 7 6 5 4 3 2 1mm/day 0 December 14, 2011 32 1 31 61 91 121 151 181 211 241 271 301 331 361 Days ET average ET fr and veg
  • 33. What did I do? Design discharge of 1 m3/s Water depth of 1 meter, bed width of 2 meters Slope of 1 in 10000 Side slope of 1 Roughness of about 45 (Strickler)December 14, 2011 33
  • 34. Result with inflow and all outlets are open. NO LEVEL CONTROLDecember 14, 2011 34
  • 35. LEVEL CONTROL WITH WEIR But as discharges downstream are very low and as there is no flow over the weir, no real improvement.December 14, 2011 35
  • 36. LEVEL CONTROL WITH WEIR With extra discharge, there is flow over the weir. Now it would be a matter of optimization…December 14, 2011 36
  • 37. Structures as the keyof a system. ExampleElche, SpainMaurits Willem ErtsenDelft University of Technology14-12-2011 Delft University of Technology Challenge the future
  • 38. Third largest city of theAutonomous Community ofValencia, SpainSome 200,000 inhabitantsIrrigated agricultureHuertasElche Palmeral: a little over 500hectares (about 5,000,000 m2)
  • 39. Landscape
  • 40. Watersources
  • 41. Canal system
  • 42. Canals
  • 43. Canals
  • 44. Walking along the water
  • 45. Walking further along the water
  • 46. Canals
  • 47. What is irrigation about?A structure asexpression ofwater rights.Remember?
  • 48. Irrigation: main system layout 1 Water Resources Management
  • 49. Ordering the disorder? Goal: • You know water demand and water smallest unit availability • Therefore you know the potential area Goal: • You know the smallest unit you have to deliver smallest unit water to ??? • You know how you want to deliver water Goal: • You have ideas about structures to smallest unit be appliedSource: river Goal: • It’s time for the canals! smallest unit December 14, 2011 2
  • 50. Main issues• Layout of the main system • Every canal above tertiary units • Determined by natural terrain and units• Capacities of main system • Losses • Rotation • Statistics• Behavior of the main system • Hydraulic flexibility • Operational flexibility • Reaction timesDecember 14, 2011 3
  • 51. Layout 1 2 3 4 5 6 7 8 9 10 km (contour lines in meters) December 14, 2011 4
  • 52. Layout 1 2 3 4 5 6 7 8 9 10 km (contour lines in meters) December 14, 2011 5
  • 53. Capacities Q is known Q at a certain level is Is total Q known??? not necessarily the sum of all Q’s at lowerResults in a Q here levels. But here???? December 14, 2011 6
  • 54. Capacities: example 1 1,2 1 0,8l/s/ha 0,6 0,4 Proportional 0,2 0 1 10 25 50 150 500 1000 1500 5000 HectaresDecember 14, 2011 7
  • 55. Capacities: example 2 2,5 2 1,5 l/s/ha 1 Proportional, 0,5 taking into 0 account losses 1 10 25 50 150 500 1000 1500 5000 HectaresDecember 14, 2011 8
  • 56. Capacities: example 3 3,5 3 2,5 Higher potential 2 demands on l/s/ha 1,5 1 lower levels 0,5 0 1 367 732 1097 1462 1828 2193 2558 2923 3289 3654 4019 4384 4750 HectaresDecember 14, 2011 9
  • 57. Capacities of the drainage systemLoads on the system: rainfall of 100 mm in 2 hours• Assuming an irrigated area of 5000 hectares, this would give a volume of 5,000,000 m3But: how to discharge this volume?• In 2 hours: 694 m3/s• In 5 days: about 6 m3/s• Water will be stored in the system: on the fields, in the canals, in the soil (?)December 14, 2011 10
  • 58. Drainage capacities: decision time• The load: how often does it occur? Probability?• Design a drainage canal for a certain maximum Q with freeboard, and allow a higher Q at times (without freeboard)?• Need to drain the irrigation supply? For example when nobody wants to irrigate?• Furthermore: like with supply canals, the sum of the Like with all individual canals does not have to be the same as the demand for peak maximum drainage discharge capacity. soil preparation! In short: enough to decide. Again…… December 14, 2011 11
  • 59. Three rainfall scenarios• Rainfall is showers (about every 10 to 15 days)• Rainfall averaged over all the days• Rainfall in showers with maximum shower at 100 mm/day• All other parameters equal • Irrigation at 100 mm per 10 days • Silty loam • Initial groundwater at 3 meter below surfaceDecember 14, 2011 12
  • 60. Rain in showers 120 3.5 3 100 2.5 80 2 mm m 60 1.5 40 1 20 0.5 0 0 1 21 41 61 81 101 121 141 161 181 201 221 241 261 281 301 321 341 361 Days Rain Irrigation Groundwater December 14, 2011 13
  • 61. Showers plus maximum 120 3.5 3 100 2.5 80 2 mm 60 1.5 40 1 20 0.5 0 0 1 21 41 61 81 101 121 141 161 181 201 221 241 261 281 301 321 341 361 days Rainfall Irrigation Groundwater December 14, 2011 14
  • 62. Average 120 3.5 3 100 2.5 80 2 mm m 60 1.5 40 1 20 0.5 0 0 1 21 41 61 81 101 121 141 161 181 201 221 241 261 281 301 321 341 361 days Rain Irrigation Groundwater December 14, 2011 15
  • 63. And the runoff?? 70 60 50 40 mm 30 20 10 0 1 20 39 58 77 96 115 134 153 172 191 210 229 248 267 286 305 324 343 362 days Average Showers Showers maximum December 14, 2011 16
  • 64. La Unit 1ayo Unit 1but Unit 2a Unit 2b December 14, 2011 17
  • 65. Water levels in the system?? + 12 m + 13 m + 12 + 0.20 + 0.15 + 0.20 = + 9.5 m 12.55 m+ 13 + 0.20 + + 10.4 m0.20 + 0.20 =13.6 m + 10.4 + 0.20 + 0.20 + 0.20 = 11 m + 15 m December 14, 2011 18
  • 66. Thus required water levels are: 16 15 14 13 12 11 10 9 8 0 1000 2000 3000 4000 5000 6000December 14, 2011 19
  • 67. Remember your NID task???? Design a canal (calculate) and determine control structures for offtakes/canal. Each offtake requires 1 m3/s in the peak season and may need less or nothing during the remaining months.December 14, 2011 20
  • 68. Your own designIssue 1: Water demand versus water availability • Timing of the demand • Timing of availability • Amount of hectares to be irrigated • Associated risk in balancing demand and availability• Issue 2: Bringing water to the field(s) • Continuously, rotation, fixed turns, days, hours, what flow is available for farmers?• Issue 3: Grouping farmers or not - units• Issue 4: Who decides? • Water delivery • Demand-based, request-based, supply-based? • Upstream or downstream control?• Issue 5: Water control structures • Discharge control, measurement, fixed or adjustable, sensitivity? December 14, 2011 21
  • 69. Dimensioning your irrigation system• Take a typical stretch of your system• Determine required water levels along this stretch, taking into account requirements from smaller canals, structures etcetera• Determine available energy gradient per section• Design canals and structures (steady flow)• Check, check and check! What happens when Q is lower, or higher, or whatever (steady flow).December 14, 2011 22

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