1-35 - BIE 5110/6110 Sprinkle & Trickle Irrigation Fall...

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BIE 5110/6110 Sprinkle & Trickle Irrigation Fall Semester 2004 – Final Exam Include units in all results. Indicate any assumptions that you might make. Don’t show more than three significant digits in any of the results. Name__________________________________ 1. (35 pts) A mature citrus orchard will be drip-irrigated (drip emitters) using a single lateral per row of trees in a 132-ha field area. Other information: Tree spacing is 6.0 x 6.0 m. Peak daily ET is U d = 5.1 mm/day. Seasonal water requirement: U = 660 mm. Effective rain, peak-use period: 1.5 mm/day (average, w/ 90% probability) Residual soil water in the spring: assume zero. Soil water holding capacity is 175 mm/m (medium texture). Irrigation water quality: EC w = 0.89 dS/m. Root zone depth is 1.5 m. Shaded area is 78%. Emitter equation: 0.481 q0 . 2 8 P = for q in lph; and P in kPa. Nominal emitter flow rate: q a = 3.85 lph. Manufacturer’s emitter coefficient of variation: 0.0487. Average wetted width at 3.85 lph: w = 2.01 m. Outlets per emitter: one. Use an MAD of 20%. What you need to do: 1. Select an appropriate emitter spacing, S e . 2. Determine the number of emitters per tree, N p . 3. Calculate percent wetted area, P w . 4. Calculate maximum net depth to apply per irrigation, d x . 5. Calculate the average peak daily “transpiration” rate, T d . 6. Calculate the maximum irrigation interval, f x . If f x 1 day, use f’ = 1day. 7. Calculate the net depth per irrigation, d n . 8. Select a reasonable target EU value. 9. Determine (EC e ) max . 10. Determine the transmission ratio, T r . 1 of 10
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11. Calculate the leaching requirement, LR t . 12. Calculate the gross depth to apply per irrigation, d. 13. Calculate the gross volume of water per tree per day, G. 14. Calculate h a , corresponding to q a = 3.85 lph, in m of water head. 15. Calculate the water application time, T a . 16. Select the number of stations, N s . 17. Determine the minimum number of emitters per tree, N p ’. 18. Calculate the system coefficient of variation, ν s . 19. Calculate the minimum allowable emitter flow rate, q n . 20. Calculate the allowable subunit pressure head variation, H s . 21. Calculate the system capacity, Q s . 22. Calculate the total gross seasonal depth to apply, D g . 23. Calculate the gross seasonal volume of irrigation water, V s . 24. Calculate the required number of operating hours per season, O t . 2. (30 pts) A rectangular field of strawberries will be trickle irrigated. The laterals are 380- m long in the direction of the 17.8-mm inside diameter PE laterals. Nominal emitter flow rate is 2.75 lph at a pressure head of 11.5 m. The emitters are in-line, without any barbs, spaced at 0.4 m along the lateral hose, which lies along a uniform ground slope of 0.761%. The strawberries are spaced at 0.5 m in the field rows. The emitter exponent is x = 0.544, and the system flow rate is 8.05 lps.
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This note was uploaded on 03/01/2012 for the course BIE 6110 taught by Professor Sprinkle during the Fall '03 term at Utah State University.

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1-35 - BIE 5110/6110 Sprinkle & Trickle Irrigation Fall...

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