2010 BRAE 236 HW21

2010 BRAE 236 HW21 - The lines are moved once a day with a...

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BRAE 236 - HW21 a) A 140 acre field is irrigated with a center pivot irrigation system. The system operational time is 26 days a month, 18 hours a day. They system DU for the lowest quarter of the field is 0.90 and there is a 4% spray loss. If the peak ETc is 7.8 inches per month, find gross GPM the irrigation system requires. A) 1556 gpm B) 1221 gpm C) 2564 gpm D) 633 gpm b) A 120 acre irrigated using microsprayers is split into 4 blocks. The system DUlq is 0.85 and pump flow rate is 1200 gpm. The gross water for a certain month is 7.59 inches Find how many hours per month for each block. A) 86 hours B) 444 hours C) 356 hours D) 683 hours c. A hand move sprinkler system with sprinkler spacing down the lateral of 30 feet and valve spacing on the mainline of 40 ft. The average sprinkler flow rate is 2.5 GPM.
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Unformatted text preview: The lines are moved once a day with a one hour move time. The estimated DUlq is 0.75 and spray loss is 5%. Determine what the soil moisture depletion should be when the next line reaches that spot. A) 4.65 inches B) 8.01 inches C) 2.65 inches D) 3.28 inches d. A 160 acre field is furrow irrigated. The furrow lengths are 880 ft with a 40 inch spacing. The field is supplied with 2000 GPM. It takes 9 days to irrigate the whole field with 8 hrs advance time (the time it takes for the irrigation water reach the end of the furrow). There is 100 acres per set. The estimated DUlq is 0.8 and runoff loss is 20% of the total applied. What is the optimum SMD? A) 4.55 inches B) 2.41 inches C) 3.82 inches D) 5.63 inches...
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