320-HW7 - BRAE 340 Irrig Water Management HW 7 IE DU Name...

Info icon This preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
BRAE 340 Irrig. Water Management Name: HW 7 - IE & DU (only odd numbered problems will be graded) [F] 1. T/F: Spray loses for under tree sprinklers range from 4-6%. Explanation See page E-5. Spray losses from hand move sprinklers are 4-6% [F] 2. T/F: Excess costs for water and energy, but decreased costs for drainage, are likely consequences of low on-farm AE's. Explanation Low AE's mean applying excess water. Water and energy costs would increase. More deep percolation would mean an increase drainage costs as well. [F] 3. T/F: DU must be at least 90% to have an IE above 100%. Explanation It is impossible to have an AE above 100% [T] 4. T/F: If an entire field is under-irrigated, the water beneficially used is equal to the average depth applied. Explanation If all is under-irrigated, Dmax is less than SMD --> no deep percolation So beneficial use = amount stored = all that infiltrates = Dave. Solution Key
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
[D] 5. Given: Soil moisture depletion = 6.01 inches; average infiltration = 8.49 inches; DU = 61.8%. Which one of the phrases below best describes the irrigation on this field? A) impossible to tell B) perfect irrigation timing C) entire field is under irrigated D) field has both under and over irrigation E) entire field is over irrigated Explanation Dave = 8.49 inches Dmin = Dave x DU/100 = 8.49 x 61.8% = 5.25 inches Dave - Dmin = 8.49 - 5.25 = 3.24 inches Dmax = Dave + 3.24 = 8.49 + 3.24 = 11.73 inches SMD = 6.01 in --> SMD is between Dmin and Dmax Some over irrigation, Some under irrigation -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 0 100 % Area -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 SMD = 6.01 Infiltrated Amounts Dmin = 5.25 Dave = 8.49 Dmax = 11.73
Image of page 2
[D] 6. Given: Soil moisture depletion = 5.25 inches; average infiltration = 8.02 inches; DU = 65.5%. Which one of the phrases below best describes the irrigation on this field? A) entire field is under irrigated B) entire field is over irrigated C) impossible to tell D) perfect irrigation timing E) field has both under and over irrigation Explanation Dave = 8.02 inches Dmin = Dave x DU/100 = 8.02 x 65.5% = 5.25 inches Dave - Dmin = 8.02 - 5.25 = 2.77 inches Dmax = Dave + 2.77 = 8.02 + 2.77 = 10.79 inches Dmin = 5.25 = SMD Since SMD = Dmin --> Perfect Irrigation Timing -1 0 1 2 3 4 5 6 7 8 9 10 11 12 0 100 % Area -1 0 1 2 3 4 5 6 7 8 9 10 11 12 SMD = 5.25 Infiltrated Depths Dmin = 5.25 Dave = 8.02 Dmax = 10.79
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
[B] 7. Given: Applied water = 8.4 inches, evaporation loss = 4 %, DU = 77 %, Average infiltration = 5.7 inches, ETc = 0.24 in/day, SMD = 3.51 inches. What is the runoff expressed in inches? A) 1.94 inches B) 2.36 inches C) 2.65 inches D) 1.29 inches E) 1.54 inches Solution: Total loss = gross application - average infiltrated Total loss = 8.4 - 5.7 = 2.70 inches Also, total loss = evap loss + runoff loss So, runoff loss = total loss - evap loss evap loss = 4 % x gross = 4 % x 8.4 inches = 0.34 in runoff = total loss - evap loss = 2.70 - 0.34 inches = 2.36 in [D]
Image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern