Soils 456 Irrigation and Drainage Answers to chapter 9 questions

1. Calculation of available pressure at the discharge point for a flow of 10 gal/min
loss calculations
a. k pipe 14.4 *.1= 1.44psi
b. 5/meter= 3.7 psi
equivalent length of pipe.
c. 3/4 corporation valve = 10 ft
d. 3/4 gate valve = 0.5 ft
e. two 2/4 elbows = 2ft
total ft= 10.25 + 275= 285.25 ft

Loss = 7.76psi/100*285.25= 27 psi

total loss= 27+ 1.44+ 3.7= 32.16psi

available head = 70- 32.16= 37.82 psi

2. 1 inch globe valve=27 ft of pipe

friction loss for 1 inch sch 40 pipe at 10 gpm=2.4 psi/100 * 27= 0.6 psi compared to 0.7 in table 9.2.
friction loss for 1 inch sch 40 pipe at 5 gpm= 0.66 psi/100*27= .17 psi compared to 0.7 in table 9.2.