Soils 456 Irrigation and Drainage Answers to chapter 2 questions

2.1

E= p*2.31

The pressure if 33lb/in^2 is displayed on a pressure gage. The height water would rise in a pipe is
E=33 *2.31 = 76.23 ft

2.2
Grand canyon is 5000ft depth Water is obtained from a stream located 2000 ft below the rim of the canyon. The Water pressure at the the canyon floor based on elevation is:
5000ft-3000ft = 2000ft elevation difference
E=p*2.31
p= 3000/2.31= 1298 lb/in^2

2.3
Flow in a 1 in. inside diameter pipe (d) with a velocity is 5 ft/s
q= va
a= pie r^2

r= D/2= .5inch/12= .041 ft

a= 0.005451 ft^2
q= 0.27 ft^3/s = 12.2 gmp

2.4

Two sprinklers at 100 ft and 175 ft elevation
Pressure difference caused by elevation
E=p*2.31
p= E/2.31 = 75/2.31=32.46psi

2.5

2 inch pipe , 1000 ft long , flow 55gpm
friction loss 2.08/100 ft *1000 ft= 20.8psi
velocity 5.3 ft/sec

2.6
3 inch pvc , 110 gpm , length 750ft
pressure loss is 6.4 psi

for class 160 friction loss per 100 ft = 0.853

0.853/100*750=6.4 psi

2.7
2 inch type m copper tube , flow 2 l/s 10 m length
10 m= 32.8 ft
2l/s= 31.8 gpm
friction loss+ 0.28 psi+1.98 kPa
velocity = 3.03 ft/s= 0.92 m/s

2.8
pipe d= 2.067 inches
c= 150
q= 55 gmp
hf= 0.208 *(100/c)^1.8752 * (q^1.852/d^4.866) = ft

hf= 0.208*(100/150)^1.852*(55^1.852/2.067^4.866)= 0.208*0.47*(1672/34.2)=4.77ft=2.06psi/100ft

2.06/100ft*1000ft=20.6psi loss

q=2.45vd^2
55=2.45 v 2.06^2
v= 5.29 ft/s