Irrigation Management MT2

True or False. As we increase the flow rate from a booster pump, the TDH increases.
a. True
b. False

b. False

You’ve measured the power entering an electric motor and determined it to be 64.2 HP. The motor efficiency is 90%. The flow rate from the pump is 1,672 gpm and the TDH is 98 feet of head. What is the PPE?
a. 74.8%
b. 68.3%
c. 58.1%
d. 64.5%
e. 78.2%

d. 64.5%

A vertical Turbine Pump has the following characteristics: Static lift = 118 feet, Drawdown = 11 feet, Pump bowls set at 207 feet deep, Discharge pressure = 41 psi, Column and Discharge Head losses = 3.0 psi, Flow rate = 277 GPM. What is the Water HP?
a. 18.4 HP
b. 22.6 HP
c. 14.2 HP
d. 20.1 HP
e. 16.1 HP

e. 16.1

A furrow irrigation system is designed to apply 4.3 inches of water with a DU = 0.70. ETC = 0.20 in/day. PI losses and runoff are both zero. If irrigation occurs 4 days AFTER the permitted timing day, what is the AE (%)?
Assume that 25% of the area is under irrigated.
a. 86%
b. 75%
c. 69%
d. 81%
e. 64%

d. 81%

Two identical pumps in series will ______.
a. double the flow rate.
b. double the pressure.
c. decrease the flow rate.
d. decrease the flow rate.
e. have no impact on flow rate or pressure.

b. double the pressure

You’ve measured the power entering an electric motor and determined it to be 72.4 HP. The motor efficiency is 89%. The impeller efficiency is estimated at 69%. What is the PPE?
a. 0.564
b. 61.4%
c. 56.4%
d. 65.7%
e. 0.691

b. 61.4%

A pump is producing 1,289 gpm at 138 feet of head. The impeller efficiency is 75% and the motor efficiency is 90%. What is the brake HP required at the pump shaft?
a. 59.9 HP
b. 74.8 HP
c. 42.6 HP
d. 84.3 HP
e. 65.2 HP

a. 59.9 HP

A furrow irrigation system is designed to apply 2.5 inches of water with a DU = 0.88. ETc = 0.26 in/day. PI losses and runoff are both zero. If irrigation occurs 1 days BEFORE the perfect timing day, how much is the stored ETc?
a. 1.26 inches
b. 2.04 inches
c. 1.94 inches
d. 1.48 inches
e. 2.27 inches

c. 1.94 inches

This week in the Sacramento Valley, almond ETc = 0.24 in/day and ETo = 0.34 in/day. This week in the Central Valley ETo = 0.28 in/day. What is the crop coefficient for almonds in the Sacramento Valley?
a. 0.81
b. 0.87
c. 0.76
d. 0.92
e. 0.71

e. 0.71

A border strip irrigation system applies enough water to infiltrate an average depth of 5.3 inches. PI losses are 5%, and DU = 0.78. Ignore runoff (it is captured but reused later on another field). With good management, what AE is attainable?
a. 71%
b. 85%
c. 76%
d. 82%
e. 74%

e. 74%

Soil AWHC = 1.9 in/ft. Crop RZ = 3 ft. MAD = 51%. ETc = 0.29 in/day. DU = 0.80. PI Losses = 7%. (Ignore salinity, i.e., LR = 0). What is DaveD_{ave}Dave​ for the irrigation?
a. 2.96 inches
b. 3.63 inches
c. 3.23 inches
d. 2.52 inches
e. 4.48 inches

b. 3.63 inches

Soil AWHC = 1.3 in/ft. Crop RZ = 2 ft. MAD = 55%. ETc = 0.24 in/day. DU = 0.71. PI Losses = 3%. (ignore salinity, i.e., leaching requirement = 0). What is the maximum allowed SMD in inches?
a. 2.72 inches
b. 1.05 inches
c. 1.43 inches
d. 1.96 inches
e. 2.36 inches

c. 1.43 inches

Soil AWHC = 1.3 in/ft. Crop RZ = 2 ft. MAD = 53%. ETc = 0.26 in/day. DU = 0.74. PI Losses = 9%. (Ignore salinity, i.e., LR = 0). What is DmaxD_{max}Dmax​ for the irrigation?
a. 1.74 inches
b. 3.86 inches
c. 3.42 inches
d. 3.14 inches
e. 2.35 inches

d. 3.14

What is required to get a good “efficiency” with a drip irrigation system? Assume no under-irrigation and at least 15 psi is available.
a. Uniform soils and good DU
b. Good DU and good timing
c. Level ground and good DU
d. Uniform soils and level ground

b. Good DU and good timing

The two major components of non-uniformity in above-ground drip irrigation systems are:
a. Cv and friction
b. Soil differences and manufacturing Cv
c. Pressure differences and plugging.
d. Irrigation scheduling and leaching.

c. Pressure differences and plugging

FC is 24%. What is FC in inches per foot?
a. 2.88 in/ft
b. 3.43 in/ft
c. 3.14 in/ft
d. 2.52 in/ft
e. 4.02 in/ft

a. 2.88 in/ft

True or False. The same plant roots in 2 different soils at the same percent AWHC will experience the same soil moisture content.
a. True
b. False

b. False

True or False. Plants respond to the sum of moisture tension and osmotic tension (due to salinity).
a. True
b. False

a. True

True or False. Between irrigations, the moisture content of the surface layers of soil cannot be drier than PWP.
a. True
b. False

b. False

A Clay Loam soil, FC = 45%, PWP = 35% moisture by volume. What is the AWHC (in/ft)?
a. 1.68 in/ft
b. 1.18 in/ft
c. 2.14 in/ft
d. 1.20 in/ft
e. 1.81 in/ft

d. 1.20 in/ft

A Clay loam soil, saturation = 41%, FC = 29%, PWP = 16%, air dry = 13%. What is the SMD if the soil moisture content is 21%?
a. 0.72 in/ft
b. 2.05 in/ft
c. 0.96 in/ft
d. 1.76 in/ft
e. 1.42 in/ft

c. 0.96 in/ft

A soil has a water content at field capacity (% by volume) of 51%. At PWP, the water content is 18%. The root zone is 48 inches, and the SMD just prior to irrigation is 6.84 inches. What MAD is the irrigation manager using?
a. 47%
b. 43%
c. 39%
d. 32%
e. 35%

b. 43%

Which one of the following irrigation systems is not a pressurized irrigation system?
a. Sloping furrows
b. Hand move
c. Subsurface drip
d. Micro Sprinklers
e. LEPA

a. sloping furrows

Which solid set sprinkler application rate (in/hr) is acceptable if the infiltration rate is 0.34 in/hr?
a. 0.38 in/hr
b. 0.42 in/hr
c. 0.66 in/hr
d. 0.34 in/hr
e. 0.31 in/hr

e. 0.31 in/hr

True or False. Doubling opportunity time will double infiltration.
a. True
b. False

b. False

Which of the following field conditions has a soil moisture tension closest to 15 bars?
a. FC
b. Saturation
c. PWP
d. Oven Dry
e. Air Dry

c. PWP

Clay loam soil, PWP = 1.9 in/ft, AWHC = 1.4 in/ft. What is FC (%)?
a. 32%
b. 37%
c. 41%
d. 27.5%
e. 22%

d. 27.5%

An irrigation system designed to apply water with a DU = 0.76. ETc = 0.28 in/day. AWHC = 1.77 in/ft and the RZ = 5 ft. MAD = 43%. The SMD today is 1.59 inches. How many days until the next irrigation is due?
a. 8.4 days
b. 9.2 days
c. 6.7 days
d. 7.9 days
e. 10.8 days

d. 7.9 days

A border strip irrigation system applies enough water to infiltrate an average depth of 4.6 inches. PI losses = 4%. DU = 0.68. Ignore runoff (it is captured, but reused later on another field). How many days should be scheduled between irrigations to match a peak ET rate of ETc = 0.32 in/day?
a. 9.8 days
b. 12.8 days
c. 11.2 days
d. 8.7 days
e. 6.6 days

a. 9.8 days

23. Given the following representative soil log for a field: Find the AWHC of the entire soil profile (to 30 inches).

Soil Layer 1: Sandy Loam, Depth 0–12 in, Thickness 1.0 ft, AWHC 1.22 in/ft
Soil Layer 2: Loamy Sand, Depth 12–18 in, Thickness 0.5 ft, AWHC 1.15 in/ft
Soil Layer 3: Fine Sand, Depth 18–30 in, Thickness 1.0 ft, AWHC 0.75 in/ft

a. 2.32 inches
b. 2.55 inches
c. 3.05 inches
d. 3.73 inches

b. 2.55 inches