SWCE PT.2

Question 1

Which one is the steepest canal side slope?

a. 1:1
b. 1:4
c. 4:1
d. 2:1

Answer 1

b. 1:4

z=(H/V)

Question 2

Which of the following describes hydraulic radius?

a. The cross-sectional area of a stream of waterway divided by its perimeter
b. Used to predict the velocity of water flow in an open channel
c. Predict the stream flow rate in an open channel
d. The average cross- sectional size of steamflow

Answer 2

a. The cross-sectional area of a stream of waterway divided by its perimeter

Question 3

Type of flow wherein the depth of flow in a prismatic channel is constant at any point in the
channel
a. Laminar flow
b. Steady flow
c. Uniform flow
d. Critical flow

Answer 3

c. Uniform flow

Question 4

A supercritical flow is a flow condition where

a. Fr= 1
b. Fr > 1
c. Fr< 1
d. Fr > 4000

Answer 4

b. Fr > 1

Question 5

Open channel flow is uniform flow and the continuity equation applies when

a. energy grade line and hydraulic grade line are parallel
b. hydraulic grade line and channel bed are parallel
c. Energy grade line and channel bed are parallel
d. Energy grade line, hydraulic grade line, and channel bed are parallel

Answer 5

d. Energy grade line, hydraulic grade line, and channel bed are parallel

Question 6

When the viscous forces are weak relative to inertial forces, the flow is

a. Laminar
b. Turbulent
c. Critical
d. uniform

Answer 6

b. Turbulent

Question 7

The Manning’s roughness coefficient for grassed channels or waterways is specifically known as,
a. Resistance coefficient
b. Retardance coefficient
c. Impendance coefficient
d. All of the above

Answer 7

b. Retardance coefficient

Question 8

A hydraulic jump is a classic example of this type of flow

a. Unsteady flow
b. Rapidly varied flow
c. Gradually varied flow
d. Critical flow

Answer 8

b. Rapidly varied flow

Question 9

Determine the side slope angle of an unlined canal with slope ratio z of 2:1?

a. 16.6 degree
b. 26.6 degree
c. 45 degree
d. 63.43 degree

Answer 9

Answer: b. 26.6

=tan^-1(1/2)

Question 10

Which one is the steepest canal side slope?

a. A side slope factor of 4
b. A side slope factor of 1
c. A side slope angle of 40o
d. A side slope angle of 10%

Answer 10

b. A side slope factor of 1

Question 11

A smooth concrete rectangular channel (n=0.012) is 1.5 m wide and 0.5 m deep. What is its critical discharge?

a. 1.66
b. 2.61
c. 5.74
d. 5.6
e. 6.1

Answer 11

a. 1.66

dc= (Q^2/(gb^2)^1/3

Question 12

Which is the most efficient irrigation canal?

a. A rectangular canal with a water area of 10 ft2 and depth of 2 ft
b. A trapezoidal canal with a water area of 10 ft2 and wetted perimeter of 8.32 ft
c. A triangular canal with a water area of 4 ft2 and depth of 2 ft.
d. Both b and c
e. All of the above

Answer 12

c. A triangular canal with a water area of 4 ft2 and depth of 2 ft.

Question 13

The critical depth of a triangular channel is 2 ft. If the side slope factor is 2, determine the critical discharge.
a. 40
b. 45
c. 52
d. 63
e. 88

Answer 13

b. 45

Question 14

Which of the following factors does not affect the Manning’s roughness coefficient, n,
a. Seasonal change
b. Silting and scouring
c. Size and shape of channel
d. Sinuosity
e. None of the above

Answer 14

e. None of the above

Question 15

The concept of most efficient or best hydraulic cross-section applies to

a. Erodible channel
b. Non-erodible channel
c. Grassed waterways
d. Prismatic channel
e. All of the above

Answer 15

b. Non-erodible channel