EXERCISE 1

In a uniform open channel flow,

• the total energy remains constant along the channel
• the total energy line either rises or falls along the channel depending on the state of the flow
• the specific energy decreases along the channel
• the line representing the total energy is parallel to the bed of the channel

A trapezoidal channel is 10.0 m wide at the base and has a side slope of 4 horizontal to 3 vertical. The bed slope is 0.002. The channel is lined with smooth concrete (Manning’s n = 0.012). The hydraulic radius (in m) for a depth of flow of 3.0 m is _________

• 20
• 3.5
• 3
• 2.1

When the Froude number < 1, the flow is categorized as _________

• Critical flow
• Supercritical Flow
• Subcritical Flow

Two channels have the same cross-sectional area, but different geometry as shown in the figure. Which channel has the largest wetted perimeter?

• A
• B

What is the depth in uniform flow called?

• Normal depth
• Uniform depth
• Critical depth
• Constant depth

Manning's equation shows that the discharge is maximized when the wetted perimeter is ______

• Maximized
• Minimized

Water flows at a depth of 2 m in the trapezoidal, float-finished concrete channel (shown in the figure). What is the cross-sectional area of the channel in m2?

Water flows at a depth of 2 m in the trapezoidal, float-finished concrete channel (shown in the figure). What is the hydraulic radius of this channel in meters? Give your answer in 2 decimal numbers.

Water flows at a depth of 2 m in the trapezoidal, float-finished concrete channel (shown in the figure). What is the discharge in m3/s if the channel slope is 30 cm in 450 m? Give your answer in 1 decimal number.

Water flows at a depth of 2 m in the trapezoidal, float-finished concrete channel (shown in the figure). What is the average velocity in m/s?