Name: ___________________________ Red ID No. __________________ Grade: ________

Instructions: Closed book, closed notes. Use engineering paper. When you are finished, staple your work in sequence (1 to 3), and return this sheet with your work.

1. (25%) A weir is located at the downstream end of a wide rectangular channel of bottom slope S_o = 0.0035 and (dimensionless Chezy) friction factor f = 0.0035. The unit-width discharge in the wide rectangular channel is 2.5 m³/s/m. Immediately upstream of the weir, the flow is subcritical, with depth 4 m.
   1. Calculate the upstream Froude number.
      

   2. Calculate the upstream flow depth.
      

   3. Calculate the usptream flow velocity.
      

   4. What is the type of water-surface profile?
      

   5. Provide a quick estimate of the length of the water-surface profile.
      

   
   

   
   

   
   

   
   

   
   

2. (25%) Do a tabular comparison between the direct-step and standard-step methods of steady gradually varied flow computation. State at least eight differences.
   

3. (50%) Please answer the following questions in a brief statement.

   1. What is "free board"?

   2. Is free board really free? Or, can it be used sometimes? When?

   3. What two angles enter in the design of an open channel over alluvial materials?

   4. What is "hungry water"?

   5. How many types of water surface profiles (WSP) are there in gradually varied flow (GVF)?

   6. Which water surface profiles are completely horizontal?

   7. In gradually varied flow in a hydraulically wide channel, the flow depth gradient S_y is a function of three hydraulic variables (parameters). What are these?

   8. What is the rationale for the use of a labyrinth spillway?

   9. Why is it inappropriate to operate an overflow spillway at heads above the design head?

   10. According to Chow, what is the maximum value of Froude number in a hydraulic jump?