Instructions: Closed book, closed notes. Use engineering paper. When you are finished, staple your work in sequence (1 to 4), 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 = 0.003 and dimensionless Chezy friction factor f = 0.003. The unit-width discharge in the wide rectangular channel is 2 m³/s/m. Immediately upstream of the weir, the flow is subcritical, with depth 3 m.
   1. Calculate the Froude number of the normal flow in the upstream channel.
      

   2. Calculate the normal flow depth in the upstream channel.
      

   3. Calculate the normal flow velocity in the upstream channel.
      

   4. What is the type of water-surface profile extending from the weir in the upstream direction?
      

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

   
   

   
   

   
   

   
   

   
   

2. A supercritical flow channel with S_o = 0.01 flows into a critical flow channel of S_o = 0.004. The boundary friction f is the same is both channels. The unit-width discharge is 3 m³/s/m. Find the length of the C₃ water surface profile in the (downstream) critical flow channel.

   
   

   
   

   
   

   
   

   
   

3. (25%) Do a tabular comparison between the direct-step and standard-step methods of steady gradually varied flow computation. State at least five differences.
   

4. (25%) Please answer the following questions in a brief statement.

   • What is "freeboard"?

   • What is "hungry water"?

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

   • 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?

   • What is the rationale for the use of a labyrinth spillway?