Name: ____________________ Red ID _____________________ Grade: ____________

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. (20%) A hydraulically wide channel is operating at Froude number F = 0.2. The unit-width discharge is q = 2.5 m²s^-1. What is Lagrange's relative celerity? What are two Langrange absolute celerities (upstream and downstream)?

2. (20%) You are observing the rising flood stage of a major river. At your observation point, at a certain time the discharge is 180 m³ s^-1, and the stage is rising at the rate of 9 mm hr^-1. At a point located 15 km upstream of your observation point, the stage is rising at the rate of 13 mm hr^-1. The surface width of the river at this point, and for several kilometers upstream, is 90 m. What is your estimate of the present discharge at the point 15 km upstream?

3. (40%) Please answer each question in one clear and concise paragraph:
   • What is the rationale for the use of a labyrinth spillway? When does it cease to work as intended?

   • Compare in tabular form the kinematic, diffusion, dynamic, and inertia-pressure waves in terms of their celerity and attenuation properties.

   • When did Seddon develop his formula? What are three ways in which the Seddon formula can be expressed? Which of the three did he develop? Why?

   • Under Chezy friction in hydraulically wide channels, at what Froude number do kinematic, diffusion and dynamic wave coalesce? What usually happens at that threshold Froude number?

   • Under what conditions is a wave likely to be dynamic? Give an example in practice.

   • Why does unsteady flow routing suffer from the chicken-and-egg syndrome? Explain.

   • What is the difference between sediment production and sediment yield?

   • What is the difference between sediment transport and sediment routing?

4. (20%) Write a 300-word essay on HEC-RAS. Note specifically the following, in that order: (1) history, (2) objectives, (3) equations, (4) procedures, and (5) applications. Writing style, grammar and spelling are important.