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 = 0.3. The unit-width discharge is q = 2.0 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 495 m³ s^-1, and the stage is rising at the rate of 5 mm hr^-1. At a point located 18 km upstream of your observation point, the stage is rising at the rate of 7 mm hr^-1. The surface width of the river in the study reach is 125 m. What is your estimate of the present discharge at the upstream end of the reach?

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.

   • What are three ways in which the Seddon formula can be expressed? Which of the three did he develop? In what year?

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

   • What is the Lane relation in alluvial open-channel hydraulics? What is the modified Lane relation?

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

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

   • A spherical particle falls under its own weight in a flask that is full of water. What is the velocity distribution of the water in the radial direction between the falling particle and the wall of the flask? Show a plot of the distribution and indicate its characteristics

4. (20%) Write a 300-word essay on HEC-RAS. Separate into four paragraphs (5 points each): (1) history, (2) objectives, (3) equations, and (4) data requirements. Writing style, grammar and spelling are important.