Name: ________________________ S.S. No. _________________ 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 steep rectangular channel with S_o = 0.02 changes abruptly to another rectangular channel of slope S_o = 0.005 and of the same width. The friction factor (1/8 of Darcy-Weisbach) is f= 0.005. The discharge is q = 15 cfs ft^-1. What is the length of the resulting C₃ profile on the downstream channel?

2. (20%) A hydraulic jump occurs in a rectangular channel with a design discharge of q = 1 m² s^-1. The energy loss is Delta E = 2 m. What are the initial and sequent depths?

3. (20%) You are observing the rising flood stage of a major river. At your observation point, at a certain time the discharge is 250 m³ s^-1, and the stage is rising at the rate of 55 mm hr^-1. The surface width of the river at this point, and for several kilometers upstream, is 65 m. What is your quick estimate of the present discharge at a point located 6.2 km upstream of your observation point?

4. (40%) Please answer each question in one clear and concise paragraph:

   a. What is the difference between HEC-2 and HEC-RAS?
   b. Why is it not possible to route with HEC-RAS?
   c. What is the most practical type of flood wave model?
   d. For what condition are the Seddon and Lagrange celerities equal?
   e. What two hydraulic/hydrologic characteristics determine the applicability of kinematic and diffusion models?
   f. What is the difference between the Muskingum and Muskingum-Cunge methods?
   g. Why is the Li model of kinematic wave routing bad?
   h. What is the role of the Vedernikov number in the hydraulic diffusivity?