CIV E 530 - OPEN CHANNEL HYDRAULICS
SPRING 2008
FIRST MIDTERM
FEBRUARY 25, 2008, 1600-1715

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 high overflow spillway has a downstream slope of 0.6 H to 1 V. The friction factor of smooth concrete (1/8 of Darcy-Weisbach) is f = 0.004. What is the prevailing Froude number?

  2. (20%) On July 31, 1976, the Big Thompson river, near Loveland, Colorado, experienced a record flood event. Assuming critical flow prevailed during the passage of the flood, provide a quick estimate of the flow depth (m) and velocity (m/s). Assume the largest possible discharge per unit of width (50 m2/s).

  3. (20%) The overflow spillway at Turner reservoir, in San Diego County, is 8 ft wide. On February 24, 2005, after several days of heavy rain, the head over the spillway was 5 in. In the absence of more information, what is your best estimate of the discharge?

  4. (40%) Please answer the following questions in a brief statement.

    • What two celerities does the Froude number relate?

    • What two celerities does the Vedernikov number relate?

    • What four forces are used in the analysis of open-channel flow?

    • What is a flux? How does energy differ from momentum? In what specific case does both energy and momentum apply?

    • What is the minimum value of Froude number to avoid channel clogging with sediment?

    • What is the maximum value of Froude number in open-channel flow?

    • What is the average Manning's n in typical field conditions in natural channels?

    • What is the value of Manning n used by the South Florida Water Management District for Everglades surface-water modeling?