CE444-APPLIED HYDRAULICS
FALL 2009
FIRST MIDTERM
OCTOBER 7, 2009, 0730-0845

Name: ______________________ Red ID __________________ Grade: _________

Instructions: Closed book, closed notes. Use engineering paper. When you are finished, staple your work in sequence (1 to 5), and return this sheet with your work.

  1. (20%) A 100-acre watershed has two distinct subareas: (1) an undeveloped portion, of 35 ac and runoff coefficient C= 0.3, and (2) a developed portion, of 65 ac and C = 0.7. If the 10-yr rainfall intensity is 0.5 in/hr; what is the peak flow by the rational method? Calculate the exact value (in cfs), using the appropriate unit conversions.

  2. (20%) A rectangular channel is to be designed to convey 100 cfs. The bottom width is b = 10 ft, the bottom slope is So = 0.001, and the Manning's n = 0.013. Calculate the design flow depth (3 significant digits) using trial and error.

  3. (20%) A rectangular channel has a discharge q = 2 m3/s/m. What is the critical depth? What is the critical velocity?

  4. (20%) A broad-crested weir has a length L = 12 ft and design head H = 1.5 ft. In the absence of any other information, what is the best estimate of the design discharge (in cfs)?

  5. (20%) Please answer questions in a brief statement.

    1. What is the time of concentration? In the most general case (Papadakis formula), what four physical variables is it a function of? Which two variables are in the numerator? Which two are in the denominator?
    2. What is the difference between the Manning and Chezy equations? State three differences.
    3. What four forces are normally present in open-channel hydraulics? What two of these forces are present in hydraulic jump analysis? Why?
    4. How does Froude's Law differ from the Froude number as currently used in hydraulic engineering practice?