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CE 4353/5360 Design of Hydraulic Systems
Fall 2022 Exercise Set 7

LAST NAME, FIRST NAME

R00000000

Purpose :

Apply principles of uniform flow to open channel analysis and design

Assessment Criteria :

Completion, results plausible, format correct, calculations (Jupyter Notebook) are shown.

Problem 1

A trapezoidal roadside drainage ditch with a design discharge of 3.75 $\frac{m3}{s}$ is lined with grass having a retardance of class C. The slope of the ditch is 0.004 and it has a bottom width of 2.0 m with side slopes of 3:1.

Determine:

  • Determine the design depth of flow
  • Whether the channel is stable
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Problem 2

Design a riprap-lined trapezoidal channel that has a capacity of 1000 cfs and a slope of 0.0005 ft/ft. Crushed rock is to be used and the channel bottom width is not to exceed 15 ft.

Determine:

  • The riprap size.
  • The side slopes.
  • The design depth of flow.
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Problem 3

A rectangular channel has a width of 10 ft and a Manning's n value of 0.020. Determine

Determine:

  • The channel slope such that uniform flow will always have a Froude number less than or equal to 0.5 regardless of the discharge.

Problem 4

Figure 4 is a compound channel which has symmetric floodplains, each of which is 100 m wide with Manning's n = 0.06, and a main channel, which is trapezoidal with a bottom width of 10 m, side slopes of 1.5:1, a bank-full depth of 2.5 m, and a Manning’s n of 0.03. The channel longitudinal slope is 0.001 and the total depth is 3.7 m

Figure 4. Engineered channel cross section

Determine:

  • The uniform flow discharge using the divided channel method with vertical interfaces separating the main channel from the overbank areas and including these in the wetted perimeters
  • The uniform flow discharge using the divided channel method with vertical interfaces separating the main channel from the overbank areas without including these in the wetted perimeters
  • The uniform flow discharge using the divided channel method using the diagonal interface approach to separate the flow areas, but don’t use the diagonal interfaces in the wetted perimeters.
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# list known quantities
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# governing principles
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# solution (step-by-step/computations)
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# discussion