DES 601 - Discussion Questions
These questions are intended for discussion at the end of each appropriate training module as
time permits, and in module 23 as preparation for the final examination for the training course.
1. What is meant by the term “time of concentration”?
2. How is the intensity of rainfall computed?
3. What is meant by “risk based design”?
4. How do the concepts of “probability” and “frequency” relate in the context of
hydrology?
5. What is a Flood Frequency Curve?
6. Describe the meaning of each term in the Rational Equation Q=Cd*Cr*I*A
7. How do improved flow paths influence time of concentration?
8. How do improved flow paths influence computed intensity?
9. How does urbanization influence runoff?
10. What is an IDF curve?
11. What is an outlier in a data series?
12. To what type of data series would we apply the Bulletin 17B procedure?
13. What is meant by the term “controlled” or “regulated” with respect to a watershed?
14. What restrictions exist on the use of the Rational Equation?
15. What is the primary underlying assumption in rainfall-runoff modeling?
16. What three major pieces are necessary for unit hydrograph modeling?
17. On what kind of data are regression equations for estimating flood magnitude based?
18. Can you get a hydrograph from a regression equation?
19. Which of the following is the continuity equation?
20. Does the term “velocity head” refer to potential or kinetic energy?
21. Is energy conserved across a hydraulic jump?
22. Is momentum conserved across a hydraulic jump?
23. What is meant by the term “hydraulic grade line”?
24. What equation is commonly used to model open channel flow?
25. How is “hydraulic radius” computed?
26. What is Froude number and how does it aid in describing open channel flow?
27. What slope is being referred to by “S” in Manning’s Equation?
28. What assumptions are normally made when analyzing open-channel flow?
29. At what d/D ratio (depth/diameter) does a circular pipe flowing partially full reach peak
discharge?
30. Why does peak discharge in a circular pipe flowing partially full peak at less than full
depth?
31. What is the most hydraulically efficient open channel shape?
32. What is the most hydraulically efficient trapezoidal shape?
33. What general classifications are there for culvert flow based on control?
34. How do the classifications of culvert flow relate to specific energy and Froude number?
35. What general shapes are commonly seen in culverts?
36. What is meant by the term “rating curve”?
37. What can you construct if you have a rating curve and a flood frequency curve for the
same site?
38. What should you think if a culvert you design won’t fit into the site it’s designed for?
39. What is meant by the term “low chord” as pertains to bridges?
40. What is meant by the term “perched bridge”?
41. What is meant by the term “normal depth”?
42. What is meant by the term “critical depth”?
43. If the Froude number of flow is 3.6, is it’s velocity supercritical or subcritical?
44. If the Froude number of flow is 0.3, is it’s depth greater than critical, or less than
critical?
45. What two media (at the least) do streams always transport?
46. What must happen for flow to go from supercritical to subcritical?
47. What must happen for flow to go from subcritical to supercritical?
48. What is Manning’s “n”?
49. Under what flow condition would tailwater be important in culvert design?
50. Under what flow condition would headwater be important in culvert design?