EENV 436: Storm Water Management
Exam Questions Complete Answers
Current Update (A+ Pass)
Design storm - Answers -✔✔ An arbitrary storm used in design process relating to a
return interval and satisfies risks and costs.
Return Interval (RI) - Answers -✔✔ Number of years between a given storm event;
comes from regulation and design standards for a specific storm facility.
What does duration depend on? - Answers -✔✔ Regulation or the time of
concentration
What does depth depend on? - Answers -✔✔ Duration and intensity
What does intensity depend on? - Answers -✔✔ Duration
What flow regimes are calculated in the NRCS Velocity Method? - Answers -✔✔
Sheet, shallow concentrated, and channel flow
Where is sheet flow located? - Answers -✔✔ Farthest away from point of catchment,
usually 50-100 ft long.
When does shallow concentrated flow begin? - Answers -✔✔ After sheet flow or after
50-100 ft and could be the last flow to calculate depending on if there are channels in
the basin.
Total time of concentration - Answers -✔✔ The time of sheet flow plus shallow
concentrated plus channel flow.
What does the curve number method calculate? - Answers -✔✔ The runoff volume,
given in depth units (in)
What are the difference between big q and little q when calculating the curve number
method? - Answers -✔✔ Big Q is the runoff volume in inches and little q is the peak
runoff usually in cubic feet per second.
What do you use to calculate the peak flow after you find a volume using the curve
number method? - Answers -✔✔ The TR55 Method.
What is it meant by a 24 hour rainfall depth? - Answers -✔✔ What the depth would be
if the storm stayed in one place for 24 hours.
Exam Questions Complete Answers
Current Update (A+ Pass)
Design storm - Answers -✔✔ An arbitrary storm used in design process relating to a
return interval and satisfies risks and costs.
Return Interval (RI) - Answers -✔✔ Number of years between a given storm event;
comes from regulation and design standards for a specific storm facility.
What does duration depend on? - Answers -✔✔ Regulation or the time of
concentration
What does depth depend on? - Answers -✔✔ Duration and intensity
What does intensity depend on? - Answers -✔✔ Duration
What flow regimes are calculated in the NRCS Velocity Method? - Answers -✔✔
Sheet, shallow concentrated, and channel flow
Where is sheet flow located? - Answers -✔✔ Farthest away from point of catchment,
usually 50-100 ft long.
When does shallow concentrated flow begin? - Answers -✔✔ After sheet flow or after
50-100 ft and could be the last flow to calculate depending on if there are channels in
the basin.
Total time of concentration - Answers -✔✔ The time of sheet flow plus shallow
concentrated plus channel flow.
What does the curve number method calculate? - Answers -✔✔ The runoff volume,
given in depth units (in)
What are the difference between big q and little q when calculating the curve number
method? - Answers -✔✔ Big Q is the runoff volume in inches and little q is the peak
runoff usually in cubic feet per second.
What do you use to calculate the peak flow after you find a volume using the curve
number method? - Answers -✔✔ The TR55 Method.
What is it meant by a 24 hour rainfall depth? - Answers -✔✔ What the depth would be
if the storm stayed in one place for 24 hours.
