CFS Hydrologic & Hydraulic Analysis 2

Question 1

In the Rational Method, what does the runoff coefficient 'C' represent?

Accepted Answer

The ratio of peak runoff rate to rainfall intensity

Answer

The runoff coefficient C is a dimensionless ratio representing the fraction of rainfall that becomes direct runoff, ranging from 0 to 1.

Question 2

Which hydraulic assumption underlies the HEC-RAS steady-state water surface profile computation?

Accepted Answer

The energy equation is applied between successive cross-sections assuming gradually varied flow

Answer

HEC-RAS steady-state profiles solve the energy equation (standard step method) between cross-sections under the gradually varied flow assumption.

Question 3

What is the primary purpose of a stage-discharge rating curve?

Accepted Answer

To relate water surface elevation to flow rate at a specific channel location

Answer

A rating curve defines the relationship between stream stage (water surface elevation) and discharge at a gauging station, enabling flow estimates from stage readings.

Question 4

The TR-55 graphical peak discharge method is most appropriately applied to watersheds with drainage areas up to:

Accepted Answer

20 square miles

Answer

TR-55 is intended for small watersheds up to approximately 20 square miles where simplified hydrologic assumptions are reasonable.

Question 5

In open channel hydraulics, critical flow occurs when the Froude number equals:

Accepted Answer

1.0

Answer

Critical flow is defined as the condition where the Froude number equals 1.0, representing the transition between subcritical and supercritical flow.

(CFS) Certified Floodplain Surveyor Practice Test

(CFS) Certified Floodplain Surveyor Practice Test

CFS Hydrologic & Hydraulic Analysis 2