WATER RESOURCES ENGINEER
CERTIFICATION EXAM QUESTION AND
CORRECT ANSWERS (VERIFIED
ANSWERS) PLUS RATIONALES 2026 Q&A
INSTANT DOWNLOAD PDF
1. Which component of the hydrologic cycle represents the movement of
water from land surfaces into streams and rivers?
A. Infiltration
B. Evapotranspiration
C. Groundwater recharge
D. Surface runoff
Correct Answer: D. Surface runoff
Rationale: Surface runoff is the portion of precipitation that flows over land into
channels, rivers, and streams.
2. The Rational Method is most appropriate for estimating peak runoff from
which type of watershed?
A. Large rural basins
B. Snowmelt-dominated basins
C. Small urban watersheds
D. Forested mountainous basins
Correct Answer: C. Small urban watersheds
Rationale: The Rational Method assumes uniform rainfall and is best suited for
small, impervious urban catchments.
, 3. Which factor has the greatest influence on infiltration rate?
A. Air temperature
B. Soil texture
C. Wind speed
D. Solar radiation
Correct Answer: B. Soil texture
Rationale: Soil texture controls pore size and permeability, directly affecting
infiltration capacity.
4. Darcy’s Law is used to calculate:
A. Surface runoff velocity
B. Open channel flow
C. Groundwater flow rate
D. Rainfall intensity
Correct Answer: C. Groundwater flow rate
Rationale: Darcy’s Law relates hydraulic gradient, permeability, and cross-
sectional area to groundwater discharge.
5. The unit hydrograph represents:
A. Total storm runoff volume
B. Runoff from a unit depth of effective rainfall
C. Maximum flood discharge
D. Rainfall intensity distribution
Correct Answer: B. Runoff from a unit depth of effective rainfall
Rationale: A unit hydrograph shows the direct runoff response to one unit of
effective rainfall over a watershed.
, 6. Which reservoir storage is reserved for flood control?
A. Dead storage
B. Live storage
C. Surcharge storage
D. Conservation storage
Correct Answer: C. Surcharge storage
Rationale: Surcharge storage temporarily stores excess floodwaters above
normal operating levels.
7. Manning’s equation is primarily used to compute:
A. Groundwater velocity
B. Pipe pressure loss
C. Open channel flow velocity
D. Rainfall intensity
Correct Answer: C. Open channel flow velocity
Rationale: Manning’s equation relates channel roughness, hydraulic radius, and
slope to flow velocity.
8. Which precipitation measurement instrument directly records rainfall
intensity over time?
A. Standard rain gauge
B. Snow pillow
C. Weighing rain gauge
D. Evaporation pan
Correct Answer: C. Weighing rain gauge
Rationale: Weighing rain gauges continuously record accumulated precipitation,
allowing intensity determination.
, 9. Return period is best defined as:
A. The duration of a flood event
B. The average time between occurrences of an event of equal or greater
magnitude
C. The probability of rainfall in a year
D. The time to peak discharge
Correct Answer: B. The average time between occurrences of an event of equal
or greater magnitude
Rationale: Return period is a statistical measure of event frequency.
10.Which loss accounts for water intercepted by vegetation before reaching
the ground?
A. Infiltration loss
B. Depression storage
C. Interception loss
D. Baseflow loss
Correct Answer: C. Interception loss
Rationale: Interception loss occurs when rainfall is captured by vegetation and
evaporates.
11.Baseflow in a stream is primarily sustained by:
A. Direct rainfall
B. Overland flow
C. Groundwater discharge
D. Channel storage
Correct Answer: C. Groundwater discharge
Rationale: Baseflow represents the delayed contribution from groundwater to
streams.
CERTIFICATION EXAM QUESTION AND
CORRECT ANSWERS (VERIFIED
ANSWERS) PLUS RATIONALES 2026 Q&A
INSTANT DOWNLOAD PDF
1. Which component of the hydrologic cycle represents the movement of
water from land surfaces into streams and rivers?
A. Infiltration
B. Evapotranspiration
C. Groundwater recharge
D. Surface runoff
Correct Answer: D. Surface runoff
Rationale: Surface runoff is the portion of precipitation that flows over land into
channels, rivers, and streams.
2. The Rational Method is most appropriate for estimating peak runoff from
which type of watershed?
A. Large rural basins
B. Snowmelt-dominated basins
C. Small urban watersheds
D. Forested mountainous basins
Correct Answer: C. Small urban watersheds
Rationale: The Rational Method assumes uniform rainfall and is best suited for
small, impervious urban catchments.
, 3. Which factor has the greatest influence on infiltration rate?
A. Air temperature
B. Soil texture
C. Wind speed
D. Solar radiation
Correct Answer: B. Soil texture
Rationale: Soil texture controls pore size and permeability, directly affecting
infiltration capacity.
4. Darcy’s Law is used to calculate:
A. Surface runoff velocity
B. Open channel flow
C. Groundwater flow rate
D. Rainfall intensity
Correct Answer: C. Groundwater flow rate
Rationale: Darcy’s Law relates hydraulic gradient, permeability, and cross-
sectional area to groundwater discharge.
5. The unit hydrograph represents:
A. Total storm runoff volume
B. Runoff from a unit depth of effective rainfall
C. Maximum flood discharge
D. Rainfall intensity distribution
Correct Answer: B. Runoff from a unit depth of effective rainfall
Rationale: A unit hydrograph shows the direct runoff response to one unit of
effective rainfall over a watershed.
, 6. Which reservoir storage is reserved for flood control?
A. Dead storage
B. Live storage
C. Surcharge storage
D. Conservation storage
Correct Answer: C. Surcharge storage
Rationale: Surcharge storage temporarily stores excess floodwaters above
normal operating levels.
7. Manning’s equation is primarily used to compute:
A. Groundwater velocity
B. Pipe pressure loss
C. Open channel flow velocity
D. Rainfall intensity
Correct Answer: C. Open channel flow velocity
Rationale: Manning’s equation relates channel roughness, hydraulic radius, and
slope to flow velocity.
8. Which precipitation measurement instrument directly records rainfall
intensity over time?
A. Standard rain gauge
B. Snow pillow
C. Weighing rain gauge
D. Evaporation pan
Correct Answer: C. Weighing rain gauge
Rationale: Weighing rain gauges continuously record accumulated precipitation,
allowing intensity determination.
, 9. Return period is best defined as:
A. The duration of a flood event
B. The average time between occurrences of an event of equal or greater
magnitude
C. The probability of rainfall in a year
D. The time to peak discharge
Correct Answer: B. The average time between occurrences of an event of equal
or greater magnitude
Rationale: Return period is a statistical measure of event frequency.
10.Which loss accounts for water intercepted by vegetation before reaching
the ground?
A. Infiltration loss
B. Depression storage
C. Interception loss
D. Baseflow loss
Correct Answer: C. Interception loss
Rationale: Interception loss occurs when rainfall is captured by vegetation and
evaporates.
11.Baseflow in a stream is primarily sustained by:
A. Direct rainfall
B. Overland flow
C. Groundwater discharge
D. Channel storage
Correct Answer: C. Groundwater discharge
Rationale: Baseflow represents the delayed contribution from groundwater to
streams.
