PROFESSIONAL HYDROLOGIST
CERTIFICATION EXAM QUESTION AND
CORRECT ANSWERS (VERIFIED
ANSWERS) PLUS RATIONALES 2026 Q&A
INSTANT DOWNLOAD PDF
1. The hydrologic cycle is primarily driven by
A. Gravity
B. Solar energy
C. Earth’s rotation
D. Atmospheric pressure
Rationale: Solar energy powers evaporation, which drives the hydrologic
cycle.
2. Precipitation that reaches the ground surface without interception is called
A. Throughfall
B. Net precipitation
C. Stemflow
D. Gross rainfall
Rationale: Net precipitation includes water that actually reaches the
ground.
3. Infiltration capacity is defined as
A. Total soil moisture
B. Maximum rate at which soil can absorb water
C. Groundwater storage
D. Hydraulic gradient
Rationale: Infiltration capacity limits how fast water enters the soil.
,4. Hortonian overland flow occurs when
A. Soil is saturated
B. Rainfall intensity exceeds infiltration capacity
C. Water table rises to surface
D. Evapotranspiration is high
Rationale: Hortonian flow is infiltration-excess runoff.
5. Saturation overland flow is generated when
A. Rainfall exceeds storage
B. Impervious surfaces dominate
C. Soil becomes fully saturated
D. Slopes are steep
Rationale: Runoff occurs once soil saturation prevents further infiltration.
6. Darcy’s Law describes
A. Surface runoff velocity
B. Flow through porous media
C. Open channel flow
D. Turbulent flow resistance
Rationale: Darcy’s Law governs groundwater flow.
7. Hydraulic conductivity depends primarily on
A. Temperature only
B. Fluid viscosity only
C. Soil properties and fluid characteristics
D. Slope angle
Rationale: Both soil structure and fluid properties affect conductivity.
8. Aquifers that are confined are characterized by
A. Free water table
B. Pressure greater than atmospheric
C. Direct recharge from surface
D. Unsaturated conditions
Rationale: Confined aquifers are under pressure.
, 9. Specific yield represents
A. Total porosity
B. Bound water fraction
C. Drainable water fraction
D. Capillary water
Rationale: It is the portion of water that drains by gravity.
10.The water table is defined as
A. Top of aquifer
B. Surface where pore pressure equals atmospheric
C. Base of unsaturated zone
D. Zone of capillary rise
Rationale: At the water table pressure equals atmospheric.
11.Evapotranspiration includes
A. Evaporation only
B. Evaporation and plant transpiration
C. Condensation
D. Sublimation
Rationale: ET combines evaporation and transpiration.
12.Potential evapotranspiration is
A. Actual water loss
B. Maximum possible ET under unlimited water
C. Minimum ET
D. ET during drought
Rationale: PET assumes no water limitation.
13.Lysimeters are used to measure
A. Rainfall intensity
B. Evapotranspiration
C. Groundwater flow
D. Stream discharge
Rationale: Lysimeters directly measure ET.
CERTIFICATION EXAM QUESTION AND
CORRECT ANSWERS (VERIFIED
ANSWERS) PLUS RATIONALES 2026 Q&A
INSTANT DOWNLOAD PDF
1. The hydrologic cycle is primarily driven by
A. Gravity
B. Solar energy
C. Earth’s rotation
D. Atmospheric pressure
Rationale: Solar energy powers evaporation, which drives the hydrologic
cycle.
2. Precipitation that reaches the ground surface without interception is called
A. Throughfall
B. Net precipitation
C. Stemflow
D. Gross rainfall
Rationale: Net precipitation includes water that actually reaches the
ground.
3. Infiltration capacity is defined as
A. Total soil moisture
B. Maximum rate at which soil can absorb water
C. Groundwater storage
D. Hydraulic gradient
Rationale: Infiltration capacity limits how fast water enters the soil.
,4. Hortonian overland flow occurs when
A. Soil is saturated
B. Rainfall intensity exceeds infiltration capacity
C. Water table rises to surface
D. Evapotranspiration is high
Rationale: Hortonian flow is infiltration-excess runoff.
5. Saturation overland flow is generated when
A. Rainfall exceeds storage
B. Impervious surfaces dominate
C. Soil becomes fully saturated
D. Slopes are steep
Rationale: Runoff occurs once soil saturation prevents further infiltration.
6. Darcy’s Law describes
A. Surface runoff velocity
B. Flow through porous media
C. Open channel flow
D. Turbulent flow resistance
Rationale: Darcy’s Law governs groundwater flow.
7. Hydraulic conductivity depends primarily on
A. Temperature only
B. Fluid viscosity only
C. Soil properties and fluid characteristics
D. Slope angle
Rationale: Both soil structure and fluid properties affect conductivity.
8. Aquifers that are confined are characterized by
A. Free water table
B. Pressure greater than atmospheric
C. Direct recharge from surface
D. Unsaturated conditions
Rationale: Confined aquifers are under pressure.
, 9. Specific yield represents
A. Total porosity
B. Bound water fraction
C. Drainable water fraction
D. Capillary water
Rationale: It is the portion of water that drains by gravity.
10.The water table is defined as
A. Top of aquifer
B. Surface where pore pressure equals atmospheric
C. Base of unsaturated zone
D. Zone of capillary rise
Rationale: At the water table pressure equals atmospheric.
11.Evapotranspiration includes
A. Evaporation only
B. Evaporation and plant transpiration
C. Condensation
D. Sublimation
Rationale: ET combines evaporation and transpiration.
12.Potential evapotranspiration is
A. Actual water loss
B. Maximum possible ET under unlimited water
C. Minimum ET
D. ET during drought
Rationale: PET assumes no water limitation.
13.Lysimeters are used to measure
A. Rainfall intensity
B. Evapotranspiration
C. Groundwater flow
D. Stream discharge
Rationale: Lysimeters directly measure ET.
