NGWA PROFESSIONAL
CERTIFICATION COMPREHENSIVE
PRACTICE EXAM (2026/2027 UPDATE)
1. According to Darcy’s Law, what happens to the discharge rate (Q) if the hydraulic gradient
is doubled while all other factors remain constant?
A. The discharge rate is halved
B. The discharge rate remains the same
C. The discharge rate increases fourfold
D. The discharge rate is doubled
Answer: D
Conceptual Explanation: Darcy’s Law (Q = KiA) states that discharge is directly
proportional to the hydraulic gradient (i). Doubling the gradient results in a doubling of the
discharge rate.
2. In well construction, what is the primary purpose of using a ‘packer’ in a bedrock well?
A. To increase the structural integrity of the casing
B. To isolate specific zones for water quality sampling or yield testing
,C. To prevent the pump from falling into the well
D. To filter out large sediment particles from the aquifer
Answer: B
Conceptual Explanation: Packers are inflatable or mechanical devices used to isolate
specific intervals or zones within a borehole to perform testing or to seal off poor quality
water.
3. Which parameter is defined as the volume of water an aquifer releases from or takes into
storage per unit surface area of the aquifer per unit change in head?
A. Storativity
B. Transmissivity
C. Hydraulic Conductivity
D. Specific Yield
Answer: A
Conceptual Explanation: Storativity (or the storage coefficient) is a dimensionless
measure of the volume of water released or stored per unit area per unit change in head.
4. When sizing a submersible pump, what does ‘Total Dynamic Head’ (TDH) include?
A. Only the vertical distance from the pump to the surface
B. Static head, friction loss, and operating pressure head
C. Only the friction loss in the piping
, D. The depth of the well minus the drawdown
Answer: B
Conceptual Explanation: TDH is the sum of the elevation head (vertical lift), friction head
(resistance in pipes/fittings), and the required pressure head at the discharge point.
5. Which drilling method utilizes a ‘walking beam’ to lift and drop a heavy string of tools to
crush rock?
A. Mud Rotary
B. Air Rotary
C. Cable Tool
D. Reverse Circulation
Answer: C
Conceptual Explanation: Cable tool drilling, one of the oldest methods, uses a
reciprocating motion where a heavy bit is dropped repeatedly to fracture the formation.
6. What is the ‘SDR’ rating of PVC pipe used for well casing?
A. Static Depth Ratio (Maximum depth allowed for installation)
B. Structural Density Rating (Density of the plastic material)
C. Standard Dimension Ratio (Outer Diameter divided by wall thickness)
D. Surface Displacement Rate (Flexibility of the pipe under pressure)
CERTIFICATION COMPREHENSIVE
PRACTICE EXAM (2026/2027 UPDATE)
1. According to Darcy’s Law, what happens to the discharge rate (Q) if the hydraulic gradient
is doubled while all other factors remain constant?
A. The discharge rate is halved
B. The discharge rate remains the same
C. The discharge rate increases fourfold
D. The discharge rate is doubled
Answer: D
Conceptual Explanation: Darcy’s Law (Q = KiA) states that discharge is directly
proportional to the hydraulic gradient (i). Doubling the gradient results in a doubling of the
discharge rate.
2. In well construction, what is the primary purpose of using a ‘packer’ in a bedrock well?
A. To increase the structural integrity of the casing
B. To isolate specific zones for water quality sampling or yield testing
,C. To prevent the pump from falling into the well
D. To filter out large sediment particles from the aquifer
Answer: B
Conceptual Explanation: Packers are inflatable or mechanical devices used to isolate
specific intervals or zones within a borehole to perform testing or to seal off poor quality
water.
3. Which parameter is defined as the volume of water an aquifer releases from or takes into
storage per unit surface area of the aquifer per unit change in head?
A. Storativity
B. Transmissivity
C. Hydraulic Conductivity
D. Specific Yield
Answer: A
Conceptual Explanation: Storativity (or the storage coefficient) is a dimensionless
measure of the volume of water released or stored per unit area per unit change in head.
4. When sizing a submersible pump, what does ‘Total Dynamic Head’ (TDH) include?
A. Only the vertical distance from the pump to the surface
B. Static head, friction loss, and operating pressure head
C. Only the friction loss in the piping
, D. The depth of the well minus the drawdown
Answer: B
Conceptual Explanation: TDH is the sum of the elevation head (vertical lift), friction head
(resistance in pipes/fittings), and the required pressure head at the discharge point.
5. Which drilling method utilizes a ‘walking beam’ to lift and drop a heavy string of tools to
crush rock?
A. Mud Rotary
B. Air Rotary
C. Cable Tool
D. Reverse Circulation
Answer: C
Conceptual Explanation: Cable tool drilling, one of the oldest methods, uses a
reciprocating motion where a heavy bit is dropped repeatedly to fracture the formation.
6. What is the ‘SDR’ rating of PVC pipe used for well casing?
A. Static Depth Ratio (Maximum depth allowed for installation)
B. Structural Density Rating (Density of the plastic material)
C. Standard Dimension Ratio (Outer Diameter divided by wall thickness)
D. Surface Displacement Rate (Flexibility of the pipe under pressure)
