California Certified Hydrogeologist
(CHG) Exam With Actual Questions &
Verified Answers, Plus Explained
Rationales/Expert Verified For
Guaranteed Pass 2026/Latest
Updated/Instant Download Pdf
1. Which law describes the relationship between groundwater flow
rate, hydraulic conductivity, cross-sectional area, and hydraulic
gradient?
A. Fick’s law
B. Bernoulli’s equation
C. Fourier’s law
D. Darcy’s law
Darcy’s law states that discharge per unit area (specific
discharge) is proportional to hydraulic conductivity and hydraulic
gradient; it is the fundamental equation of groundwater flow.
2. Effective porosity is best described as:
A. Total pore volume divided by total volume
B. Interconnected pore volume available for flow divided by total
volume
C. Pore volume filled only with water divided by total pore volume
D. Pore throat diameter distribution
, Effective porosity excludes isolated pores and counts only pores
that contribute to flow, so it is the interconnected pore volume
divided by total volume.
3. The hydraulic head at a point in an aquifer combines which two
components?
A. Pressure and temperature
B. Elevation and pressure (or pressure head and elevation head)
C. Velocity and elevation
D. Specific yield and porosity
Hydraulic head is the sum of elevation head and pressure head
(often expressed as head in meters of water).
4. Specific yield is defined as:
A. The volume of water held in pores under tension
B. The volume of water that will drain by gravity from a
saturated material per unit bulk volume
C. The porosity of an unconfined aquifer
D. The water content at field capacity
Specific yield is the fraction of water that is released by gravity
from a saturated porous medium; it is key for groundwater
storage in unconfined aquifers.
5. In a confined aquifer, pumping causes water levels in observation
wells to:
A. Rise above land surface
B. Change only at the pumping well
C. Decline due to drawdown transmitted as pressure change
D. Remain constant because confined aquifers are incompressible
Pumping from a confined aquifer reduces pressure and causes
, decline (drawdown) in piezometric head that propagates
through the aquifer.
6. Transmissivity (T) of an aquifer is the product of:
A. Hydraulic gradient and porosity
B. Hydraulic conductivity and saturated thickness
C. Specific yield and porosity
D. Storage coefficient and thickness
Transmissivity equals hydraulic conductivity (K) times the
saturated thickness (b) and describes the ability of an aquifer to
transmit water across its full thickness.
7. The Theis solution is used to analyze:
A. Saltwater intrusion
B. Solute transport in fractured rock
C. Radial transient flow to a well in a confined aquifer
D. Long-term recharge estimation from precipitation
The Theis (non-equilibrium) solution models time-drawdown
behavior for pumping tests in confined, homogeneous, isotropic
aquifers under transient conditions.
8. When characterizing an unconfined aquifer with a pumping test,
the Cooper-Jacob straight-line method approximates early Theis
solutions by assuming:
A. Recharge dominates flow
B. Late-time behavior where drawdown vs. log(time) becomes
linear
C. Constant-head boundary effects
D. Anisotropy is negligible
Cooper-Jacob linearization is a late-time approximation of Theis
, where drawdown behaves linearly with log(time), simplifying
transmissivity and storage estimation.
9. Hydraulic conductivity primarily depends on:
A. Chemical composition of water only
B. Groundwater temperature only
C. Pore size distribution and fluid viscosity
D. Aquifer depth only
Hydraulic conductivity depends on the medium’s pore
size/connectivity and the fluid’s properties (viscosity and
density), per fundamental flow theory.
10. Specific storage (Ss) in a confined aquifer is defined per unit
volume as:
A. Volume of water released from storage per unit surface area
B. Volume of water released from storage per unit volume of
aquifer per unit decline in head
C. Porosity multiplied by gravity
D. Volume of water taken in by compression only
Specific storage quantifies water release from storage due to
compressibility of the matrix and water per unit volume per unit
head change.
11. Which aquifer test result indicates significant anisotropy?
A. Constant drawdown at all directions
B. Identical drawdown in observation wells at all angles
C. Different drawdown/time responses in observation wells at
equal radial distances but different azimuths
D. No drawdown observed
Anisotropy causes directional differences in hydraulic
(CHG) Exam With Actual Questions &
Verified Answers, Plus Explained
Rationales/Expert Verified For
Guaranteed Pass 2026/Latest
Updated/Instant Download Pdf
1. Which law describes the relationship between groundwater flow
rate, hydraulic conductivity, cross-sectional area, and hydraulic
gradient?
A. Fick’s law
B. Bernoulli’s equation
C. Fourier’s law
D. Darcy’s law
Darcy’s law states that discharge per unit area (specific
discharge) is proportional to hydraulic conductivity and hydraulic
gradient; it is the fundamental equation of groundwater flow.
2. Effective porosity is best described as:
A. Total pore volume divided by total volume
B. Interconnected pore volume available for flow divided by total
volume
C. Pore volume filled only with water divided by total pore volume
D. Pore throat diameter distribution
, Effective porosity excludes isolated pores and counts only pores
that contribute to flow, so it is the interconnected pore volume
divided by total volume.
3. The hydraulic head at a point in an aquifer combines which two
components?
A. Pressure and temperature
B. Elevation and pressure (or pressure head and elevation head)
C. Velocity and elevation
D. Specific yield and porosity
Hydraulic head is the sum of elevation head and pressure head
(often expressed as head in meters of water).
4. Specific yield is defined as:
A. The volume of water held in pores under tension
B. The volume of water that will drain by gravity from a
saturated material per unit bulk volume
C. The porosity of an unconfined aquifer
D. The water content at field capacity
Specific yield is the fraction of water that is released by gravity
from a saturated porous medium; it is key for groundwater
storage in unconfined aquifers.
5. In a confined aquifer, pumping causes water levels in observation
wells to:
A. Rise above land surface
B. Change only at the pumping well
C. Decline due to drawdown transmitted as pressure change
D. Remain constant because confined aquifers are incompressible
Pumping from a confined aquifer reduces pressure and causes
, decline (drawdown) in piezometric head that propagates
through the aquifer.
6. Transmissivity (T) of an aquifer is the product of:
A. Hydraulic gradient and porosity
B. Hydraulic conductivity and saturated thickness
C. Specific yield and porosity
D. Storage coefficient and thickness
Transmissivity equals hydraulic conductivity (K) times the
saturated thickness (b) and describes the ability of an aquifer to
transmit water across its full thickness.
7. The Theis solution is used to analyze:
A. Saltwater intrusion
B. Solute transport in fractured rock
C. Radial transient flow to a well in a confined aquifer
D. Long-term recharge estimation from precipitation
The Theis (non-equilibrium) solution models time-drawdown
behavior for pumping tests in confined, homogeneous, isotropic
aquifers under transient conditions.
8. When characterizing an unconfined aquifer with a pumping test,
the Cooper-Jacob straight-line method approximates early Theis
solutions by assuming:
A. Recharge dominates flow
B. Late-time behavior where drawdown vs. log(time) becomes
linear
C. Constant-head boundary effects
D. Anisotropy is negligible
Cooper-Jacob linearization is a late-time approximation of Theis
, where drawdown behaves linearly with log(time), simplifying
transmissivity and storage estimation.
9. Hydraulic conductivity primarily depends on:
A. Chemical composition of water only
B. Groundwater temperature only
C. Pore size distribution and fluid viscosity
D. Aquifer depth only
Hydraulic conductivity depends on the medium’s pore
size/connectivity and the fluid’s properties (viscosity and
density), per fundamental flow theory.
10. Specific storage (Ss) in a confined aquifer is defined per unit
volume as:
A. Volume of water released from storage per unit surface area
B. Volume of water released from storage per unit volume of
aquifer per unit decline in head
C. Porosity multiplied by gravity
D. Volume of water taken in by compression only
Specific storage quantifies water release from storage due to
compressibility of the matrix and water per unit volume per unit
head change.
11. Which aquifer test result indicates significant anisotropy?
A. Constant drawdown at all directions
B. Identical drawdown in observation wells at all angles
C. Different drawdown/time responses in observation wells at
equal radial distances but different azimuths
D. No drawdown observed
Anisotropy causes directional differences in hydraulic
