CALIFORNIA CERTIFIED HYDROGEOLOGIST EXAMINATION
2026-2027 NEWEST REAL EXAM QUESTIONS AND CORRECT
DETAILED ANSWERS LATEST UPDATES (VERIFIED ANSWERS)
ALREDY GRADED A+
Question 1
In an unconfined aquifer, the volume of water that a unit volume of aquifer drains under the
force of gravity is referred to as:
A) Storativity
B) Specific storage
C) Specific yield
D) Transmissivity
Answer: C
Rationale: Specific yield (Sy) is the ratio of the volume of water that drains by gravity from a
saturated unconfined aquifer to the total volume of the aquifer. Storativity (A) is used for
confined aquifers and includes specific storage and aquifer thickness. Specific storage (B) is
the elastic storage component. Transmissivity (D) is the product of hydraulic conductivity and
saturated thickness.
Question 2
Darcy’s Law states that the specific discharge (q) is proportional to the hydraulic gradient and
the:
A) Porosity
B) Hydraulic conductivity
C) Transmissivity
D) Grain size
Answer: B
Rationale: Darcy’s Law is q = –K (dh/dl), where K is hydraulic conductivity. Hydraulic
conductivity directly controls the flow rate for a given gradient. Porosity influences the actual
seepage velocity but not the specific discharge directly in Darcy's equation. Transmissivity
integrates K with thickness, and grain size is a factor but not the coefficient.
,Question 3
A pumping test in a confined aquifer yields drawdown data that plot as a straight line on
semi-log paper (drawdown vs. log time). This behavior is characteristic of:
A) Theis type curve
B) Cooper-Jacob straight-line method for late time
C) Slug test analysis using Hvorslev
D) Neuman method for unconfined aquifers
Answer: B
Rationale: For the Jacob approximation to the Theis solution, drawdown versus the logarithm
of time forms a straight line when u ≤ 0.01. The Theis type curve (A) is a log-log plot. The
Hvorslev (C) method is for slug tests. The Neuman (D) method is for unconfined aquifers with
delayed yield.
Question 4
Which of the following best describes the term “transmissivity” (T)?
A) The volume of water that can be drained from an aquifer
B) The rate at which water of a given viscosity is transmitted through a unit width of aquifer
under a unit hydraulic gradient
C) The ratio of hydraulic conductivity to storativity
D) The average linear velocity of groundwater
Answer: B
Rationale: Transmissivity is defined as T = K × b (saturated thickness) and has units of length
squared per time (e.g., ft²/day). It represents the flow capacity of the aquifer per unit width.
Option A describes specific yield, C is a ratio not defined, D is seepage velocity (v = KI / ne).
Question 5
In a typical groundwater flow net, the equipotential lines are:
A) Parallel to flow lines
B) Intersecting flow lines at any angle
C) Perpendicular to flow lines
D) Curved with no relation to flow lines
,Answer: C
Rationale: Flow lines and equipotential lines must intersect at right angles in an isotropic
medium, forming curvilinear squares. This property is fundamental to constructing flow nets.
They are not parallel (A) or randomly oriented (B, D).
Question 6
The Sustainable Groundwater Management Act (SGMA) in California requires that
groundwater sustainability agencies (GSAs) develop and implement Groundwater
Sustainability Plans (GSPs) for:
A) All groundwater basins in the state
B) Only overdrafted basins
C) Medium- and high-priority basins designated by the Department of Water Resources
D) Only basins with adjudicated water rights
Answer: C
Rationale: SGMA mandates that GSAs be formed for basins designated as medium or high
priority by DWR. GSPs must be developed for those basins to achieve sustainability within 20
years. Low-priority basins are not required to form GSAs but may voluntarily. All basins are
not covered, only designated ones. Adjudicated basins may be exempt or have different
requirements.
Question 7
During a constant-rate pumping test, the specific capacity of a well is defined as:
A) The pumping rate divided by the drawdown
B) The drawdown divided by the pumping rate
C) The product of pumping rate and drawdown
D) The time required for the cone of depression to stabilize
Answer: A
Rationale: Specific capacity is the well yield per unit drawdown, typically expressed as Q/s
(e.g., gpm/ft). It is a measure of well performance. The reciprocal would be (B). The product
(C) has no physical meaning. Stabilization time (D) is not specific capacity.
, Question 8
Which of the following is a primary mechanism of solute transport in groundwater that
results from the differences in concentration?
A) Advection
B) Dispersion
C) Diffusion
D) Sorption
Answer: C
Rationale: Molecular diffusion is the movement of solute from areas of higher concentration
to lower concentration due to the random motion of molecules, even in the absence of
groundwater flow. Advection (A) is bulk transport with flowing water. Dispersion (B) is
mechanical mixing. Sorption (D) is a retardation process.
Question 9
In a slug test, a known volume of water is suddenly added to or removed from a well, and the
water level recovery is measured over time. The method most commonly used to interpret a
slug test in a fully penetrating well in a confined aquifer is:
A) Theis type curve
B) Cooper-Bredehoeft-Papadopulos (CBP) method
C) Hvorslev method
D) Cooper-Jacob method
Answer: C
Rationale: The Hvorslev method is commonly used for slug tests to estimate hydraulic
conductivity, applicable to various well geometries. The CBP method (B) is specifically for
oscillatory recovery in high-K aquifers. The Theis and Cooper-Jacob methods are for constant-
rate pumping tests, not slug tests.
Question 10
Which California code section establishes the authority for the State Water Resources Control
Board to regulate groundwater extraction that is not subject to SGMA in a condition of severe
overdraft?
A) California Water Code Section 1020
B) California Water Code Section 10720 et seq. (SGMA)
2026-2027 NEWEST REAL EXAM QUESTIONS AND CORRECT
DETAILED ANSWERS LATEST UPDATES (VERIFIED ANSWERS)
ALREDY GRADED A+
Question 1
In an unconfined aquifer, the volume of water that a unit volume of aquifer drains under the
force of gravity is referred to as:
A) Storativity
B) Specific storage
C) Specific yield
D) Transmissivity
Answer: C
Rationale: Specific yield (Sy) is the ratio of the volume of water that drains by gravity from a
saturated unconfined aquifer to the total volume of the aquifer. Storativity (A) is used for
confined aquifers and includes specific storage and aquifer thickness. Specific storage (B) is
the elastic storage component. Transmissivity (D) is the product of hydraulic conductivity and
saturated thickness.
Question 2
Darcy’s Law states that the specific discharge (q) is proportional to the hydraulic gradient and
the:
A) Porosity
B) Hydraulic conductivity
C) Transmissivity
D) Grain size
Answer: B
Rationale: Darcy’s Law is q = –K (dh/dl), where K is hydraulic conductivity. Hydraulic
conductivity directly controls the flow rate for a given gradient. Porosity influences the actual
seepage velocity but not the specific discharge directly in Darcy's equation. Transmissivity
integrates K with thickness, and grain size is a factor but not the coefficient.
,Question 3
A pumping test in a confined aquifer yields drawdown data that plot as a straight line on
semi-log paper (drawdown vs. log time). This behavior is characteristic of:
A) Theis type curve
B) Cooper-Jacob straight-line method for late time
C) Slug test analysis using Hvorslev
D) Neuman method for unconfined aquifers
Answer: B
Rationale: For the Jacob approximation to the Theis solution, drawdown versus the logarithm
of time forms a straight line when u ≤ 0.01. The Theis type curve (A) is a log-log plot. The
Hvorslev (C) method is for slug tests. The Neuman (D) method is for unconfined aquifers with
delayed yield.
Question 4
Which of the following best describes the term “transmissivity” (T)?
A) The volume of water that can be drained from an aquifer
B) The rate at which water of a given viscosity is transmitted through a unit width of aquifer
under a unit hydraulic gradient
C) The ratio of hydraulic conductivity to storativity
D) The average linear velocity of groundwater
Answer: B
Rationale: Transmissivity is defined as T = K × b (saturated thickness) and has units of length
squared per time (e.g., ft²/day). It represents the flow capacity of the aquifer per unit width.
Option A describes specific yield, C is a ratio not defined, D is seepage velocity (v = KI / ne).
Question 5
In a typical groundwater flow net, the equipotential lines are:
A) Parallel to flow lines
B) Intersecting flow lines at any angle
C) Perpendicular to flow lines
D) Curved with no relation to flow lines
,Answer: C
Rationale: Flow lines and equipotential lines must intersect at right angles in an isotropic
medium, forming curvilinear squares. This property is fundamental to constructing flow nets.
They are not parallel (A) or randomly oriented (B, D).
Question 6
The Sustainable Groundwater Management Act (SGMA) in California requires that
groundwater sustainability agencies (GSAs) develop and implement Groundwater
Sustainability Plans (GSPs) for:
A) All groundwater basins in the state
B) Only overdrafted basins
C) Medium- and high-priority basins designated by the Department of Water Resources
D) Only basins with adjudicated water rights
Answer: C
Rationale: SGMA mandates that GSAs be formed for basins designated as medium or high
priority by DWR. GSPs must be developed for those basins to achieve sustainability within 20
years. Low-priority basins are not required to form GSAs but may voluntarily. All basins are
not covered, only designated ones. Adjudicated basins may be exempt or have different
requirements.
Question 7
During a constant-rate pumping test, the specific capacity of a well is defined as:
A) The pumping rate divided by the drawdown
B) The drawdown divided by the pumping rate
C) The product of pumping rate and drawdown
D) The time required for the cone of depression to stabilize
Answer: A
Rationale: Specific capacity is the well yield per unit drawdown, typically expressed as Q/s
(e.g., gpm/ft). It is a measure of well performance. The reciprocal would be (B). The product
(C) has no physical meaning. Stabilization time (D) is not specific capacity.
, Question 8
Which of the following is a primary mechanism of solute transport in groundwater that
results from the differences in concentration?
A) Advection
B) Dispersion
C) Diffusion
D) Sorption
Answer: C
Rationale: Molecular diffusion is the movement of solute from areas of higher concentration
to lower concentration due to the random motion of molecules, even in the absence of
groundwater flow. Advection (A) is bulk transport with flowing water. Dispersion (B) is
mechanical mixing. Sorption (D) is a retardation process.
Question 9
In a slug test, a known volume of water is suddenly added to or removed from a well, and the
water level recovery is measured over time. The method most commonly used to interpret a
slug test in a fully penetrating well in a confined aquifer is:
A) Theis type curve
B) Cooper-Bredehoeft-Papadopulos (CBP) method
C) Hvorslev method
D) Cooper-Jacob method
Answer: C
Rationale: The Hvorslev method is commonly used for slug tests to estimate hydraulic
conductivity, applicable to various well geometries. The CBP method (B) is specifically for
oscillatory recovery in high-K aquifers. The Theis and Cooper-Jacob methods are for constant-
rate pumping tests, not slug tests.
Question 10
Which California code section establishes the authority for the State Water Resources Control
Board to regulate groundwater extraction that is not subject to SGMA in a condition of severe
overdraft?
A) California Water Code Section 1020
B) California Water Code Section 10720 et seq. (SGMA)
