Washington Hydrogeologist Licensing Exam: Latest Verified Questions and Detailed Answers

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Washington Hydrogeologist Licensing Exam: Latest
Verified Questions and Detailed Answers

OVERVIEW DESCRIPTION:
The Washington Hydrogeologist Licensing Exam is a state-specific specialty examination
administered by the Washington State Board of Registration for Geologists. It is typically held
twice yearly in conjunction with the national ASBOG exam and is required for licensed
geologists seeking to demonstrate advanced competency in hydrogeology. The exam rigorously
tests expertise in groundwater hydrology, aquifer mechanics, contaminant transport, subsurface
characterization, and geochemistry. It also emphasizes practical applications such as well
construction, remediation system design, and compliance with Washington's specific
groundwater laws and regulations (primarily Chapters 173-160 and 246-291 WAC). This set of
200 multiple-choice questions is designed to reflect the format and subject matter of the actual
exam, providing a comprehensive review tool for candidates.

QUESTION 1
What is the primary mechanism for groundwater flow in a confined aquifer?
A) Tidal fluctuations
B) Differences in fluid density
C) Variations in hydraulic head
D) Capillary action in the vadose zone
CORRECT ANSWER: C
EXPERT RATIONALE: Groundwater flows from areas of high hydraulic head to low
hydraulic head, which represents the total mechanical energy per unit weight of fluid .

QUESTION 2
In Washington State, what is the minimum required setback distance for a ground
source heat pump boring from a public water supply well, unless a variance is
granted?
A) 50 feet
B) 75 feet
C) 100 feet

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D) 200 feet
CORRECT ANSWER: C
EXPERT RATIONALE: WAC 173-160-453 explicitly prohibits locating a ground source
heat pump boring within 100 feet of any water supply well, with stricter standards for
public supply wells .

QUESTION 3
Which anion is considered the least reactive and most persistent tracer for mapping a
contaminant plume in groundwater?
A) Sulfate (SO₄²⁻)
B) Bicarbonate (HCO₃⁻)
C) Chloride (Cl⁻)
D) Nitrate (NO₃⁻)
CORRECT ANSWER: C
EXPERT RATIONALE: Chloride is highly conservative, meaning it does not readily
participate in chemical reactions, sorb to aquifer materials, or degrade, making it an
ideal tracer .

QUESTION 4
A hydrogeologist is characterizing a site for a potential aquifer recharge project. Which
zone is defined as the interval immediately below the land surface where pores
contain both air and water?
A) Saturated zone
B) Zone of confinement
C) Aeration zone
D) Phreatic zone
CORRECT ANSWER: C
EXPERT RATIONALE: The aeration zone, also known as the vadose or unsaturated
zone, extends from the land surface to the water table .

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QUESTION 5
According to WAC 246-291-125, what is the minimum required radius for a Sanitary
Control Area (SCA) around a new Group B public water system well in Washington?
A) 50 feet
B) 100 feet
C) 200 feet
D) 600 feet
CORRECT ANSWER: B
EXPERT RATIONALE: The regulation requires an SCA with a minimum radius of 100
feet, though this can be reduced with technical justification or increased by the health
officer based on hydrogeologic data .

QUESTION 6
In an eolian (wind-blown) sand aquifer, how would hydraulic conductivity generally be
characterized?
A) Highly anisotropic and variable
B) Uniform
C) Decreasing with depth only
D) Controlled by fracture density
CORRECT ANSWER: B
EXPERT RATIONALE: Eolian sands are typically well-sorted, which results in a
relatively uniform pore size distribution and consequently a more uniform hydraulic
conductivity compared to glacial till or alluvial deposits .

QUESTION 7
What does the term "specific yield" measure in an unconfined aquifer?
A) The volume of water released from storage per unit surface area per unit decline in
head
B) The ratio of the volume of water drained by gravity to the total volume of the rock
C) The total porosity of the aquifer material
D) The rate of water movement through a unit cross-sectional area

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CORRECT ANSWER: B
EXPERT RATIONALE: Specific yield is the drainable porosity; it represents the water
that will drain from an unconfined aquifer due to gravity, as opposed to specific
retention which is held by capillary forces .

QUESTION 8
When collecting duplicate samples for a contaminated site investigation to validate
laboratory results, what is a critical procedure?
A) Label the duplicates clearly for the lab to ensure they analyze them as QC samples
B) Collect them from the same location at the same time but give them different
sample IDs unknown to the lab
C) Ensure they are collected on different days to capture temporal variation
D) Send the duplicate to a different laboratory than the original
CORRECT ANSWER: B
EXPERT RATIONALE: To ensure a blind performance evaluation of the laboratory, the
geologist must submit the duplicate sample in a way that the lab cannot identify it as a
quality control sample .

QUESTION 9
Which of the following is NOT typically considered a natural constituent of
groundwater, but rather an indicator of anthropogenic contamination?
A) Calcium
B) Bicarbonate
C) Silica
D) Nitrate
CORRECT ANSWER: D
EXPERT RATIONALE: While some nitrate occurs naturally, elevated concentrations are
almost always linked to human activities such as fertilizer application, septic systems,
or livestock waste .