CERTIFIED HYDROGEOLOGIST (CHG)
EXAMINATION
100 PRACTICE QUESTIONS WITH ANSWERS AND
RATIONALES
2026–2027 TESTING CYCLE
SECTION 1: PROJECT PLANNING (Questions 1–20)
Question 1: A community is evaluating the feasibility of using wastewater to irrigate a local golf
course. Which of the following regulatory requirements would most likely prohibit this method
of discharge?
Answer: Potential degradation of groundwater quality.
Rationale: Groundwater quality protection is a primary regulatory concern. Wastewater
irrigation can introduce contaminants (nitrates, salts, pathogens, trace organics) to the
subsurface, potentially degrading groundwater quality. While permeable bedrock and high
percolation rates affect infiltration, they are not regulatory prohibitions; rather, they are site
characteristics that influence the degree of risk. The presence of a downgradient municipal
supply well is a concern but does not itself prohibit the discharge; it would be evaluated in a risk
assessment.
,Question 2: A hydrogeologist is developing a conceptual site model (CSM) for a site with
suspected groundwater contamination. What is the FIRST step in this process?
Answer: Identify potential sources of contamination and the nature of the contaminants.
Rationale: The conceptual site model begins with identifying the source of contamination and the
contaminants of concern. This step establishes the basis for understanding the potential extent
and movement of contamination. It includes characterizing the chemical and physical properties
of the contaminants and the nature of the release.
Question 3: When developing a hydrogeologic investigation approach, a hydrogeologist must
determine the type, collection methods, quantity, and quality of data needed to achieve project
objectives. This determination is based on:
Answer: The anticipated hydrogeology and the specific project objectives.
Rationale: BPELSG Professional Activity 2 states that the hydrogeologist must determine the
type, collection methods, quantity, and quality of data based on anticipated hydrogeology and
project objectives. This ensures that the investigation is appropriately scaled and focused for the
specific geologic setting and project needs.
Question 4: Which of the following is a key element of preparing a conceptual site model
(CSM)?
,Answer: Integration of geologic, hydrogeologic, and contaminant data to develop a working
hypothesis of site conditions.
Rationale: The conceptual site model integrates all available data to develop a working
hypothesis that describes the site's geology, hydrogeology, and the nature and extent of
contamination. It is a living document that is refined as more data becomes available. The CSM
guides the investigation and informs remediation decisions.
Question 5: A hydrogeologist is evaluating potential sources of water supply for a new
development. Which of the following should be evaluated FIRST?
Answer: The regional and local hydrogeologic conditions, including basin boundaries and
aquifer characteristics.
Rationale: Before evaluating specific water sources, the hydrogeologist must understand the
regional and local hydrogeologic framework, including aquifer boundaries, recharge areas, and
flow patterns. This provides the context for evaluating the sustainability and reliability of
potential water sources.
Question 6: What is the primary purpose of identifying technical and regulatory requirements at
the start of a hydrogeologic investigation?
, Answer: To ensure that the investigation complies with all applicable laws, regulations, and
permitting requirements.
Rationale: Identifying technical and regulatory requirements early ensures that the investigation
meets all legal and permitting obligations. This includes federal, state, and local regulations
governing groundwater quality, water rights, well construction, and waste disposal. Compliance
is essential to avoid project delays and regulatory penalties.
Question 7: A hydrogeologist is tasked with assessing the potential for saltwater intrusion in a
coastal aquifer. Which of the following factors should be evaluated?
Answer: Groundwater pumping rates, aquifer hydraulic properties, and the hydraulic connection
between the aquifer and the ocean.
Rationale: BPELSG Professional Activity 7 requires the hydrogeologist to determine the
potential for saltwater intrusion. Key factors include the rate of groundwater pumping (which
can lower water levels and induce intrusion), the hydraulic properties of the aquifer (which
control flow), and the hydraulic connection between the aquifer and the ocean (which determines
the rate of saltwater movement).
Question 8: A conceptual hydrogeologic model is refined as:
Answer: Additional data is collected and analyzed during the investigation.
EXAMINATION
100 PRACTICE QUESTIONS WITH ANSWERS AND
RATIONALES
2026–2027 TESTING CYCLE
SECTION 1: PROJECT PLANNING (Questions 1–20)
Question 1: A community is evaluating the feasibility of using wastewater to irrigate a local golf
course. Which of the following regulatory requirements would most likely prohibit this method
of discharge?
Answer: Potential degradation of groundwater quality.
Rationale: Groundwater quality protection is a primary regulatory concern. Wastewater
irrigation can introduce contaminants (nitrates, salts, pathogens, trace organics) to the
subsurface, potentially degrading groundwater quality. While permeable bedrock and high
percolation rates affect infiltration, they are not regulatory prohibitions; rather, they are site
characteristics that influence the degree of risk. The presence of a downgradient municipal
supply well is a concern but does not itself prohibit the discharge; it would be evaluated in a risk
assessment.
,Question 2: A hydrogeologist is developing a conceptual site model (CSM) for a site with
suspected groundwater contamination. What is the FIRST step in this process?
Answer: Identify potential sources of contamination and the nature of the contaminants.
Rationale: The conceptual site model begins with identifying the source of contamination and the
contaminants of concern. This step establishes the basis for understanding the potential extent
and movement of contamination. It includes characterizing the chemical and physical properties
of the contaminants and the nature of the release.
Question 3: When developing a hydrogeologic investigation approach, a hydrogeologist must
determine the type, collection methods, quantity, and quality of data needed to achieve project
objectives. This determination is based on:
Answer: The anticipated hydrogeology and the specific project objectives.
Rationale: BPELSG Professional Activity 2 states that the hydrogeologist must determine the
type, collection methods, quantity, and quality of data based on anticipated hydrogeology and
project objectives. This ensures that the investigation is appropriately scaled and focused for the
specific geologic setting and project needs.
Question 4: Which of the following is a key element of preparing a conceptual site model
(CSM)?
,Answer: Integration of geologic, hydrogeologic, and contaminant data to develop a working
hypothesis of site conditions.
Rationale: The conceptual site model integrates all available data to develop a working
hypothesis that describes the site's geology, hydrogeology, and the nature and extent of
contamination. It is a living document that is refined as more data becomes available. The CSM
guides the investigation and informs remediation decisions.
Question 5: A hydrogeologist is evaluating potential sources of water supply for a new
development. Which of the following should be evaluated FIRST?
Answer: The regional and local hydrogeologic conditions, including basin boundaries and
aquifer characteristics.
Rationale: Before evaluating specific water sources, the hydrogeologist must understand the
regional and local hydrogeologic framework, including aquifer boundaries, recharge areas, and
flow patterns. This provides the context for evaluating the sustainability and reliability of
potential water sources.
Question 6: What is the primary purpose of identifying technical and regulatory requirements at
the start of a hydrogeologic investigation?
, Answer: To ensure that the investigation complies with all applicable laws, regulations, and
permitting requirements.
Rationale: Identifying technical and regulatory requirements early ensures that the investigation
meets all legal and permitting obligations. This includes federal, state, and local regulations
governing groundwater quality, water rights, well construction, and waste disposal. Compliance
is essential to avoid project delays and regulatory penalties.
Question 7: A hydrogeologist is tasked with assessing the potential for saltwater intrusion in a
coastal aquifer. Which of the following factors should be evaluated?
Answer: Groundwater pumping rates, aquifer hydraulic properties, and the hydraulic connection
between the aquifer and the ocean.
Rationale: BPELSG Professional Activity 7 requires the hydrogeologist to determine the
potential for saltwater intrusion. Key factors include the rate of groundwater pumping (which
can lower water levels and induce intrusion), the hydraulic properties of the aquifer (which
control flow), and the hydraulic connection between the aquifer and the ocean (which determines
the rate of saltwater movement).
Question 8: A conceptual hydrogeologic model is refined as:
Answer: Additional data is collected and analyzed during the investigation.
