NV C-23 DRILLING WELLS EXAM SCRIPT 2026
COMPREHENSIVE EXAM Q&A STUDY GUIDE
◉ (D) A client needs a water supply well in a coastal area of Quebec
where both salt water intrusion and artesian conditions exist in
different aquifers. What investigation techniques and well design
considerations should be implemented? Answer: Investigation
techniques should include: (1) Vertical electrical soundings or
resistivity profiling to identify fresh/salt water boundaries; (2) Test
borings with specific conductance measurements at various depths;
(3) Geophysical logging of test holes to identify water quality
transitions and confining layers; (4) Monitoring of existing wells in
the area for seasonal changes in salinity and pressure. Well design
considerations should include: (1) Targeting confined freshwater
aquifers with sufficient overlying protection; (2) Installing pressure-
rated casings and fittings to handle artesian conditions; (3)
Designing an appropriate wellhead with flow control capabilities for
artesian conditions; (4) Full-length grouting of the annular space
with pressure-rated grout; (5) Minimal screen length positioned
well above the salt water interface; (6) Establishing a conservative
pumping rate to prevent upconing of salt water; (7) Installation of
monitoring points to detect early changes in water quality; and (8)
Automated conductivity monitoring with pump controls to prevent
excessive pumping during seasonal changes in the interface position.
◉ (E) What causes water hammer in a well system and how can it be
prevented? Answer: Water hammer is a pressure surge caused by
,the sudden stopping or direction change of water in pipes, typically
when a pump shuts off or a valve closes quickly. It can damage pipes,
connections, pump components, and pressure tanks. Prevention
methods include: (1) Installing slow-closing check valves; (2) Using
pressure tanks with proper air charge; (3) Installing water hammer
arrestors at key points; (4) Using variable speed pumps that ramp
down gradually; (5) Properly securing pipes to prevent movement;
and (6) Designing pipe systems with adequately sized components
and appropriate materials to absorb pressure surges.
◉ (M) What information should be recorded during the drilling of a
water well to create a complete well log? Answer: A complete well
log should record: (1) Property and owner information; (2) Precise
well location with GPS coordinates; (3) Date of drilling; (4) Drilling
method used; (5) Detailed geological information (soil and rock
types, color, texture, hardness) at various depths; (6) Water-bearing
zones encountered and estimated yields; (7) Static water level; (8)
Well construction details (casing type, diameter, depth, screen type
and position); (9) Grouting/sealing details (materials, depth
intervals); (10) Well development method and duration; (11)
Pumping test results; (12) Water quality observations; (13)
Problems encountered during drilling; and (14) Weather conditions
that might affect drilling or development.
◉ (E) What is a confined aquifer and how does it differ from an
unconfined aquifer? Answer: A confined aquifer is a water-bearing
geological formation that is bounded above and below by
impermeable layers (aquitards or aquicludes), placing the water
,under pressure. It differs from an unconfined aquifer, which has the
water table as its upper boundary with no confining layer above. In
confined aquifers, the water level in wells often rises above the top
of the aquifer, creating artesian conditions, while in unconfined
aquifers, the water level in wells equals the water table level.
◉ (M) What is the recommended minimum height for a well casing
above ground level in Quebec and why is this important? Answer:
The recommended minimum height for a well casing above ground
level in Quebec is 12 inches (30 cm) according to the Regulation
respecting groundwater catchment. This height is important to
prevent surface water, snow melt, and potential contaminants from
entering the well, to protect against flooding, to allow for proper
attachment of the well cap, and to make the well visible to prevent
accidental damage from vehicles or equipment.
◉ (D) A pumping test on a new 300 ft (91.4 meters) well shows
unexpected drawdown patterns, with rapid initial drawdown
followed by stabilization, then another drop after several hours of
pumping. What does this pattern suggest and what further
investigation is needed? Answer: This step-drawdown pattern
suggests multiple aquifer systems or boundary conditions affecting
the well. The initial drawdown likely represents the response of the
immediate formation around the well. The stabilization indicates a
recharge boundary or more permeable zone that was activated. The
secondary drop suggests either a barrier boundary (such as a fault
or impermeable formation) being reached by the cone of depression,
or dewatering of a specific fracture system. Further investigation
, should include: (1) Extended pumping tests with observation wells
at different distances; (2) Geophysical logging to identify fracture
zones or formation changes; (3) Water quality sampling during
different phases of pumping to check for different aquifer
signatures; and (4) Analysis of regional geological structures that
might explain the boundary conditions observed.
◉ (E) What is the purpose of a GPS location in a well drilling report?
Answer: The purpose of recording GPS coordinates (latitude and
longitude or UTM X and Y) in a well drilling report is to provide
precise location information for future reference. This allows
accurate mapping of groundwater resources, helps in identifying the
well for future servicing or testing, enables correlation with other
geological and hydrological data, facilitates tracking of water quality
patterns across regions, and complies with the reporting
requirements in the Regulation respecting groundwater catchment.
◉ (M) What is the minimum water flow rate typically required for a
single-family residence in Quebec? Answer: The minimum water
flow rate typically required for a single-family residence in Quebec is
3-5 gal/min (11.4-18.9 l/min) for basic needs. However, 5-10
gal/min (18.9-37.8 l/min) is recommended for comfortable use of
multiple fixtures simultaneously. The actual requirement depends
on household size, fixture count, and peak demand periods. For
homes with low-yield wells, storage tanks and management systems
can compensate for wells producing below these rates.
COMPREHENSIVE EXAM Q&A STUDY GUIDE
◉ (D) A client needs a water supply well in a coastal area of Quebec
where both salt water intrusion and artesian conditions exist in
different aquifers. What investigation techniques and well design
considerations should be implemented? Answer: Investigation
techniques should include: (1) Vertical electrical soundings or
resistivity profiling to identify fresh/salt water boundaries; (2) Test
borings with specific conductance measurements at various depths;
(3) Geophysical logging of test holes to identify water quality
transitions and confining layers; (4) Monitoring of existing wells in
the area for seasonal changes in salinity and pressure. Well design
considerations should include: (1) Targeting confined freshwater
aquifers with sufficient overlying protection; (2) Installing pressure-
rated casings and fittings to handle artesian conditions; (3)
Designing an appropriate wellhead with flow control capabilities for
artesian conditions; (4) Full-length grouting of the annular space
with pressure-rated grout; (5) Minimal screen length positioned
well above the salt water interface; (6) Establishing a conservative
pumping rate to prevent upconing of salt water; (7) Installation of
monitoring points to detect early changes in water quality; and (8)
Automated conductivity monitoring with pump controls to prevent
excessive pumping during seasonal changes in the interface position.
◉ (E) What causes water hammer in a well system and how can it be
prevented? Answer: Water hammer is a pressure surge caused by
,the sudden stopping or direction change of water in pipes, typically
when a pump shuts off or a valve closes quickly. It can damage pipes,
connections, pump components, and pressure tanks. Prevention
methods include: (1) Installing slow-closing check valves; (2) Using
pressure tanks with proper air charge; (3) Installing water hammer
arrestors at key points; (4) Using variable speed pumps that ramp
down gradually; (5) Properly securing pipes to prevent movement;
and (6) Designing pipe systems with adequately sized components
and appropriate materials to absorb pressure surges.
◉ (M) What information should be recorded during the drilling of a
water well to create a complete well log? Answer: A complete well
log should record: (1) Property and owner information; (2) Precise
well location with GPS coordinates; (3) Date of drilling; (4) Drilling
method used; (5) Detailed geological information (soil and rock
types, color, texture, hardness) at various depths; (6) Water-bearing
zones encountered and estimated yields; (7) Static water level; (8)
Well construction details (casing type, diameter, depth, screen type
and position); (9) Grouting/sealing details (materials, depth
intervals); (10) Well development method and duration; (11)
Pumping test results; (12) Water quality observations; (13)
Problems encountered during drilling; and (14) Weather conditions
that might affect drilling or development.
◉ (E) What is a confined aquifer and how does it differ from an
unconfined aquifer? Answer: A confined aquifer is a water-bearing
geological formation that is bounded above and below by
impermeable layers (aquitards or aquicludes), placing the water
,under pressure. It differs from an unconfined aquifer, which has the
water table as its upper boundary with no confining layer above. In
confined aquifers, the water level in wells often rises above the top
of the aquifer, creating artesian conditions, while in unconfined
aquifers, the water level in wells equals the water table level.
◉ (M) What is the recommended minimum height for a well casing
above ground level in Quebec and why is this important? Answer:
The recommended minimum height for a well casing above ground
level in Quebec is 12 inches (30 cm) according to the Regulation
respecting groundwater catchment. This height is important to
prevent surface water, snow melt, and potential contaminants from
entering the well, to protect against flooding, to allow for proper
attachment of the well cap, and to make the well visible to prevent
accidental damage from vehicles or equipment.
◉ (D) A pumping test on a new 300 ft (91.4 meters) well shows
unexpected drawdown patterns, with rapid initial drawdown
followed by stabilization, then another drop after several hours of
pumping. What does this pattern suggest and what further
investigation is needed? Answer: This step-drawdown pattern
suggests multiple aquifer systems or boundary conditions affecting
the well. The initial drawdown likely represents the response of the
immediate formation around the well. The stabilization indicates a
recharge boundary or more permeable zone that was activated. The
secondary drop suggests either a barrier boundary (such as a fault
or impermeable formation) being reached by the cone of depression,
or dewatering of a specific fracture system. Further investigation
, should include: (1) Extended pumping tests with observation wells
at different distances; (2) Geophysical logging to identify fracture
zones or formation changes; (3) Water quality sampling during
different phases of pumping to check for different aquifer
signatures; and (4) Analysis of regional geological structures that
might explain the boundary conditions observed.
◉ (E) What is the purpose of a GPS location in a well drilling report?
Answer: The purpose of recording GPS coordinates (latitude and
longitude or UTM X and Y) in a well drilling report is to provide
precise location information for future reference. This allows
accurate mapping of groundwater resources, helps in identifying the
well for future servicing or testing, enables correlation with other
geological and hydrological data, facilitates tracking of water quality
patterns across regions, and complies with the reporting
requirements in the Regulation respecting groundwater catchment.
◉ (M) What is the minimum water flow rate typically required for a
single-family residence in Quebec? Answer: The minimum water
flow rate typically required for a single-family residence in Quebec is
3-5 gal/min (11.4-18.9 l/min) for basic needs. However, 5-10
gal/min (18.9-37.8 l/min) is recommended for comfortable use of
multiple fixtures simultaneously. The actual requirement depends
on household size, fixture count, and peak demand periods. For
homes with low-yield wells, storage tanks and management systems
can compensate for wells producing below these rates.
