AZ L-83 Stormwater Systems Contractor
Exam Practice Questions And Correct
Answers (Verified Answers) Plus
Rationales 2027 Q&A | Instant
Download Pdf
Question 1
What is the primary purpose of a stormwater drainage system?
A. Increase groundwater contamination
B. Collect, convey, control, and safely discharge stormwater
C. Eliminate all groundwater
D. Increase surface erosion
Answer: B. Collect, convey, control, and safely discharge stormwater
Rationale: A stormwater system is designed to manage runoff so that
flows are safely collected, conveyed, detained or treated, and discharged
while minimizing flooding and erosion.
,Question 2
Which factor most directly affects the amount of stormwater runoff
generated from a paved site?
A. Soil color
B. Impervious surface area
C. Pipe color
D. Air temperature
Answer: B. Impervious surface area
Rationale: Impervious surfaces such as pavement and rooftops prevent
infiltration and generally increase the volume and rate of runoff.
Question 3
What does the term "watershed" describe?
A. A single storm drain
B. An area of land draining to a common outlet
C. A type of drainage pipe
D. A groundwater well
Answer: B. An area of land draining to a common outlet
Rationale: A watershed is the land area from which surface water flows
toward a common drainage point or receiving body.
,Question 4
What is the main function of a catch basin?
A. Store potable water
B. Collect surface runoff and convey it into a drainage system
C. Increase soil compaction
D. Pump sewage into a building
Answer: B. Collect surface runoff and convey it into a drainage system
Rationale: Catch basins collect surface water and commonly include an
inlet structure and sump for sediment and debris collection.
Question 5
Why is proper pipe slope important in a gravity stormwater system?
A. It determines pipe color
B. It promotes adequate flow and helps prevent standing water
C. It eliminates the need for pipe joints
D. It prevents all pipe movement
Answer: B. It promotes adequate flow and helps prevent standing water
Rationale: Proper slope provides the hydraulic gradient necessary for
gravity flow and helps reduce sediment deposition and stagnant water.
, Question 6
What is the most appropriate tool for checking the elevation of a storm
drain pipe during installation?
A. Pipe wrench
B. Level or laser level
C. Hammer
D. Tape measure only
Answer: B. Level or laser level
Rationale: Elevation-control instruments such as lasers and levels allow
workers to establish and verify the designed invert elevations and slopes.
Question 7
What is the "invert" of a stormwater pipe?
A. Outside top of the pipe
B. Bottom inside elevation of the pipe
C. Pipe wall thickness
D. Centerline of the road
Answer: B. Bottom inside elevation of the pipe
Rationale: The invert is the lowest interior point of a pipe or drainage
structure and is commonly used to establish drainage elevations.
Exam Practice Questions And Correct
Answers (Verified Answers) Plus
Rationales 2027 Q&A | Instant
Download Pdf
Question 1
What is the primary purpose of a stormwater drainage system?
A. Increase groundwater contamination
B. Collect, convey, control, and safely discharge stormwater
C. Eliminate all groundwater
D. Increase surface erosion
Answer: B. Collect, convey, control, and safely discharge stormwater
Rationale: A stormwater system is designed to manage runoff so that
flows are safely collected, conveyed, detained or treated, and discharged
while minimizing flooding and erosion.
,Question 2
Which factor most directly affects the amount of stormwater runoff
generated from a paved site?
A. Soil color
B. Impervious surface area
C. Pipe color
D. Air temperature
Answer: B. Impervious surface area
Rationale: Impervious surfaces such as pavement and rooftops prevent
infiltration and generally increase the volume and rate of runoff.
Question 3
What does the term "watershed" describe?
A. A single storm drain
B. An area of land draining to a common outlet
C. A type of drainage pipe
D. A groundwater well
Answer: B. An area of land draining to a common outlet
Rationale: A watershed is the land area from which surface water flows
toward a common drainage point or receiving body.
,Question 4
What is the main function of a catch basin?
A. Store potable water
B. Collect surface runoff and convey it into a drainage system
C. Increase soil compaction
D. Pump sewage into a building
Answer: B. Collect surface runoff and convey it into a drainage system
Rationale: Catch basins collect surface water and commonly include an
inlet structure and sump for sediment and debris collection.
Question 5
Why is proper pipe slope important in a gravity stormwater system?
A. It determines pipe color
B. It promotes adequate flow and helps prevent standing water
C. It eliminates the need for pipe joints
D. It prevents all pipe movement
Answer: B. It promotes adequate flow and helps prevent standing water
Rationale: Proper slope provides the hydraulic gradient necessary for
gravity flow and helps reduce sediment deposition and stagnant water.
, Question 6
What is the most appropriate tool for checking the elevation of a storm
drain pipe during installation?
A. Pipe wrench
B. Level or laser level
C. Hammer
D. Tape measure only
Answer: B. Level or laser level
Rationale: Elevation-control instruments such as lasers and levels allow
workers to establish and verify the designed invert elevations and slopes.
Question 7
What is the "invert" of a stormwater pipe?
A. Outside top of the pipe
B. Bottom inside elevation of the pipe
C. Pipe wall thickness
D. Centerline of the road
Answer: B. Bottom inside elevation of the pipe
Rationale: The invert is the lowest interior point of a pipe or drainage
structure and is commonly used to establish drainage elevations.
