AR STW Stormwater Systems Contractor
Exam Practice Questions And Correct
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Rationales 2027 Q&A | Instant
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1. What is the primary purpose of a stormwater management system?
A. To provide potable water
B. To eliminate all surface water
C. To collect, convey, control, and manage runoff
D. To increase pavement drainage rates
Answer: C. To collect, convey, control, and manage runoff
Rationale: Stormwater systems are designed to safely manage runoff
while reducing flooding, erosion, and adverse water-quality impacts.
2. What is the primary function of a catch basin?
,A. Increase groundwater pressure
B. Collect runoff and debris
C. Treat drinking water
D. Store sewage
Answer: B. Collect runoff and debris
Rationale: Catch basins receive surface runoff and commonly provide a
sump that captures sediment and debris before water enters the
conveyance system.
3. Which factor most directly affects the amount of stormwater runoff
from a developed site?
A. Paint color
B. Impervious surface area
C. Building height alone
D. Pipe color
Answer: B. Impervious surface area
Rationale: Impervious surfaces such as roofs, concrete, and asphalt reduce
infiltration and generally increase runoff volume and peak flow.
4. What does a drainage swale primarily do?
,A. Convey surface runoff
B. Store potable water
C. Support structural columns
D. Seal underground utilities
Answer: A. Convey surface runoff
Rationale: A properly graded swale provides a controlled surface path for
collecting and conveying stormwater.
5. Which condition generally increases runoff?
A. Increased infiltration
B. Increased vegetation
C. Increased impervious area
D. Increased soil porosity
Answer: C. Increased impervious area
Rationale: Impervious surfaces prevent much of the rainfall from
infiltrating into the soil, increasing surface runoff.
6. What is the purpose of a storm drain inlet?
A. To collect surface runoff
B. To pressurize a water main
, C. To ventilate a building
D. To discharge sewage gases
Answer: A. To collect surface runoff
Rationale: Storm drain inlets intercept runoff and direct it into
underground or surface conveyance systems.
7. What is a detention basin designed primarily to do?
A. Permanently eliminate runoff
B. Temporarily store runoff and release it at a controlled rate
C. Produce drinking water
D. Increase peak discharge
Answer: B. Temporarily store runoff and release it at a controlled rate
Rationale: Detention facilities temporarily hold stormwater and discharge
it gradually to reduce downstream peak flows.
8. What is a retention basin generally intended to provide?
A. Permanent or extended water storage
B. Immediate discharge of all runoff
C. Underground utility access
D. Sewer ventilation
Answer: A. Permanent or extended water storage
Exam Practice Questions And Correct
Answers (Verified Answers) Plus
Rationales 2027 Q&A | Instant
Download Pdf
1. What is the primary purpose of a stormwater management system?
A. To provide potable water
B. To eliminate all surface water
C. To collect, convey, control, and manage runoff
D. To increase pavement drainage rates
Answer: C. To collect, convey, control, and manage runoff
Rationale: Stormwater systems are designed to safely manage runoff
while reducing flooding, erosion, and adverse water-quality impacts.
2. What is the primary function of a catch basin?
,A. Increase groundwater pressure
B. Collect runoff and debris
C. Treat drinking water
D. Store sewage
Answer: B. Collect runoff and debris
Rationale: Catch basins receive surface runoff and commonly provide a
sump that captures sediment and debris before water enters the
conveyance system.
3. Which factor most directly affects the amount of stormwater runoff
from a developed site?
A. Paint color
B. Impervious surface area
C. Building height alone
D. Pipe color
Answer: B. Impervious surface area
Rationale: Impervious surfaces such as roofs, concrete, and asphalt reduce
infiltration and generally increase runoff volume and peak flow.
4. What does a drainage swale primarily do?
,A. Convey surface runoff
B. Store potable water
C. Support structural columns
D. Seal underground utilities
Answer: A. Convey surface runoff
Rationale: A properly graded swale provides a controlled surface path for
collecting and conveying stormwater.
5. Which condition generally increases runoff?
A. Increased infiltration
B. Increased vegetation
C. Increased impervious area
D. Increased soil porosity
Answer: C. Increased impervious area
Rationale: Impervious surfaces prevent much of the rainfall from
infiltrating into the soil, increasing surface runoff.
6. What is the purpose of a storm drain inlet?
A. To collect surface runoff
B. To pressurize a water main
, C. To ventilate a building
D. To discharge sewage gases
Answer: A. To collect surface runoff
Rationale: Storm drain inlets intercept runoff and direct it into
underground or surface conveyance systems.
7. What is a detention basin designed primarily to do?
A. Permanently eliminate runoff
B. Temporarily store runoff and release it at a controlled rate
C. Produce drinking water
D. Increase peak discharge
Answer: B. Temporarily store runoff and release it at a controlled rate
Rationale: Detention facilities temporarily hold stormwater and discharge
it gradually to reduce downstream peak flows.
8. What is a retention basin generally intended to provide?
A. Permanent or extended water storage
B. Immediate discharge of all runoff
C. Underground utility access
D. Sewer ventilation
Answer: A. Permanent or extended water storage
