CPII Drainage & Stormwater Management 3

Question 1

What is the primary function of a sediment trap or sediment basin on a construction site?

Accepted Answer

To capture sediment-laden stormwater and allow sediment to settle before discharge

Answer

Sediment traps and basins capture stormwater runoff and detain it long enough for suspended sediment particles to settle out before the water is discharged.

Question 2

During a drainage system inspection, an inspector identifies a pipe with a large void in the surrounding soil visible through a joint opening. What is the MOST immediate concern?

Accepted Answer

Subsurface erosion (piping) that could cause pavement or ground surface failure

Answer

A void around a leaking joint indicates subsurface piping erosion, which can rapidly expand and cause catastrophic sinkhole formation or pavement failure.

Question 3

Which type of inlet is generally preferred in areas with high pedestrian or bicycle traffic due to safety considerations?

Accepted Answer

Curb-opening inlets or combination inlets with pedestrian-safe grate designs

Answer

Curb-opening inlets or combination inlets with pedestrian-safe grates prevent bicycle wheels and canes from falling through, making them safer in high-pedestrian areas.

Question 4

When reviewing drainage as-built plans during an inspection, what does a dashed line typically represent on a storm drain plan sheet?

Accepted Answer

An existing underground pipe or structure not visible from the surface

Answer

Dashed lines on plan sheets conventionally represent underground or hidden features such as existing buried pipes, utilities, or structures.

Question 5

What is the recommended minimum pipe cover depth for storm drain pipes under roadways to prevent crushing from traffic loads?

Accepted Answer

2 to 3 feet (depending on pipe material and loading)

Answer

A minimum cover of 2 to 3 feet (depending on pipe material, diameter, and traffic loading) is typically required to distribute traffic loads and prevent pipe crushing.

(CPII) Certified Public Infrastructure Inspector Practice Test

(CPII) Certified Public Infrastructure Inspector Practice Test

CPII Drainage & Stormwater Management 3