NETTCP Drainage & Stormwater Management

Question 1

Which type of culvert pipe material is most resistant to corrosion in acidic soil environments common in New England?

Accepted Answer

High-density polyethylene (HDPE) pipe

Answer

HDPE pipe is highly resistant to corrosion from acidic soils and is commonly specified in New England where acidic glacial soils are prevalent.

Question 2

What is the primary purpose of a catch basin in a highway drainage system?

Accepted Answer

To collect surface runoff and trap sediment before it enters the storm sewer

Answer

Catch basins are designed to intercept surface runoff and allow sediment and debris to settle before water enters the storm sewer system.

Question 3

Manning's equation is used in drainage design primarily to calculate:

Accepted Answer

Flow velocity and discharge in open channels and pipes

Answer

Manning's equation relates channel geometry, roughness coefficient, slope, and hydraulic radius to determine flow velocity and discharge.

Question 4

During a culvert inspection, you observe headwater depth approaching the crown of the inlet. This condition indicates:

Accepted Answer

The culvert barrel is undersized or partially blocked and flow is restricted

Answer

When headwater approaches the crown, it signals the culvert is near or at hydraulic capacity, indicating potential undersizing or blockage that requires attention.

Question 5

What minimum pipe bedding material gradation is typically required beneath drainage pipe to provide uniform support and prevent settlement?

Accepted Answer

Clean crushed stone or gravel free of fines, typically 3/4" to 1-1/2"

Answer

Clean, well-graded crushed stone or gravel free of fines provides uniform bearing, promotes drainage around the pipe, and prevents point loading that causes cracking.

(NETTCP) New England Transportation Technician Certification Program Practice Test

(NETTCP) New England Transportation Technician Certification Program Practice Test

NETTCP Drainage & Stormwater Management