CPII Drainage & Stormwater Management 2

Question 1

What does the Manning's equation primarily calculate in open-channel drainage design?

Accepted Answer

The flow velocity and discharge in an open channel

Answer

The volume of a detention pond required for a 100-year storm

Answer

The groundwater infiltration rate beneath a drainage swale

Answer

The sediment load carried by a stream over time

Question 2

An inspector finds that a roadside drainage ditch has experienced severe erosion and channel widening. Which BMP would BEST stabilize the channel long-term?

Accepted Answer

Lining the channel with riprap or seeding with erosion-resistant vegetation

Answer

Installing a temporary silt fence along the ditch bank

Answer

Placing orange construction barrels along the eroded section

Answer

Increasing the ditch depth by excavating to original design elevation

Question 3

In drainage infrastructure, what is the primary difference between a retention pond and a detention pond?

Accepted Answer

Retention ponds hold a permanent pool of water; detention ponds drain completely between storms

Answer

Retention ponds are lined with concrete; detention ponds use natural materials

Answer

Retention ponds are above ground; detention ponds are underground structures

Answer

Retention ponds are for industrial use; detention ponds are for residential areas

Question 4

When inspecting a reinforced concrete pipe (RCP) storm drain, which defect classification indicates the pipe requires immediate action?

Accepted Answer

Full circumferential cracking with active leakage and soil intrusion

Answer

Hairline surface cracks with no spalling

Answer

Moderate joint offset with minor leakage

Answer

Slight discoloration from mineral deposits

Question 5

What is the purpose of a check dam installed in a drainage swale or channel?

Accepted Answer

To reduce flow velocity and promote sediment deposition upstream

Answer

To increase channel velocity and flush accumulated sediment

Answer

To redirect flow to an adjacent retention basin

Answer

To prevent unauthorized vehicle access to drainage easements

Question 6

Under the NPDES program, which document must be completed before a stormwater discharge from a construction site can legally begin?

Accepted Answer

A Notice of Intent (NOI) filed with the appropriate permitting authority

Answer

A soil boring report from a licensed geotechnical engineer

Answer

An Environmental Impact Statement (EIS) approved by the EPA

Answer

A dewatering plan signed by a licensed civil engineer

Question 7

Which measurement is most important when evaluating whether a storm drain pipe can handle design storm flows without surcharging?

Accepted Answer

Pipe diameter, slope, and Manning's roughness coefficient

Answer

Pipe material and wall thickness

Answer

The pipe installation depth below finished grade

Answer

The number of joints per linear foot of pipe