CPESC Sediment Control Best Practices 2

Question 1

What is the primary purpose of a sediment forebay in a sediment basin?

Accepted Answer

To trap coarse sediment before water enters the main pool

Answer

A sediment forebay traps coarse sediment near the inlet, protecting the main pool and reducing maintenance frequency.

Question 2

Which condition would MOST likely cause a silt fence to fail prematurely?

Accepted Answer

Concentrated flow directed against the fence

Answer

Silt fences are designed for sheet flow only; concentrated flow creates hydraulic pressure that overwhelms the fabric and causes blowouts.

Question 3

A check dam in a drainage channel should be constructed so that water overtops:

Accepted Answer

At the center, which should be lower than the edges

Answer

The center of a check dam is kept lower than the edges so overflow is concentrated at the center, preventing flanking and bank erosion.

Question 4

During a CPESC site inspection after a storm event, you observe sediment accumulation of 12 inches in a 24-inch deep sediment trap. What action is required?

Accepted Answer

Clean out the sediment trap immediately

Answer

Standard practice requires cleanout when sediment accumulation reaches half the design depth (typically 50% capacity) to maintain effectiveness.

Question 5

What is the recommended maximum drainage area for a standard rock check dam in a small channel?

Accepted Answer

5 acres

Answer

Rock check dams are typically limited to drainage areas of about 5 acres or less because larger watersheds generate flows that can destabilize the structure.

(CPESC) Certified Professional in Erosion and Sediment Control Practice Test

(CPESC) Certified Professional in Erosion and Sediment Control Practice Test

CPESC Sediment Control Best Practices 2