CESSWI - Certified Erosion, Sediment, and Storm Water Inspector Sediment Control BMPs Questions and Answers

Question 1

An inspector observes a rock check dam in a channel with a 4% grade.
The crest of the downstream dam is at the same elevation as the toe of the upstream dam.
Sediment has accumulated to approximately half the height of the downstream dam.
What is the most appropriate action for the inspector to recommend?

Accepted Answer

Remove the accumulated sediment from the upstream side of the dam.

Answer

Add another check dam between the existing ones to improve efficiency.

Answer

Reconstruct the dam to be 12 inches lower in the center than at the edges.

Answer

No action is needed as the check dam is functioning as designed.

Question 2

A CESSWI is inspecting a large construction site (over 10 acres) with significant grading. Which of the following sediment control BMPs is most appropriate for managing sediment-laden runoff at the primary discharge point for a large drainage area?

Accepted Answer

A sediment basin designed to detain runoff and allow sediment to settle.

Answer

A series of silt fences installed along the site perimeter.

Answer

Inlet protection devices on all nearby storm drains.

Answer

Fiber rolls placed along the contours of the disturbed slopes.

Question 3

During a site inspection, you notice a silt fence has been installed in a swale where concentrated flow is expected. The fabric is bulging and there is evidence of undercutting. What is the fundamental issue with this installation?

Accepted Answer

Silt fences are not intended for use in areas of concentrated flow.

Answer

The support posts are spaced too far apart.

Answer

The fabric was not properly trenched into the ground.

Answer

The accumulated sediment has not been removed in a timely manner.

Question 4

Which of the following is a critical maintenance requirement for all storm drain inlet protection devices?

Accepted Answer

Ensuring the device is removed as soon as the contributing drainage area is stabilized.

Answer

Replacing the filter fabric after every measurable rainfall.

Answer

Re-grading the area around the inlet to create a permanent sediment trap.

Answer

Anchoring the device with concrete blocks to prevent movement.

Question 5

A site superintendent plans to use straw bales as the primary perimeter sediment control measure. As a CESSWI, what advice should you provide?

Accepted Answer

Advise against using straw bales due to their high failure rate and suggest alternatives like silt fence or fiber rolls.

Answer

Ensure the bales are tightly bound and staked securely to be effective.

Answer

Recommend using straw bales only for concentrated flow channels.

Answer

Suggest wrapping the straw bales in geotextile fabric to improve their filtering capacity.

Question 6

According to the NPDES Construction General Permit (CGP), when must sediment be removed from a sediment basin?

Accepted Answer

When sediment storage capacity has been reduced by 50% (i.e., it is half full).

Answer

When the basin is completely full.

Answer

At the completion of the construction project.

Answer

When sediment has accumulated to one-third of the basin's design capacity.