CESSWI Sediment Control BMPs 5

Question 1

A polymer-enhanced sediment control BMP (such as PAM-treated straw wattles) works primarily by:

Accepted Answer

Causing fine clay particles to flocculate and settle faster

Answer

Polyacrylamide (PAM) and similar polymers cause fine clay particles to coagulate (flocculate), forming larger aggregates that settle much more rapidly than individual clay particles.

Question 2

Which inspection frequency is typically required for sediment control BMPs during a period of active construction?

Accepted Answer

After every rainfall event of 0.5 inches or more, and at least weekly

Answer

Most NPDES construction general permits require BMP inspections after any storm event producing 0.5 inches or more of rainfall and at least once per week during active construction.

Question 3

What is the MOST critical location to install sediment controls on a construction site draining toward a wetland?

Accepted Answer

At the perimeter of the disturbed area and at all discharge points near the wetland

Answer

Perimeter controls at the downslope boundary and at all potential discharge points near sensitive resources provide the last line of defense before sediment reaches the wetland.

Question 4

Why is geotextile fabric specification (AOS) important when selecting a silt fence material?

Accepted Answer

AOS (Apparent Opening Size) controls which particle sizes are filtered versus passed through the fabric

Answer

Apparent Opening Size (AOS) specifies the equivalent pore size of the fabric; selecting the correct AOS balances sediment retention with hydraulic conductivity to prevent blowouts.

Question 5

A site inspection reveals that silt fence posts are leaning at more than 30 degrees from vertical after a storm. The CORRECT corrective action is:

Accepted Answer

Remove accumulated sediment, pull posts back to vertical, and re-drive or replace

Answer

Leaning posts indicate overloading from sediment accumulation or hydrostatic pressure; the proper fix is to remove sediment and restore the fence to its original installed position.

(CESSWI) Certified Erosion, Sediment, and Storm Water Inspector Practice Test

(CESSWI) Certified Erosion, Sediment, and Storm Water Inspector Practice Test

CESSWI Sediment Control BMPs 5