CESSWI Erosion & Sediment Control Principles 5

Question 1

A construction SWPPP must be updated when which of the following occurs?

Accepted Answer

Site conditions change in a way that affects stormwater discharges

Answer

NPDES Construction General Permits require SWPPP amendments whenever there are changes in design, construction, operation, or maintenance that affect the potential for pollutant discharges.

Question 2

Which factor most directly determines the settling velocity of a sediment particle in a quiescent (still) water environment?

Accepted Answer

Particle size, density, and shape

Answer

Settling velocity in still water is governed by Stokes' Law, which relates particle diameter, density, and shape to the rate at which a particle sinks.

Question 3

A slope with a 3:1 (horizontal:vertical) gradient is considered what relative to erosion risk compared to a 4:1 slope?

Accepted Answer

Higher risk because a 3:1 slope is steeper than a 4:1 slope

Answer

A 3:1 slope is steeper than a 4:1 slope (33% vs. 25% grade), resulting in higher flow velocities and greater erosion potential.

Question 4

What is the most common cause of silt fence failure in the field?

Accepted Answer

Concentrated flow overtopping or breaching the fence at low points

Answer

Silt fences most commonly fail when runoff concentrates and overtops or flows around the ends of the fence at topographic low points rather than as sheet flow.

Question 5

During final stabilization inspection, what minimum percentage of vegetative cover is typically required before a CGP Notice of Termination (NOT) can be submitted?

Accepted Answer

70%

Answer

EPA's Construction General Permit defines final stabilization as achieving 70% vegetative cover density compared to pre-disturbance conditions, or equivalent permanent stabilization.

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

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

CESSWI Erosion & Sediment Control Principles 5