CESSWI Sediment Control BMPs 2

Question 1

What is the primary failure mode of silt fence installations on slopes exceeding 2%?

Accepted Answer

Overtopping due to insufficient ponding capacity

Answer

On steeper slopes, flow velocity increases and ponding area behind the fence is insufficient to contain runoff, leading to overtopping rather than filtration.

Question 2

A sediment basin is designed for a 2-acre drainage area. What is the minimum required surface area using the standard 0.01 acre-ft per acre of drainage area design criterion?

Accepted Answer

0.02 acres

Answer

The minimum surface area is calculated as 0.01 acre-ft/acre × 2 acres = 0.02 acre-ft of storage, and surface area is derived from this volume requirement.

Question 3

Which sediment control BMP is MOST appropriate for protecting a storm drain inlet in a paved parking lot during active construction?

Accepted Answer

Inlet protection filter bag or sediment trap

Answer

Filter bags or inlet sediment traps are specifically designed to fit over or around paved inlet grates, capturing sediment while allowing drainage.

Question 4

When installing a rock check dam, what is the recommended height-to-width ratio for the notch or spillway?

Accepted Answer

The notch should be 6 inches below the top of the dam edges

Answer

The spillway notch in a rock check dam is typically cut 6 inches below the top edges so that design flow passes through the notch while preventing flanking around the sides.

Question 5

How does a floating turbidity curtain differ from a silt fence in its primary mechanism of sediment control?

Accepted Answer

It creates a physical barrier that settles sediment within an enclosed water area

Answer

Floating turbidity curtains act as physical barriers in water bodies, enclosing an area to allow suspended sediment to settle out before water is released.

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

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

CESSWI Sediment Control BMPs 2