CESSWI Stormwater Management Practices 3

Question 1

In a constructed stormwater wetland, the shallow marsh zone typically operates at what average water depth to support emergent vegetation?

Accepted Answer

6–18 inches

Answer

The shallow marsh zone of a constructed wetland is typically maintained at 6–18 inches depth, which supports emergent plants like cattails and bulrushes that provide biological treatment.

Question 2

Which BMP design parameter ensures that sediment trapped in a basin will not be resuspended and discharged during large storm events?

Accepted Answer

Length-to-width ratio

Answer

A length-to-width ratio of 3:1 or greater promotes plug flow, reducing turbulence and short-circuiting that could resuspend settled sediment during high-flow events.

Question 3

A stormwater harvesting system (cistern or rain barrel) primarily reduces which component of the urban water cycle?

Accepted Answer

Runoff volume by capturing and reusing rainfall

Answer

Stormwater harvesting captures rooftop runoff for non-potable reuse (irrigation, toilet flushing), directly reducing the volume of stormwater discharged to drainage systems.

Question 4

When inspecting a grassed swale, which condition indicates that the swale is NOT functioning properly?

Accepted Answer

Rill erosion channels and bare soil visible along the flow path

Answer

Rill erosion and bare soil in a grassed swale indicate that flow velocities are exceeding permissible limits or vegetation is inadequate, causing erosion rather than filtration.

Question 5

The rational method equation Q = CiA calculates peak runoff rate. What does the coefficient 'C' represent?

Accepted Answer

Runoff coefficient reflecting land cover and soil type

Answer

The runoff coefficient C (dimensionless, 0–1.0) accounts for the fraction of rainfall that becomes surface runoff based on land use, soil type, and slope.

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

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

CESSWI Stormwater Management Practices 3