CESSWI Stormwater Management Practices 5

Question 1

What is the primary difference between infiltration trenches and infiltration basins as stormwater BMPs?

Accepted Answer

Trenches are narrow, subsurface stone-filled features; basins are shallow surface depressions

Answer

Infiltration trenches are narrow excavations filled with stone aggregate that receive runoff and infiltrate it underground, while infiltration basins are open surface areas that allow ponded water to percolate into the soil.

Question 2

A stormwater management facility that reduces peak discharge rate but does NOT reduce total runoff volume is best described as a:

Accepted Answer

Detention facility

Answer

Detention facilities temporarily store runoff to reduce peak discharge rates but release the entire volume over time, providing no net reduction in total runoff volume.

Question 3

Which stormwater practice provides the greatest co-benefit of groundwater recharge in addition to runoff volume reduction?

Accepted Answer

Infiltration-based BMP (trench, basin, or permeable pavement)

Answer

Infiltration-based BMPs direct stormwater into the soil profile, directly recharging groundwater and sustaining baseflows in receiving streams, unlike detention or rooftop practices.

Question 4

During inspection of a stormwater BMP maintenance access road, an inspector notes the road surface is eroding and depositing sediment into an adjacent wet pond forebay. The BEST corrective action is to:

Accepted Answer

Stabilize the access road with gravel or pavement and install edge protection

Answer

The access road should be surfaced with stable aggregate or pavement and provided with edge protection such as rolled erosion control products or riprap to prevent sediment delivery to the pond.

Question 5

The 'first flush' phenomenon in urban stormwater refers to:

Accepted Answer

Disproportionately high pollutant concentrations in early runoff from impervious surfaces

Answer

The first flush describes the elevated concentrations of pollutants (oil, metals, nutrients) mobilized from impervious surfaces by the initial portion of a storm before dilution occurs.

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

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

CESSWI Stormwater Management Practices 5