CSM Remediation & Mitigation Strategies 2

Question 1

Which bioremediation technique uses plants to extract heavy metals from contaminated stormwater sediments?

Accepted Answer

Phytoremediation

Answer

Phytoremediation uses hyperaccumulator plants to take up and concentrate heavy metals from contaminated soil and water.

Question 2

A stormwater pond is experiencing algal blooms due to excess phosphorus. Which in-situ chemical treatment is most commonly applied to precipitate phosphorus?

Accepted Answer

Alum (aluminum sulfate)

Answer

Alum injected into stormwater ponds reacts with phosphorus to form insoluble aluminum phosphate that settles to the bottom.

Question 3

Which design feature of a bioretention cell is most critical for preventing clogging and maintaining long-term infiltration rates?

Accepted Answer

Properly sized mulch layer and engineered soil media

Answer

An engineered soil media (typically 60% sand, 20% compost, 20% topsoil) combined with a shallow mulch layer prevents fine sediment from clogging pores over time.

Question 4

When remediating a polluted stream channel, which approach best restores natural hydrologic function while providing sediment and nutrient mitigation?

Accepted Answer

Stream daylighting with natural channel design

Answer

Stream daylighting removes culverts or hardened channels and restores natural meander patterns, reconnecting floodplains and improving pollutant removal.

Question 5

A detention basin is not meeting TSS removal targets. Which remedial modification is most likely to improve performance?

Accepted Answer

Adding a forebay and extending the permanent pool

Answer

A forebay traps coarse sediment before it reaches the main pool, and a larger permanent pool increases hydraulic residence time, improving TSS settling.

(CSM) Certified Stormwater Manager Practice Test

(CSM) Certified Stormwater Manager Practice Test

CSM Remediation & Mitigation Strategies 2