Remediation & Mitigation Strategies Flashcards
7 cards from real CSM practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Remediation & Mitigation Strategies flashcards as text
Which bioremediation technique uses plants to extract heavy metals from contaminated stormwater sediments?
Answer: Phytoremediation
Phytoremediation uses hyperaccumulator plants to take up and concentrate heavy metals from contaminated soil and water.
A stormwater pond is experiencing algal blooms due to excess phosphorus. Which in-situ chemical treatment is most commonly applied to precipitate phosphorus?
Answer: Alum (aluminum sulfate)
Alum injected into stormwater ponds reacts with phosphorus to form insoluble aluminum phosphate that settles to the bottom.
Which design feature of a bioretention cell is most critical for preventing clogging and maintaining long-term infiltration rates?
Answer: Properly sized mulch layer and engineered soil media
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.
When remediating a polluted stream channel, which approach best restores natural hydrologic function while providing sediment and nutrient mitigation?
Answer: Stream daylighting with natural channel design
Stream daylighting removes culverts or hardened channels and restores natural meander patterns, reconnecting floodplains and improving pollutant removal.
A detention basin is not meeting TSS removal targets. Which remedial modification is most likely to improve performance?
Answer: Adding a forebay and extending the permanent pool
A forebay traps coarse sediment before it reaches the main pool, and a larger permanent pool increases hydraulic residence time, improving TSS settling.
Which metric is used to quantify the effectiveness of a stormwater BMP in reducing peak runoff flow rates?
Answer: Peak flow attenuation ratio
Peak flow attenuation ratio compares post-BMP peak discharge to pre-BMP peak discharge, directly measuring a BMP's ability to reduce flooding risk.
Under EPA's National Stormwater Best Management Practice database, which BMP type consistently shows the highest median total phosphorus removal efficiency?
Answer: Bioretention/rain gardens
Bioretention systems with engineered media consistently demonstrate high TP removal (often 50–80%) through plant uptake, adsorption, and microbial processes.