Remediation & Mitigation Strategies Flashcards

A project site is located in an area with a high water table that precludes infiltration BMPs. Which alternative volume reduction strategy should be prioritized?

Answer: Rainwater harvesting for non-potable reuse

Rainwater harvesting captures runoff for irrigation or toilet flushing, achieving volume reduction without relying on infiltration into saturated soils.

Which approach is used to address stormwater quality impacts from a brownfield site where contaminated soils prevent standard infiltration practices?

Answer: Using lined bioretention with underdrain routed to treatment

Lined bioretention cells with an underdrain prevent stormwater from mobilizing soil contaminants while still providing surface runoff water quality treatment.

Which design element in a stormwater green infrastructure network provides the greatest resilience against a 100-year storm event flooding?

Answer: Distributed micro-bioretention cells throughout the catchment

Distributed green infrastructure reduces runoff volume and peaks across the entire watershed, providing redundancy and resilience that a single regional facility cannot match.

When applying monitored natural recovery (MNR) as a sediment remediation strategy, which condition is essential for the approach to be protective?

Answer: Active source of clean sediment deposition burying contaminated material

MNR relies on natural burial by clean sediment, biodegradation, and dilution; without net deposition of clean material, contaminant isolation will not occur.

Which stormwater mitigation practice is most effective for reducing hydrocarbon and heavy metal loading from a high-traffic parking lot?

Answer: Catch basin inserts combined with bioretention islands

Catch basin inserts provide gross solids and sediment removal, while bioretention islands treat the fine fraction and dissolved metals through sorption and plant uptake.

Which factor most strongly influences the selection between wet pond and dry extended detention basin for stormwater quality treatment in a residential area?

Answer: Availability of year-round baseflow or groundwater to maintain a permanent pool

Wet ponds require a reliable water source to maintain a permanent pool; without baseflow or groundwater, the pond will dry out and lose its treatment function.

Which TMDL implementation strategy best addresses nonpoint source stormwater contributions to a 303(d)-listed impaired water body?

Answer: Developing a watershed-based permit with load allocation schedules for MS4s

Watershed-based MS4 permits assign pollutant load allocations and require scheduled BMP implementation, directly translating TMDL wasteload allocations into enforceable requirements.