Underflow dam is a containment method used for spills that float on water.

Underflow dam is a containment method used for spills that float on water.

• A. It blocks high water levels
• B. It filters contaminants
• C. It contains liquids that float on water
• D. It diverts water around a spill

Answer: (C)

The key idea is that underflow dam is meant to contain spills that sit on the water’s surface, such as oil or other hydrocarbons. Because these liquids float, a barrier that interacts with the surface and uses the water flow to help keep the slick in place can isolate and concentrate the floating material for recovery. It’s not about lowering water levels, filtering contaminants, or diverting water around a spill—those describe other containment methods. So the best fit is that it contains liquids that float on water.

The key idea is that underflow dam is meant to contain spills that sit on the water’s surface, such as oil or other hydrocarbons. Because these liquids float, a barrier that interacts with the surface and uses the water flow to help keep the slick in place can isolate and concentrate the floating material for recovery. It’s not about lowering water levels, filtering contaminants, or diverting water around a spill—those describe other containment methods. So the best fit is that it contains liquids that float on water.