Which type of dam is used to contain materials with a specific gravity less than one?

Which type of dam is used to contain materials with a specific gravity less than one?

• A. Overflow
• B. Sluice
• C. Underflow
• D. Retention

Answer: (C)

Materials with a specific gravity less than water are lighter than water and will float on the surface. When you’re containment-focused, you want a barrier that sits with the surface layer to keep those floatables from spreading or reaching drains. An underflow dam is used in this scenario because it targets and traps the floating layer at the surface, making it easier to recover the material, while the heavier liquid can continue to flow beneath. Overflow dams would let the surface material spill over with the water; sluice barriers rely on gates for flow control and don’t specifically trap floatables; retention dams hold back water and solids in general but aren’t optimized for isolating a surface-floating layer. So for a contaminant lighter than water, deploying an underflow dam provides the most practical containment of the floatable material.

Materials with a specific gravity less than water are lighter than water and will float on the surface. When you’re containment-focused, you want a barrier that sits with the surface layer to keep those floatables from spreading or reaching drains. An underflow dam is used in this scenario because it targets and traps the floating layer at the surface, making it easier to recover the material, while the heavier liquid can continue to flow beneath. Overflow dams would let the surface material spill over with the water; sluice barriers rely on gates for flow control and don’t specifically trap floatables; retention dams hold back water and solids in general but aren’t optimized for isolating a surface-floating layer. So for a contaminant lighter than water, deploying an underflow dam provides the most practical containment of the floatable material.