Certified Storm Water Operator Practice Exam

Sediment deposition occurs when what happens to wind or water?

1. It speeds up rapidly

2. It flows erratically

3. It slows down enough to allow soil particles to settle out

4. It evaporates completely

The correct answer is: It slows down enough to allow soil particles to settle out

Sediment deposition occurs when wind or water slows down sufficiently to allow the larger soil particles to settle out of the moving fluid. When the velocity of wind or water decreases, it can no longer carry the sediment in suspension, and the heavier particles begin to fall out and settle on the ground or in bodies of water. This process is critical in natural environments, as it aids in the formation of soil layers, habitats, and influences the trajectory of water flow. In contrast, if wind or water speeds up rapidly or flows erratically, the energy within the system remains high, preventing sediment from settling. Evaporation, on the other hand, typically pertains to the loss of water but does not directly relate to sediment transport and deposition in this context. Understanding the dynamics of how and when sediment settles is essential for managing sediment control practices in stormwater management.