In sedimentation basins, what purpose do baffles serve?

• A. Prevent short-circuiting
• B. Increase turbulence
• C. Promote rapid mixing
• D. Reduce sedimentation

Answer: (A)

Baffles manage flow to prevent water from shortcutting straight from inlet to outlet. By forcing the water along a longer, more meandering path, they reduce short-circuiting so a larger fraction of the basin volume is used for settling. This also creates calmer, more uniform velocities and increases hydraulic retention time, giving suspended solids time to settle by gravity. They are not meant to increase turbulence or promote rapid mixing; that would hinder settling. They don’t reduce sedimentation—quite the opposite: by slowing and directing flow, baffles improve the efficiency of sedimentation.