As water passes through the throat of a weir, the water is described as?

• A. Slow and Deep
• B. Fast Moving and Shallow
• C. Turbulent and Deep
• D. Laminar and Deep

Answer: (B)

When water goes through the throat of a weir, the cross-sectional area tightens, so the flow must speed up to carry the same discharge (continuity). As velocity increases due to this constriction, the water depth drops, making the flow at the throat fast and shallow. That combination—high velocity with reduced depth—is why fast moving and shallow is the best description. The other options don’t fit because they imply a deeper flow or a different flow state than what a narrowed throat produces.