Which statement correctly describes an emergency spillway?

Which statement correctly describes an emergency spillway?

• A. It operates only during droughts.
• B. It is the primary outlet for normal flows.
• C. It dissipates energy through vegetation.
• D. It provides an overflow path during extreme events to prevent structural damage.

Answer: (D)

An emergency spillway is a safety feature that kicks in when the reservoir has more water than the normal outlets can handle. Its purpose is to carry off excess water during extreme flood events to prevent the dam from being overtopped and damaged. It isn’t used during normal operations or droughts, since the regular spillway and outlet works handle routine releases. Energy dissipation for large floods is achieved through purpose-built hydraulic structures like stilling basins, not vegetation. So the statement that correctly describes an emergency spillway is that it provides an overflow path during extreme events to prevent structural damage.

An emergency spillway is a safety feature that kicks in when the reservoir has more water than the normal outlets can handle. Its purpose is to carry off excess water during extreme flood events to prevent the dam from being overtopped and damaged. It isn’t used during normal operations or droughts, since the regular spillway and outlet works handle routine releases. Energy dissipation for large floods is achieved through purpose-built hydraulic structures like stilling basins, not vegetation. So the statement that correctly describes an emergency spillway is that it provides an overflow path during extreme events to prevent structural damage.