What component of retention or detention ponds is designed to manage normal water levels?

The principal spillway is specifically designed to manage the normal water levels in retention or detention ponds. Its primary function is to control the outflow of water during regular rain events, ensuring the pond maintains an optimal water level for effective stormwater management and environmental functions. By allowing water to drain slowly, the principal spillway helps prevent flooding and encourages sedimentation, while also supporting wildlife habitats.

In contrast, the outlet structure serves to manage how water exits a pond, but it may not specifically focus on regulating normal water levels the way a principal spillway does. The emergency spillway is a safety feature designed to handle excess water during extreme storm events, preventing overflow or structural failure, but it primarily functions when water levels exceed normal thresholds. A bypass channel is used to divert water around the pond or around a specific area during high-flow conditions, which does not relate to maintaining normal water levels in the pond itself.