What does the wetted perimeter refer to?

The wetted perimeter refers to the part of the channel that is in contact with water. In the context of surface water and river hydraulics, it plays a crucial role in determining various aspects of flow, including the flow velocity and the friction along the channel. The wetted perimeter is significant in hydraulic calculations because it influences the resistance to flow and helps in calculating the conveyance of the channel.

Understanding the wetted perimeter is essential for assessing how water interacts with the channel boundaries, which affects the overall hydrodynamics of a stream. When analyzing a river or stream for engineering or ecological purposes, knowing the wetted perimeter helps assess how much of the channel's surface is actually influencing the flow characteristics, which in turn informs designs and management practices.