What characterizes an Open Channel?

An open channel is characterized by its configuration that allows for fluid flow without being completely enclosed. It is defined as a passageway that is exposed to the atmosphere, which means that the water or fluid flowing through it is subject to atmospheric pressure and environmental factors. This direct exposure is significant because it influences the hydraulic behavior of the flow, including factors like evaporation, wind effects, and sediment transport.

In contrast, an enclosed fluid pathway, such as a pipe, relies on pressure differences to move the fluid and does not allow for direct interaction with the surrounding environment. Similarly, a channel with artificially controlled flow typically refers to modifications such as dams or gates that manage the flow rate or volume but does not inherently define an open channel. A subterranean course of water, like an aquifer or underground river, is also distinctly different as it is completely below the surface and lacks the characteristics of openness to the atmosphere. Thus, the defining feature of an open channel lies in its exposure to the air, which allows for a variety of natural behaviors and interactions with the environment.