When can a submerged condition occur in a flume?

A submerged condition in a flume occurs when the water level rises above the flume's crest or the point where water flows out of the flume. This situation can be influenced by various factors, such as the environmental conditions and the operational status of the sewer system.

Debris accumulation or improper slope in the downstream sewer can indeed lead to a situation where the flow capacity is exceeded. When debris obstructs the flow, it can cause water to back up, leading to increased water levels within the flume. Similarly, if the downstream sewer does not have the correct slope, it may not drain effectively, causing water to back up and create a submerged condition in the flume.

Overall, the relationship between the debris, the slope of the sewer, and the resulting water levels effectively illustrates the conditions under which a submerged state can occur, making this response accurate and relevant to the understanding of flow dynamics in wastewater treatment systems.