Which of the following factors affects the flow capacity of a sewer line?

The flow capacity of a sewer line is influenced significantly by the physical characteristics of the pipe itself, including its size, the material from which it is constructed, and its grade or slope.

Pipe size is crucial because larger diameter pipes can carry more flow than smaller ones, reducing the risk of blockages and promoting efficient flow. The material of the pipe also matters; different materials have varying roughness and resistance to flow, impacting how smoothly the wastewater can travel through. For instance, smoother materials like PVC offer less friction than rough or corroded materials like old cast iron.

The grade of the pipe affects the velocity of the flow; a steeper gradient can enhance flow speed and help prevent stagnation. Therefore, the correct answer effectively captures the essential factors that determine how much wastewater can be transported through a sewer line, making it critical for operational efficiency and maintenance considerations in collection system management.