Storm Sewer System Construction

The city of Norman is installing a new storm sewer system near the junction of Lindsey and Elm streets to avoid future flooding. The sewer system is designed to discharge a capacity of 7.5 ft³/s when the pipe flows at 80% full, as shown in the figure. The slope of the sewer is 0.003.

Determine the required pipe size.

• Assume the flow is uniform.
• The Manning coefficient for concrete pipe is n = 0.015.