Capacity ($Q = \frac{a \sqrt{2gH}}{\sqrt{1 + K_e + K_b L}}$):

Where:

• $Q$ is the flow capacity, in cubic meters per second (L³/T).
• $a$ is the conduit cross-sectional area, in square meters (L²).
• $H$ is the head causing flow, in meters (L).
• $K_e$ is the entrance loss coefficient.
• $K_b$ is the loss coefficient for bends in the culvert.
• $L$ is the length of the flow path, in meters (L).