where Q was the flow rate, n was the Manning's roughness coefficient, A was the cross-sectional area, R was the hydraulic radius, and S was the slope.

I = (b * h^3) / 12

Next, Alex turned her attention to the structural design of the culvert. She had to ensure that the culvert could support the weight of the soil and the vehicles passing over it. She used the following formula to calculate the moment of inertia of the culvert:

When the project was completed, the community celebrated. The new box culvert was a success, handling the water flow and traffic with ease. Alex and her team had designed a safe, efficient, and environmentally friendly solution that would serve the community for years to come.

For those interested in learning more about the design calculations for a box culvert, a sample PDF is available:

As she worked through the calculations, Alex realized that the culvert's size and shape would have a significant impact on its hydraulic capacity. She decided to use a rectangular box culvert with a 3-meter width and 2-meter height. She assumed a Manning's roughness coefficient of 0.015 and a slope of 0.005.