**Introduction:** Proper sizing of stormwater pipes is crucial for effective drainage and flood prevention. The Storm Water Pipe Size Calculator provides a practical solution for estimating the recommended size of a stormwater pipe based on factors such as desired flow rate, pipe slope, and Manning’s roughness coefficient.

**Formula:** The calculator utilizes a hydraulic design formula to calculate the recommended stormwater pipe size based on the desired flow rate, pipe slope, and Manning’s roughness coefficient.

**How to Use:**

- Enter the desired flow rate in cubic feet per second.
- Input the pipe slope in inches per 100 feet.
- Enter Manning’s roughness coefficient.
- Click the “Calculate” button to obtain the recommended stormwater pipe size.

**Example:** Suppose you have a desired flow rate of 5 cubic feet per second, a pipe slope of 0.5 inches per 100 feet, and a Manning’s roughness coefficient of 0.013. By entering these values into the calculator and clicking “Calculate,” you can estimate that the recommended stormwater pipe size is approximately 8.23 inches.

**FAQs:**

*Why is sizing stormwater pipes important?*- Proper sizing ensures efficient drainage, preventing flooding and water damage.

*What is Manning’s roughness coefficient?*- Manning’s coefficient represents the pipe’s resistance to flow. It is a dimensionless value indicating the smoothness of the pipe.

*Can this calculator be used for different types of stormwater systems?*- Yes, the calculator is suitable for various stormwater systems, including urban drainage and industrial applications.

*Should I consider future growth when sizing stormwater pipes?*- It’s advisable to factor in potential future development and increased runoff when sizing stormwater pipes.

*What units should I use for flow rate, pipe slope, and Manning’s coefficient?*- Ensure consistent units, such as cubic feet per second for flow rate, inches per 100 feet for pipe slope, and a dimensionless value for Manning’s coefficient.

**Conclusion:** The Storm Water Pipe Size Calculator is a valuable tool for engineers, urban planners, and anyone involved in stormwater management. By considering flow rate, pipe slope, and Manning’s coefficient, users can efficiently estimate the recommended size for stormwater pipes, contributing to effective drainage solutions.