Which method is commonly used for calculating stormwater runoff?

The Rational Method is a widely used approach for calculating stormwater runoff, particularly for small urban watersheds. This method is based on a simplified equation that estimates the peak discharge of runoff from a specific area during a rainfall event. It takes into account the rainfall intensity, the area of the watershed, and a runoff coefficient that reflects the land use and surface conditions.

The effectiveness of this method lies in its ability to provide quick and relatively accurate estimates of peak flow rates, making it particularly useful for designing drainage systems and managing stormwater in urban settings. It is suitable for smaller storms and smaller drainage areas, which is where its simplicity and ease of use make it advantageous.

In contrast, other methods such as the SCS method would be more appropriate for larger watersheds and involve a more complex calculation of runoff volumes based on soil types, land use, and other factors, which is not as straightforward as the Rational Method. The Volume method focuses on total runoff volume management rather than peak discharge. The Peak method, while useful in certain contexts, typically refers to calculating peak flow rates but does not specify a single standardized approach like the Rational Method does. Thus, the focus on peak discharge in a convenient and manageable format is what distinguishes the Rational Method and just