What is the size of the gutter at a 2% slope for maximum rainfall of 150 mm over 13 m?

To determine the proper size of the gutter for a maximum rainfall of 150 mm over a length of 13 m with a 2% slope, it is essential to consider the principles of drainage and flow capacity.

When calculating the required gutter size, various factors come into play, including the intensity of rainfall, the area the gutter will be draining, and the slope of the gutter itself. A 2% slope is optimal for encouraging water flow toward the drain, helping to prevent backups and overflow.

The maximum rainfall intensity of 150 mm is measured over a given time and area. The gutter must be adequately sized to handle this volume of water without overflowing. The drainage rate calculations typically consider Rainfall Intensity = Storm Rate / Area, and they often require applying specific flow formulas (such as Manning's equation) which take into account the slope, type of material, and cross-sectional shape of the gutter.

In this scenario, a gutter size of 200 mm is ideal because it provides sufficient capacity to handle the peak flow generated by the maximum rainfall over the specified distance. This larger size ensures that the water flows efficiently without risk of overflow, especially during periods of heavy rainfall.

Choosing a smaller gutter size, for instance, 175 mm