Which factor does not affect the rate of runoff?

The size of the catch basin does not directly affect the rate of runoff in the same way the other factors do. The rate of runoff is influenced primarily by how storm conditions, vegetation, and the characteristics of the watershed itself interact with rainfall.

The length of the storm can significantly impact runoff; prolonged rainfall events generally lead to increased runoff as the soil becomes saturated. Similarly, the amount of vegetation in the watershed plays a crucial role because vegetation helps absorb water and can slow down the flow, thereby reducing runoff. The overall size of the watershed also matters; a larger watershed might collect and channel more water, leading to higher rates of runoff.

In contrast, while the size of a catch basin does influence water management and can dictate how much volume of water is temporarily stored, it does not inherently change the rate at which water runs off the landscape. The primary determinants of runoff rates are environmental factors like precipitation, soil saturation, vegetation, and watershed characteristics, rather than the capacity of a specific catchment or storage feature.