What does a high runoff coefficient indicate?

A high runoff coefficient indicates significant rainfall runoff. The runoff coefficient is a dimensionless number that represents the percentage of rainfall that is converted to runoff. When the coefficient is high, it suggests that a large proportion of the precipitation that falls on the surface will flow away as runoff rather than infiltrating into the soil or being absorbed by vegetation.

This scenario is typical in urban areas where impervious surfaces, such as roads and buildings, prevent water from seeping into the ground. In contrast, areas with low runoff coefficients typically have more vegetation or permeable surfaces, leading to greater absorption of rainfall. Therefore, significant rainfall runoff is associated with a high runoff coefficient, reflecting an important consideration in stormwater management and drainage planning.