What is meant by "hydrologic soil group"?

The term "hydrologic soil group" refers to a classification system primarily centered on the runoff potential of varying soil types. This system divides soils into four groups (A, B, C, and D) based on their infiltration rates and their capacity to retain moisture. Group A soils, for instance, are typically very well-draining and have high infiltration rates, while Group D soils retain water and have a low infiltration rate, leading to a higher likelihood of surface runoff during rainfall events.

This classification is critical for stormwater management because understanding the runoff potential helps in predicting how much water will flow over the land surface during a storm, influencing flood risks, erosion potential, and water quality in receiving water bodies. By assessing soil characteristics in the context of hydrological response, planners and engineers can design more effective stormwater management systems that take into account natural soil behavior related to stormwater runoff. Therefore, this option captures the essence of what hydrologic soil groups represent in stormwater management contexts.