A soil classified as Hydrologic Group D may consist of what type of surface?

A soil classified as Hydrologic Group D is characterized by having poor drainage capabilities and a high potential for runoff. This classification is typically associated with soils that have high clay content, particularly clay near the surface. The presence of a clay layer can significantly impede water movement, resulting in prolonged saturation of the soil and increased surface runoff during rainfall events.

This classification is important for understanding how water behaves within different soil types, especially in the context of erosion and stormwater management. The clay layer near the surface contributes to the soil's inability to absorb water efficiently, which is a critical factor for inspectors to consider when evaluating sites for potential erosion control measures and stormwater management practices. Soils in this group require particular attention during construction and development to mitigate erosion and manage water efficiently.