What do "impermeable surfaces" refer to in drainage design?

The term "impermeable surfaces" in drainage design refers to surfaces that do not allow water to penetrate. This definition is crucial in understanding how different materials affect water movement and management in drainage systems. Impermeable surfaces are typically those made from materials such as concrete, asphalt, or certain types of compacted soils that prevent water from soaking into the ground.

In drainage design, identifying impermeable surfaces is important for planning how water runoff will be managed. These surfaces lead to increased surface runoff because water cannot infiltrate the ground, thereby necessitating effective drainage solutions to prevent flooding and erosion. This understanding informs decisions regarding the positioning and design of drains, culverts, and other drainage infrastructure to effectively manage the flow of water and protect both infrastructure and the environment.

Recognizing that impermeable surfaces do not allow permeability is essential for designing effective drainage systems that mitigate water accumulation and manage stormwater effectively.