Surface infiltration

When rainwater seeps from the surface (infiltration area), it is infiltrated into a grass-covered, plane area that receives run-off from nearby paved surfaces (figure 1). The surface is built with a slight incline towards the centre to lead the water away from paved areas and buildings. Grassroot growth and earthworm activity prevent the area from clogging. As the infiltration takes place from the terrain surface, this method can also be used in areas with a high water table. Infiltration areas are the WSUD element that produces the highest evaporation.

Figure 1: Infiltration area in a residential area (Photo: A. Backhaus)