Swales

Swales are fairly wide, U-shaped channels covered with vegetation and with gently sloping sides (1:5) designed for transporting water (see figures 1 og 2). They can also store water, and a certain amount of seepage and evaporation also takes place. Contaminants can be retained. Ditches, which are V-shaped channels, can also be used, but because they pose a risk to bicycles and cars, swales are better suited to urban environments.

Figure 1: Grass-covered swale (Photo: M.B. Jensen)

Figure 2: Swale during rainfall event (Sketch by A. Backhaus)