Infiltration bed

An infiltration bed is a vegetation bed where rainwater can be retained temporarily and slowly seep down into the soil. The bed has a suitable top layer of fertile soil over a sand/gravel layer suitable for infiltration. To cope with overflow in situations with extreme rain, an additional area suitable for infiltration and retention of rainwater can be established next to the infiltration bed. Finally, a dry well can be established under the infiltration bed.

Infiltration beds can be used in many places, such as by homes, offices and industrial buildings, as well as in shopping areas and car parks. Infiltration beds can be established with varies types of surface. The plants are typically planted directly in the soil, however, the surface can also be covered by gravel or pebbles. There is less maintenance with pebbles but also a risk of sand and small pieces of litter finding their way down through the cobbles to the soil below which may then compact and gradually impede the infiltration.

An infiltration bed can be established in a corner of your garden or as a solitary bed in the lawn. In public spaces, they can be established along roads, in the central reservation, in car parks to mark off parking spaces, or as a larger vegetation bed in areas between buildings.

The Danish Technological Institute is developing a new variant of infiltration bed which, rather than conveying water to a dyke, pumps it into a "green screen". The green screens will be placed along bike paths in Copenhagen and will help manage surplus surface water. The screens are covered with vertical vegetation that helps evaporate water, thereby relieving the local sewerage system.