Lindevang Street

Along the residential road “Lindevang”, seven green rain gardens have been established. The rain gardens have a modular design and are able to store and purify the water in order to prepare it for infiltration. The gardens receive water from the sealed surfaces on the road (sidewalk and road surface) as well as some water from nearby houses (e.g. form driveways or other sealed areas on the gorund). The rain gardens were placed in locations where they also have a speed reducing effect on passing cars.

The road has been established in fall 2012.

The rain gardens have a built-in soakaway (dry well) to provide retention volume and infiltration. The gardens are bordered by concrete curbs, which protect soil and plants from damage and provide stability. The top layer of the bed is filled with filter soil and drought-resistant plants, which purify the soil and increase evaporation.

The new prain gardens were placed in locations, upstream of the existing road gullys. The water reaches the existing wells only during heavy rainfall events, when the rain gardens are fully filled with rainwater. The rain gardens have small pre-basins, where large particles in the road water are held back. From there, the water flows further into the garden, where it will infiltrate the filter soil and the plants. The soil absorbs heavy metals and polluting particles. Through the filter soil, the rainwater infiltrates downwards through a membrane into the soakaway, where it is stored and slowly infiltrates into the soil.

When it rains so much that the roadbeds and the underlying soakaways (dry wells) are completely filled and the soil is saturated, the water will flow into the sewers. A bypass has been established in the rain garden, which creates a shortcut towards the soakaway (dry well), so that the soakaway is completely filled up, before there is an overflow via the road into the road gullys at the low points of the road.

Already in during the planning phase, local residents were invited to get involved. During multiple public workshops, residents were interviewed about thier preferences, possible issues they saw and asked to make suggestions about aesthetic aspects.

The residents emphasized that they wished for the rain gardens to be presentable all year round. Therefore the landscape architects chose the mix of plants in a way that there would always be one or more plants blossoming, between spring and fall, and some evergreen plants for winter. All of the chosen plants drought resistant and able to tolerate the difficult soil conditions that road runoff could cause.