The necessity of a noise barrier at the pilot location in Sachsenheim, Germany (build Sept. 2014) offered Helix the opportunity to provide a vertical green habitat of 557 m² on 49 m² floor size. Instead of building a noise barrier out of other materials the city council decided to use the budget for a green noise barrier which provided more added value from an ecological viewpoint.
Soundproofing: DLSI,G = 31 dB. High absorbing noise barrier – documents are available.
Wall: 97.5 m long, 2.60 m tall and 0.45 m wide
The continuous real time ecological welfare impacts of the green noise barrier at the pilot location are clearly visible. These positive impacts include cooling capacity, carbon dioxide reduction, production of oxygen and the use of rainwater. The impacts can be measured thanks to the use of data from a former study by the University of Dresden in combination with the climate data and irrigation data from Sachsenheim. This kind of impact monitoring can be done at any location. View further documentation available
Remote monitoring of the irrigation system from the green wall enables the management of the vegetation‘s growth on a professional horticultural level. This remote monitoring also gathers valuable data to allow the further development of the maintenance system. The system is able to provide up to date ecological welfare impacts in real time, starting with yesterday‘s data and adding this to data from the previous days and months.
This ecological data offers an additional value that can be leveraged for many purposes.
The investment in the instant green noise barrier needs to be holistically integrated in an early stage of the infrastructure planning. It contributes to local storm water management by using rainwater. This presents cost-effective advantages for local authorities when considering the construction of new building areas – the upcoming adjustment of the sewage system can be reduced or eliminated.
In the pilot location the precipitation water is collected in a specially built retention tank (75 m³). The goal is to water the wall only by using rainwater. The size of the tank was calculated to ensure a sufficient supply of water for the plants throughout the year (average yearly need: 500 m³). Short dry periods can be tolerated due to the existing thickness of the substrate. The irrigation of the wall and also the supply with nutrients are automatically regulated.
Left: The water from the roofs of the REWE supermarket as well as the adjacent houses is collected in order to irrigate the noise barrier. Right: Retention tank, capacity: 75 m³
The green noise barrier ensures a fast, instant green solution. The leaf area index of the used system is 3 – 5 in the first year and more than 7 starting in year two.
Climate Change Adaption
Unlike conventional concrete noise reduction walls, the 557 m² vertical surface in Sachsenheim does not add further to the concrete surface area supporting the urban heat island effect in this municipality. In fact the opposite is true! The evapotranspiration of the surface vegetation using rainwater is continuously reducing the heat island effect.
The vertical green habitat of 557m² is mainly planted with ivy. The ivy covers the vertical area well and offers a green coverage also in winter. In addition, Virginia creeper is used mostly on the roadside. Towards the housing area there are also different flowering perennials. Various insects are living and hiding in the vegetation, e.g. bees are visiting the flowering perennials during their flowering period. Due to aesthetic specification by the city council of Sachsenheim no emphasis was laid on specific habitat types. This can be different in other projects, i.e. the vegetation can be chosen specifically to support certain target species. Our green noise barrier is an Urban Green Infrastructure and can be a habitat stepping stone of various kinds.
Bee enjoying flowering Geranium.