Smart irrigation for urban green spaces
A blue-green transformation of the central square in Raalte, the Netherlands

Urban trees have a significant influence on the micro-climate. They not only ensure an appealing atmosphere, but also mitigate the effects of climate change. Unlike stone and asphalt, which heat up significantly, trees function as shade providers and water reservoirs, whereby they also have a significant influence on the air temperature close to the surface. In addition, they also produce oxygen, bind dust particles, clean the air and absorb noise. While sealed surfaces are prone to flooding, planted surfaces offer an opportunity for any falling rainwater to trickle away and thereby relieve the sewer system. However, sufficient irrigation is necessary to ensure that these positive effects are achieved.

A total of twelve tree beds have been established and planted as part of the renovation project for the central Grote Markt and De Plas squares, while they are optimally and automatically irrigated by a smart irrigation system developed by ACO that utilises rainwater.

The rainwater is collected by a line drainage system and stored in an underground tank.

This is then available to irrigate the tree beds. Any surplus water is discharged into the groundwater via an infiltration system. Various sensors are used to ascertain the quality and quantity of the water for the native plants and trees. They have been built into the tree beds and collect data about the soil moisture, water level, temperature and air pressure. At the same time, the irrigation control system also receives the current weather forecast.

If a plant bed becomes too dry, the corresponding individual water supply valves are activated in a specifically equipped underground technical control room. Once installed, the system functions fully automatically. The data can be viewed and controlled using the dashboard or a mobile telephone. The smart irrigation system is suitable for both new plantings and existing trees.

The automated system optimally irrigates the urban green spaces, while also ensuring minimum water consumption. This not only eliminates the costs for vehicles, fuel, maintenance and employees associated with manual watering, but also reduces CO₂ emissions. Furthermore, noise and traffic obstructions are also reduced.