An Innovative Stormwater Treatment System Is Being Installed in Smiltene Old Park

In April 2026, construction work began in the territory of Smiltene Old Park as part of the Interreg Central Baltic Sea Region project “StoPWa”. A stormwater filtration system is being installed there to test the use of construction debris in stormwater treatment. The system is expected to improve the ecosystem of the park ponds and demonstrate a practical solution for applying circular economy principles in the urban environment.

The aim of the project “Use of Construction and Demolition Waste in Stormwater Treatment” (hereinafter “StoPWa”) is to develop and test multilayer filtration systems through cross-border cooperation, using recovered construction waste in the pond cascade of Smiltene Old Park.

The construction work is currently taking place at the highest pond in Old Park, near the small bridge on the walking path. The system being built will collect urban stormwater, treat it, and only then discharge it further into the pond cascade. This is an important solution for reducing pond overgrowth and sludge formation in the long term, while keeping the water clean and the landscape visually attractive.

The project’s unique approach is the use of recovered construction waste in water treatment. This makes it possible to study how demolition debris can be turned into a valuable resource and how climate resilience can be strengthened.

Smiltene Municipality construction engineer Andris Jaunpetrovičs emphasises: “Instead of traditional filter materials, specialists are experimenting with recycled construction debris – crushed concrete obtained from building demolition. The crushed material is carefully sorted and crushed into suitable fractions so that it can serve as an effective filtering layer. As the solution is experimental, its performance will be monitored, and, if necessary, the system will be supplemented with certified filter material.”

The project also includes improvement of the park’s public outdoor space. A new pedestrian path and viewing platform for recreation are being built near the highest pond. The pond banks will be landscaped with water-loving plants, which will not only create a visually attractive and well-maintained recreation area, but will also naturally support water filtration.

After the filtration system has been built, regular water analyses will be carried out and the results will be monitored in order to assess the system’s efficiency, follow changes in water quality, and confirm whether the selected solution is suitable in the long term. The data obtained will make it possible to evaluate how the filtration system affects the ecological condition of the pond and will provide valuable information for the future use of similar nature-based solutions elsewhere.

Before this type of filtering material is used in nature, it has been carefully tested and analysed at three universities: LUT University and the University of Helsinki in Finland, and Tallinn University of Technology, or TalTech, in Estonia. Some reports on the research process are already available on the StoPWa project website.

At the Smiltene pilot site in Old Park, the works are being carried out by SIA “Woltec”, construction supervision is provided by SIA “Marčuks”, and the construction design was developed and author supervision is provided by SIA “JL9”. The construction works are planned to be completed by the end of May 2026.