Rainwater management in the city: ‘Rainwater pretreatment plant in the city of Łódź’.
About this good practice
The installation is part of a wider project carried out by the City of Łódź, which aims to increase the efficiency of rainwater and snowmelt management. The existing reservoir at Liściasta Street was open and no longer met the requirements both in terms of the quantity of water retained and the quality of its treatment. Effective treatment of rainwater and snowmelt is crucial, given the water flowing from the nearby housing estate through the stormwater drainage system. Up to now, they have gone partially treated directly into the reservoir and the Sokołówka river, which flows through the site.
The new retention basins use a method that, thanks to special water-filtering separators, retains sediment as well as mineral and oil-based pollutants, i.e. everything that can run off into the sewer system from the housing estates. The water flows through gravel placed on the surface of the tanks and hydrophytic plants planted there. This technology is not only environmentally friendly but also allows the water collected in the tanks to be reused for street and sewer cleaning and also for watering plants.
Resources needed
The cost of the investment is more than PLN 5 million (approximately €1.2 million). The project was implemented with European Union funds under the European Cohesion Fund.
Evidence of success
The project has strengthened the city's resilience to the risks associated with climate change, particularly flooding, by slowing down runoff caused by heavy rainfall. Thanks to the use of natural methods (hydrophytic plants), not only has the water status improved, but also the attractiveness of the urban area for residents or investors. The investment ensured a treatment effect of less than 100 mg/dm3 of total suspended solids and 15 mg/dm3 of oil-derived substances.
Potential for learning or transfer
The solutions used can be applied to concreted markets and other sealed urban squares, providing a break with the greenery so expected in such places. The problem of so-called ‘concreted cities’ is one of the most important in the context of adapting cities to climate change.
The practice also allows for a comprehensive approach to urban retention as it takes into account both water storage and water purification, so that it can be reused for municipal purposes.
The investment also took into account the aesthetics of the site. It was a recreational area intended for the residents of the estate, so the implementation interfered minimally with the surrounding space. This can serve as an inspiration for cities where limited retention areas are a problem, as the solution presented can also be used in parks or other places where residents enjoy activities.
Further information
Good practice owner
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