Palimpsest: Testing

Łódź Meanders and Rain Flowers – innovative solutions for adapting cities to climate change

The experimental nature of the PALIMPSEST project allowed many artists, experts, institutions, and residents to join forces and search for new green solutions at the intersection of art, design, and climate challenges. In the Łódź edition of the project, we focused on issues related to water management, its excess during heavy rainfall and shortages during periods of drought. From the very beginning, we wanted residents to be an important part of the process: it was during workshops and discussions that observations about local water problems emerged, as well as ideas on how to counteract them on a small scale, such as in backyards, flower beds, or small public spaces.

The joint work led to the selection of two solutions – Łódź Meanders and Rain Flowers – which were then developed as prototypes and submitted for testing to two institutions: the European Regional Center for Ecohydrology of the Polish Academy of Sciences and the Faculty of Biology and Environmental Protection of the University of Łódź. The aim was to check how these small structures behave under controlled conditions and what hydrological processes they can support.

Research conducted by ERCE confirmed that meanders made of natural materials can perform both retention and filtration functions. Sawdust showed the best absorbency, retaining water in an amount exceeding nine times its own weight, which makes it an extremely effective material for storing short-term excess rainfall. During quality tests, pine and oak sawdust removed up to 99% of nitrates and over 85% of phosphates and ammonium ions from water, i.e., substances that can deteriorate the condition of watercourses and soils. At the same time, small amounts of natural organic compounds were released, which may promote the restoration of the soil microbiome, especially in urban areas where the soil is most often depleted.

Research conducted by Rain Flowers confirmed the effectiveness of traditional porous vessels adapted to urban conditions. Ceramic walls regulated moisture levels through evaporation and gradual filtration, and the infiltration rate depended on the structure of the ceramics, ranging from several dozen to about 80 ml per minute. BiOŚ UŁ showed that the water released by the vessel most strongly moisturizes the soil in the zone up to about 10 cm from its center, while further absorption takes place mainly vertically, in accordance with gravity. The research also confirmed that the funnel is a key structural element – even a slight change in its diameter affects the amount of water captured and reduces evaporation.

In addition to their hydrological function, the Łódź Meanders have also been found to promote the creation of micro-plant habitats: spontaneous plant growth has been observed within them, indicating that these structures can support natural succession and biodiversity. Field research results also showed that the soil above the meanders maintains higher moisture levels than the areas below, with the highest values recorded inside the retention meanders.

The collected results confirm that Rain Flowers and Łódzkie Meandry have real potential as micro-solutions supporting water management in the city. They can store excess rainfall, irrigate the soil during dry periods, retain and purify surface runoff, support soil microorganisms, and improve plant growth conditions. Research also indicates that both systems can complement existing green-blue infrastructure, increasing the resilience of urban landscapes to extreme weather events. Although these are prototype solutions, their performance is promising enough to warrant further development and testing in real-world conditions—in places where local water problems are most evident.

Available only in Polish

Available only in Polish