Adopted solutions include a restoration project, implemented on the Sokołówka river, and the development of an overall approach to urban planning based on the Blue-Green Network concept. The SWITCH project introduced a multi-stakeholder process (i.e. Learning Alliance) involving all the actors in the city with an interest in water and natural resources management as well as the regional and national stakeholders. This multi-stakeholder approach with strong research elements resulted in the application of the principles of ecohydrology (studying the interactions between water and ecosystems) and Integrated Urban Water Management in the demonstration project “restoration of the Sokołówka River”.
The Sokołówka River, which is mostly supplied by storm water outlets, runs partially in an artificial channel and has been prone to algal blooms due to high content of nutrients in the storm water. The objectives of the restoration project were as follows:
- Apply innovative ecosystem biotechnologies following the principles of eco-hydrology;
- Increase the capacity of the river system to reduce urban flooding by increasing water storage and purification capacity;
- Restore the river functions to improve the quality of life of the citizens and the attractiveness of the city.
The first step of the pilot project was the acquisition of accurate baseline data (e.g. chemical analysis of bottom sediments and water, biological and ecological data, river water budget and models for storm water management) that were used to select the appropriate measures to be implemented. This step provided the information for the design and construction of three storm water reservoirs (completed in 2006, 2009 and 2010) and a sequential sedimentation bio-filtration system for storm water purification (completed in 2011) which was patented as a SWITCH innovation. Moreover, the project led to a wider plan for rehabilitation of the Sokołówka river and a plan for the development of Sokołówka River park.
The Sokołówka river restoration project and the demonstrated approach to urban planning have contributed towards resolving the following climate change-related challenges:
- Reduction of the storm water sewage flow peaks by means of a series of ponds and reservoirs, creation and restoration of river valley and wetlands;
- Increase of water retentiveness in the city landscape (mitigation of extreme flows, increase of groundwater level, support of city vegetation) by application of phytotechnology;
- Increase of the water quality, ecological stability of freshwater resources and their carrying capacity by instream ecohydrological regulation;
- Increase of quality of life and aesthetic values in the catchment by restoration of the river corridor, ecotone zones and landscape;
- Increase of human health through promotion of healthy urban environments by incorporating the blue-green network into the development plan of the city.
The changes in the Sokołówka valley raised interest among local developers. A company, investing in a housing area near the river, was interested in contributing to more sustainable storm water management, and decided to introduce related solutions such as retention wells, in a way that all storm water can be stored entirely within their investment area. Several bottom-up initiatives focusing on rivers and green spaces emerged in other areas of the city, e.g., the historical area of Księży Młyn and Jasień river. Several NGOs became interested in green and blue infrastructure and the possible use of its services, e.g., alternative sustainable transportation routes (cycle paths) or green backyards.
The pilot river restoration activities implemented around the Sokołówka have been a success and have convinced the Lodz authorities and water professionals of the value of replicating these for other rivers across the city. During the first years of the Sokołówka river demonstration project, a Blue-Green Network concept was developed by the researchers from the European Regional Centre for Ecohydrology at the Polish Academy of Science in Lodz. The idea is to frame the development in the city by a network of (restored) river systems and green spaces (agricultural areas, parks and brownfield land). Connecting ‘blue’ and ‘green’ spaces could help maintain the continuity of ecological processes and provide an integrated approach to storm water retention as well as purification and amelioration of the city microclimate, thus allowing flexible adaptation to climate change, improvements to the quality of life and more liveable environment in the urban area. The concept has not been completely implemented at a full scale but remains important in city planning and has been revisited in the on-going development of the city’s strategy to climate change adaptation (Ecopact). The city planners of Lodz attempt to incorporate the ideas of the blue-green network into plans in the city centre when the local conditions and regulations allow it. All green elements such as parks, trees and flower beds are important part of urban designs in Lodz and the city aims to create green corridors to connect them.
The experiences and preliminary results of the Sokołówka river restoration project were also utilized in an EU LIFE+ project that took place in 2010-2015: ER-REK, Ecohydrologic rehabilitation of recreational reservoirs Arturówek (Łódź) as a model approach to rehabilitation of urban reservoirs. The rehabilitated Arturówek reservoirs provide an important recreational area for the city inhabitants that is visited by up to 3,000 people a day in high season. The sequential sedimentation-biofiltration system (SSBS) for stormwater purification developed in Sokołówka and EH-REK has been later utilized for the upgrade of efficiency in small sewage treatment plants.
The plan of the Sokołówka River park initiated during the demonstration project was approved by the city council in 2016 and the construction has started with paths and recreational infrastructure. Also, a new concept for the wider rehabilitation of the Sokołówka river and three parks on its course was developed in 2020. The new development project called Sokołówka Valley aims to connect Sokołówka River Park, Mickiewicz’s Park and Wasiak’s Pond with a hiking trail, water and ecosystem themed educational path and a bicycle path. Also, the river rehabilitation continues in the project area; ponds in the Mickiewicz’s Park will be cleaned up and the SSBS for storm water purification will be improved. In addition to this, the infrastructure and facilities of the parks will be significantly improved, including new paths, street furniture, playgrounds, toilets and a renovated restaurant.