Work on plans to restore a more natural character to the Bogdanka watercourse has moved into its next stage, with detailed surveys of the plants, trees and wildlife along the river now underway.
Aquanet and Aquanet Retencja are developing a concept for the renaturalisation and modernisation of the Bogdanka between Park Sołacki and Pułaskiego. The area under consideration includes parts of Park Sołacki, Skwer Czesława Janickiego and the retention valley in Park Wodziczki.
The long-term proposal is centred on keeping more rainwater within the landscape while creating better conditions for the river, wetlands and the wildlife that depend on them. It is part of a wider approach to urban water management in which rainfall is retained and used locally rather than being moved away from the city as quickly as possible.
A closer look at the Bogdanka valley
The Bogdanka catchment receives rainwater from a substantial part of northern and western Poznań. During intense rainfall, large volumes of water can overflow the drainage system and cause local flooding.
The opposite problem can occur during prolonged dry periods. Water levels in the natural environment fall, while green areas and wetland habitats have less water available.
The concept being prepared by Aquanet and Aquanet Retencja is intended to address both situations. Increasing the amount of water that can be temporarily held within the Bogdanka valley could help reduce pressure during heavy rainfall, while retaining water in the landscape could support local groundwater levels and wetland habitats during drier periods.
This approach is often described as the 'sponge city' model, with urban landscapes designed to absorb, hold and gradually release rainwater.
What could change along the river?
The project is still at the concept stage, so the final design has not yet been determined. Several nature-based measures are being examined, including:
increasing the retention capacity of the Bogdanka valley
creating small ponds and wetland areas
restoring more natural features to sections of the watercourse and valley
introducing areas that can become temporarily waterlogged
improving conditions for wetland and marsh vegetation
creating better habitats for animals associated with aquatic environments
upgrading selected infrastructure used to manage rainwater
improving the recreational landscape around the river.
Designers are also examining whether water could be temporarily held back around the Sołackie ponds during periods of particularly heavy rainfall. Options for improving the safety and operation of the retention valley in Park Wodziczki are also being assessed.
These are proposals being studied as part of the concept work rather than confirmed construction plans.
Survey teams are already in the field
One of the first practical steps is a detailed environmental inventory.
The work includes dendrological and ecological surveys designed to establish a clear picture of the existing landscape before any future intervention is planned. Trees are being marked as part of this survey process.
According to the project information, these markings should not be interpreted as a list of trees intended for removal. Their purpose is to collect the information needed to understand the existing vegetation and inform the concept.
The wildlife survey also includes fish sampling in the ponds and the Bogdanka channel. Specialists are recording the species currently present and checking for non-native and invasive species, including introduced crayfish.
The fish are being caught by a qualified ichthyologist using methods intended to minimise disturbance. After identification, they are returned to the water.
The current inventory is scheduled to continue until mid-October.
A greener approach to managing rainwater
Renaturalisation of an urban watercourse does not simply mean leaving a river untouched. In a city such as Poznań, waterways also form part of a wider drainage and flood-management system.
The Bogdanka project therefore brings together several objectives that need to work alongside one another: retaining rainfall, reducing the effects of heavy downpours, supporting the landscape during drought, protecting existing habitats and maintaining the recreational value of some of Poznań's best-known green spaces.
The intention is to use natural processes wherever possible, while modernising infrastructure where necessary.
If the concept progresses to implementation, the resulting landscape could include a mixture of open water, wetland habitats, naturalised sections of the river and areas designed to hold water temporarily after heavy rain.
Further consultations will shape the project
The concept will require consultation and agreements with a number of institutions, including Państwowe Gospodarstwo Wodne Wody Polskie, the Municipal Heritage Conservator and local neighbourhood councils.
The proposed solutions will be assessed from technical, environmental, economic and social perspectives.
The concept is intended to provide the basis for future design documentation and applications for external funding. It does not, at this stage, represent a final construction scheme.
Residents will be informed as the work progresses.
For Poznań, the Bogdanka valley offers an opportunity to test how established urban parks and waterways can respond to increasingly variable rainfall while retaining their role as places for nature and everyday recreation.
The immediate task is to understand what is already there. The surveys now underway will provide some of the information needed to decide what should happen next.
See more: New Poznań Główny: Design Work Begins for the Future Poznań Main Station
Source: Aquanet, Poznań City Council
