Kirkkolehto Wetland Restoration Project

The Kirkkolehto wetland restoration project, completed in 2020, was part of the City of Kokkola’s landscape and environmental initiative. The goal was to improve the quality of stormwater flowing into the urban river using nature-based solutions. These are structures and practices inspired by nature that support biodiversity and human well-being.

In the project, a sedimentation basin was constructed to improve water quality before it enters the city river. In addition to clarifying the water, the basin also increases the river’s capacity during spring floods and heavy autumn rains by acting as a retention basin. The wetland area also serves as a nesting ground for waterfowl and migratory birds, and as a spawning habitat for various fish species – promoting biodiversity in the region.

The site was designed from the start to serve recreational and educational purposes, making landscape design a key element of the project. During construction, walking paths were created and new vegetation was planted to support this goal.

Tallqvist served as the main contractor throughout the project.
A natural-looking basin was excavated and finished with coarse gravel to blend with the surroundings. On the river side, small weirs were built to guide part of the water flow through the wetland.

Expertise and Equipment for Demanding Conditions

“Restoring the Kirkkolehto wetland required special expertise,” says project manager Rickard Smeds. “Working near water requires specific know-how and the right machinery – fortunately, Tallqvist has both.”

While construction did not take place directly on water, the wet and soft soil required skilled planning and execution. The rainy autumn also brought challenges in the form of floodwater, which was managed through continuous pumping from the wetland side.

Part of the basin's finishing had to be done in dry conditions. Tallqvist developed a work plan that included building two temporary dams and excavating a bypass flow channel for a few weeks. The bypass was carefully reinforced to prevent erosion from the flowing water.

In Landscape Construction, the Operator’s Eye Makes the Difference

In addition to technical expertise, the restoration required a strong visual sense. Plans and designs on paper were constantly adapted on-site. The key to a successful result was the skilled excavator operator, whose eye for shaping the land played a crucial role in achieving a natural and visually appealing outcome.

“The project was a great success in terms of quality, and the area is now truly impressive,” Smeds concludes. “The site is surrounded by residential housing and frequently used by the public. That’s why collaboration and clear communication with local residents and the City of Kokkola were also essential to the project’s success.”