Construction always has an impact on nature - and also on water areas. Since the human eye cannot see below the surface, it is more challenging to perceive their changes. Nature-based construction and related solutions are the way of the future, which is important to include in all construction.
Heavy rains brought by climate change, drained swamps, clear-cutting of forests and the increase in the built environment have led to a situation where the quantities and speeds of flowing water are too large for the size and shape of the watercourses.
"The water then floods where it can reach most easily, which is typically roads, fields and house structures," explains Perheyhtiö Ajalin Group's environmental director Elina Erkkilä.
"In construction projects, it is typical for water to be piped into a pipe and quickly run out along it. In this way, the water will get further away from the object, but the probability is that the damage will be repeated elsewhere. The flow of water should always be viewed as a whole and find areas in the catchment area where, for example, the flow of water can be delayed," he points out.
The renovation of the track work spawned a pilot supported by the ELY Center
In Pohja, Raasepor, the renovation work of the beach track got the Ajalin Group, which handled the contract, into real action. It was noticed that the catchment area suffers from frequent floods and river bed erosion.
The bed of Dalkarbybäcken flows into Pohjanpitäjänlahti, which is overgrown and luxuriant. The water in Merenlahti is also very cloudy. Since there are wide open fields in the area, but few lakes, ponds or swamps, the water has stood in the fields after the rains. The coastal railway crossing the catchment area has partly affected the flow of water. And the water, in turn, affected the track, which was now being renovated.
"There were not enough places to rest in the water, and the water conditions were in a vicious circle. When it rains, the water floods the fields, from which the soil comes off, which blocks the riverbed. This leads to the bed growing over, and there is even less space left for the water, sums up Elina.
In the pilot project, a water management complex imitating the effects of a natural bog was built in the catchment area of Dalkarbybäcken. It includes a wetland, flood and seasonal wetlands, erosion protection and small structures imitating natural rapids.
"The water basin has sections of different depths with versatile plants, which moderates the water flow rate. Also, the loose soil with its nutrients that is transported with the water remains in the wetland, and does not travel all the way to the sea to make it euphoric," says Elina.
Water management must be thought of as a whole
Many water management plans are made in cities and municipalities, but if water is managed where problems are visible, it is often already too late. The timeline shows that even in construction planning, the surrounding nature of the area and water management must be taken into account.
"Nature-based construction is the way of the future, in which the whole is managed with the values of sustainable development. That's why it's important to get the issue built into the entire construction and infrastructure side of things," says Elina.
He believes in the potential of the vision: "Even flood times are part of the natural cycle of water. A century ago, there were more places for the water to rest in the catchment areas, which prevented the flow velocities from increasing too much. Then the bog was drained, the river beds were straightened, and the built environment is covered with, for example, asphalt, from which the water flows freely over. The buffering capacity of catchment areas against extreme weather phenomena has weakened. Now is the time to bring it back.”
Elina's perspectives in promoting water management
- Nature: Restoring water areas creates a buffer for the habitat-destroying effects of climate change. Aquatic life and vegetation thank you, and the water ecosystem is strengthened when, for example, wetlands are built in the catchment area or the river bed is paved. Restoration has both a water protection and flood control effect.
- Man: Water areas have an important health and recreation effect: the Solina stream and the flow of water are calming elements. Property structures and road areas stay in better condition, and maintenance intervals are extended when water treatment is done with environmental considerations in mind. Farming becomes easier when the floods decrease. Rehabilitated catchment areas reduce the leaching of soil nutrients into the sea or lake: swimming waters remain cleaner, there are fish to catch, and the cottage beach is not affected, which affects the value of the property.
- Company: The infrastructure sector has huge opportunities to influence nature and the environment. Water management and treatment already in the planning phase increase cooperation and information sharing among different actors. The solutions are not necessarily more expensive, but require a different attitude to planning and cooperation.
In a nutshell
- The family company Ajalin forms a group that, in addition to the parent company, includes Ralf Ajalin Oy and the Pihamaa brand. Ralf Ajalin Oy is one of the few quality-certified companies that can do challenging bridge and railway superstructure projects. The group invests heavily in environmental work, because the fight against climate change and halting the loss of nature challenge changing old methods.
- The Dalkarbybäcken catchment area project received a water and marine management grant from the ELY Center. Half of the project's costs are financed by Ralf Ajalin Oy. In addition, the landowner has done clearing work and made the area available. Most of the construction work was done in the spring of 2022 and finishing touches were made during the fall. The pilot project ended on November 15.11.2022, XNUMX. The goal is that similar measures will be taken elsewhere.
Read more about the pilot >
Text: Tia Härkönen
Photos: Family company Ajalin