Green is emphasised in the street design of the Malmi Airport blocks
Cultural history, natural impacts, stormwater management and the circular economy guided the street and park planning of the Malmi Airport blocks. The new residential area will become a walkable district, the comfort of which will be enhanced not only by parks but also by abundant street greenery.
Street plan for Helsinki’s infill area
The City of Helsinki is growing rapidly, and in autumn 2025, the construction of a new residential area will begin at the old Malmi Airport. The nationally significant built cultural environment will gradually be transformed into a home for 25,000 Helsinki residents.
“In the next decade, Malmi Airport will become the most important infill construction area of the City of Helsinki,” says Heikki Takainen, Project Director of the City of Helsinki’s Urban Environment.
Construction will proceed in stages, and during construction, the operations of the rescue department and recreational use will be safeguarded in the area, for example. The planning began with the airport blocks on the south side of the terminal. Sweco was responsible for the street and park planning and construction design of seven streets and Lentoreitinpuisto.
Street and park planning with 40 experts
The planning area is exceptionally extensive, so more than 40 experts from Sweco participated in the street and park planning. In addition to the project management, the project involved street designers, water supply and stormwater designers, as well as landscape and lighting designers.
“Expertise in geotechnical engineering was also emphasised due to the clayey soil conditions in the area,” says Antti Partanen, Project Manager at Sweco. A third of the area will have to be stabilised. Structural engineering, on the other hand, was important in retaining wall and wall structures, which are used both in seating areas and as protection for historical fortifications.
According to Takainen, the planning entity expanded along the way, but the schedule has been kept well in relation to the additional work. In project management, he particularly appreciates work meetings in different fields of technology. “They streamlined the work and kept the more general project meetings close.”
Trees create comfort on the streets all year round
According to Takainen, one of the starting points for street design was greenness. This is emphasised both in the wishes of the residents and in the guidance of the City of Helsinki. The general forest-like appearance of the rocky Lentoreitti Park was preserved in the park design, and squares, green islands, plantings and rows of trees were planned for the streets. “Trees can be seen in the streetscape in all seasons.”
Street greenery was also increased. “We reduced the number of parking spaces by 10 per cent compared to the previous planning phase, which is a small change in the total number of parking spaces, but a big improvement in street greening,” says Partanen. People will mainly move around the walkable district on foot, by bicycle and by public transport, such as the Viikki-Malmi light rail that will eventually extend to the area.
Sweco’s illustration of Spilvenaukio.
Street planning prevents stormwater floods
According to Partanen, special attention was paid to the delay and quality of stormwater in street design. The street area will have underground stormwater retention structures and a biofiltrating stormwater basin. The water-permeable surface has been increased with lawns in the parking spaces.
“In addition, we propose a new kind of solution in which stormwater is led from stormwater sewers directly into the substrate of street trees. It reduces maintenance costs.”
The protection of Malmi’s aquatic nature was an important theme in the risk management meetings of the entire planning team led by Sweco. “The goal was to reduce the impacts of construction on Longinoja and Pumppaamonpuro,” says Partanen. A separate plan was drawn up for the management of construction site water.
The project has used the City of Helsinki’s new Environmental Document. “The new set of documents has been a major effort for the city and the designers, but the multidisciplinary design entity provided important experience on the basis of which we can update the guidelines,” says Takainen.
Circular economy plan for street and park construction
The goals of sustainable urban planning were promoted with Sweco’s emission reduction calculation and circular economy plan. It was carried out in cooperation with designers from different fields. The plan provides an overall picture of the opportunities offered by the circular economy in the airport blocks.
“We are studying, among other things, the utilisation of excavated soil, rock material formed at the site, and various demolition and recycled materials,” says Nina Aarras, Chief Circular Economy Specialist at Sweco. Recycled materials can be used to replace soil and rock materials needed in construction, and a low-carbon binder can be used to stabilise the soil.
According to Aarras, the greatest potential in terms of mass is in soil and rock material as well as in buildings to be demolished. “The aim is to recover usable materials, such as asphalt, natural stones and lighting, for later use or recycling.”