Karting, Latin dance and technology – a second city underground
Increasingly versatile spaces are situated in a Helsinki that is getting more densely built over time. Thanks to underground building, building land above ground is spared for other purposes.
A Latin dance lesson is starting at Maunula Sports Hall. The lesson starts with a warm-up and the instructor, neighbourhood trainer Jenna Haarainen, shows the attendees how it is done. The movements are familiar to the majority of the cheerful group, since many of the attendees are regular clients.
The Maunula residents are an active bunch – they are really putting in their best effort at the gym. It gets sweaty when the participants switch from rowing machines to crosstrainers and barbells.
The Sports Hall is situated below ground – something that barely comes to mind when training. The residents are so used to their underground facilities. They are places for travelling, parking, eating, drinking, visiting the theatre, target shooting, archiving, storing and servicing.
Exceptional versatility below ground
It is Saturday morning at Formula Center in Myllypuro. A group that has been racing their go-karts on the track are taking off their helmets and checking for results from a screen at the café to see which one of them drove the fastest lap this time. They smile contentedly and give each other high fives for hitting good speeds.
This, too, occurs below ground, and this experience attracted Fanny Lépine, a reporter from the French-German TV channel Arte, as well as photographer Elsa Kleinschmager to the tracks. Arte is a culture channel that produces and presents news and documentaries.
There are underground spaces in other large cities as well, but in Helsinki they are used in an exceptionally versatile fashion. If need be, Formula Center also functions as a bomb shelter, as does Maunula Sports Hall and for example Itäkeskus Swimming Hall.
The world's first underground city plan
In Helsinki, plenty of technology has been placed below ground, but for example the parliament's secret premises for times of crisis also intersect there. "Ghost" metro stations have been dug for future metro routes for instance in Munkkivuori. Helen's artificial reservoirs have been built below Esplanadi and in Pasila. The reservoirs function as energy reserves for the district cooling system.
Nearly 400 different facilities have been built below ground. They have been built in different layers: there are tunnels for technical maintenance about 80 meters below ground, and at the deepest point, facilities have been dug at 100 meters below ground.
Thanks to underground building, several hundred million euros worth of aboveground building land has been spared for other purposes.
In Helsinki, there are 12,7 million cubic metres of rock facilities and 293 kilometres of technical tunnels. The amount corresponds to 117 Parliament Houses. The amount is so massive that, as far as is known, the world's first underground city plan has been drawn up for future building and planning. The plan is currently being updated.
Ilkka Vähäaho, director of the soil and bedrock unit at the City of Helsinki, points out that it is difficult to later change an already built rock facility, which is one of the reasons for drawing up the city plan.
"We want to make sure that all the projects we know about are taken into consideration so we can work on different jobs simultaneously.
In the new update for the city plan, a possible underground collector road in the city centre is being prepared for. The City Rail Loop is also included in the city plan.
Architectural attraction leads under ground
The space in the city centre is getting increasingly cramped, and there are not many free spots for building above ground. This was up for discussion at Amos Anderson Art Museum when its future was considered. A new idea was born and it concerned acquiring more space below ground as well as connecting Lasipalatsi and the museum together as a whole. The project was named Amos Rex and the museum is going to be opened again in May after renovations and building.
Museum Director Kai Kartio says that expanding museums below ground is not very exceptional on a global scale.
"In our case, the exceptional part is how it was planned. Amos Rex is becoming an architectural attraction," Kartio says.
The underground building is not something that is emphasised at Amos Rex, quite the opposite. The transition from Lasipalatsi's square under ground is unnoticeable, and natural light is led into the building.
Kartio is pleased with the fact that Amos Rex can be built in the centre of Helsinki thanks to the underground facilities.
Sharks feel comfortable below ground
There are also tunnels going from Sörnäinen to Katri Vala underground heating and cooling plant. One of the longest tunnels is the one from the power plant in Vuosaari to Salmisaari.
My guide at the heating and cooling plant is Helen's Product Specialist Tuomas Ojanperä. He states that the plant is the biggest heat pump plant in the world to produce both district heating and district cooling. Another unique part about the plant is its ability to salvage waste energy for example by using waste water from Viikinmäki wastewater treatment plant. At the same time, the thermal stress on the Gulf of Finland caused by waste water is reduced.
The technology at the plant is impressive. The heat pump, for instance, is so big that it could not possibly be transported on a regular lorry. The plant's yearly energy production corresponds to the energy needs of a city the size of Kotka. It stands for 7 per cent of the heating in Helsinki and 79 per cent of the cooling.
The tunnels in joint use have previously been used for bus transports and tunnel marathons. These days the tunnels are very quiet. So quiet that when the peace-loving sharks from Linnanmäki's Sea Life needed a temporary home during a renovation, the sharks were brought under ground.
Waste water is purified effectively
We continue our tour to the Viikinmäki wastewater treatment plant. Here it becomes clear that the waste water from Helsinki and the rest of Uusimaa is purified mainly below ground.
The wastewater treatment plant is a massive space, all in all over a million cubic metres large or the equivalent of over ten Parliament Houses.
Waste water is purified in several different phases, and because of that there are multiple big reservoirs below ground. On a shelf, there are objects that have been found during the first phase. The objects include mobile phones, toy cars and dolls.
HSY's Project Manager Anna Kuokkanen says that the purified waste water goes from the place we are standing at in the rock tunnel to ten kilometres from the shore of Katajaluoto, at 20 metres deep. Before that over 90 per cent of the nitrogen, phosphorus and organic matter has been removed from the waste water.
21 million views of Helsinki
Underground Helsinki was presented on the German-French TV channel Arte in the beginning of January, and during spring it is going to be shown to the channel's weekly audience of 21 million viewers.
During the Helsinki visit, they filmed for example icebreakers at Pohjoisranta as well as city views from the roof of Hotel Torni.
Text: Kirsi Riipinen
Images: Ilkka Ranta-aho