Growing cities underground
© Patrik Jones / Flickr under Creative Commons license
Around the world, cities are growing as people leave the countryside to participate in urban life. Anxious to sustain and improve the quality of living in their cities, urban developers are beginning to look down, not up, for buildable space. A recent article in the Neue Zürcher Zeitung (NZZ) explores this underground expansion, highlighting the role played by Professor Aurèle Parriaux of the EPFL's GEOLEP lab in studying out how to include the underground in urban land-use planning.
Far from encouraging the construction of entire underground cities, the EPFL professor contends that only those buildings that make sense underground should be built there. According to his calculations, the construction of subterranean projects can cost between 10 and 26 percent more than traditional above-ground ones, depending on whether they are built in solid bedrock or in more difficult terrain. Since they are sheltered from the weather and exposed to smaller temperature variations, their maintenance costs may actually be lower. Good planning can further increase cost-efficiency by making underground projects multi-functional or by coupling the construction of multiple projects, such as a highway tunnel and a geothermal plant. By tapping into this largely unused underground resource, buildable space, cities can continue to grow and improve their infrastructure, discreetly, underground and out of sight.