Urban underground space: Solving the problems of today's cities

The world-wide trend of increased urbanisation creates problems for expanding and newly-developing cities alike. Population increase leads to an increased demand for reliable infrastructure, nowadays combined with a need for increased energy efficiency and a higher environmental awareness of the public. The use of underground space can help cities meet these increased demands while remaining compact, or find the space needed to include new functions in an existing city landscape. In many cases, underground solutions to urban problems are only considered if all other (above ground) options have been exhausted. When underground solutions are considered and evaluated from the planning or initial project stages onwards, more optimal solutions will become possible. Use of the underground is not limited to large scale infrastructure projects. This paper also shows innovative use of the underground for commercial and residential use, storage, water conveyance and treatment, and heritage conservation, and highlights how use of underground can bring more optimal solutions for urban development. (C) 2015 The Author. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).