PREFACE: The Urban Subsurface – from Geoscience and Engineering to Spatial Planning and Management

With the growing global population and increasing urbanization worldwide, sustainable urban development is now one of the greatest challenges faced by the modern world. This is acknowledged in the United Nations’ Sustainable Development Goals (SDGs) for "Transforming our world: the 2030 Agenda for Sustainable Development". Of the 17 "Global Goals", Goal 11 is Sustainable Cities and Communities, and Goal 6 is the related Clean Water and Sanitation Goal. Despite these goals, the potential importance, and contribution, of the subsurface to sustainable urban development, and clean water and sanitation, is often unrecognized, or misunderstood, and at worst ignored.