Sustainable cities and the groundwater governance challenge

With over half the world’s population now living in towns and cities, serious questions are being asked about the sustainability of urban water supplies. Groundwater is a particular concern as it represents over 95 % of the world’s available fresh water reserves and supplies over 1.5 billion city dwellers with water essential for their drinking and sanitation needs. Within 20 years, the global population is projected to rise from 7 billion to 8 billion with this entire growth accommodated in urban areas. Much of the additional water required will be sought from groundwater due to the generally modest cost of waterwells and the close, “well’s length” proximity of the resource. Fortunately, significant progress has been made in the science of urban groundwater during the past 25 years, most notably with respect to the nature of urban recharge and components of the urban water balance, contaminant source characterisation, recharge management and methods of assessing aquifer vulnerability. There have also been major advances in the development and use of advanced ground and surface water modelling tools, some of which are linked with GIS and urban databanks to provide unprecedented support for resource management decision making. What is missing are appropriate systems of urban water governance that are essential for effective and responsible groundwater resource management. Despite the growing popularity of “integrated water resource management” models that promote urban water management in a comprehensive, holistic, way, it is not clear that such techniques adequately incorporate the unique storage and flow attributes of groundwater, behaviours that merit special management considerations. Today, a significantly increased awareness for the valuable role of groundwater in the urban water cycle is beginning to raise its profile at the political level. Improved groundwater governance with the full involvement of all stakeholders in the decision-making process is now recognised as the key to resolve sustainability concerns over water in the world’s rapidly growing cities.