Water has become a challenge of global dimensions, especially in the fast-growing urban areas, which is an under-recognized issue for many citizens, a recent study published in Science by a research team from Switzerland and Netherlands pointed out.
Usually, attention has been paid to such water-related issues as drought, flood, agriculture, food, and the quality of water received. Little concern has been given to the ability of cities to handle the urban water cycle adequately.
With rapidly aging infrastructure, population growth and increasing urbanization, current urban water management strategies are questionable, especially in the fast-growing urban areas in Asia and Africa.
The existing urban water management system is mainly built on a well-established socio-technical system that has solved most of the water and hygiene-related problems afflicting cities, especially in the more affluent part of the world. It relies on investment-intensive, usually underground, pipe networks that provide single-quality drinking water and evacuate stormwater and wastewater.
In many urban areas, reservoirs and long-distance water conveyance systems compensate for inadequate local water resources. In addition, water and wastewater treatment plants provide an interface to the aquatic environment, treating raw water for drinking-water purposes and wastewater for water pollution control.
In the existing urban water management system, the core centralized services include the provision of safe drinking-water, urban hygiene, and protection against flooding, complemented by water pollution control. These approaches have worked well at a good quality in many cities and metropolitans.
Apart from the provision of safe drinking-water and wastewater handling for public health, an additional important infrastructure is the stormwater drainage system. Without adequate drainage infrastructure, unwanted urban flooding events will occur. Thus, protection against flooding is one of the top priorities for urban water sustainability.
According to the study, conventional urban water management system is not the best solution for rapidly growing cities because of its strong dependence on large quantities of water, high investment costs, and a need for stable institutions, long planning horizons, as well as inefficient use of resources. Of these disadvantages, inefficient use of resources is a global issue. Currently, the conventional system is incurring increasing economic, social and environmental costs as a result of aging built infrastructures, increasing urbanization, emerging contaminants, and competitive water uses.
Currently, the overall treatment of the collected wastewater remains highly insufficient in many cities, especially those in Africa and Asia, because of the scarcity of sewers and treatment plants. This backlog is compounded with the current unprecedented global population growth rate. Small and medium-sized towns will bear the brunt of this future urbanization growth, notably in the provision of access to safe drinking water and sewers. High urban growth rates lead to high planning uncertainty.
As the currently dominant conventional approach to water management is unlikely to meet the increasing challenges of a globalizing world, the authors pointed out that a shift toward “new paradigms” is required. These paradigms included integrated water resources management, adaptive management, and ecosystem-based approaches. A shared feature of these reform agendas is that they orient water management toward providing sustainable water services rather than merely delivering quantities of water.
The authors further pointed out that it is not enough to hope for technological breakthroughs or to believe in the wisdom of more inclusive governance arrangements alone. Rather, the joint development of new institutional conditions and technological designs is needed. They have documented a number of alternative technological and institutional approaches which look promising, such as stormwater drainage, increasing water productivity, source separation of waste, and on-site treatment of wastewater.
Currently, rapid urbanization in the areas with water scarcity and/or missing or aging urban water infrastructure is an immense challenge and a formidable chance for developing next-generation technologies and management structures. There is an urgent need to develop more cost-effective and resource-efficient systems that deliver the desired water services for the areas with fast-growing urbanization, the authors said.
Relevant scholars in the University of Hong Kong further pointed out that it would also be important to raise the public’s awareness and appreciation of the importance of attaining long-term water sustainability for urban residents. They have recently launched a 3-year JC-WISE (Jockey Club Water Initiative on Sustainability and Engagement) project, funded by The Hong Kong Jockey Club Charities Trust, aiming at elevating the level of public awareness of the importance of water conservation and sustainability by enhancing the understanding of the multiple values of water through re-connecting the public with local rivers and recognizing the impacts of consumption habits on local and distant freshwater resources.
Informed by this new understanding, one can then take personal and collective actions to reduce the size of water footprint, and thus the extent of its impacts, to contribute to water sustainability goals, scholars in the University of Hong Kong said. Hong Kong’s experience may have implications for water management in other cities or urban areas.