The World Water Day is observed on March 22 as a means of highlighting the importance of freshwater and advocating sustainable management. An international day to celebrate freshwater was recommended at the 1992 United Nations Conference on Environment and Development (UNCED). Accordingly, March 22, 1993, became the first World Water Day. Each year, a specific aspect of freshwater is highlighted. This year's theme, ‘Water for Cities: Responding to the Urban Challenges,' is aimed at spotlighting and encouraging governments, organisations and communities and individuals to address urban water management.
The world is inexorably becoming urban. Half of the humanity now lives in cities. By 2030, all developing regions, including Asia and Africa, will have more people living in urban than rural areas. Developing countries are experiencing structural transformations, with a decreasing role for agriculture and increasing dominance of the industrial and service sectors. Furthermore, globalisation has led to increased foreign capital that is substantially invested in urban areas.
The exploding urban population growth and economical activities pose unprecedented challenges to the water sector of cities. Urban populations are heavy users of land and water resources. Hence, rivers, tanks and lakes have been significantly exploited or are lost. Moreover, wastes generated in urban areas are more concentrated. In many rapidly developing cities, sewerage and industrial effluent treatment and solid waste management systems are not to a satisfactory level. Moreover, urbanisation adversely affects the drainage systems and their networks in the city and adds up with another dimension of water-related crisis like floods.
In India, the urban population has increased from 11 per cent (1901) to 17 (1951) and further to 28 (2001). Similarly, the number of towns also increased from 1,916 to 2,422 to 4,689 in the respective years. Among the States, Tamil Nadu has the highest level of urbanisation (44 per cent). The ongoing research under the Crossing Boundaries Project of the Centre for Water Resources, Anna University, Chennai, examines water issues with respect to rapid urbanisation of Chennai.
Mobilising huge quantities of water for meeting the increasing urban need is a big challenge. The efficiency of the public supply system is questionable as sources are highly uncertain. Groundwater in most parts of Chennai is not of good quality. In areas where public supply is not efficient or does not exist, people depend on suburban groundwater resources transferred through tankers and in packaged cans. This informal market has led to excessive exploitation of groundwater, and in many suburban villages the water table has diminished and the quality deteriorated. Moreover, coastal areas are experiencing seawater intrusion.
Added to them is the indiscriminative discharge of sewage, industrial effluents and disposal of solid wastes. Socially vulnerable communities are compelled to use the groundwater unfit for consumption and are hence exposed to water-borne diseases. Solid wastes are disposed of in low-lying public land and groundwater pollution in the surrounding areas is severe due to leachate transfer. The multi-functionality (socio-ecological services) of the waterbodies has also diminished considerably.
Unplanned urbanisation with rigorous land use changes has also had significant impacts on storage structures and drainage canals, which have historically discharged floodwater into the sea. The Pallikarani marsh (near Chennai) and the Buckingham canal used to play a significant role in moderating the floods in south Chennai. Recently, the marsh has been considerably encroached on; hence its storage capacity has reduced. Generally, the reduction in the natural recharge options increases the runoff and makes the city more prone to inundation.
Urban ecosystems, in other words, are “built environments” and they sustain various economic activities, including in the industrial, commercial, residential and institutional sectors. Hence, infrastructure such as water supply and sanitation has to be planned not only for the population but also for the economic sectors. New solutions for improving the sustainability of cities are being explored. Urban water resources management is complex and requires not only water and wastewater infrastructure but also pollution control and flood prevention. What is needed is a paradigm shift in urban water resources management through the coordinated efforts of various stakeholders with community participation.
(Prakash Nelliyat is Research Coordinator and Ambujam N.K. is Director, Centre for Water Resources, Anna University, Chennai. Their email ids: nelliyatp@yahoo.co.uk and nkambuj@ annauniv.edu)
