When city growth exceeds supply / Purushottam Khanna & Bindu Koshy

World Health • July-August 1992 11 When city growth exceeds supply Purushottam Khanna & Bindu Koshy A great surge in the population of India's big cities poses huge problems for safeguarding water supplies. I n India, about 190 million people in 1989 lived in urban areas; they constituted 24% of the total population, compared to a meagre ll % at the beginning of the twentieth century. In the 40 years after inde- pendence, while the total population of India has doubled, the urban population has tripled; it is estimated to reach a staggering 315 million at the turn of the century. This amazing surge in the population of the cities has inevitably resulted in inadequate shelter and basic amenities, lack of access to clean water in adequate quantities, poor sanitation, environmental pollution and resource depletion - all of which pose insurmountable health and environmental risks. Around 30% of the population in urban agglomerations today live in squatter areas - and the largest single cause of infant mortality in India is diarrhoea! and other intestinal disorders. Several government programmes aimed at dispersing the urban popula- tion have met with only marginal success due to the multiplicity of planning and implementation agen- cies, the absence of an integrated approach to the problem, and the lack of financial resources. The targets for the International Drinking Water Supply and Sanitation Decade (1981-90) in India were fixed at l 00% coverage for urban and rural water supply, 80% for urban sanitation and 25% for rural sanitation. The erstwhile Ministry of Works and Housing proposed an outlay ofRs. 190 883 million (ap- proximately US$ 11 .5 million) to achieve Decade objectives, but resource constraints permitted an outlay of only Rs. 65 220 million (almost US$ 4 million, based on exchange rates in 1989). As a result, the targets for urban water supply and sanitation were cut back to 90% and 50% respectively. Cost-effective designs were able to alleviate the problem but only to a certain extent. Our studies on cost reduction through optimization of water supply and wastewater systems suggested that any integrated solution to the problem of water supply in the big cities should include: • Integration of water and wastewater management, coupled with health education for cost-effectiveness and promotion of preventive measures for health; • Prospecting for water resources through state-of-the-art techniques of remote sensing and geophysical surveys; • Protection of water sources against pollution; • Decentralization of water supply, matching the required quality and quantity with the supply through waste recycle and reuse; • Maintenance of the water distribu- tion system, which can prevent up to 50% of the purified water from being lost; • Application of mathematical programming techniques with exact fluid flow relationships in the design of water and waste water systems, so as to ensure functionality and to conserve material and financial resources. • Or Purushottom Khanna is Director of the National Environmental Engineering Research Institute, Nagpur 400 020, India. Mrs Bindu Kashy is a junior Research Fellow in the same Institute.