Engineering: issues, challenges and opportunities for development ...

ENGINEERING FOR DEVELOPMENT: APPLICATIONS AND INFRASTRUCTURE6.2 Engineering infrastructure6.2.1Water supply and sanitationKalanithy Vairavamoorthy andDamir BrdjanovicExisting conditionsWater supplyThe problem of water scarcity in urban areas of developingcountries is a major concern. It is estimated that by 2050, halfof India’s population will be living in urban areas and will faceacute water problems (Singh, 2000). 130 It was reported in 2002that about 1.1 billion people were still using water from unimprovedsources, and two thirds of these people live in Asia.The number of people without improved water sources inChina alone is equal to the number of un-served in the wholeof Africa ( UNICEF/ WHO, 2004). 131 The quality of water thatpeople receive is also questionable. In India, 85 per cent of theurban population has access to drinking water, but only 20 percent of the available drinking water meets the health and qualitystandards set by the World Health Organization (WHO)(Singh, 2000).The daily water supply rate in developing countries is very lowcompared to the industrial world. In India, it ranges from 16 to300 litres per day, depending on the locality and the economicstrata (Singh, 2000), whereas this figure ranges from 100 to 600litres per day in developed countries. The populations thatare not served by a piped water supply receive even smallerquantities of water. In East Africa, the daily supply rate of unpipedwater was nearly a third less than for piped users of lowincomecommunities (Thompson et al., 2001). 132The prevailing water stress in many developing countries isnot only due to source limitations but other factors such aspoor distribution efficiency through city networks and inequalitiesin service provision between the rich and the poor(UN-HABITAT, 1999). 133 One of the main reasons is the highrate of water loss from the distribution systems. Many studiesshow that water losses in cities of developing countries are atlevels between 40–60 per cent of the water supplied (Arloso-130 Singh, N. 2000. Tapping Traditional Systems of Resource Management, Habitat Debate,UNCHS, Vol.6, No.3.131 UNICEF/ WHO. 2004. Meeting the MDG drinking water and sanitation target - Amid term assessment of progress. United Nations Children’s Fund and World HealthOrganization, p.36.132 Thompson, J., Porras, I. T., Tumwine, J. K., Mujwahuzi, M. R., Katui-Katua, M., Johnstone,N. and Wood, L. 2001. Drawers of Water II. International Institute for Environment andDevelopment, London, UK.133 UN-HABITAT. 1999. Managing Water for African cities - Developing a Strategy forUrban Water Demand Management, Background Paper No. 1, Expert Group MeetingUNEP & UN-HABITAT.roff, 1999). 134 In many cases the water loss indicators reflectthe inefficiency of the management of the water supply system.Any reduction in water losses requires coherent action toaddress not only the technical and operational issues but alsothe institutional, planning, financial and administrative issues(WHO, 2000). 135The design of water distribution systems in general has beenbased on the assumption of continuous supply. However, inmost of the developing countries, the water supply systemis not continuous but intermittent (Vairavamoorthy et al.,2007). 136 The Asian Development Bank has reported that, in2001, ten of the eighteen cities studied supplied water for lessthan 24 hours a day (ADB, 2004). 137 The situation is similarin other regions of the world, for example in Latin Americaten major cities receives rationed supplies (Choe and Varley,1997). 138 Only 11 per cent of the consumers with a piped supplyin Nigeria received water once in every two days in 1995.Intermittent supply leads to many problems including severesupply pressure losses and great inequities in the distributionof water. Another serious problem arising from intermittentsupplies, which is generally ignored, is the associated high levelsof contamination. This occurs in networks where there areprolonged periods of interruption of supply due to negligibleor zero pressures in the system (Vairavamoorthy and Mansoor,2006). 139SanitationThe sanitation sector is often a lower priority compared towater supply. Therefore it is not surprising that some 2.6 billionpeople, half of the developing world, live without improvedsanitation. Sanitation coverage in developing countries (49 percent) is half that of the developed world (98 per cent). In sub-Saharan Africa the coverage is a mere 36 per cent, and over halfof this is without improved sanitation. Similarly, nearly 1.5 bil-134 Arlosoroff, S. 1999. Water Demand Management. International Symposium on EfficientWater Use in Urban Areas, IECT-WHO, Kobe, Japan.135 WHO. 2000. Global Water Supply and Sanitation Assessment Report, World HealthOrganization-United Nations. Children Fund, Geneva, Switzerland.136 Vairavamoorthy, K., Gorantiwar, S.D., and Mohan, S. 2007. Intermittent water supplyunder water scarcity situations. Water International, Vol. 32, No. 1, pp. 121–132.137 ADB. 2004. Second Water Utilities Data Book Asian and Pacific Region. Asian DevelopmentBank (ADB). Manila, Philippines.138 Choe, K., Varley, R., and Bilani, H. 1996. Coping with Intermittent Water Supply; Problemsand Prospects, Environmental Health Project. Activity Report No. 26, USAID,USA.139 Vairavamoorthy, K. and Mansoor, M.A.M. 2006. Demand management in developingcountries. In: Butler, D., and Memon, F. A. (Eds.) Water Demand Management. IWAPublishing, London, UK. pp. 180–214.© SAICE Stone arch construction.283