African Water Development Report 2006 - United Nations Economic ...

African Water Development Report 2006resort to traditional water sources that may becontaminated. Contamination of distributionpipelines due to intermittent supply, low waterpressure in the distribution network, inadequatewastewater collection systems and leaking pipesare also common problems in developing countries.If contaminated water penetrates distributionmains, water that has already been treatedand disinfected may become re-contaminated(O&M Working Group, 2002).Technical Problems of Urban WaterSupply Systems in AfricaUnaccounted-for-water is a major water supplyproblem in many African cities (Table 7.4). Alagre part of this water is lost through leakingpipes or overflowing service reservoirs after abstraction,pumping or treatment, or during distribution.Those who suffer most from this inefficiencyare people living in the impoverished,outlying urban areas; but if measures are taken toboost sustainability and improve organization offacilities, coverage can be extended to the fringeand poor areas of large cities. This would bringabout considerable improvements in health and,at the same time, minimize the need to expandtreatment and distribution facilities, thus releasingresources for other development activities.One of the crucial problems facing the sector islack of sustainability of sanitation services. Despitehuge efforts made in the past years, there isstill a great need for further work to define principles,generate political will, formulate strategiesand search for new technological, financial andinstitutional solutions.Health impactsUrbanization can be a major source of healthproblems: nearly half of the world’s people willbe living in urban centres by the end of the 20thcentury but, currently, 30-60 per cent of the urbanpopulation is in low-income countries andlack adequate housing with sanitary facilities,drainage systems, and piping for clean water(UNCHS 1996). This number is expected toincrease since local and city authorities oftenlack the resources, knowledge, trained personneland financial capacity needed to meet theirresponsibilities in providing services and amenitiesessential for healthy living. Increased exposureto biological and chemical health risks inurban areas is particularly harmful to children.Children suffer the greatest number of deathsfrom diarrhoeal diseases (2.5 million deaths peryear). Prevalence of asthma, often exacerbatedby air pollutants, has also increased among children(Woolcock and Peat 1997). Studies suggesta quantitative relationship between atmosphericcarcinogen levels and lung cancer, and WHOhas estimated that 50 per cent of the global burdenof chronic respiratory illnesses is associatedwith air pollutants (WHO 1997b). As the globalpopulation continues to grow, there is increasingpressure to develop agriculture, roads and transportationsystems in previously uninhabited areas.This kind of land conversion can encouragethe spread of diseases harmful to human health.For example, leishmaniasis, an infectious diseasetransmitted through a sandfly bite, has increasedto 12 million cases (WHO 1998) each yearalongside increasing land development in Africa,Latin America and West Asia (WHO 1997b).Forest clearing, in particular, is associated withhigher incidence of diseases such as malaria.In search of performance indicatorsA transition from traditional familiar terminologyand methods is never easy to accomplish, anda commitment is needed from all water suppliersin Africa to effect some important changes.For example, the terms ‘Non-Revenue Water’ and‘Water Losses’ should replace the familiar (but oftenvague) term ‘Unaccounted-for-Water’ – since,with modern techniques, it is now possible to accountfor virtually all water entering a water distributionsystem (Alegre, H et al., 2000). The productioncharacteristics of urban water utilities insome African countries are shown in table 7.6.172