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

African Water Development Report 2006population of 36 million will more than tripleto 112 million in 2025, forty-four million morethan it can feed with intermediate inputs. By2025, Nigeria’s population is projected to reach338 million, which will be 123 million in excessof its carrying capacity with intermediate inputs.Even with high inputs, Kenya’s lands can supportonly 51 million people a total that will be passedby 2010. By 2025, there may be 83 million Kenyans,with as many as 111 million before thepopulation reaches its plateau (Nana-Sinkam,1995).In the context of the general population pressure,the fast-growing urban centres in Africa,influenced mainly by rural migration, are makingheavy demands on the environment, as urbanresidents generally consume more resources thanrural dwellers, and generate large quantities ofsolid waste and sewage (table 6.9). Urbanizationbrings with it expansion of infrastructure whichin turn transforms part of the land surface intobuilt area (figure 6.12). In northern Africa, atleast 20 per cent and as much as 80 per cent ofthe urban solid wastes are disposed of by dumpingin open spaces. Rapid urbanization in Lagosincreased solid waste generation sixfold to about3.7 million tons a year in 1990, plus another half amillion tons of largely untreated industrial waste,because 90 per cent of the industries in Nigerialack pollution control facilities (UNEP Geo-2000, IMO 1995). The 1.3 million inhabitants ofLusaka produce 1 400 tons of solid waste daily,90 per cent of which is not collected owing to thevery poor staffing, finances and equipment of thelocal authority. As only 36 per cent of Lusaka’sresidents have sewerage services, most of the restuse pit latrines, a common situation throughoutAfrica (UNEP Geo-2000, Agyemang and others1997). The concentration of industries in ornear cities is also a major source of environmentalpollution and resource depletion. In 1994, thespill of toxic chemicals from a pulp and papercompany into the Usuthu river in Swazilandkilled many fish (UNEP Geo-2000, Mavimbela1995). In Mozambique, more than 126 factoriesin and around Maputo discharge their waste directlyinto the environment (UNEP Geo-2000,Couto 1995). In Tanzania, textile mills are reportedto release dyes, bleaching agents, alkalisand starch directly into Msimbazi Creek in Dares Salaam (UNEP Geo-2000, Bwathondi andothers 1991).Threats to environmental sustainabilityThe threat to environmental sustainability is duein part to failure to recognize the life-supportingfunctions of ecosystems (terrestrial and aquatic).In fact, the water quantity and quality requirementsof ecosystems are not normally takeninto account in the overall allocation of availablewater resources in much of Africa. Hencethe important role played by wetlands in manyrural economies (for the provision of highlyproductive agricultural land, dry season grazingfor migrant herd, fish, fuelwood, timber needsand medicines) have, until recently, not beenadequately recognized and reflected in nationalwater policies. As a result, such wetlands are increasinglybeing endangered by poor cultivation,deforestation and overgrazing.148