142 The Future of Water in African Cities
Selection of Variables The selection of variables included in the 31 cities diagnostic is based on the existing knowledge and practices of IUWM. As defined in the book, IUWM adopts a holistic view of all components of the urban water cycle in the context of the wider watershed to develop efficient and flexible urban water systems. The variables chosen for the diagnostic focus on the aspects of IUWM highlighted in the book and present the main capacities and challenges for IUWM faced by major urban areas in Sub-Saharan Africa. For this exercise, seven different variables were identified that would best represent the challenges and capacities of IUWM faced by cities in Sub-Saharan Africa: urbanization challenges, solid waste management, water resources availability, water supply services, sanitation services, flood hazards in river basins, and economic and institutional strength. Urbanization Challenges One of the major impacts on urban water management is urban growth. Rapidly expanding cities will need sustainable solutions as they face an increase in water demand and expansion of water coverage. Increasingly dense urban areas will also need new planning tools to cope with the future demand of urban services and infrastructure. IUWM presents the opportunity to do things differently and to prepare for the future challenges faced by cities in Sub-Saharan Africa. Solid Waste Management By integrating urban planning with water supply and resource management, IUWM focuses on the linkages between different urban services and their impact on population and the urban waterscape. The lack of solid waste collection and management in urban areas can increase the risk of disease and health problems among the populations directly or indirectly exposed to the waste. Additionally, the lack of proper containment and management of solid waste causes environmental degradation as well as pollution of water resources through seepage and leakage from dumping sites. Poor solid waste collection can also increase urban runoff by blocking inadequately maintained drainage channels during storm events. Water Resources Availability The need to supply water to growing urban populations has to take into account the availability of water resources within the catchment in which the city is located. By considering the close link between water resources in the watershed and urban water demand, IUWM integrates these com-