Appendix 2 145
Urbanization Challenges While population growth and urbanization are major drivers for change in Africa, indicators had to be at city level to make sense for this particular variable, which restricted the selection of indicators. The six indicators chosen (see Appendix 3) complement each other by illustrating both quantity and quality of urbanization challenges. The first four indicators quantify past, current, and future city growth in relation to national population growth, while indicators five and six quantify current city population in terms of pressure on urban infrastructure by looking at density and the share of population living in informal areas. Indicators for quantifying current and projected city population growth, as well as city density, came from relatively homogeneous sources (see Appendix 3). However, the last indicator (percentage of city population living in informal areas) came from a variety of sources and years, which leads to discrepancies in the data in terms of validation, definition, and consistency. Solid Waste Management It is solid waste collection and disposal, or more precisely the lack thereof, that impacts infrastructure efficiency by clogging drains, leads to health issues, and aggravates the effects of extreme weather events in a city. We looked for indicators that determined the lack of solid waste management both at household and business levels (primary collection) and municipal level (secondary collection). This corresponds to indicators seven and eight respectively (see Appendix 3). From this, the proportion of solid waste that does not enter the formal disposal chain can be derived and utilized for integrated urban planning. The lack of a single and comprehensive global source for solid waste management at city level for all 31 cities presented a problem, which restricted the number of indicators for this variable, and impeded efforts to quantify informal waste disposal more rigorously. Furthermore, the data used still presents some inconsistencies; for instance, data sources rarely indicated whether the percentage collected is on a wet or dry basis. Water Resources Availability As IUWM goes beyond the limits of the city and includes the water resources available for the city within a wider geographical context, water resources indicators were selected to encompass the following: • Past and current water supply from precipitation (indicators 9 and 10) in the basin from which the city derives its water supply. These indica-