Variations across cities in Africa, Asia and Latin America.
Left: a distribution of the urban population across different parts of a city in Africa, Asia and Latin America (LatAm). The average sparseness in Asia is only 3.5, whereas the average sparseness in Africa is 6.9, which is nearly twice as high. The three models for urban form expansion considering the impact of population growth: compact, persistent and horizontal expansion. To obtain the effect of urban expansion, we assume that the population and constructed surface of the city double, with the only difference being where the city’s footprint expands, as indicated by the predicted probabilities in Fig. 5. For the three scenarios, cities expand radially from the center, as in Fig. 3. Estimated share of the urban population with access to piped water and sewage in Africa, Asia and LatAm, considering cities with twice the population. Three forms of urban expansion are analyzed. One is where the urban expansion is from the city center through infill development, one where urban growth follows the current population distribution and one where expansion is mostly horizontal. Right: the sparseness (horizontal axis) and tariffs paid for 15 m3 of water40 and mean proximity to critical infrastructure (vertical axis). The water tariffs are influenced by a variety of factors, including scarcity, availability of infrastructure and local economic conditions. Moreover, tariffs do not correspond with affordability, and there are significant disparities in affordability across and within cities.
[8/8] L’accès à l’eau dépend surtout de l’urbanisme. Une ville compacte est plus résiliente, moins coûteuse à équiper et limite la pression sur les marges écologiques. La géographie urbaine devient donc un levier décisif pour sécuriser l’accès à l’eau.
#geography #urbanform #wateraccess