Session 11. 2.

The boundary between the formal waste collection system, managed by the official sector, and the informal system, led by independent collectors, is blurred. However, the coexistence of these two systems ensures the collection of all waste in the Metropolitan area of Mexico City, forming a complex urban order marked by tacit rules, controversies, and diverse practices. This system constantly adapts to survive, but increasing regulations, field challenges, and competition among collectors threaten its balance and make it vulnerable to collapse.

The study defines this system as hybrid and, through mapping practices, identifies the various waste collectors to reveal the vulnerabilities of the system in the analyzed areas.

The methodology relies on extensive field research conducted between 2021 and 2024, combining tools from social sciences, such as direct observation and comprehensive interviews, with urban planning techniques like mapping, photo/video analysis, and on-site surveys.

The cross-analysis of qualitative data and theoretical concepts identified the street as a key network in waste management, where (in)formal collectors, (non-)valuable materials, and individual or collective actions shape the urban order. This mapping highlights the system’s vulnerabilities and suggests that the territorialization of (in)formal practices prompts a reconsideration of the sustainability of hybrid systems like that of Mexico City. The study also shows that collecting qualitative data is a powerful planning tool, supporting the development of anticipatory plans to prevent a potential collapse of the waste collection system.

For decades, the inhabitants of Dakar have been affected by the consequences of rapid urbanization. Particularly in the urban periphery—referring to the transitional area between cities and rural zones, which serves multiple roles such as housing migrants, agricultural production, and absorbing environmental impacts (Simone, 2010)—changes in the waterscape are occurring. Dakar's periphery is characterized by dunes and lowlands, threatened by groundwater and stormwater excesses. Hereby, it pushes urban planning strategies to improve drainage and sanitation services and to tackle environmental challenges like drought, flooding, and water pollution.
In this paper, two cases of fluctuating waterscapes in the urban periphery exemplify the potential for both abandonment and reclamation of urban spaces. The first case—situated in the department of Rufisque—explores informal flood defenses and drainage systems in low-lying areas, adapted or built by local communities. The second case—situated in Pikine—reveals flooding and seasonal water pollution by addressing communal wells and irrigation systems to manage water for urban agriculture, demonstrating resilience and resourcefulness, particularly during the dry season.
In these cases, the dual role of water as both a threat and a resource is thus central to the adaptability of anticipatory practices at the local level. The paper aims to discuss these cases reflecting the notion of "anticipatory politics"—the preparing for and responding to future uncertainties—introduced by Simone (2010). Reinforced by literature recognition, communities establish unofficial means of navigating the urban environments through social networks and informal platforms to fill the gaps left by inadequate urban planning (Benjamin and Brudney 2018, Ostrom 1973). The cases aim to explore how communities in low-lying areas construct informal flood defenses and drainage systems. Forms of acceptance and resilience demonstrate adaptation as they build water drainage systems to autonomously handle flooding issues.

Water management is proving to be a major challenge for our urban environments: soil sealing, land cover, climate change, demographic pressure are some of the drivers exacerbating water urban challenges from North to South. Despite the peculiarity of each urban context (social, economic, topographic, …) and the diversity of water related risks that have to be tackled, a methodological challenge is shared among these contexts: how to reframe social and administrative scales of intervention within hydrographic territorial rationales?

This contribution focuses on the description and analysis of socio-spatial water geographies of Kinshasa (DRC) experiencing an increasing pressure of hydrogeological risks (e.g. landslides and flooding) due to fast paced and unplanned urbanization accentuated by more recent climate change effects. The sub-watershed of the Bumbu River, a tributary of the Congo River, nested in the dispersal urbanization, is taken as a research ground for a trans scalar analysis aiming to link the human scale of local practices to the hydrographic scale of river basin. Despite his central position within the geography of Kinshasa, the valley is weakly connected to the public utilities and his water management system is sustained by hybrid forms of governance: based on the participation of several actors from public and private domain.

Following a nine-month period of immersive field research through three years, and drawing on a variety of representation tools (cartographies, sketches, pictures & videos), the contribution aims to develop a methodologic approach starting from storytelling of collective and personal water trajectories. Acknowledging the inadequacy of the local "Urban Plan" to deal with complex urban dynamics (i.e. demographic explosion and land occupation) and to tackle social and environmental injustice in the context of a sub-Saharan African metropolis, the research intends to focus on the management of water resources (rain water, underground water) as urban commons capable of shaping place-based solidarities as well as place-based conflicts at different scales.

In contrast with diffused geographies of socio-spatial injustice at the urban scale, local carto-graphic chronicles are presented as counter-geographies challenging the socio-ecological spatial gaps within the city. In this sense, the study and description of the specific spatiality of hydro-social narratives embedded in the urban territory of Kinshasa constitute a first step towards the recognition of the systemic relations structuring its specific urbanization.

Both top-down, state-driven planning in the Global North and bottom-up, informal practices in the Global South have proven inadequate for addressing contemporary urban challenges. A promising hybrid alternative lies in the principle of the urban commons, which advocates for the collective management of shared resources by its community of users, supported by multilevel institutional frameworks. However, bridging the gap between these approaches within complex urban settings remains a significant challenge.
Drawing from personal research experiences in Brussels, Belgium and Yaoundé, Cameroon, this presentation illustrates the limitations of dominant governance models in both contexts when addressing large-scale urban transitions, particularly in waste and water management, mobility, and social infrastructure. It emphasizes the importance of Northern cities learning from contexts where self-production and self-management of the urban environment occur on a large scale.
By comparing the methodologies developed to address challenges in these two contrasting settings, the presentation also identifies emerging convergences and complementarities. In both cases, adopting a multiscalar approach in both descriptive research—such as the combination of urban-scale mapping and in-depth on-site surveys—and prospective research—such as the integration of Research Through Design, prototyping, and action research—is crucial for driving social learning processes aimed at fostering the urban commons.