In the Name of Justice: The Case of Riverine Dwellers and the Restoration of the Matanza Riachuelo River, Argentina

Abstract

The Matanza Riachuelo River in Buenos Aires—long considered one of the world's most polluted waterways—became the focus of a landmark 2006 Supreme Court ruling mandating its restoration in the name of environmental justice. This article examines how that mandate unfolded through the lens of political ecology and environmental justice. Drawing on ethnographic research, we show how judicial orders and technocratic planning translated global imaginaries of "green corridors" into local interventions, as state actors interpreted and operationalized notions of risk and justice in ways that often displaced riverine dwellers. These interventions deepened inequality by neglecting residents' territorial ties, everyday practices, and right to remain. We highlight how technocratic planning sidelined vulnerable populations and how communities resisted through claims to rootedness and in situ re-urbanization. Building on Latin American scholarship, the article demonstrates that restoration framed solely as ecological repair risks reproducing social inequities. We argue that river restoration must embrace governance frameworks that center affected populations, integrate ecological goals with social equity, and advance justice as recognition, participation, and distribution.

Resumen

El río Matanza Riachuelo en Buenos Aires—considerado durante mucho tiempo uno de los cursos de agua más contaminados del mundo—fue objeto de un fallo histórico de la Corte Suprema en 2006 que ordenó su restauración en nombre de la justicia ambiental. Este artículo analiza desde la perspectiva de la ecología política y la justicia ambiental cómo se implementó ese mandato. A partir de investigación etnográfica, mostramos cómo los mandatos judiciales y la planificación tecnocrática tradujeron imaginarios globales de "corredores verdes" en intervenciones locales, mientras los actores estatales interpretaban y operacionalizaban nociones de riesgo y justicia de formas que a menudo desplazaron a los pobladores ribereños. Estas intervenciones profundizaron la desigualdad al ignorar los vínculos territoriales, las prácticas cotidianas y el derecho a permanecer. Destacamos cómo la planificación tecnocrática marginó a poblaciones vulnerables y cómo las comunidades resistieron mediante reclamos de arraigo y procesos de reurbanización in situ. Inspirados en la literatura académica latinoamericana, el artículo muestra que una restauración concebida solo como reparación ecológica corre el riesgo de reproducir inequidades sociales. Sostenemos que la restauración fluvial debe centrarse en las poblaciones afectadas, articular objetivos ecológicos con equidad social y promover justicia como reconocimiento, participación y redistribución.

Introduction

River restoration has become increasingly popular due to its multifaceted benefits for ecosystems, communities, and climate resilience. Restored rivers help revive biodiversity, improve water quality, and provide critical habitat for aquatic and terrestrial species (Palmer et al., 2005; Wohl et al., 2015). From a societal perspective, river restoration enhances flood protection, boosts recreational opportunities, and can even increase property values (Bernhardt & Palmer, 2007; European Environment Agency, 2019). Additionally, it mitigates the impacts of climate change by improving water retention in droughts and floodplains during heavy rains, thus building resilience against extreme weather (Skidmore & Wheaton, 2022). River systems that are free-flowing and naturally functioning are better equipped to provide essential services such as groundwater recharge and pollution filtration (Stanford et al., 1996; Wohl, 2020). Legislative drivers, like the European Water Framework Directive, and a growing public awareness of the ecological and economic value of healthy rivers, have further fueled this movement globally (European Environment Agency, 2019).

River restoration has also been done in the name of environmental justice. The restoration of the Matanza Riachuelo River Basin in Argentina represents a significant case of addressing environmental justice through legal, political, and community-driven efforts. Historically, this river basin has been one of the most polluted in the world, primarily due to unregulated industrial activity and inadequate waste management, which have disproportionately impacted marginalized communities living nearby. These communities suffer from severe health issues such as lead poisoning and respiratory diseases due to exposure to toxic contaminants (Barber, 2024). In 2004, local residents initiated a legal battle against the government and industrial polluters, culminating in a landmark 2006 Supreme Court decision that mandated comprehensive restoration of the river in the name of environmental justice. This judgement led to the establishment of the Matanza Riachuelo River Basin Authority (Autoridad de Cuenca Matanza Riachuelo [ACUMAR]), an interjurisdictional authority tasked with coordinating restoration activities and implementing pollution control measures. The project has included the construction of wastewater treatment plants and hydraulic tunnels and the restoration of the riverbanks to improve water quality and reduce the health risks associated with contamination (Barber, 2024).

This article unravels the political ecology of a river restoration project aimed at addressing pollution in the basin. It mainly focuses on the restoration of the Matanza Riachuelo's riverbank within the City of Buenos Aires, where a towpath was cleared as part of the initiative. The project was part of a broader restoration program intended to improve residents' quality of life and reduce climate-related risks with a sufficient and reasonable degree of predictability (Instituto de Vivienda de la Ciudad, 2019).

Political ecology research on river restoration highlights the complex interplay among social, ecological, and economic factors, framing restoration as an inherently political process shaped by governance structures and power dynamics. For example, restoration projects are shaped by the strategic-relational actions of state actors, who balance ecological goals with economic imperatives under neoliberal governance frameworks (Jessop, 2007; Robertson, 2015). Governance systems often overlook marginalized voices and fail to address historical inequalities, revealing a significant gap in participatory justice (Sánchez-Soriano et al., 2024). Even more striking is the displacement of marginalized communities that can result from restoration projects. Political ecology contributes to this discourse by emphasizing how gender, race, and class intersect to influence environmental management. It also critiques the limited inclusivity of mainstream restoration approaches and calls for the integration of diverse knowledge systems and equitable participation (Clement et al., 2019; Elias et al., 2021; Sundberg, 2017). Under the concept of "hydrosocial territories" (Boelens et al., 2016) there is now an increasing understanding of these complex socionatural systems compounding human and non-human agencies.

Despite this progress, gaps remain in understanding the everyday practices of state agents acting at different institutional levels and their role in shaping outcomes, as well as in creating governance frameworks that address systemic inequalities and legitimize pluralistic values (Clement et al., 2019; Ranganathan & Balazs, 2015). Empirical research addressing these issues could significantly enhance the equity and transformative potential of river restoration efforts.

The Matanza Riachuelo River Basin (MRRB) case in Argentina illustrates the scale dynamics of these promoted "solutions" and how they shape environmental conflicts. The case reveals the politics, inequality, and powerful networks influencing them. The MRRB continues to face serious social and environmental challenges, including industrial and agro-industrial contamination, frequent flooding, urban sprawl into wetlands, a housing deficit, and the growth of both gated communities and informal settlements or villas-informal settlements or urban slums common in Argentina, marked by infrastructural neglect and socio-legal marginalization-in high-risk areas, many of which lack secure tenure, basic services, and water and sanitation infrastructure. This case also underscores significant gaps in research related to long-term governance frameworks and the socio-political dynamics of interjurisdictional cooperation in urban river restoration efforts. Furthermore, incomplete implementation, weak accountability, and the now waning political will have hindered progress, casting uncertainty over the basin's recovery (Barber, 2024).

This case highlights the intersection of environmental degradation and social inequity, demonstrating how environmental justice requires integrating technical solutions with equitable governance and community empowerment. In this process, different environmental injustices occur at different spatial scales. To illustrate them, we will pay attention to how the imaginaries on river restoration internationally promoted by the sustainable development discourse (Ríos, 2023) played a defining role in relocating dwellers living on the Matanza Riachuelo riverbank in Argentina. As Swyngedouw (2011) argues, this discourse depoliticizes by advancing universal ideals without a clear political subject, thereby sidelining local agency and contestation. We argue that in territorializing these imaginaries-internationally and locally promoted by an epistemic community (Haas, 1992; Rodríguez de Francisco & Boelens, 2015)–the State unfairly claimed back the river's margins from the riverine dwellers and, therefore, "adapted" the MRRB and its population to the conditions required by the international environmental discourse.

We begin by outlining the theoretical framework that underpins our analysis, providing a foundation for understanding the key dynamics of this case. In particular, we draw on the lens of political ecology to explore how power dynamics and governance failures have shaped outcomes, as seen in the MRRB restoration project in Argentina. This framework highlights the displacement of marginalized communities and systemic inequities exacerbated by top-down interventions, such as the clearing of riverbanks to establish green spaces. Next, we detail the methodology, emphasizing its reflective nature. This approach includes insights from direct engagement with riverine dwellers, capturing their lived experiences and challenges during the relocation process. We then present an in-depth case study, highlighting the historical, legal, and socio-political context of the Matanza Riachuelo River restoration, including judicial interventions that framed communities as "obstacles" rather than stakeholders. This is followed by a discussion of our findings, examining their broader implications for environmental justice and governance frameworks. Finally, we conclude with a summary of insights and practical recommendations, advocating for inclusive and equitable decision-making processes that address both ecological and social justice dimensions (Ranganathan & Balazs, 2015; Sundberg, 2017).

Defining the lens of inquiry

Political ecology conceptualizes hydrosocial territories as dynamic spatial configurations shaped through the interaction of water flows, infrastructures, governance systems, and socio-cultural practices (Boelens et al., 2016). These territories are not neutral or fixed; rather, they are the contested outcomes of historical and ongoing power relations over water access, control, and meaning. From this perspective, river restoration cannot be understood as a purely ecological or technical intervention. It is a politically charged process, deeply embedded in social hierarchies, economic interests, and the relational entanglements between humans and non-humans (Boelens et al., 2023). Empirical cases reveal how restoration practices aligned with dominant political and economic agendas often facilitate the displacement of vulnerable populations under the rationale of ecological rehabilitation (Porto-Gonçalves & Leff, 2015; Robertson, 2015).

Displacement, framed as an environmental necessity, frequently reproduces existing inequalities. Affected populations, particularly those residing in informal settlements along riverbanks, are subjected to forced relocation without adequate compensation or resettlement options, leading to intensified social exclusion and marginalization (Clement et al., 2019; Kaufmann et al., 2021; Sundberg, 2017). Environmental justice, as an integral dimension of political ecology, offers a multidimensional analytical lens for examining the socio-environmental implications of restoration (Osborne et al., 2021; Svarstad & Benjaminsen, 2020). The distributive dimension interrogates the allocation of benefits and burdens, revealing how restoration projects disproportionately impact marginalized communities (Walker, 2012). Procedural justice emphasizes the importance of inclusive and participatory governance structures, yet in many contexts, the voices of affected communities remain peripheral to formal decision-making processes (Toxopeus et al., 2020). Recognition justice concerns the acknowledgment and respect for diverse epistemologies, cultural identities, and historical relationships to place, which are frequently overlooked or undermined in technocratic planning frameworks (Agyeman et al., 2016; Ranganathan & Balazs, 2015).

Conventional restoration paradigms often rely on universalized, technocratic models that are designed for replication and scale rather than situated adaptation. These approaches marginalize local knowledge and lived experience, reproducing forms of exclusion under the guise of ecological progress. In contrast, Viveiros de Castro (2019) offers a compelling anthropological critique of this logic by distinguishing between "models-for" and "examples-of." He argues that models function as normative templates imposed vertically, enforcing standardization and control, whereas examples emerge horizontally as situated responses that adapt to specific socio-ecological conditions. This perspective aligns with efforts to reimagine restoration as a plural and contingent process, one that makes room for diverse modes of coexisting with damaged ecologies rather than prescribing homogenized futures. Recent scholarship strengthens this conceptual orientation: Osborne et al. (2021) propose a multiscalar, relational framework that embeds environmental justice within restoration planning. Their work emphasizes the need to align ecological outcomes with social equity, recognizing the co-constitution of ecological and political processes.

Looking at the practical implementation of justice-oriented restoration, Moran et al. (2019) and Smardon et al. (2018, 2019) argue that restoration must acknowledge rivers as cultural and relational spaces, rebuild social-ecological ties disrupted by degradation, and institutionalize participatory governance capable of addressing entrenched power asymmetries. In addition to participatory inclusion and cultural recognition, the spatial and social distribution of restoration benefits and harms remains a critical concern. Projects implemented in low-income or historically marginalized areas must guard against environmental gentrification and ensure that investments contribute to long-term social repair and equitable access to ecosystem services (Merlinsky, 2013; Moran et al., 2019). These concerns are echoed by Osborne et al. (2021), who stress the need to restore land tenure rights and rectify historical injustices, particularly in Global South contexts.

The concept of environmental risk must also be problematized within this framework. Risk is often defined in narrow technical terms, yet, as Merlinsky (2013) contends, it is socially constructed and reflects deeper structural inequalities. The absence of essential infrastructure, insecure housing, and socio-economic precarity all shape the experience and distribution of environmental risk. In such contexts, restoration initiatives that fail to address these underlying conditions may inadvertently reproduce the very injustices they purport to resolve. This dynamic is echoed by Olejarczyk (2021), who shows how environmental risk operates as a flexible category mobilized by both institutions and residents in relocation processes in the MRRB, often reflecting institutional logics more than lived vulnerability.

In sum, this conceptual framework reconceptualizes river restoration as a relational, political, and ethical practice. It calls for a shift from managerial approaches to ones rooted in both material equity and procedural legitimacy. In the case of the Matanza Riachuelo basin, environmental justice must be under-stood as inherently territorial and social, tied to the right to remain, to participate meaningfully, and to shape the conditions of collective life. Political ecology and environmental justice together provide a rigorous foundation for imagining restoration not merely as ecological repair, but as a transformative process aimed at dismantling historical injustices and fostering inclusive, regenerative futures (Merlinsky, 2013; Porto-Gonçalves & Leff, 2015; Ranganathan & Balazs, 2015).

Methods

This article is based on ethnographic research focused on the institutional dynamics and territorial effects of river restoration and housing relocation processes in the MRRB. The research is grounded in a collaborative autoethnographic project conducted between 2015 and 2021, in which one of the authors participated alongside colleagues from institutions directly involved in relocation plans and researchers from the University of Buenos Aires (Carman et al., 2022). Building on this foundation, the study employs a qualitative ethnographic methodology, including participant observation, semi-structured interviews, and document analysis. Fieldwork included notes from public hearings, workshops, neighborhood meetings, and informal conversations with residents, public officials, and civil society actors. In total, the study incorporates eight interviews with riverine dwellers and two with professionals from the Public Defender's Office, complemented by site visits and participatory observation in several neighborhoods. Additionally, the research draws on public documents, institutional reports, judicial records (including the Mendoza ruling and proceedings in Federal Court No. 2 of Quilmes and Morón), and successive versions of ACUMAR's Integral Sanitation Plan (Plan Integral de Saneamiento Ambiental, PISA).¹ The ethnographic orientation follows Mosse's (2004) insight that policy cannot be understood merely as a set of rational plans to be implemented, but rather as a field of contested practices, shaped by institutional dynamics, social relationships, and situated negotiations over meaning and legitimacy. In this sense, tracing how justice and risk were interpreted, operationalized, and contested on the ground required an embedded, multi-scalar, and reflexive approach.

In 2013, the first author joined the social team responsible for relocating people living on the riverbank as a member of the City Housing Institute (Instituto de Vivienda de la Ciudad [IVC]). Afterward, she worked at the ACUMAR as Director of Territorial Ordering for four years (2016–2020) with part of the team. In her role, she oversaw a technical office responsible for managing relocation processes, assessing environmental risks, and collaborating with multiple levels of government and residents in the basin to develop policies and instruments aimed at mitigating risks. This positionality allowed for an embedded ethnographic perspective that was not only grounded in proximity to affected communities, but also in direct participation in the institutional routines, internal conflicts, and discretionary spaces where policy was interpreted and enacted. As Mosse (2004) suggests, understanding policy requires tracing how meaning is produced within implementation itself, where practitioners do not simply apply pre-existing rules, but actively negotiate, reinterpret, and often contest the goals and logics of official mandates.

This multi-scalar and layered methodology make it possible to examine not only how environmental governance is formally structured, but how it is enacted, negotiated, and resisted by those affected by its interventions.

The matanza riachuelo river basin (mrrb)

The spatial and historical evolution of the Riachuelo basin helps illuminate the long-standing entanglements between environmental degradation, urban expansion, and social inequality in Buenos Aires. The map below shows the general boundaries of the MRRB and its location within the metropolitan region (Figure 1).

Its upper stretch was called "Matanzas" after the indigenous Querandíes confronted the Spaniards during colonization, while the lower stretch that flows into the Río de la Plata was called "Riachuelo". The surroundings of this last stretch were chosen for both foundations of the city by Pedro de Mendoza (in 1536) and Juan de Garay (in 1580).

The river functioned as a natural port for ships (Defensoría del Pueblo de la Nación, 2003) and gradually began to be used as an open-air waste system for the tanneries, slaughterhouses and salting plants that were set up along its banks. By the middle of the nineteenth century, its state was critical and the authorities tried the first responses to pollution, for example, the prohibition of dumping waste from the slaughterhouses into the river in 1830 and 1860 (Defensoría del Pueblo de la Nación, 2003, pp. 22–23). With the yellow fever epidemic in early 1871, the saladeros, early meat-salting facilities that processed cattle for export during the nineteenth century, on the Riachuelo were blamed for causing the disease, and the Congress of the Province of Buenos Aires voted in favor of their eradication.

Between 1860 and 1930, Argentina became increasingly integrated into the global economy as a major agro-exporter, supplying meat, wool, and cereals. This export-led boom spurred significant infrastructure development along the Riachuelo River and drove industrial expansion (Defensoría del Pueblo de la Nación, 2003, p. 16). In response, the government initiated the first major efforts to channel, straighten, and dredge the river. Two new ports –Puerto Madero and Dock Sud– were also constructed to support the growing volume of trade.

The floodplains of the Riachuelo were occupied by immigrants, contributing to the growth of the city. Most of them worked in industries and activities related to the port. At that time, there had been a series of floods that seriously affected the possibilities of living there (Defensoría del Pueblo de la Nación, 2003, p. 26). During the Second World War, Argentina began a process of import substitution and there was a greater concentration of industries and services on the banks of the Riachuelo, which brought new migrants from rural areas seeking new jobs to Buenos Aires. Many of these families could not access the formal land market and the tenements in Buenos Aires were insufficient. Consequently, in 1940, working-class families began to occupy vacant land on the banks of the river, built their own houses and formed shantytowns that lacked basic services, giving rise to the so-called villas miseria (Verbitsky, 1957).

Figure 1.

Map of the Matanza Riachuelo Basin and main tributaries (Source: produced by Luca Rosasco for the authors).

During the last civil-military dictatorship in Argentina (1976-1983), a plan to eradicate the villas was carried out in Buenos Aires, which drastically reduced the population living in slums by transferring them to the provinces or countries of origin without any housing compensation (Snitcofsky, 2018). Once in democracy, the housing policies changed and by the end of the twentieth century, state housing programs consisted mainly of regularizing property rights and improving housing and urban quality (Di Virgilio et al., 2013).

In terms of environmental policies, the 1994 constitutional reform declared the right to a healthy environment and, in 2002 and 2003, Congress passed the first laws on the use and regulation of natural resources. These years witnessed the emergence of several social movements organized around reversing and preventing the damage that the economic model was causing to the health of the population and ecosystems. This gave rise to a new environmentalism in the country, which led to interventions in the Matanza Riachuelo case (Gutiérrez & Isuani, 2014) in search of the longed-for "sustainable development".

The matanza riachuelo environmental conflict

The Riachuelo has been the focus of extensive research addressing various dimensions of the conflict that emerged following the 2008 judicial ruling by the Argentine Supreme Court (Corte Suprema de Justicia de la Nación [CSJN]) (see Auyero & Swistun, 2008; Carman, 2017; Carman et al., 2022; Caruso & Ríos, 2021; Maldonado, 2019 Merlinsky, 2013; López Olaciregui, 2019; Olejarczyk & Demoy, 2017; Olejarczyk, 2021; Ríos & Caruso, 2021; Schmidt, 2019). However, little analysis has been undertaken of the influence that international environmental discourse had on the MRRB case and the environmental justice effects on the ground, such as the evictions and relocation of dwellers living on the riverbank. The promotion of ideas of sustainable development changed the imaginaries about river basins and riverbanks² (Ríos, 2023) in such a way that the riverbanks turned into spaces that needed to be controlled by the State, transformed and restored as close as possible to what they "naturally" used to be.

In 2004, a group of neighbors from Villa Inflamable, an informal settlement in Dock Sud, Province of Buenos Aires, presented a lawsuit at the CSJN against the national government, the government of the province of Buenos Aires, the government of the city of Buenos Aires and 44 private companies. They accused all these actors of damage caused by the contamination of the Matanza Riachuelo River. The lawsuit was based on the right to a healthy environment recognized by the Constitution in 1994. Known as the Mendoza case, it is the most significant environmental litigation in Argentina's history (Gutiérrez & Isuani, 2014).

Following the lawsuit and several representations by NGOs and the Ombudsman, the CSJN issued its first ruling on the case in 2006. Grounded in the constitutional right to a healthy environment, the Court stated:

Protecting the environment implies fulfilling the duties that every citizen has with respect to rivers, biodiversity, surrounding soils, and the atmosphere. These duties correspond to the fact that citizens have the right to enjoy a healthy environment for themselves and future generations, since the damage one causes to collective goods is ultimately damage to oneself. The improvement or degradation of the environment benefits or harms the entire population, as it is a good that belongs to the social and transindividual sphere, hence the particular urgency with which judges must act to enforce these constitutional mandates.

(Corte Suprema de Justicia de la Nación, 2006, June 20, Consideration 18; authors' translation)

The CSJN ordered the national, provincial, and Buenos Aires City governments to submit a joint plan within 30 days to begin the remediation of the river. In 2006, the ACUMAR was created under the National Secretariat of Natural Resources and Sustainable Development. This interjurisdictional body includes representatives from the national, provincial, and city governments. Together, they submitted the first remediation plan for the MRRB, which was subsequently challenged by NGOs, the Ombudsman's Office, and independent experts. As a result, the CSJN issued its final ruling in 2008, assigning responsibility for the river's remediation to the three levels of government and requiring ACUMAR to develop a new integral sanitation plan (PISA). The plan was to meet several objectives, including the obligation to clean up and transform the riverbank areas into green spaces (Corte Suprema de Justicia de la Nación, 2008, July 8, Consideration 17.V). However, the ruling did not specify how these goals should be operationalized, and they were later translated into concrete action items in the revised PISA.

The CSJN was just one of several organizations that aimed to transform the riverbank into a green space and manage its maintenance. Even before the final Court's decision, various plans were proposed by the Executive Committee of the river, the City of Buenos Aires, universities, and NGOs to create a riverine park on the Riachuelo's borders. Some plans included reforestation of the riverbank areas for urban environmental restoration, while others focused on cleaning up the riverbanks or creating an urban nature park to attract real estate investment (Defensoría del Pueblo de la Nación, 2003). Another NGO proposed turning the riverbank into an "Integrated Area for Conservation and Sustainable Development" under the form of a "Natural Park," "Green Corridor," or "Biological, Historical, or Tourist" area (see for example Fundación Ciudad, 2002). The first PISA also recommended cleaning up and reforesting the riverbanks (Autoridad de Cuenca Matanza Riachuelo, 2007, p. 106).

All these initiatives took into account the existence of one or two specific villas on the riverbanks –but never all of them– and proposed consolidating their urban development to integrate them into the city. This proves that none of these actors actively promoted the eviction of riverine dwellers that happened later; on the contrary, they were all willing to integrate villas into the city. However, the prevailing idea was that the riverbank should be turned into a green corridor or a riverine park as part of the restoration of the river basin, in line with other international projects like the Thames in London or the Rhine in Germany, which by this time were international models. They functioned as an epistemic community of the sustainable development discourse without foreseeing the possible injustices that occurred later in the riverbank's transformation. These plans and proposals were changing the river's imaginaries by emphasizing the need for its restoration, which helped create the conditions for future evictions.

In the ruling of July 2008, the Court also designated Federal Judge Armella to ensure the implementation of the commitments. Everyone feared Judge Armella because the CSJN had granted him the power to impose fines for non-compliance with the deadlines of his mandates. Backed by these powers, he too defined how to implement the ruling. In 2009, he invoked an old feature of the Civil Code–the towpath (camino de sirga in Spanish)–to territorialize the mandate to clean up the riverbanks. The towpath refers specifically to the area of land with a width of 35 meters parallel to the river (Carman et al., 2022).

In its original legal definition, the towpath imposes a restriction on property rights, requiring the area to remain free of construction to ensure public access to the riverbank. However, the federal judge extended this mandate beyond cleaning up the towpath, and further promoting its transformation into a multi-purpose green corridor. Initially, the justification was to prevent water contamination from potential illegal dumping (Juzgado Federal de Primera Instancia de Quilmes, 2009, July 7). Later, the objectives expanded to include recreation, landscape enhancement, and even international tourism (Juzgado Federal de Primera Instancia de Quilmes, 2011, October 31).

In the 2009 resolution, the judge stated:

Let the Matanza Riachuelo River Basin Authority know that within 15 days it must submit a report detailing the planned actions for the definitive eradication of informal settlements (…) so that the stated objective of "cleaning the margins of the river" is achieved, along with any other works currently being obstructed.

(Juzgado Federal de Primera Instancia de Quilmes, 2009, July 7; authors' translation)

Judge Armella requested that ACUMAR measure the towpath and ensure that any obstacles were removed. The new territory, the towpath, needed to be monitored and turned into a new linear park. Furthermore, the government was instructed to relocate all riverbank dwellers according to a prescribed plan. Any individuals living on the 35-meter strip were eligible–or not– for the new housing policy that was created for this purpose. Those living within the demarcation line were either part of a recognized villa or were an independent household on the riverbank. The conditions for these individuals varied: those living in officially recognized villas within the towpath were to be relocated to social housing and those independent households on the towpath were to be removed; the former became a beneficiary of the new housing policy while the latter became an obstacle for the construction of the towpath.

As part of the territorialization process, soon after the Judge's Resolution in July 2009, ACUMAR measured out an area 35 meters wide along 20 kilometers of both banks of the river in the lower basin and identified the riverine dwellers as "obstacles" in the updated PISA required by the judiciary. Also, the City of Buenos Aires presented an urban project for the area, which was the result of a national contest of ideas,³ and announced that 50 legal notices were to be issued to industries and riverine dwellers to vacate the area of the towpath, focusing on the illegal occupation of the riverbanks (Autoridad de Cuenca Matanza Riachuelo, 2010, p. 155). Ironically, the city justified these actions as "humanization" and improvement of public space (Autoridad de Cuenca Matanza Riachuelo, 2010, p. 156).

In 2011, after ACUMAR and the City showed little progress in clearing the towpath, Judge Armella recognized the difficulties, especially in removing the "obstacles", so he released a new resolution and declared the whole basin as a "critical zone of special protection" with an environmental towpath. Together with the declaration, he mandated the immediate eviction of the obstacles (Juzgado Federal de Primera Instancia de Quilmes, 2011, March 28). The resolution had severe consequences on the dwellers' lives. In Carman's words, "This legal sanction –the line in front of or behind which life can be lived– creates the 'affected' [by the towpath], and at the same time brings, as we shall see later, unforeseen and contradictory consequences" (2017, p. 46).

The court's mandate realized: relocation and spatial reconfiguration

The Supreme Court's ruling on the Matanza Riachuelo case set in motion a series of institutional responses that reconfigured the river's urban banks (Figure 2), with far-reaching consequences for the populations residing there. Central to this process was the enforcement of the towpath clearance and the implementation of the PISA, coordinated by ACUMAR. This section traces how the Court's mandate was operationalized through relocation protocols, urban planning, and interinstitutional coordination, revealing how legal orders were materialized in the territory and how they reshaped the lived geographies of vulnerable communities:

It ruled that due to pollution and everything and because they wanted to build the [tow]path, the people who lived by the Riachuelo had to… they had to relocate, I am not sure if that's how it is put. Because it is an unhealthy place because of the pollution and also because we are impeding the [tow]path, the one that they wanted to make also, I do not remember if it was… they said 15 meters, 20 meters from the riverbank they wanted to make this [towpath] road, as they had already done to neighbors who were on the Luján, further ahead. I don't know why they did it. One of the things must be so that people would not come back, but I don't know, they did it…. it's kind of touristy, I don't know why, it looks nice but…

(Riverine dweller of Villa 26; interview, 2018, authors' translation)

In order to explain the consequences of the decision, we will focus on the relocations that occurred when the towpath was cleared between 2011 and 2016 in the southern area of Buenos Aires City, specifically in Villa 21-24, Villa 26, and the Padre Mugica and Luzuriaga housing complexes, where some of the riverbank dwellers were relocated. The enforcement of the Judge's ruling in Buenos Aires was the responsibility of the center-right coalition starting in December 2007. The IVC was tasked with relocating those who lived near the river and created a dedicated unit for this purpose.

According to the first census conducted by IVC, 1837 families⁴ from various informal settlements on the towpath had to be relocated. However, the first actions taken by the city government were evictions of the families living on scattered plots of land along the edges of the Riachuelo or as independent households. It was easier for the local state to displace families from scattered settlements than from more populated, dense and organized villas.

In December 2010, Judge Armella conducted an inspection of the Riachuelo riverbanks and observed three precarious informal dwellings near Alsina Bridge on the city's riverbank. He informed ACUMAR and the City of Buenos Aires that he would return

Figure 2.

Demolition area and relocation boundary in Villa 21-24 (Barracas, Buenos Aires)(Source: Scharager (2021, p. 226), adapted by Luca Rosasco for the authors). Original map by Dirección General de Desarrollo Habitacional – IVC. (Note to print readers: See the online version for a color map).

in three months for another inspection to verify the "definite eradication of the shanty dwellings and constructions." The Judge justified these actions by arguing that:

(…) environmental protection finds its effective purpose in respect for human dignity (…) To a greater extent, it is worth highlighting that we are before a mega objective of environmental character whose foundations are sustained in our constitutional law and the international norms (…) in this respect such understanding finds its obligatory cause in the person of the officials who hold the great responsibility of guiding the destinies of the inhabitants.

(Juzgado Federal de Primera Instancia de Quilmes, 2010, December 13; authors' translation)

The Judge ordered the first round of evictions without requiring the local administration to guarantee housing alternatives. The City of Buenos Aires carried out the orders and demolished the homes of families living on the Riachuelo riverbanks. The judicial files referred to these families as sueltitos, a term used for individuals who were not associated with any specific villa. The typical consequences of resettlement, such as uprooting, were compounded by the fact that these families had no information about why and how they were being forced to leave their homes. Such evictions had a particularly devastating effect on children and disabled individuals. Many affected families ended up homeless or living in worse conditions than before.⁵ Only after the intervention of the Ombudsman and the Public Defender did the IVC relocate some of the families to social housing in 2013. One of the affected individuals, Alberto, who lived near the Alsina Bridge, shared his experience in his own words:

A judge in Quilmes came up with the idea of removing everyone from the Riachuelo path or something. They wanted to make the river cleaner and they never did it. I wish.…I had the right to stay and go to the river to fish. I would have liked to be left there, next to the Riachuelo. If I wasn't bothering anyone, I wasn't screwing anyone, I was just there in Alsina Bridge. There were only three little houses. Do you know how Dario [from the Public Defender's Office] called us? He called us 'los sueltitos'.

(Riverine dweller in Alsina Bridge; field notes, 2015, authors' translation)

The relocation of Villa Luján, El Pueblito and Magaldi, all relatively small settlements, came later. Unfortunately, these relocations were done without spaces for participation and access to information. Many families were informed only a few days before the relocation; others found out through listings stapled on public lamp posts in the villa. Families had to move into unknown apartments that were often unsuitable for their family size and were far from their original homes. No meetings were held to organize the families or provide information on what to expect in their new neighborhood. As a result, relocated families had complaints about the size of the apartments and the lack of nearby social services, such as community kitchens, hospitals, and schools. These apartments were not planned with an understanding of the types of economic activities that the families engaged in for subsistence purposes in their homes in the original villa. For example, people would work doing repairs, painting, brass works, and carpentry in their front plots, activities that were no longer possible in an apartment. Once moved, the IVC did not follow up with the families or assist them. Thus, the relocation was not an integral planned process; it was reduced to a short intervention that removed people and their possessions in a couple of days. During this period, riverine dwellers were treated in accordance with a dominant logic that viewed them as obstacles to restoration, rather than as people with rights (Carman et al., 2022).

Things changed when IVC had to confront "obstacles" that were much more organized and resisted the compulsory and compulsive displacements in different ways, as in the cases of villas 21-24 and 26. Other key factors were relevant to the move away from that first modus operandi. During 2012, there was high judicial pressure on the IVC for not complying in time with the mandate of clearing the towpath. In the meantime, the now former Judge Armella was accused of corruption and subsequently removed from office. The new Judge Rodríguez approached the case in a more sensitive manner. Additionally, there were allegations from the Public Defender's Office that the housing policy was being implemented without considering or acknowledging the opinions of the riverine dwellers, which was a violation of their rights.⁶ These factors were pivotal in the case reaching a turning point. Calls for a genuine participatory process by dwellers, supported by the Public Defender's Office and NGOs, were finally heard by the IVC. The authorities understood that an authori-tarian process would likely be ineffective in clearing the towpath (Carman et al., 2022; Maldonado, 2019).

Consequently, in 2013, the IVC recruited new officials to handle the relocation processes on the riverbank. One of the authors was part of this team of four workers. After a group of riverbank dwellers protested on the streets of the IVC offices, the meetings with them and other stakeholders resumed. As social workers, we opposed the IVC's previous relocations⁷ and we were able to leverage our position as intermediaries between civil servants and riverine dwellers. We referred to this interinstitutional space as the "trench" (Olejarczyk & Demoy, 2017) and occupied it as a privileged but challenging workspace, navigating between the dwellers' skepticism and the public servants' pressures to speed up the clearing of the towpath. Nonetheless, this was our most valuable asset in dismantling the dominant relocations that had occurred so far and redirecting them towards more democratic practices.

Just before the change of government in 2016, we made significant progress by getting a protocol approved. The protocol established the framework for a comprehensive and participatory relocation process.⁸ It took three years of intensive work, and we drew upon past relocations to improve future processes. The fear of a new government potentially undoing our minimum achievements motivated us to collaborate with riverine dwellers, social organizations, researchers, and Public Defender's Office workers to develop the protocol. Additionally, it served as a precedent for the future protocol we would create two years later for the whole river basin⁹ in ACUMAR.

By July 2024, only 40 percent of the planned housing relocations to safer locations had been undertaken by the authorities, while the long-anticipated completion of a sewerage system initiated in 2016 is still pending (Barber, 2024). At the end of 2024, the CSJN concluded its supervision of the Riachuelo River pollution lawsuit after over 15 years, as its active involvement in the case led to a structural reform that was necessary to align the actions of the State with the environmental rights enshrined in the Constitution. ACUMAR will proceed with its physical cleanup efforts without Court oversight (Barber, 2024).

Discussion

The restoration of the MRRB highlights the intricate and often contentious relationship between environmental restoration, social justice, and economic development. As demonstrated by this case study, political ecology offers crucial insights into the power dynamics that shape restoration projects, emphasizing the need to balance ecological goals with the rights and needs of marginalized communities (Boelens et al., 2023; Jessop, 2007; Robertson, 2015). This framework critiques mainstream restoration practices for systematically excluding local and informal knowledge systems, forms of knowledge that embody the lived experiences of the communities most affected by environmental degradation (Ranganathan & Balazs, 2015; Sundberg, 2017). In response, this study engages with the framework of environmental justice to analyze how knowledge, participation, and the distribution of costs and benefits were addressed in the MRRB. This framework aligns with broader theoretical contributions that emphasize the interplay between environmental and social justice, particularly through the lenses of recognition, participation, and distribution (Agyeman et al., 2016).

A key issue in the MRRB restoration has been the use of judicial mandates and top-down governance strategies, such as the clearing of the towpath. These efforts, though ecologically motivated, often excluded riverine dwellers from decision-making processes, reinforcing the misrecognition of these communities framing them as obstacles rather than as legitimate stakeholders (Sánchez-Soriano et al., 2024). As Osborne et al. (2021) argue, justice in restoration must address recognition, participation, and distribution. Yet, in the MRRB community voices were often sidelined, and displacement decisions neglected cultural and territorial ties. Framing these residents as uniformly exposed to environmental risk and therefore relocatable concealed the structural urban inequalities–such as lack of drinking water or sewage infrastructure-that actually shaped vulnerability. Justice, then, is not inherent to relocation itself, but to whether communities are granted voice, permanence, and rights in the places they inhabit.

The vision of transforming the riverbanks into a "green corridor"–inspired by international models like the Thames or the Rhine–reflects how global environmental discourses often prioritize sanitized aesthetics over the lived realities of local populations (Tsing et al., 2019; Vidal, 2008). These projects typically operate through what Viveiros de Castro (2019) calls "models-for", that means prescriptive templates meant to be replicated across contexts, often detached from the particular socio-environmental conditions they are applied to. In the case of the MRRB, this logic translated into a vision of restoration that privileged uniform solutions over situated responses. Rather than allowing locally grounded "examples-of" alternative futures to emerge, riverine communities were expected to adapt to preconfigured notions of order and cleanliness. This undermined the legitimacy of existing social ties to the river and reinforced top-down spatial planning logics. As Porto-Gonçalves and Leff (2015) remind us, dominant environmental models often travel embedded in global epistemologies that marginalize alternative territorial rationalities, particularly in Latin American urban peripheries.

One reason for the limited emergence of alternative imaginaries in the MRRB process lies in how participation was institutionally framed. Residents were not invited to envision futures beyond the choices already defined by judicial and technical actors. Participatory mechanisms were generally confined to implementing pre-established relocation plans, rather than challenging their legitimacy. Nevertheless, some openings occurred. A notable case is that of an upstream riverside settlement that successfully resisted relocation; residents challenged the official designation of environmental risk and asserted their right to remain, ultimately leading to a plan for in situ reurbanization, the upgrading and formal integration of an informal settlement through infrastructure, services, and legal recognition. This community engaged in the drafting of ACUMAR's 2018 protocol, which established rootedness as a guiding principle and required that environmental risk be properly justified in relocation processes (Ruete & López Olaciregui, 2024). Rather than replicating a top-down template, this process followed the logic of what Viveiros de Castro (2019) would describe as "bricolage": an adaptive and collaborative effort built from past failures, situated knowledge, and community engagement. Similarly, some riverbank dwellers expressed desires to remain near the river, fish, and sustain their livelihoods. These are grounded perspectives that challenge dominant assumptions about risk and displacement and illustrate how more open-ended participatory methodologies might have enabled alternative visions of justice to emerge.

This case also exemplifies what Merlinsky (2020) has described as the productive dimension of environmental conflict. While judicialization imposed significant constraints, it also triggered institutional innovation, community resistance, and new definitions of environmental risk. Although limited in scope, the disputes around relocation and participation led to the creation of protocols and practices that challenged the dominant logics of technocratic restoration.

While the severity of public health conditions in the MRRB is undeniable, and "toxic uncertainty"¹⁰ (Auyero & Swistun, 2008) remains a defining feature of environmental governance in the area, it is important to differentiate between environmental risk as defined by proximity to the river and the material conditions that actually generate vulnerability. In many riverside villas, the most serious threats to health stem not from direct contact with pollutants in the river, but from poor urban conditions: lack of drinking water, inadequate sewage infrastructure, overcrowded housing, and accumulated solid waste. These dynamics highlight how the MRRB must be understood as a hydrosocial territory (Boelens et al., 2016), where risk is co-produced through socio-technical, spatial, and political configurations, not merely through exposure to ecological hazards. Framing these residents as uniformly exposed and therefore relocatable conceals these structural inequalities and forecloses other possibilities, such as in situ reurbanization. As Olejarczyk (2021) argues, environmental risk is not a neutral or fixed condition, but a contested category shaped through legal and institutional frameworks, often disconnected from the lived conditions of vulnerability on the ground. Urban planning could have envisioned access to the river with its residents, not in their absence. Justice, then, is not inherent in relocation itself, but in whether communities are granted voice, permanence, and rights in the territories they inhabit.

Ultimately, the MRRB case illustrates both the challenges and possibilities of aligning ecological restoration with social justice in fragmented governance contexts. The displacement of riverine dwellers and the limited scope of participatory processes reflect broader tensions in top-down restoration initiatives, which often prioritize global sustainability goals while disregarding local socio-political realities (Jessop, 2007; Swyngedouw, 2011). Future frameworks must be not only ecologically effective, but also attentive to territorial histories, community agency, and the complex politics of place.

Conclusions

The MRRB case serves as both a cautionary tale and a guiding example for how to integrate environmental justice into river restoration projects. Judicial interventions, while important, cannot be seen as a panacea for addressing the complex social inequities that often accompany ecological restoration. The case underscores the importance of developing governance frameworks that are not only legally robust but also genuinely inclusive and participatory, allowing marginalized communities to shape the restoration process and its outcomes (Clement et al., 2019).

To ensure more equitable and effective river restoration projects, future efforts must consider both ecological and social dimensions. By embedding principles of recognition, procedural equity, and distributive justice into the governance of these projects, we can move beyond a model of restoration that prioritizes ecological goals over social justice. Moreover, the shift from globalized "models-for" to locally relevant "examples-of" can help tailor restoration practices to the singularity of each territory, recognizing the multiplicity of knowledge systems and the rights of local communities (Tsing et al., 2019; Viveiros de Castro, 2019). The MRRB case shows that restoration framed as environmental justice can deepen dispossession if it ignores the ontologies, attachments, and political claims of affected communities. A justice-based restoration must begin with, not just include, those most impacted.