Puzzle or chess? Looking at the role urban rivers in Latin America play in terms of waste management
Photo via Rios del Planeta
Latin American rivers are some of the most polluted in the world. High levels of urbanization are both the cause and recipients of the consequences of the lack of urban waste management.
Figure 1. Source: Author.
Polluted rivers have become a major issue all over the world. Research from Helmholtz-Centre for Environmental Research (UFZ) states that 95% of the plastic pollution in oceans around the world comes from 10 rivers- shown in Figure 1. However, no Latin American river was included in the UFZ study, which led me to wonder what the situation of the region in terms of rivers’ pollution actually is. The investigation from UFZ highlighted the population scale related to the waste scale, the quality of waste management in cities, and the acknowledgement of waste flows and water flows as crucial points in understanding rivers’ pollution.
Based on the first criteria, I chose 3 of the most populated cities in Latin America to explore what their situation is in terms of waste management and the role that their rivers play in such a process. Despite the different geographical settings in which Mexico City, Bogotá, and Buenos Aires are located, I use them as examples of similar ways in which Latin American cities have been dealing with their waste. The roots of these management strategies must be tracked to different periods and decisions made throughout the history of each city.
Water in Latin America
Despite being a region with abundant water resources, Latin America is also known as a thirsty region due to the low access to drinking water for millions of people. Additionally, Latin American rivers are some of the most polluted in the world. High levels of urbanization are both the cause and recipients of the consequences of the lack of urban waste management. The following sections illustrate key case studies for the region:
Mexico City, Mexico
Figure 2. Left image: Mexico – Tenochtitlan 16th Century. Right image: Mexico City current state. (Source: Bibiana Monsavais)
In Mexico City, we must consider not just the visual differences seen through the city’s expansion (seen in Figures 2 and 3) but also the decisions made to produce such changes. The Spanish colonial period led to transformations such as draining the main lake as well as the existing network of canals in order to establish a new city. At the end of the 1950s, due to flooding issues and the tradition of using urban rivers as toilets, places to dump waste, and washing places, the city authorities decided to tube most urban rivers through big concrete pipes, in order to isolate and conduct rain and wastewater outside the urban area. Today, Mexico City has flooding and hygiene under control but faces water scarcity as a result of its growing population and the way water bodies are managed in the city.
For instance, only 20% of the Magdalena River, one of the city’s water sources, is used for water supply. The rest is used for sewage or as a rubbish dump. Another example is the Piedad River, a piped river for which designers, urbanists, and environmentalists have proposed interventions to open the pipe and integrate the river to the urban ecosystem and landscape; however, its 15km are currently used as sewage. There are around 45 piped rivers under the city, presumably in similar conditions, following the principle of “let waste go with the river”.
Bogota, Colombia
Figure 3. Beyond the city scale, the Bogota River pours thousands of tons of pollution every day into the Magdalena River, one of the main rivers of Colombia. It used to be the main link between the north coast of the country and Bogota which means pollution is transferred to many other sites. The importance of this river either for Colombia’s history or biodiversity is recorded in texts written by Gabriel García Marquez and Alexander von Humboldt. (Source: Mónica Páez Pérez and María José Castillo Ortega. Tangrama, 2014)
The history of the Bogotá River can be described as a history of pollution. This river has had a key role in the clearance of urban waste since colonial times. Subsequently, during the modernization of Bogotá, and as the Colombian capital’s population increased, so did water demand and urban waste. The provision of water to a higher amount of people reduced its availability for waste removal which means waste remained in the city. This situation led to public health issues, between 1910-1920, such as a significant rise in death rates caused by typhoid fever and dysentery.
Around 1970, with a much higher population and, as a result, waste generation, pollution of the Bogotá River became a political and public issue. In the 1990s city authorities outlined a strategy for river sanitation, focusing on the use of technology to treat the pollution. Now, the river’s pollution transcends its own scale. This still-polluted water has been used for decades to irrigate farming as well as for livestock located in Bogotá’s outskirts along the river, which might result in transferring toxic content to the food sources of inhabitants. Currently there are plans, that will be funded by the World Bank, to expand one of the main wastewater treatment plants to improve the current situation.
Buenos Aires, Argentina
Figure 4. The quality of the urban waste management along the affluents that converge at Rio de la Plata also has to be understood. For instance, Asunción, Paraguay, is the only capital city in South America with no wastewater treatment plants, which means the contribution of the Paraguay River to pollution from urban waste might be higher. Yet, the scale of settlements along the river might also play an important role to consider. (Source: Author, based on Rios del Planeta)
Buenos Aires, and in particular the Río de la Plata, is an example of transboundary pollution in waterways, similar to the situation experienced along the Rhine River in the 1980s. Even though Rio de la Plata’s high level of pollution is considered a biological danger in Argentina, a wider geographical scale must be analyzed to be more accurate. As seen in Figure 5, Rio de la Plata’s main effluents correspond to rivers which officially belong to neighbor countries in the north of Argentina such as the Paraguay River, the Paraná River (Brazil) and the Uruguay River. Agrochemical and urban waste are common elements found in these waters, which are produced by the settlements along their ways before gathering at Rio de la Plata basin.
Additionally, the way Buenos Aires uses the Riachuelo River on a city scale as a waste dump leads it to be thought of as one of the most polluted waterways in Latin America, which also at its final stage pours its water into Rio de la Plata, bringing more pollution into an already polluted water body. This situation is considered as Argentina’s never ending environmental disaster.
Puzzle or chess?
Although cities are seen as places in which virtually nature stops, these examples show how high dependency of urban areas for water is not just for drinking purposes, but also to deal with urban waste. Clear patterns of colonial and modernist views of water have led these cities to their current outcomes, in which rivers are seen only as pieces of a big puzzle with determined functions and impact areas. Urban rivers should instead be approached as a sort of chess game, as a strategic matter in which the role, movement, and influence of every piece must be understood, so that cities can be planned accordingly.
The examples of Mexico City, Bogotá, and Buenos Aires lend the image of rivers and urban planners playing different games in terms of urban waste. Keeping the “let waste go with the river” model for longer is unsustainable and shows the extent to which water bodies are understood as isolated pieces in cities. The Latin American situation for plastic pollution in rivers might be just better than those rivers drawn on figure 1, but if further pollutants are considered, then this analysis concludes that the thirsty region still does not know how to play with its water sources.
Thanks to Ailed Perez in Mexico and Myriam Heredia in Argentina for their tremendous support for writing this article.
Mauricio Estrada is a Colombian architect that holds a M.Sc. in Integrated Urbanism and Sustainable Design from the University of Stuttgart in Germany. Currently he works for the Leibniz Institute for Regional Geography in Leipzig, Germany, where he focuses his research in analysing nature-based solutions and their implications for urban development and environmental justice across different cities.