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December 4, 2023

Rio Rimac: From a Talking River to an Environmental Tragedy

Roberto Young / Lima - El río Rímac y el Cerro San Cristóbal / March 20, 2008 / Uploaded in Flickr / Roberto Young-NonCommercial-NoDerivs 2.0 Generic

A talking river called Rio Rimac: In Lima, Perú the river called “Rio Rimac” or “Talking River”, is famous for its importance to the community and the ancient myth that surrounds it. The myth of this river tells the story of Rimac, who lived next to his father “Inti”, the Sun, and the other gods in the superior world “Hanan Pacha”. Rimac would visit the human world to tell beautiful stories, and the humans loved him. One day, Rimac and the other gods asked his father to liberate the humans from a great drought, and Inti answered that if they wanted to get water, according to the law a god had to sacrifice his life to provide water. Chaclla, one of Inti’s most virtuous daughters, volunteered herself for the sacrifice, but Rimac, who loved his sister, asked his father to take his life instead. Rimac and Chaclla were not able to get to an agreement with Inti, and both decided to sacrifice themselves to break the drought. With their sacrifice, they were both transformed into water, Chaclla becoming rain, and Rimac changing into the busiest river on the Peruvian Coast. The story says that if you pay attention closely to the river, you can still listen to Rimac telling stories.1

A detail drawing of the Rio Rimac, a rock breach and some people visiting it.
Figure 1. Drawing of the Rio Rimac with people visiting.”colección privada”.Ampliación del grabado anterior; vista de Lima, autor desconocido (1863). Copyright: Carlos Andrés Gamero Esparza. 2017.2
Similar to the myth, the present-day Rio Rimac still bustles with activity, yet in contrast to the myth, you cannot lend an ear to hear enchanting tales; instead, you are more likely to hear a tale of sorrow. The Rio Rimac is not just a myth though, is a real basin that starts in the Andes Mountains, and runs for 140 km until it flows into the Pacific Ocean.3 This river has a long history, going back to the pre-Hispanic cultures of the area that used the water from the Rio Rimac to irrigate their crops and had a spiritual connection with it.4 Years later, when the Spain conquistadors formed the Viceroyalty of Perú, they initiated a rapid urbanization process around the river and used the Rio Rimac not just as a water source, but also for dumping waste and, perhaps ironically, as a central attraction for tourism (Figure 1).5  Urban waste contamination has persisted, but now other industries such as mining have affected Rio Rimac. By 1955, the biodiverse river environment that had once included small fish known as silversides and shrimp had disappeared completely.6 In the 21st century, Rio Rimac continues to be contaminated by the mining-metallurgy industry, domestic waste from urban centers, and industrial and agricultural waste.7 Nonetheless, this river is the principal source of water for the province of Lima, the constitutional province of Callao, and the province of Huarochiri, with a 2015 population of almost 6.5 million people.8  

 Mario Chumpitazi.CUENCA RÍMAC EN PELIGRO(Panel-Infografía).Lima, Peru. Ministerio de agricultura (ANA). accessed 2023 Nov 29.
Figure 2. La cuenca del rio Rimac. Mario Chumpitazi.CUENCA RÍMAC EN PELIGRO(Panel-Infografía).Lima, Peru. Ministerio de agricultura (ANA). accessed 2023 Nov 29.9
A tale of sorrow or a tale of joy?: The Rio Rimac has many contaminant sources, and one of the principal ones is the mining industry. Both legal and illegal mining operations have exploited the watershed for lead, gold, and other metals, and by 2014, there were 38 mining wastewater discharges and 13 piles of waste tailings (Figure 2) affecting Rio Rimac.  If that was not enough, by 2014 there were 14 industrial wastewater discharges and even the same population that lives around the river has affected the river they live next to, with almost 500 pipes connected to untreated domestic wastewater (Figure 2). From these three types of contaminants, by 2013 50% out of the 1,184 contaminant point sources were due to domestic wastewater. This situation alarmed the Peruvian National Authority of Water (ANA), and in 2015 they signed a memorandum of understanding with the South Korean government to develop a “Plan Maestro” or master plan to restore the Rio Rimac.10 This 550-page document explains a 10-year plan to develop water resources by building water reservoirs, establishing sewage treatment for industrial and domestic wastes, and restoring the river through flood protection programs.11 Other efforts like this one have helped to restore the river’s health by reducing point sources of pollution from almost 1,200 in 2012 to 722 in 2015, but the domestic wastewater component remains at 50 percent.12 Nevertheless, in 2020 the Rio Rimac unexpectedly showed crystal-clear water and some fauna returned to the river. This occurred due to the quarantine implemented during the SARS-CoV-2 (COVID-19) outbreak, leading to a 90% reduction in waste introduced into the river.13‌ Numerous news reports emerged regarding this incident, with some sources indicating a 30-40% decrease in the use of water purification chemicals.14

Carlos Orlando Zegarra Zamalloa,Pavel J. Contreras ,Laura R. Orellana,Pedro Antonio Riega Lopez, Bivariate map of Social Vulnerability Index and death rate from COVID-19 per 10,000 inhabitants. Lima, Peru.
Figure 3. Bivariate map of Social Vulnerability Index and death rate from COVID-19 per 10,000 inhabitants. Copyright: Figure created by Carlos Zegarra et al. 2022. 15
The improvement in water quality during COVID-19 clearly shows that human activities are closely connected with the health of the Rio Rimac, and continued improvements will require a focus on the populations that live around it. Researchers are working to identify places where the population could be helped, and at the same time, there is significant environmental contamination. For example, researchers have developed a  bivariate Local Indicators of Spatial Association (LISA) analysis to explore geographical connections between different indicators such as biodiversity conservation priorities, social vulnerability, and climate risks. Researchers using multi-objective methods like LISA to examine public data from the southern border region of Texas found spatial relationships between high levels of social vulnerability and high levels of biodiversity. In larger urban areas, however, the research indicated groups of low biodiversity and low social vulnerability.16

The LISA method has also been used in Perú to find areas where social vulnerability links to COVID-19 (Figure 3), and it could also be used to find areas along the Rio Rimac where there are high levels of social vulnerability and groups of domestic wastewater or high levels of solid contaminants. These types of geospatial methods could help to find areas that not only focus help on the socially vulnerable but also help to reduce river contamination at the same time.

A chance for a new tale: In 2018, the Peruvian Ministry of Environment (MINAM) launched a campaign employing motion sensors and speakers that mimicked the voice of the Rio Rimac whenever someone attempted to toss their trash in the river. The aim was to raise awareness among the public, and remarkably, 80% of individuals who heard the simulated voice of Rio Rimac refrained from disposing of their waste in the river. This innovative approach to protecting an endangered environmental resource shows the potentially strong links between cultural narratives and scientific research in developing effective environmental policy.

Rio Rimac has experienced numerous changes throughout its history, marked by both efforts to protect it and actions that worsened its condition. However, the preservation of the river is not the responsibility of a single individual, but rather a collaborative effort involving various organizations. It does not matter if it is a comprehensive action plan to restore the river’s health, an ingenious campaign to sensitize the people, or just someone promoting taking care of it, this river needs all the help possible, and every possible help counts.

  1. Colchado Lucio Ó, Ycaza R. 2015. La doncella que quería conocer el mar: y otras leyendas peruanas. 1a ed. Lima: Ministerio de Educación.Santillana, S.A.,1947-2023. ISBN: 978-612-01-0302-9.
  2. Carlos Andrés Gamero Esparza (leondeurgel). 2017. 22814393_1560804290665015_3971029877622548815_n.accessed 2023 Nov 7.
  3. Lossio J. 2003. Acequias y gallinazos: salud ambiental en Lima del siglo XIX. 1a ed. Lima, Perú: IEP Instituto de Estudios Peruanos (Colección Mínima).
  4. Canziani Amico J. 2012. Ciudad y territorio en los Andes : contribuciones a la historia del urbanismo prehispánico. Pontificia Universidad Católica del Perú. Fondo Editorial.
  5. Aronson J, Renison D, Rangel-Ch JO, Levy-Tacher S, Ovalle C, Pozo AD. 2007. Restauración del Capital Natural: sin reservas no hay bienes ni servicios: Ecosistemas. 16(3).
  6.  Río Rimac, historia del #RíoHablador 🌊📜. wwwyoutubecom.
  7. Guillén G. O, Cóndor Evaristo EV, Gonzáles Torres MA, Iglesias León S. 1998. Contaminación de las aguas del Río Rímac: Trazas de metales. Revista del Instituto de Investigación FIGMMG.
  8. Observatorio del Agua Chillón Rímac Lurín. (2019). Diagnóstico Inicial para el Plan de Gestión de Recursos Hídricos de las cuencas Chillón, Rímac, Lurín y Chilca (p. 151). Lima, Perú.
  9. Ministerio de agricultura (ANA). 2014. CUENCA RÍMAC EN PELIGRO. accessed 2023 Dec 5.
  10. Autoridad Nacional del Agua. 2015. En 10 años se recuperará calidad del río Rímac. Lima, Peru.
  11. K-water, Yooshin Engineering Corporation, Pyunghwa Engineering Consultants.2015.Plan maestro del proyecto de restauración del río Rímac: Informe final. Lima, Peru.
  12. Plan Maestro de Recuperación del Río Rímac. wwwyoutubecom. accessed 2023 Nov 29.
  13. GESTIÓN N. 2020 Apr 21. Coronavirus Perú: Río Rímac presenta aguas cristalinas tras reducción de basura en un 90% durante aislamiento social obligatorio | Minagri | Sedapal | Estado de emergencia nndc | PERU. Gestión.
  14. García Delgado F. 2020 Apr 21. Coronavirus en Perú: el río Rímac se recupera debido a la falta de actividad humana | VIDEO. El Comercio. accessed 2023 Nov 29.
  15. Zegarra Zamalloa CO, Contreras PJ,
    Orellana LR, Riega Lopez PA, Prasad S, Cuba
    Fuentes MS.2022.Bivariate map of Social Vulnerability Index and death rate from COVID-19 per 10,000 inhabitants. accessed 2023 Dec 5.
  16. Zoll D, Lieberknecht K, R. Patrick Bixler, J. Amy Belaire, Jha S. 2023. Integrating equity, climate risks, and population growth for targeting conservation planning. Environmental Science & Policy. 147:267–278. doi:

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