MANAGEMENT OF URBAN WETLANDS IN LATIN AMERICA AND THE CARIBBEAN

Mexico City is home to a population of 9 million, with the metropolitan area growing to over 23 million. Located more than 2,000 meters above sea level, the city faces poor air quality, frequent flooding, and severe water shortages.

The restoration of Lake Texcoco, located on the founding site of ancient Tenochtitlán, began in 2018 following the cancellation of a large-scale airport project that would have occupied 5,000 hectares and threatened to dry up the last vestige of water northeast of Mexico City.

Until the 1950s, it was still possible to stroll along freshwater canals in Xochimilco and enjoy the large bodies of saltwater in Texcoco. However, urban growth transformed the lake into a flood regulator and a wastewater dump, with the most degraded land used for solid waste disposal. Thus, Texcoco became a marginalized and forgotten place, far from the financial center and surrounded by urban settlements.

Texcoco Lake, México City. Photo of the map taken by the author.

In 2018, the new administration decided to cancel the airport project and turn it into a large ecological park, presenting it as an effort of environmental and social justice. Following this decision, the water resumed its natural course, and in 2021 a huge recovery of the bodies of water was observed.

The restoration project focuses on identifying large floodable areas on saline and alkaline soils, conducive to the development of unique wetlands due to their physical-chemical characteristics. These salt water bodies have a pH of up to 9 or 10, creating a halophytic lake habitat of high ecological relevance. In addition, with the return of large vegetated areas and water bodies, exposure to suspended particles that seriously affect health is minimized, especially PM10 and PM2.5, which can damage the respiratory system.

Following the identification of landscape units–including factors such as soil types, vegetation cover, water depth, plant-animal interactions, among others—the National Commission of Protected Natural Areas (CONANP) incorporated a total area of 14,013 ha, designating it as a protected natural area and Ramsar site.

Currently, some areas of the park have been opened for recreational and sporting activities; however, much remains to be done to fully restore this emblematic ecosystem.

Bogotá, with approximately 8 million inhabitants and a territory of 163,000 hectares (75% of which is rural), has been promoting the restoration of its wetlands for more than 20 years. Many of these ecosystems were on the verge of disappearing due to human activity. It is estimated that at the beginning of the 20th century, Bogotá had more than 50,000 hectares of lakes and wetlands, while today only 901.43 ha remain–approximately 1.80% of the original area.

Thanks to the mobilization of citizens and organizations, 17 wetlands have been designated as nature reserves. Since 2002, the protected area has increased from just 10 hectares to 900 hectares in 2023. In 2018, 11 of these wetlands were designated as Ramsar sites under the name “Urban Wetlands Complex of the Capital District of Bogotá.”

This achievement has been the result of continuous effort. Citizen mobilization in defense of wetlands began in 1993, and in 2007, the local government adopted the first public policy for the protection of wetlands, which consolidated citizen demands with the support of academia and official institutions, and remains in force, favoring the coordination of efforts for their conservation.

Tibabuyes Wetland by Jorge Emmanuel Escobar / humedalesbogota.com

An emblematic case is the La Vaca wetland, which was very close to disappearing in 2002 and by 2023 had almost 10 hectares recovered and protected. Bird diversity is a good indicator of recovery: in 2002, fewer than 10 species were reported, while today there are 85.

There is no doubt this has been a significant step forward, with ups and downs, but overall, these actions have improved the quality of life for both biodiversity and the people who live in this city.

Jorge Emmanuel Escobar, Director of the Bogotá Wetlands Foundation (2024)

At the end of 2021, the Development Bank of Latin America and the Caribbean (CAF) established the BiodiverCiudades Network, an initiative for “the identification, structuring, and financing of sustainable, high-quality, high-impact urban interventions, based on people and biodiversity” in our region. This initiative is implemented in collaboration with the Humboldt Institute and the United Nations Human Settlements Programme (UN-Habitat).

Two cities in the network, Luján in the province of Buenos Aires (Argentina) and Sobral in the state of Ceará (Brazil), are incorporating wetlands as a fundamental part of their urban water security projects. CAF financed these projects through credit operations and plans to provide continuous technical and financial cooperation to local governments to mainstream biodiversity into their urban development projects.

CAF is currently funding the Prodesol program in the city of Sobral (Brazil). Among the interventions proposed in the sanitation component, the installation of filter gardens in the tributary streams of the Acaraú River, the main watercourse in the urban area of Sobral, stands out. These gardens contribute to its decontamination through purification systems that incorporate natural elements to improve water quality, using aquatic plants, stone and sand to treat wastewater, while avoiding the use of chemicals. Sobral is home to the largest filter garden in a public area in Brazil. In addition to their positive impact on the aquatic ecosystem, the gardens improve public spaces, creating an environment for recreation and sports. The presence of wildlife serves as a strong indicator that these gardens are successfully integrated into the natural ecosystem.

Filter gardens in the municipality of Sobral in Brazil. Author: CAF

On the other hand, through the loan “Implementation of the Integrated Management Plan for the Luján River Basin” in the province of Buenos Aires (Argentina), CAF supports the construction of a network of sewage collectors, pumping stations and an effluent treatment plant with a system of artificial wetlands. This intervention will collect, transport and treat the effluents of the inhabitants of the town of Olivera, in the Luján District, to gradually reduce the diffuse sources of contamination of the soil, the aquifer and the surface water in the area, which currently suffers from absorption wells.

The wetland will have a system of emergent macrophytes that root in the substrate, with a stem in the water column and aerial leaves and flowers, generating a vertical subsurface flow. The macrophyte species selected for this project is the reed (Phragmites australis), although the use of Typha domingensis, tested in previous studies on the Paraná River, is also viable.

These interventions demonstrate CAF’s commitment to the design and implementation of projects that integrate urban wetlands as an essential part of water security in cities. The BiodiverCiudades Network promotes the crucial role of biodiversity in generating co-benefits for Latin America and the Caribbean local authorities. These interventions not only create habitat for biodiversity and improve water quality, but also increase green areas in public spaces, offering recreational and sporting opportunities for residents.

This summary was compiled by Alejo Ramírez Cione, Coordinator of the CAF BiodiverCiudades Network, with contributions from different technical areas of the bank in September 2024.

Ad Gr / humedales Vado Rio Putana / Shutterstock.com

In Chile, community-based environmental organizations play a fundamental role in the protection of wetlands, actively participating in their legal recognition¹ since 2020, when the urban wetlands law was enacted². According to the YEW registry (2023), there are at least 21 organizations focused on wetlands in Chile, of which about 76% have significant youth participation³.

Youth have become agents of change through Communication, Education, and Public Awareness (CEPA) programs⁴, engaging in activities of biodiversity monitoring and ecological restoration. Outstanding initiatives include:

• The “Participatory Community Water Monitoring Network”⁵ initiative (2022-2024), led by the Manzana Verde Foundation, has trained more than 170 certified water quality monitors, including students, teachers and youth organizations, using the Global Water Watch water monitoring methodology.
• The environmental education program “Red de restauradores”⁶ (2023-2024), run by El Árbol Foundation, has implemented 11 school programs (18 sessions each), assisting 246 children from eight educational establishments in communities severely affected by forest fires.
• The LCOY Project⁷, aimed at sharing Chilean youth perspectives on climate change through the
  “National Youth Declaration on Climate Change” (2023), was created by 70 volunteers and involved
  over 600 young people.

These initiatives not only transmit knowledge and raise awareness among young people, but also strengthen social capacities for the management, restoration and environmental governance of wetlands.

Rodrigo Toledo-Román, American regional representative at Youth Engaged in Wetlands (YEW), 2024.

1. Barrios, C. (2021, 4 de agosto). Organizaciones socioambientales ingresan expediente de los humedales Pichimapu y Estero Cárcamo de Concepción. Periódico Resumen.
2. Ley de humedales urbanos 21.201. (2020, 23 de enero). D.O. 42.560.
3. Elaboración propia. (2023). Catastro organizacional en las Américas (no publicado).
4. Convención sobre los Humedales. (2015). Resolución XII.9: Programa de la Convención de Ramsar sobre comunicación, fomento de capacidad, educación, concienciación y participación (CECoP) para 2016-2024. Secretaría de la Convención.
5. Fundación Manzana Verde. (s. f.) Datos obtenidos por medio de comunicación directa a través de redes sociales.
6. Fundación El Árbol. (2023). Memoria 2023.
7. LCOY Chile. (2023). Declaración nacional de la juventud sobre cambio climático.