Responding to water-related hazards in Cali

Carlos A. Madera (Universidad del Valle) and Daniel Ascuntar Rios (Local Environmental Urban Authority of Cali City, DAGMA) illustrate the hydro-meteorological hazards affecting the Cali area (RECONECT collaborator), the solutions implemented and the diffusion of the NBS approach in Colombia.

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A view of Cali. Credits: DAGMA

Cali is a tropical city of almost 2.3 million inhabitants, economically based on services and tourism, with an important presence of small and medium industries.

Cali is sunny, warm and windy. It is a water treasure full of birds, crossed by 7 rivers, almost 2.000 water springs and more than 6.000 surface water currents that flow into the valley area. Cali means also salsa music, joy, festivity, cinema and theatre, a special combination within a multi-ethnic and multi-cultural territory.

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Figure 1. CaMeLi (Cañaveralejo, Meléndez and Lilí rivers) basin and bordering basins. Source: Adapted from IDESC — DAPM (2020)

Cali’s land distribution is 21% urban and 79% rural. Most of the rural area hosts National Protected areas, where three main river basins are identified: (i) Cali River, (ii)Cañaveralejo, Meléndez and Lili Rivers and (iii) Jamundí-Pance rivers (Fig. 1).

Many disaster events concerning hydro-meteorological risks, such as flooding, flash floods and landslides, occurred in the past, causing not only economic and social affectations but also fatalities, especially in human settlements near the urban border.

The case included as a RECONECT collaborator is the “CaMeLi” basin, a big area conformed by the rivers Cañaveralejo, Meléndez and Lili, recognized nationally with this name. It displays itself as a strategic part for the whole city’s dynamics, considering that includes almost all the urban area. When a hydro-meteorological hazard affects the city, large chaos reveals, since this area contains nearly all schools and universities, principal hospitals and core transit roads in all directions. Moreover, Cali is the Pacific Ocean capital of Colombia, and the CaMeLi basin is crossed by a strategic corridor that allows transportation and connection with the rest of the country and its neighbours to the south, Ecuador, Peru and onward.

Nature-Based Solutions have received many denominations over time. Some implementations applied in Cali were not necessarily called NBS at the moment, but can be identified as infrastructural designs that combine green and grey infrastructure (Fig. 2, 3 and 4).

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Figure 2. Recovered Isaías Duarte Cancino urban wetland in CaMeLi basin. Credits: DAGMA (2019)

One good example is the urban wetland recuperation. In the last two years, almost 50 hectares of urban wetlands water mirrors have been recovered, places that were absorbed by urban expansion, clogged o landfilled. Restoration of places like these allowed a better comprehension of the hydrological connection between rivers and wetlands, to reduce ecological fragmentation and improve green coverage, by efficiently combining processes of a natural wetland with the city’s dynamics. Also contribute with a better runoff.

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Figure 3. Recovered Limonar urban wetland in CaMeLi basin. Credits: DAGMA (2019) / Figure 4. Recovered Charco Azul urban wetland in CaMeLi basin Credits: Univalle (2017)

There are also examples of potential NBS implementation. The Cañaveralejo river reservoir requires several adjustments to fulfil its risk management purpose and can be projected under the NBS approach. Also, the Melendez river lineal park, where the river was confined with dams that are too close to the water stream, leaving slight room for the river to flow and causing flooding problems on the south of the city. Finally, in the valley area of the CaMeLi basin, natural wetlands on rural soil have been affected by urban expansion and agro-industrial activities, reducing its buffering capacity and fragmenting biological connectivity between the mountains and the valley area. It would be an opportunity of NBS implementation for ecosystem services and co-benefits restoration.

Some of the NBS implementations on Cali began to display ecosystem services that were lost during the urban expansion (Fig. 5, 6, 7 and 8). Some benefits and co-benefits are:

  • Improvement of urban drainage system management, combined with NBS;
  • Flood risk reduction in urban areas;
  • Restoration of biological connectivity;
  • Provision of habitat for biodiversity development;
  • Development of environmental education skills;
  • Social acceptance and participation during NBS implementation;
  • Creation of recreational sustainable activities after NBS implementation;
  • Community appropriation of NBS recovered sites;
  • Municipal acceptance of NBS for developments plans of the city.
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Figure 5. Birdwatching on Charco Azul recovered wetland / Figure 6. Biodiversity returned to Charco Azul urban wetland in CaMeLi basin / Figure 7. Biodiversity hatching on recovered wetlands / Figure 8. Environmental education on recovered sites. (Images credits: DAGMA 2019)

Stakeholders from different levels from government, society and academic take part in the selection, design and implementation of NBS. The Universidad del Valle-Univalle as an academic actor and the Cali urban environmental authority (DAGMA) are the most involved stakeholders. Other sectors have joined, such as Risk Management, Public Utilities, Planning and Housing, water company, community and local organizations. In the future, many other stakeholders will be added, like regional and national environmental authorities, health and social protection, etc.

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Cali, Melendez River. Credits: DAGMA (2019)

Colombia is a tropical country with excellent environmental conditions for NBS, such as wide biodiversity, large photoperiods along the year, extensive sun radiation, several natural wetlands, among others. We are on the way to strengthen the data system information, the database of climate conditions and the legislation of the country to allow the NBS implementation.

The awareness of Colombia society about environmental degradation and the effects of the natural/man-made disasters is increasing. Likewise, the government at different level (national, regional, local), settled the regulations and legislations that allow NBS.

As mentioned before, NBS have received many denominations throughout time. Colombia has advanced towards sustainability by applications that may not have been conceived as NBS, but their results are similar. Colombia has environmental policies and legislation that promote and allow the use of natural conditions to reduce risk situations like floodings and flash floods. To be more effective, coordination is needed to embrace this concept and insert it on planning instruments that allow its articulation at all levels: national, regional and local level.

In this context, the academic and scientific sectors play an important role, working on the theoretical and applied research and innovation, taking into account the environmental, cultural, social, political and legal context of the country. In this sense, support and alliances with partners around the world could be important.

Universidad del Valle based in Cali-Colombia, trough EIDENAR School and CINARA Institute of Engineering Faculty has been working in the water sector for more than 40 years. Univalle has historical and long cooperation with IHE institute (RECONECT coordinator) working in research, development and academic projects as partners. Locally, Univalle participated in different initiatives and has cooperation with the government, environmental authority, social organizations, NGO and community. In this context, DAGMA as a local authority is working together with Univalle in several water-related projects.

Taking into account the main purpose and objectives of RECONECT, Univalle and DAGMA decided to join the project as International Collaborators, meaning that we can be aware of all developments and innovations that partners of the project produce. According to the local context of Cali, we can use these outcomes for our local problems with the support of international experts. This is a win-win situation, where we can contribute with our experience and learn from the multidisciplinary RECONECT team at the same time. Finally, there is potential for upscale insights from RECONECT project outcomes in guidelines and regulations that can contribute to Colombia and Cali institutional organizations for NBS implementation.

The RECONECT project demonstrates the effectiveness of Nature-Based Solutions for hydro-meteorological risk reduction in rural and natural areas www.reconect.eu

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