Magdalena River Basin (Colombia)
The Magdalena Basin is Colombia’s principal watershed located in the central part of the country, going through the Andinas region. The total size of the basin area is around 273,459 km2 covering 24 percent of the national territory (including 19 of 32 Colombian departments, Figure 3). The catchment constitutes the most important region of the country due to their economic and environmental value. The watershed inhabits about 75% of Colombian population with a density of 130 people/Km2, and urbanization rate of 77%. It produces 86 % of the country’s gross domestic product (Nature Conservancy, 2017). Agriculture and fishery are the major economic activities in the basin followed by construction, industry, transport and mining activities.
Figure 1: Political Boundaries - Departments.
(Source of data: IGAC. http://www.ideam.gov.co/web/siac/catalogo-de-mapas)
Agriculture and fishery
75 % of the nation’s agricultural production is allocated in the Magdalena Basin. Rice, corn, sesame seeds and sorghum belong to the mainly grown products (Pontificia Universidad de Valparaíso (2015). Large part of agriculture and livelihoods production takes place in the Momposina Depression. The types of agriculture regimes range from small-sized farms to medium-scale private holdings.
The basin system contains more than 226 native fish species and at least 16 that undertake reproductive migration from the low floodplain to the foothills of the Andes. This richness and high species endemism, in addition to the proximity to main human settlements, has made the river the country’s main and most productive fishery, which is based on at least 40 species (Angarita et al., 2018).
Currently Magdalena River Basin provides 70 % of Colombia’s hydropower, equivalent to 49% of the country’s electricity supply. Medium and large hydropower plants have a total capacity of 6.89 GW. The remaining hydroelectric potential of the catchment is estimated at 35GW (Departamento Nacional de Planeación, 1979). By 2050, electricity use in Colombia is expected to increase by between 105 and 147% with respect to 2010 ) (Angarita et al., 2018). In order to ensure the energy security there is a great interest in developing the remaining hydroelectric potential of the Magdalena catchment. A number of large hydropower dams are currently under development or in an advance stage of planning.
The expansion of hydropower may cause substantial cumulative environmental impacts. Hence there is a huge demand for scientific based studies to assess the impacts of hydropower development on the environment and other water users.
With above 150 MT/ year the Magdalena River is a world-class river, in the top 10 in terms of sediment load and the most significant contributor to the Caribbean Sea. The sediment load and morphological structure of the basin makes today river navigation very limited (Chavez, 2015). However, the river has a huge potential to improve the transport infrastructure in Colombia. Strategic economic centers such as Barranacabermeja and Cartagena, main producers of oil and coal are located in the basin. The mouth at the Caribbean Sea provides connections with international waterways.
Hence, the national government of president Santos initiated 2014 an infrastructure project called “Recovering Navigability in the Magdalena River” with the investment of $1.3 billion and 13-years project time. The project aims in restoring the navigability of the Magdalena River and promoting an integrated transport network using roads, rails, rivers and air (Latin American Association of Ports and Terminals, 2014).
Angarita, H., Wickel, A. J., Sieber, J., Chavarro, J., Maldonado Ocampo, J. A., Herrera-R, G. A., Delgado, J., Purkey D. (2018) Basin-scale impacts of hydropower development on the Mompós Depression wetlands, Colombia. Hydrology and Earth System Sciences (2018) 22, 2839–2865, DOI: 10.5194/hess-22-2839-2018.
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Chavez, L. E., (2015) Paper 75 - The threats and challenges in navigating the Magdalena river. Smart Rivers 2015, http://www.pianc.org.ar/_stage/pdf/papers_sr2015/75_paper_ChavezPerdomo_COL_7.pdf.
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U.S. Agency for International Development (2017), ENV - Ecosystem-Based Adaptation in the Magdalena River Basin, https://www.usaid.gov/news-information/fact-sheets/env-ecosystem-based-adaptation-magdalena-river-basin.