Biodiversity, wetland ecosystems and flood risks: Implications of hydropower expansion on the Magdalena River

SEI, The Nature Conservancy and USAID fact sheet

Author(s): Angarita, H. ; Escobar, M. ; Wickel, B. ; Delgado, J.
Year: 2015

This fact sheet presents the first results of modelling in the Magdalena River Basin in Colombia using new WEAP enhancements to capture large-scale floodplain and wetland flooding processes.

The Mompos Depression in Colombia includes one of the largest wetland systems in the world. Annual large-scale inundation of its floodplains and associated wetlands regulates water, nutrient and sediment cycles – which, in turn, sustain a wealth of ecological processes and ecosystem services that are critical to communities' food supplies, in particular fisheries. However, flooding also poses a serious threat to communities, which are often ill prepared for extreme events.

The Magdalena River Basin has great hydropower potential, and there is a growing interest in making the most of it. A number of large hydropower dams are in advanced stages of planning in the upstream reaches of the two largest rivers (out of four) that converge in the Mompos Depression, the Cauca and Upper Magdalena. While these dams are expected to more than double national hydropower production, the implications for the wetlands and the people that depend on them are highly uncertain.

Aiming to ensure that hydropower development is sustainable and does not disrupt key ecosystems and the services they provide, The Nature Conservancy (TNC) has promoted a basinwide integrated management and planning approach, "Hydropower by Design". As part of this approach, a model of the basin is being developed with SEI's Water Evaluation And Planning (WEAP) system, in collaboration with SEI.

This fact sheet presents the first results of modelling with new WEAP enhancements developed collaboratively by TNC and SEI to capture large-scale floodplain and wetland flooding processes and provide a new way to assess how changes in upstream water resource development practices, including existing reservoir operations and future dam development, could alter these dynamics.

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