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

The document examines how increasing the Degree of Regulation (DOR) through hydropower dams in the Magdalena River Basin affects the Mompos Depression. While current regulation is low, the addition of 30 planned projects could increase the DOR from 5% to 30%, significantly altering seasonal and low flows critical for biodiversity. The analysis finds that these dams would not protect against extreme floods, as safety releases during peak flows are necessary, and that reducing lateral connectivity via levees could increase peak flows downstream in cities like Barranquilla.

• The Mompos Depression is a tectonic basin covering approximately 32,198 km², representing 11.8% of the total Magdalena basin area, and is characterized by high biodiversity, including over 200 indigenous fish species.
• Colombia's planned hydropower expansion is concentrated in the Magdalena basin, which already provides 70% of the country's hydropower. In addition to 26 existing reservoirs and two under construction, 30 large projects are planned for the next decade, which could add 7.64 GW of installed capacity.
• The Degree of Regulation (DOR) upstream of the Mompos Depression is estimated at 5% of average annual runoff based on 2010 storage capacity; however, completing all 30 planned projects would increase the DOR to approximately 30%.
• High levels of hydropower regulation (30% DOR) are projected to reduce seasonal flows and virtually eliminate low flows during dry months, which could severely impact ecosystem functions, fish and bird reproduction, and riparian vegetation.
• Hydropower dams are unlikely to mitigate extreme flood risks for downstream communities because reservoirs must release water during peak flow conditions to ensure dam safety.
• Loss of lateral connectivity between the river and wetlands due to roads or levees could increase peak flows downstream of the Mompos Depression by up to 900 m³/s (+7.2%) during extreme wet conditions, adding 9.4 billion m³ of floodwaters to areas such as Barranquilla.

APA

Stockholm Environment Institute (2015). Biodiversity, wetland ecosystems and flood risks: Implications of hydropower expansion on the Magdalena River. https://www.sei.org/mediamanager/documents/Publications/SEI-TNC-USAID-DB-2015-Mompos-Depression-WEAP.pdf

Chicago

Stockholm Environment Institute. Biodiversity, wetland ecosystems and flood risks: Implications of hydropower expansion on the Magdalena River. 2015. https://www.sei.org/mediamanager/documents/Publications/SEI-TNC-USAID-DB-2015-Mompos-Depression-WEAP.pdf.

Wikipedia

{{cite report |author=Stockholm Environment Institute |title=Biodiversity, wetland ecosystems and flood risks: Implications of hydropower expansion on the Magdalena River |date=2015 |url=https://www.sei.org/mediamanager/documents/Publications/SEI-TNC-USAID-DB-2015-Mompos-Depression-WEAP.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{stockholmenvironmentinstitute2015biodiversity, author = {{Stockholm Environment Institute}}, title = {{Biodiversity, wetland ecosystems and flood risks: Implications of hydropower expansion on the Magdalena River}}, institution = {Stockholm Environment Institute}, year = {2015}, url = {https://www.sei.org/mediamanager/documents/Publications/SEI-TNC-USAID-DB-2015-Mompos-Depression-WEAP.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }