Cauca

The Cauca river flows across Colombia, connecting the Occidental and Central Cordilleras. Its sources are at Popayán in southwestern Colombia, and it meets the Magdalena River near Magangué in Bolvar Department, where it eventually flows into the Caribbean Sea. It runs for 965 kilometers till it meets the Magdalena, for a total distance of 1,350 kilometers from source to sea mouth. The river is navigable for 640 kilometers above its confluence with the Magdalena and is supervised by the Corporación Regional del Cauca and the Corporación Autonoma Regional del Valle del Cauca.

The river was receiving an average of 500 tons of leftover debris every day. Pollution from the city of Popayán, seven gold mines that emit industrial pollutants including mercury, eight sand mills, and a few of coal and bauxite mines Cali, the largest city on the river, is 76 percent reliant on it. Other affluent rivers absorb residual waters from other big cities and deposit an estimated 330 tons of residual garbage into the river. The river is devoid of oxygen by the time it reaches Yumbo.

The Cauca River has been severely impacted by the Hidroituango hydropower dam project. The dam's flow has been reduced by up to 80% in some areas.

Length: 600 miles