Cauca River
The Cauca River is a river in Colombia that lies between the Occidental and Central cordilleras. From its headwaters in southwestern Colombia near the city of Popayán, it joins the Magdalena River near Magangué in Bolívar Department, and the combined river eventually flows out into the Caribbean Sea. It has a length of to its junction with the Magdalena, for a total length of. The river is under the supervision of the Cauca Regional Corporation and the Cauca Valley Regional Autonomous Corporation, and is navigable for above its junction with the Magdalena.
Environmental issues
On November 18, 2007, Colombian newspaper El Tiempo reported that the river was receiving an average of 500 tons of residual waste a day. Pollution from the city of Popayán, seven gold mines that also add industrial pollutants such as mercury, some 8 sand mills, plus a couple of mines of coal and bauxite. Cali, the largest city on the river, depends on the river for 76 percent of its water supply. Adding to this, other affluent rivers collect residual waters from other major cities and deposit an approximate 330 tons of residual waste into the river. By the time it gets to Yumbo, the river has no oxygen.The Hidroituango energy dam project has seriously affected the Cauca River. The dam has decreased its flow, in some parts by up to 80%.