longest and, commercially, most important river in Côte d'Ivoire (Ivory Coast); with its major tributaries, the Red Bandama (Marahoué) and the Nzi, it drains half of the surface area of the country. It rises as the White Bandama in the northern highlands and flows southward for 497 miles (800 km) to enter the Gulf of Guinea and the Tagba Lagoon near Grand-Lahou. A hydroelectric plant at Kossou, just north of the confluence with the Marahoué, provides power for Côte d'Ivoire. Kossou is the site of the largest dam in the country and major agricultural fishery projects. Manganese and timber are shipped coastwise from the Tagba Lagoon and the river's lower section via the Asagny Canal to Abidjan for export. The Bandama is navigable for about 35 miles (56 km) upstream from Grand-Lahou.