As suggested by its name, the Branco (literally "white" in Portuguese) has whitish water that may appear almost milky due to the
inorganic sediments it carries. It is traditionally considered a
whitewater river, although the major seasonal fluctuations in its physico-chemical characteristics makes a classification difficult and some consider it
clearwater. Especially the river's upper parts at the
headwaters are clear and flow through rocky country, leading to the suggestion that sediments mainly originate from the lower parts. There is a visible contrast with the waters of the
Rio Negro at the confluence of the two rivers. The Rio Negro is a
blackwater river with dark tea-colored acidic water (pH 3.5–4.5) that contains high levels of dissolved organic carbon. ==River capture==