The river rises as the Caquetá River in the
Andes in southwest
Colombia. The Caquetá River rises near the sources of the
Magdalena River, and augments its volume from many branches as it courses through Colombia. It flows southeast into
Brazil, where it is called the Japurá. The Japurá enters the
Amazon River through a network of channels. It is navigable by small boats in Brazil. West of the
Rio Negro, the
Solimões River (as the Amazon's upper Brazilian course is called) receives three more imposing streams from the northwest—the Japurá, the
Içá (referred to as the Putumayo before it crosses over into
Brazil), and the
Napo.
Brazilian Course On the border with Brazil, it meets the long
Apaporis River (which is 1,370 km long when combined with one of its sources, the
Tunia River), near the town of La Pedrera. It then enters Brazilian territory, in the Amazon, where it is known as the Japurá River. In its lower course, it is joined by the Auati Paraná and Mirim Pirajuana rivers (the latter is sometimes considered a secondary branch, or a dead or backwater of the river). The Caquetá-Japurá is a "white water" river, which, like all rivers descending from the Andes, carries a significant alluvial load that it partly deposits when joining the Solimões (Amazon) River on its left bank. This is why the accumulated sediments on the banks have shaped a complex mouth that stretches for several hundred kilometers. Firstly, the Japurá receives a long bifurcation from the Solimões itself and then drains into it through a main mouth located opposite the city of Tefé. However, a secondary branch, the Paraná Copea, continues its winding course until it rejoins the Solimões River 300 km downstream. This multiple confluence (resembling a very elongated delta) complicates the measurement of the length of the Caquetá-Japurá, which varies, depending on the method used, from 2200 to 2800 km, especially because the boundaries between the basins of other tributaries and sub-tributaries of the Amazon system are unclear in this flat, flooded, and swampy area. Some tributaries of the Japurá River originate very close to the Solimões River (Auati Paraná River), and some tributaries of the Negro River arise near the Japurá (Uneiuxi, Cuiuni, and Unini rivers), with connections and bifurcations between them during flood seasons. Although the Caquetá/Japurá is a broad and voluminous river, the existence of numerous rapids throughout its course has significantly hindered navigation. == History ==