TheSan Javier River (Spanish,Río San Javier[1]) is ananabranch (arm or side channel) of theParaná River in theprovince ofSanta Fe,Argentina.
The lower Paraná River is highlybraided, with a complex system ofchannels on either side of themain stem. Superficially, the San Javier River seems to be atributary river originating in the Paraná River'salluvial plain. But it is linked by several channels to the main stem Paraná, from which it probably receives most of its water. From its primary source on the Paraná River, about 15 kilometres (9.3 mi) south ofReconquista, the San Javier flows generally south, parallel to the Paraná. It passes bySan Javier andHelvecia. Itsmouth does not discharge directly into the Paraná River but rather into several channels nearSanta Rosa de Calchines. These not only connect to the main stem Paraná but also to other side channels that continue down the west side of the Paraná's floodplain and into the Laguna Setúbal system. Like the San Javier River, the Laguna Setúbal system superficially appears to be a tributary system, but it is cross-cut by channels linked to the main stem Paraná.[2]
The mouth of the San Javier River is located at31°29′50″S60°20′32″W / 31.49722°S 60.34222°W /-31.49722; -60.34222,[3] about 40 kilometres (25 mi) northeast ofSanta Fe City, the provincial capital. Its primary source, on the Paraná River, is located at29°16′32″S59°36′8″W / 29.27556°S 59.60222°W /-29.27556; -59.60222.[4]
The distance from its source to its mouth is about 250 kilometres (160 mi), over which it flows in a highlymeandering and braided course.
The San Javier, formerly known as Quiloazas River, was the cause of the abandonment of the initial site of the provincial capital atCayastá, 85 km upstream from the current one, due to theerosion it caused (and still causes) on theravine where the town was built.