It originates in the Müller mountain range at the center of the island and flows west into the South China Sea creating an extended marshy delta. The delta is located west-southwest of Pontianak, the capital of the West Kalimantan province.
The river is 1,143 km (710 mi) long and up to 700 m (2,300 ft) wide at its delta; with a total area of 98,740 km2 (38,120 sq mi), the river basin covers more than 67% of West Kalimantan.
The river originates near the center of Borneo, south from the Indonesian-Malaysian border, in the joint between the western slope of the Müller Mountain Range, which runs through the island center, and the southern slope of the Upper Kapuas Range (Indonesian: Kapuas Hulu), which is located more to the west. This Kapuas River should be distinguished from another Kapuas River, which starts on the other side of the same mountain range in central Borneo, but flows to the south, merging with the Barito River and discharging into the Java Sea.
About 300 species of fish have been identified in the river basin, of which 234 are of high economical value. They belong to 120 genera and 40 families with the two major groups being cyprinids and catfish. More than 30% of the species originate from the sea and inhabit the delta areas.
The Kapuas River is the major waterway connecting the center of the island with its western coast. The large river width and depth (up to 27 meters) support intensive cargo and passenger shipping over most of the river length.
According to Wikipedia
