The river discharges into the South China Sea creating a marshy delta, which spreads both inland and into the sea, with the silt deposits extending up to 50–60 km (31–37 mi) from the Borneo coast.[8] The delta is located west-southwest of Pontianak, the capital of West Kalimantan province, which lies at the equator.[10] The delta has five arms, of which the northernmost one is the widest, and is therefore called the Big Kapuas (Indonesian: Kapuas Besar). The largest tributary is the Melawi River, which occurs to the left near the city of Sintang, about 465 km from the mouth. Other major tributaries are the Landak, Kubu, Punggur and Sekayam rivers.[10]