Belayan River

Map of Belayan, Kedang Kepala and Mahakam rivers

The river traverses 3 districts in the upstream area of Kutai Kartanegara Regency, namely Kenohan, Kembang Janggut, and Tabang.[4] The high flow rate during flooding constantly eroded the land on the river banks, causing damages to the houses built next to it.[5] Belayan flows into Mahakam River near Muhuran, Kotabangun, and Bukit Tinjawang.[6]

The river flows in the eastern area of Borneo island with predominantly tropical rainforest climate (designated as Af in the Köppen-Geiger climate classification).[8] The annual average temperature in the area is 23 °C. The warmest month is March, when the average temperature is around 24 °C, and the coldest is January, at 22 °C.[7] The average annual rainfall is 2780 mm. The wettest month is December, with an average of 351 mm rainfall, and the driest is August, with 138 mm rainfall.[9]

Belayan river is vital for the population along its banks for transportation, water source for daily life, and also for occupation for some inhabitants,[10] such as fish and gold.[4] The river is important for the people of three districts: Kenohan, Kembang Janggut, and Tabang, even for centuries was the only access route to those three districts.[4] At the upstream of Belayan there are some villages of Dayak Kenyak tribe, such as Ritan Baru, Tabang District, which can be reached about 1 or 2 days by boat or ferry from Samarinda.[11] It took about two days and one night to travel from Tabang to Tenggarong using river transportation.[10] The local Dayak tribe is known for wood sculptures and other handicrafts.[10]

Along the river there are many ports to transport coals from the mines in Kutai Kartanegara for export.[10]

Due to sedimentation, Belayan river needs to be dredged regularly, so that it flows steadily to the downstream and doesn't cause much flooding.[12]

Belayan River is a habitat of Mahakam or Irrawaddy dolphin (Orcaella brevirostris), one of the river animals in the IUCN Red List of Threatened Species,[10] and also of little egret (Egretta garzetta).[10]

• List of rivers of Indonesia
• List of rivers of Kalimantan

• (in Indonesian) Konsepsi pola penatagunaan hutan secara mikro, daerah aliran sungai Belayan, propinsi Dati I Kalimantan Timur. Banjarbaru, 1980.