| Brang Biji River Sungai Brang Biji | |
| Map Size: | 285 |
| Pushpin Map: | Indonesia Sumbawa#Indonesia |
| Pushpin Map Size: | 285 |
| Pushpin Map Caption: | Location of the mouth |
| Subdivision Type1: | Country |
| Subdivision Name1: | Indonesia |
| Subdivision Type2: | Province |
| Subdivision Name2: | West Nusa Tenggara |
| Subdivision Type3: | Region |
| Subdivision Name3: | Sumbawa Regency |
| Subdivision Type5: | City |
| Subdivision Name5: | Sumbawa Besar |
| Source1 Location: | Batu Lanteh |
| Mouth: | Flores Sea |
| Mouth Location: | Sumbawa Besar |
| Mouth Coordinates: | -8.4661°N 117.4039°W |
| Mouth Elevation: | 0m (00feet) |
The Brang Biji River (Indonesian: Sungai Brang Biji; in Sumbawarese, "Brang" means "river") is a river in the island of Sumbawa, Indonesia, about 1,200 km east of the capital Jakarta.[1] It is also known as Brang Sumbawa.[2]
The drainage basin of the Brang Biji covers an area of 225 km². The main river has a length of 33.20 km, with an upstream inclination of 17.14%, and the middle part inclination of 5.15%. It flows from south to north, passing Batu Lanteh at upriver and the city of Sumbawa Besar at downriver, into the Flores Sea.[3]
For years, the Brang Biji River suffers from rapid sedimentation, which reduces its water capacity, and decreasing width due to uncontrolled house building along the river banks.[4] These factors contribute to annual flood, submerging houses along the banks in the districts of Bugis, Brang Bara, Pekat, Samapuin, Lempeh and Brang Biji,[3] as happened in February 2017.[5]
The Brang Biji River is also heavily polluted by high concentrations of E-coli and mercury, reaching unsafe levels for people to use for drinking or washing.[6] The pollution is attributed to the unhygienic lifestyle of the community, such as throwing thrash and using the river as a restroom.[7]
The river flows along the northwestern area of Sumbawa with predominantly tropical savanna climate (designated as As in the Köppen-Geiger climate classification).[8] The annual average temperature in the area is 26 °C. The warmest month is October, when the average temperature is around 30 °C, and the coldest is February, at 24 °C.[9] The average annual rainfall is 1539 mm. The wettest month is January, with an average of 321 mm rainfall, and the driest is August, with 3 mm rainfall.[10]