Brang Biji River


Brang Biji River is a river in the island of Sumbawa, Indonesia, about 1,200 km east of the capital Jakarta. It is also known as Brang Sumbawa.

Hydrology

The drainage basin of 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 Flores Sea.
For years, Brang Biji river suffers from rapid sedimentation, which reduces its water capacity, and decreasing width due to uncontrolled house building along the river banks. These factors contribute to annual flood, submerging houses along the banks in the districts of Bugis, Brang Bara, Pekat, Samapuin, Lempeh and Brang Biji, as happened in February 2017.
Brang Biji river is also heavily polluted by high concentration of E-coli and mercury, reaching an unsafe level for people to use for drinking or washing. The pollution is attributed to the unhygienic lifestyle of community, such as throwing thrash and using the river as restroom.

Geography

The river flows along the northwestern area of Sumbawa with predominantly tropical savanna climate. 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. 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.