(Period of data: 2009–2013)720 m3/s (25,000 cu ft/s)[1]
The Siak (Sungai Siak) is a river of Riau province, in the east of Sumatra, Indonesia, about 1000 km northwest of the capital Jakarta.[2] Approximately 370 kilometres in length, the Siak is a blackwater river which owes its brown color to dissolved organic matter (DOM) leached from surrounding, heavily disturbed peat soils; it is heavily polluted, notably by the petroleum industry. It flows through the town of Pekanbaru before emptying into the Strait of Malacca.[3]
Geography
The river flows in the central area of Sumatra with predominantly tropical rainforest climate (designated as Af in the Köppen-Geiger climate classification).[4] The annual average temperature in the area is 23 °C. The warmest month is October, when the average temperature is around 25 °C, and the coldest is January, at 22 °C.[5] The average annual rainfall is 2673 mm. The wettest month is November, with an average of 418 mm rainfall, and the driest is January, with 106 mm rainfall.[6]
