| Lamandau River Sungai Lamandau, Sungai Kotawaringin | |
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  River mouth location Show map of Kalimantan Lamandau River (Indonesia) Show map of Indonesia | |
| Location | |
| Country | Indonesia |
| Physical characteristics | |
| Source | |
| • location | Kalimantan |
| Mouth | |
• location | Java Sea |
| Length | 300 km (190 mi) |
Lamandau River (Indonesian:Sungai Lamandau) is a river ofKalimantan, southern-centralBorneo, Indonesia.[1][2] Downstream after passing the village ofNanga Bulik it becomes the Kotawaringin River.[3]
The ancient town of Kotawaringin is located in the valley formed by the river and its tributary along with gold and gemstone mining areas. In the upper reaches of the tributary valley ofArut River thePangkalan Bun town flourishes on its banks.
Lamandau River flows through southernCentral Kalimantan andPangkalan Bun, discharging into theJava Sea nearKumai at2°51′20″S111°43′14″E / 2.85556°S 111.72056°E /-2.85556; 111.72056. It is a major tributary of the Kotawaringin River, known by this name after its confluence below Naga Bulik village. Tributaries include theArut River, where in its upper reaches thePangkalan Bun town is located. While the lower reaches of the river are densely populated, the upper reaches have contiguous forest areas where Orangutans can be seen.[3] Kotawaringin town to the west of the Lamandau River was the ancient capital of a Sultanate.[4]
The catchment of the Lamandau River comprises the western district ofCentral Kalimantan andWest-Kotawaringin. West Kotawaringin district has a population of 200,000 people constituted by Tuman Dayaks (about 33%) who are Christians. The capital of this district isPangkalan Bun, which has a sub-district, a traditional area of the Dolang, close to the Kundangan city where 7000 Dayaks reside in about 100longhouses spread over 19 villages.[5]
Pangkalan Bun town is a waterfront town, which has a plywood manufacturing plant. Its fame is due to the mines nearby where gold andamethyst stones are extracted. In support of these mining activities, several shops selling diesel sets for use in mining have been set up. Another spin-off from the mines is the establishment of several gem stores in the town. The particularly popular item of sale is the five-set lucky stones of dark coloured amethysts, duly polished and made to shimmer for sale.[6]
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The river flows in the mid-southern area ofBorneo island with a predominantlytropical rainforest climate (designated asAf in the Köppen-Geiger climate classification).[8] The annual average temperature in the area is 23 °C. The warmest month is October when the average temperature is around 24 °C, and the coldest is January, at 22 °C.[7] The average annual rainfall is 2778 mm. The wettest month is November, with an average of 386 mm of rainfall, and the driest is September, with 66 mm of rainfall.[9]
The river valley is inhabited by theDayak peoples, particularly theTumon in the upper course of the river. The river is popular with tourists who take trips along the rivers by speedboats and traditionalklotok boats to visit and experience the lives of the Dayaks. Buddhist influence has also been traced to the Lamandau River valley in Kotawaringin town. Buddhist statues with the god's name of Dewata or Mahatara have been found here.[10]
Much of the land between theJelai-Bila River and the Lamandau River is developed by agriculture.[3]
The river flows through the 76,000-hectareLamandau River Wildlife Reserve, in the unique primary forest in Borneo, which has many endangered species, includingBornean orangutans. Human exploitation in the area has led to the pollution of the Lamandau River from gold andzircon mining,illegal logging, and large-scale deforestation to create palm oil plantations. However, an awareness campaign has been initiated by NGOs to preserve the Orangutans in the park and also introduce agricultural practices compatible with forest preservation actions.[11]
Within the park, there are two camps namely, Camp Siswoyo and Camp I, which are maintained by the Orangutan Foundation International (OFI). They are close to Pangkalan Bun and Pasir Pajang, on its eastern border. The infrastructure facilities in these camps have been improved here since September 2003, with funding provided by the Orangutan Foundation, United Kingdom. A guard post has also been established to prevent incursions into the forest or the river by illegal loggers who had in the past created large-scale destruction of the forests in the region.[12]
2°51′20″S111°43′14″E / 2.85556°S 111.72056°E /-2.85556; 111.72056