West Papua (region) - Geography

Geography

The region is 1,200 km from east to west and 736 km from north to south. It has an area of 420,540 km2 (162,371 sq mi), which equates to approximately 22% of Indonesia's land area. The border with Papua New Guinea mostly follows the 141st meridian east, with one section defined by the Fly River.

The island of New Guinea was once part of the Australian landmass and lie on the Sahul. The collision between the Indo-Australian Plate and Pacific plate resulting in the Maoke Mountains run through the centre of the region and are 600 km (373 mi) long and 100 km (62 mi) across. The range includes about ten peaks over 4,000 metres (13,120 feet), including Puncak Jaya (4,884 m), Puncak Mandala (4,760 m) and Puncak Trikora (4,750 m). The range ensures a steady supply of rain from the tropical atmosphere. The tree line is around 4,000 m (13,100 ft) and the tallest peaks feature small glaciers and are snowbound year round. Both north and west of the central ranges the land remains mountainous — mostly 1,000 to 2,000 m (3,300–6,660 ft) high with a warm humid climate year round. The highland areas feature alpine grasslands, jagged bare peaks, montane forests, rainforests, fast flowing rivers, and gorges. Swamps and low-lying alluvial plains of fertile soil dominate the southeastern section around the town of Merauke. Swamps also extend 300 km around the Asmat region.

The province has 40 major rivers, 12 lakes, and 40 islands. The Mamberamo river is the province's largest and runs through the north of the province. The result is a large area of lakes and rivers known as the Lakes Plains region. The southern lowlands, habitats of which included mangrove, tidal and freshwater swamp forest and lowland rainforest, are home to populations of fishermen and gatherers such as the Asmat people. The Baliem Valley, home of the Dani people, is a tableland 1,600 m (5,250 ft) above sea level in the midst of the central mountain range.

The dry season across the region is generally between May and October; although drier in these months, rain persists throughout the year. Strong winds and rain are experienced along the north coast in November through to March. However, the south coast experiences and increase in wind and rain between April and October, which is the dry season in the Merauke area, the only part of West Papua to experience distinct seasons. Coastal areas are generally hot and humid, whereas the highland areas tend to be cooler.