Lorentz River

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title: "Lorentz River" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["rivers-of-south-papua", "drainage-basins-of-papua"] description: "River in Indonesia" topic_path: "general/rivers-of-south-papua" source: "https://en.wikipedia.org/wiki/Lorentz_River" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary River in Indonesia ::

::data[format=table title="Infobox river"]

Field	Value
name	The Lorentz River
name_other	Undir, North River
image	COLLECTIE TROPENMUSEUM Papoea' s op de Lorentzrivier TMnr 10009529.jpg
image_size	300
image_caption	The Lorenz during the third South New Guinea expedition (1912-13)
pushpin_map	Indonesia South Papua#Indonesia
pushpin_map_size	285
pushpin_map_caption	Location in South Papua##Location in Indonesia
subdivision_type1	Country
subdivision_name1	Indonesia
subdivision_type2	Province
subdivision_name2	South Papua
length	276.84 km
discharge1_location	Arafura Sea (Eilanden Delta)
discharge1_avg	380 m3/s
source1	Southeast of the Puncak Trikora in the Jayawijaya Mountains
source1_location	Highland Papua, Indonesia
source1_coordinates
basin_size	4,169 km2
::

| name = The Lorentz River | name_other = Undir, North River | name_etymology = | image = COLLECTIE TROPENMUSEUM Papoea' s op de Lorentzrivier TMnr 10009529.jpg | image_size = 300 | image_caption = The Lorenz during the third South New Guinea expedition (1912-13) | map = | map_size = | map_caption = | pushpin_map = Indonesia South Papua#Indonesia | pushpin_map_size = 285 | pushpin_map_caption= Location in South Papua##Location in Indonesia | subdivision_type1 = Country | subdivision_name1 = Indonesia | subdivision_type2 = Province | subdivision_name2 = South Papua | subdivision_type3 = | subdivision_name3 = | subdivision_type4 = | subdivision_name4 = | subdivision_type5 = | subdivision_name5 = | length = 276.84 km | width_min = | width_avg = | width_max = | depth_min = | depth_avg = | depth_max = | discharge1_location= Arafura Sea (Eilanden Delta) | discharge1_min = | discharge1_avg =380 m3/s | discharge1_max = | discharge2_location= | discharge2_min = | discharge2_avg = | discharge2_max =

| source1 = Southeast of the Puncak Trikora in the Jayawijaya Mountains | source1_location = Highland Papua, Indonesia | source1_coordinates= | source1_elevation = | mouth = | mouth_location = | mouth_coordinates = | mouth_elevation = | progression = | waterfalls = | river_system = | basin_size =4,169 km2 | tributaries_left = | tributaries_right = | custom_label = | custom_data = | extra =

The Lorentz River (also Unir or Undir in Indonesian, or Noordrivier in Dutch) is located in the Indonesian province of South Papua in Western New Guinea, about 3,500 km northeast of the Indonesian capital Jakarta. It originates in the central east-west mountain range of New Guinea and flows southwards into the Arafura Sea at Flamingo Bay. During the first two Dutch expeditions to Southern New Guinea (1907–10) it was called Northern River. In 1910 it was renamed after the Dutch explorer Hendrikus Albertus Lorentz. After it became part of Indonesia, it was renamed to Unir, as in the language of the local Asmat people, while the Lorentz name is still in use.

History

At the beginning of the 20th century, the navigable part of the river played an important role in the exploration of Dutch New Guinea in western New Guinea. Three large Dutch expeditions led from the mouth upstream to the central snow-capped mountains, which were still unexplored. The expeditions aimed to cover the Wilhelmina summit (now called Puncak Trikora ) covered by "eternal snow". The first of the three South New Guinea expeditions failed before the mountain could be reached. The second expedition reached the snow-capped foot of Wilhelmina, but it was only during the third expedition that the mountain could be conquered on 21 February 1913.

Geography

The river flows in the southwest area of Papua with a predominantly tropical rainforest climate (designated as Af in the Köppen-Geiger climate classification). The annual average temperature in the area is 21 °C. The warmest month is October when the average temperature is around 23 °C, and the coldest is July, at 20 °C. The average annual rainfall is 4,238-5,547 mm. The wettest month is May, with an average of 594 mm rainfall, and the driest is July, with 384 mm rainfall.

References

References

1. link
2. link
3. [http://www.geonames.org/1637248/sungai%20lorentz.html Sungai Lorentz] at Geonames.org (cc-by); Last updated 2013-06-04; Database dump downloaded 2015-11-27
4. (). "Updated world map of the Köppen-Geiger climate classification". Hydrology and Earth System Sciences.
5. (30 January 2016). "NASA Earth Observations Data Set Index". NASA.
6. (30 January 2016). "NASA Earth Observations: Rainfall (1 month - TRMM)". NASA/Tropical Rainfall Monitoring Mission.

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::