Fly River

The Fly River is the third longest river in the island of New Guinea, after the Sepik River and Mamberamo River, with a total length of 1,060 km (660 mi). It is the largest by volume of discharge in Oceania, the largest in the world without a single dam in its catchment, and overall the 20th-largest primary river in the world by discharge volume. It is located in the southwest of Papua New Guinea and in the South Papua province of Indonesia.[4] It rises in the Victor Emanuel Range arm of the Star Mountains, and crosses the south-western lowlands before flowing into the Gulf of Papua in a large delta. The Fly-Strickland River system has a total length of 1,220 km (760 mi), making it the longest river system of an island in the world. The 824 km (512 mi) Strickland River is the longest and largest tributary of Fly River, making it the farthest distance source of the Fly River.

Fly
Aerial view of the Fly River
Location of the Fly
Location
CountryPapua New Guinea and Indonesia
Physical characteristics
Source 
  locationStar Mountains, Papua New Guinea
  coordinates5°32′14.6076″S 141°53′15.576″E
  elevation3,000 m (9,800 ft)[1]
MouthGulf of Papua
  location
Papua New Guinea
  coordinates
8.5°S 143.5°E / -8.5; 143.5
  elevation
0 ft (0 m)
Length1,060 km (660 mi)[2]
Basin size76,000 km2 (29,000 sq mi)[2]
Discharge 
  locationFly Delta, Gulf of Papua, Papua New Guinea
  average7,500 m3/s (260,000 cu ft/s)[2] 220 km3/a (7,000 m3/s) to 238 km3/a (7,500 m3/s)[1]
  maximum29,500 m3/s (1,040,000 cu ft/s)
Discharge 
  locationOgwa (370 km upstream of mouth; Basin size: 58,874 km2 (22,731 sq mi)
  average(Period: 1998-2022)7,332 m3/s (258,900 cu ft/s)[3]
  minimum1,757 m3/s (62,000 cu ft/s)(2004/11/30)[3]
  maximum18,575 m3/s (656,000 cu ft/s) (1999/04/30)[3]
Discharge 
  locationObo (400 km upstream of mouth; Basin size: 18,400 km2 (7,100 sq mi)
  average2,800 m3/s (99,000 cu ft/s)[1]
  minimum300 m3/s (11,000 cu ft/s)[1]
  maximum3,500 m3/s (120,000 cu ft/s)[1]
Discharge 
  locationKiunga (900 km upstream of mouth)
  average1,110 m3/s (39,000 cu ft/s)[1]
  minimum57 m3/s (2,000 cu ft/s)[1]
  maximum1,950 m3/s (69,000 cu ft/s)[1]
Basin features
Tributaries 
  leftStrickland River
  rightOk Tedi River

Description

NASA blue marble satellite image of the Fly River

The Fly flows mostly through the Western Province of Papua New Guinea and for a small stretch, it forms the international boundary with western New Guinea. This section protrudes slightly to the west of the 141°E longitude line.[5] To compensate for this slight gain in territory for Papua New Guinea, the border south of the Fly River is slightly east of the 141°E longitude line. As part of this deal, Indonesia has the right to use the Fly River to its mouth for navigation.

The principal tributaries of the Fly are the Strickland and the Ok Tedi.

The Fly River

Close to its mouth, the flow of the Fly River encounters a tidal bore, where an incoming high tide pushes water upstream until the tide changes. The range of this tidal bore is still undocumented.[6]

Discharge

Average, minimum and maximum discharge of the Fly River at Ogwa (Lower Fly). Period from 1998 to 2022.[3]

Year Discharge (m3/s) Year Discharge (m3/s)
Min Mean Max Min Mean Max
1998 3,887 7,658 11,185 2011 3,030 6,382 11,341
1999 4,757 10,148 18,575 2012 4,609 8,004 13,993
2000 5,150 9,738 15,510 2013 4,023 6,246 9,629
2001 3,940 8,762 16,203 2014 4,675 6,759 11,794
2002 2,310 5,645 10,712 2015 2,546 5,760 8,575
2003 2,599 5,269 10,060 2016 3,665 8,366 14,918
2004 1,757 4,231 9,881 2017 5,760 10,264 17,509
2005 2,314 5,913 15,595 2018 4,766 8,741 13,772
2006 2,395 7,057 12,429 2019 3,498 7,488 13,533
2007 3,574 6,788 12,935 2020 4,158 6,868 10,567
2008 4,430 7,672 11,848 2021 4,518 8,706 15,338
2009 3,464 7,509 14,355 2022 4,032 6,604 9,569
2010 3,316 6,086 10,009 1,757 7,332 18,575

Delta

The original survey map created by L.M. D'Albertis in 1876

The delta of the Fly River is over 100 km wide at its entrance, but only 11 km wide at the apex upstream of Kiwai Island. The delta contains 3 main distributary channels (the Southern, Northern, and Far Northern Entrances) that branch from a common point (the “apex”). The distributary channels are 5 to 15m in depth, separated by elongate, sand-mud islands that are stabilised by lush mangrove vegetation. The islands are eroded and rebuilt rapidly in the apex area, where they have lateral migration rates of up to 150 m/a, with slower rates for the more seaward islands. Upstream from the apex the river gradually narrows to a width of 1.6 km or less. The Fly Delta exhibits a distinctive funnel shape in plan view, attesting to the fundamental role of tidal currents in shaping the Delta's geomorphology. Mean spring tidal ranges are amplified within the delta, from around 3.5m at the seaward entrance of the distributary channels, reaching a peak of about 5m at the delta apex.[7] Seismic profiles and radiometrically dated core samples indicate that the delta is prograding seawards at an average rate of about 6 m/a [8] The Fly Delta is considered as a global "type case" of a tide-dominated delta and the patterns of sedimentation seen in the Delta today have been studied by sedimentary geologists as a model for interpreting the ancient rock record [9]

The river delta is studded with low and swampy islands covered with mangrove and nipa palm, with villages and cultivated areas on these islands. The land on both sides of the estuary is of the same character. The islands in the estuary are flat and covered with thick, fertile alluvial soil. The largest islands are Kiwai Island, Purutu Island, Wabuda Island, Aibinio Island, Mibu Island, and Domori Island. Kiwai, Wabuda and Domori are inhabited.

A list of the river delta islands is:

  • Dawari Island
  • Wariura Island
  • War Island
  • Kesuguruguru Island
  • Abaura Island
  • Abo Island
  • Boromura Island
  • Ura Island
  • Dogope Island
  • Sumogi Island
  • Sobowada Island
  • Abaurai Island
  • Samari
  • Reginimi Island
  • Dibiri Island
  • Sobuwabuda Island
  • Orope Island
  • Aeginimi Islands
  • Umuda Island
  • Midima Island
  • Domori Island
  • Dubuwaro Island
  • Kuragimini Island
  • Daura Island
  • Kunagimini Islands
Map of Fly River Delta

The inhabitants of the Fly River delta engage in agriculture and hunting. Coconut palm, breadfruit, plantain, sago palm, and sugar cane are grown.

Fly River turtle

The Fly River turtle, also known as the Pig-nosed turtle due to its odd nose, is notably different from other turtles due to its piglike nose. The only freshwater turtle to have flippers, the turtle is known to rarely leave water, except in dire circumstances. They are also known to be omnivores who rarely consume meat.

History

The Fly was first discovered by Europeans in 1845 when Francis Blackwood, commanding the corvette HMS Fly, surveyed the western coast of the Gulf of Papua.[10] The river was named after his ship and he proclaimed that it would be possible for a small steam-powered boat to travel up the mighty river.[11]

In 1876, Italian explorer, Luigi D'Albertis, was the first person to successfully attempt this when he travelled 900 km into the interior of New Guinea, in his steamer, Neva. It was the furthest any European explorer had ever been into the island.[11]

Environmental issues

Both the Strickland and the Ok Tedi Rivers have been the source of environmental controversy due to tailings waste from the Porgera Mine and the Ok Tedi Mine, respectively. Sediment sampling and coring in the distributary channels of the Fly Delta had not detected copper concentrations significantly higher than background as of 1994.[12] In 2008, Ian Campbell, a former advisor to Ok Tedi Mining Limited, claimed that company data suggest significant portions of the Fly River floodplain are at a high risk from acid mine drainage.[13]

See also

References

  1. David, Lawrence; Tim, Cansfield-Smith (1990). "Sustainable Development for Traditional Inhabitants of the Torres Strait Region".
  2. "IUCN: The Fly River Catchment - A Regional Environmental Assessment". International Union for Conservation of Nature The Department of Environment and Conservation, Papua New Guinea. 1995. Retrieved 22 November 2020.
  3. "River Discharge and Reservoir Storage Changes Using Satellite Microwave Radiometry".
  4. "Fragmentation and Flow Regulation of the World's Major River Systems" (PDF). Archived from the original (PDF) on 2012-03-30. Retrieved 2011-08-17.
  5. Frank Jacobs (March 13, 2012). "Who Bit My Border?". The New York Times.
  6. p.159, Barrie R. Bolton. 2009. The Fly River, Papua New Guinea: Environmental Studies in an Impacted Tropical River System. Elsevier Science. ISBN 978-0444529640.
  7. Harris, P.T., Baker, E.K., Cole, A.R., Short, S.A., 1993. A preliminary study of sedimentation in the tidally dominated Fly River Delta, Gulf of Papua. Continental Shelf Research 13, 441-472.
  8. Harris, P.T., Hughes, M.G., Baker, E.K., Dalrymple, R.W., Keene, J.B., 2004. Sediment transport in distributary channels and its export to the pro-deltaic environment in a tidally-dominated delta: Fly River, Papua New Guinea. Continental Shelf Research 24, 2431-2454.
  9. Dalrymple, R. W., E. K. Baker, P. T. Harris and M. G. Hughes (2003). Sedimentology and stratigraphy of a tide-dominated, foreland-basin delta (Fly River, Papua New Guinea). Tropical Deltas of Southeast Asia and Vicinity - Sedimentology, Stratigraphy, and Petroleum Geology. F. H. Sidi, H. W. Posamentier, H. Darman, D. Nummedal and P. Imbert. Tulsa, Oklahoma, SEPM Special Publication 76. 76: 147–173.
  10. Blackwood, Francis Price (1809 - 1854). Australian Dictionary of Biography.
  11. Lightbody, Mark; Wheeler, Tony (1985). Papua New Guinea: a travel survival guide (3 ed.). Lonely Planet. p. 172. ISBN 0-908086-59-8.
  12. Harris, P.T., 2001. Environmental Management of Torres Strait: a Marine Geologist’s Perspective, in: Gostin, V.A. (Ed.), Gondwana to Greenhouse: environmental geoscience - an Australian perspective. Geological Society of Australia Special Publication, Adelaide, pp. 317-328.
  13. "PNG warned of environmental mining disaster". ABC News. Australian Broadcasting Corporation. 2008-09-06. Retrieved 2008-01-06.
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