Map of the Amazon Basin with the Marañón River highlighted
|Basin countries||Peru, Ecuador|
|Length||1,737 km (1,079 mi)|
|Avg. discharge||16,708 m3/s (593,000 cu ft/s)|
|Basin area||358,000 km2 (138,000 sq mi)|
The Marañón River (Spanish: Río Marañón, IPA: [ˈri.o maɾaˈɲon]) is the principal or mainstem source of the Amazon River, arising about 160 km to the northeast of Lima, Peru, and flowing through a deeply eroded Andean valley in a northwesterly direction, along the eastern base of the Cordillera of the Andes, as far as 5 degrees 36' southern latitude; from where it makes a great bend to the northeast, and cuts through the jungle Andes, until at the Pongo de Manseriche it flows into the flat Amazon basin. Although historically, the term "Marañon River" often was applied to the river all the way to the Atlantic Ocean, nowadays the Marañon River is generally thought to end at the confluence with the Ucayali River, after which most cartographers label the ensuing waterway the Amazon River.
Marañón River as the source of the Amazon
The Marañon River was considered the source of the Amazon River starting with the 1707 map published by Padre Samuel Fritz, who indicated the great river “has its source on the southern shore of a lake that is called Lauricocha, near Huánuco." Fritz’ reasoning was based on the fact that the Marañon River is the largest river branch one encounters when journeying upstream, something clearly evident on his map. For most of the 18th-19th centuries and into the 20th century, the Marañon River was generally considered the source of the Amazon. The Marañon River continues to claim the title of the "mainstem source" or "hydrological source" of the Amazon due to its contribution of the highest annual discharge rates, a distinction similar to the Mississippi's "source" at/near Lake Itasca in Minnesota and the Nile's "source" at/near Lake Tana on the Blue Nile in Ethiopia.
Description of Marañón River from the source
On current topographic maps, the Marañon River nominally begins by the town Rondos at the junction of the Lawriqucha and the Nupe Rivers, but its true source lies up one of these branches. While the Lawriqucha River is the longer of the two, the Nupe River may contribute more water overall. The Lawriqucha River emerges from a series of lakes, starting at the lake Niño Qucha (Niño Cocha) and ending at the lake Lawriqucha. The Nupe River emerges from the lake Qarwaqucha near Mt. Yerupaja. Downstream of Rondos, the Marañon River flows as a small stream until other tributaries join it, the most important being the Urqumayu (Vizcarra), Puchka, Yanamayu, Crisnejas, Silaco and Chamaya which together make the Marañon a major river with higher average flow than the Colorado River through Grand Canyon.
Just before entering the jungle, the Utcubamba and Chinchipe Rivers join the Marañon, usually more than doubling the flow. In the Andean jungle area, additional major tributaries join, including the Chiriaco, Cenepa, Nieva, and Santiago Rivers. This is an area inhabited by the Aguaruna people. After leaving the Andes, the Marañon is joined by additional major tributaries, including the Morona, Pastaza, Huallaga, Pacaya-Samiria, and Tigre Rivers. By the time it reaches the gauging station of San Regis (before the Ucayali confluence), the Marañon has nearly the same average discharge rate as the Mississippi River at its mouth.
La Condamine's descent and the pongos
One of the first popular descents of the Marañon River occurred in 1743 by the Frenchman Charles Marie de La Condamine, who journeyed from the Chinchipe confluence all the way to the Atlantic Ocean. La Condamine did not descend the initial section of the Marañon by boat due to the plethora of pongos, which are gorges in the jungle areas often with difficult rapids. From the point he did begin his boating descent (by the Chiriaco confluence), La Condamine still had to confront several pongos, including the Pongo de Huaracayo (or Guaracayo) and the Pongo de Manseriche.
The Pongo de Manseriche is the final pongo on the Marañon and just before the river enters the flat Amazon basin. It is 5 km (3.1 mi) long and located between the confluence with the Rio Santiago, and the village of Borja. According to Captain Carbajal, who attempted ascent through the Pongo de Manseriche in the little steamer "Napo," in 1868, it is a vast rent in the Andes about 600 m (2000 ft) deep, narrowing in places to a width of only 30 m (100 ft), the precipices "seeming to close in at the top." Through this canyon the Marañón leaps along, at times, at the rate of 20 km/h (12 miles an hour). The pongo is known for wrecking many ships and many drownings.
Downstream of the Pongo de Manseriche the river often has islands, and there is usually nothing visible from its low banks but an immense forest-covered plain known as the selva baja ("low jungle") or Peruvian Amazonia. It is home to indigenous peoples such as the Urarina of the Chambira Basin, the Candoshi, and the Cocama-Cocamilla peoples.
The Grand Canyon of the Amazon and descent history
A 552 km (343 mile) section of the Marañon River between Puente Copuma (Puchka confluence) and Corral Quemado is a class IV raftable river that is similar in many ways to the Grand Canyon of the United States and has been labeled the "Grand Canyon of the Amazon". Raft trips are now offered on the section Most of this section of the river is in canyon that is up to 3000 m deep on both sides - over twice the depth of the Colorado's Grand Canyon. It is in dry desert-like terrain, much of which receives only 250–350 mm/rain per year (10-14"/year) with parts such as from Balsas to Jaén known as the hottest "infierno" area of Peru. The Marañon Grand Canyon section also flows by the village of Calemar, where Peruvian writer Ciro Alegría based one of his most important novels: La serpiente de oro (1935).
The upper Marañon River has seen a number of descents. An attempt to paddle the river was made by Herbert Rittlinger in 1936. Another descent was done by Sebastian Snow, an adventurer who journeyed down most of the river by trekking (to Chiriaco) and by boat (the rest of the way) after starting at the source near Lake Niño Cocha. The section from Chagual to the jungle was descended in 1976 and/or 1977 by Laszlo Berty in raft.In 1977, a group composed of Tom Fisher, Steve Gaskill, Ellen Toll, and John Wasson spent over a month descending the river from Rondos to Nazareth with kayaks and a raft. In 2004, Tim Biggs and companions kayaked the entire river from the Nupe River down to Iquitos. In 2012, Rocky Contos descended the entire river as well, with various companions along the way.
Dams planned for the Marañón and opposition
The Marañon River is endangered with 20 hydroelectric dams planned for it in the Andes, with most of the power destined for export to Brazil. Dam survey crews have drafted construction blueprints for many of these dams. The Environmental Impact Statements are available for two: the Veracruz dam and the Chadin2 dam. Opposition has arisen because the dams will disrupt the major hydrological source of the Amazon, alter normal silt deposition into the lower river, destroy habitat and migration patterns for fish and other aquatic life, displace thousands of residents along the river, and destroy a national treasure "at least as nice as the Grand Canyon in the USA". Efforts are being launched to halt the dams by residents along the river and conservation groups such as SierraRios and International Rivers.
- "Río Marañon guided raft/kayak trip". Retrieved 22 February 2013.
- "My Amazon Adventure". Retrieved 22 February 2013.
- "Laszlo Berty: rafting pioneer in Peru". Retrieved 22 February 2013.
- "First Descent of Río Marañon: Fisher, Gaskill, Toll, and Wasson Expedition". Retrieved 22 February 2013.
- "Three Rivers of the Amazon". Retrieved 10 February 2013.
- "First Descent of the Amazon Expedition". Retrieved 22 February 2013.
- "The Economist: Peru's Energy Ambitions". Retrieved 22 February 2013.
- "Veracruz Dam on Río Marañon". Retrieved 22 February 2013.
- "EIS Chadin2 Dam". Retrieved 22 February 2013.
- "Save Río Marañon". Retrieved 22 February 2013.
- "International Rivers: Río Marañon". Retrieved 22 February 2013.
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