Pororoca

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The Pororoca ( Tupi : big roar , loud noise ), and Amazonian wave called, is one of the Amazon up running Tidenwelle .

Origin and course

Pororoca on the Rio Araguari

At full moon and new moon , huge amounts of water are pushed from the Atlantic Ocean into the river mouth twice a day . Most Pororocas emerge in February and March. Since the Amazon has very little water at this time of year, the floods are not stopped.

The resulting spring tide piles up to a height of five meters and begins - favored by the low gradient of the river - to roll up the stream. The wave reaches speeds of up to 65 kilometers per hour and is able to travel up to 800 km to Óbidos . In doing so, it pulls with it what is in its way and floods the bank regions up to 100 meters from the bank.

The rumble, which heralds the arrival of the wave long before you can see it, is called poro'roka by the indigenous people in the language of the Tupí , which translates as "water thundering noise ". Warned by this background noise, you usually have enough time to leave the shore zones.

From a physics point of view, this solitary wave is a soliton .

Effects

Due to the great power of the wave, it can be assumed that it causes considerable damage to the flora and fauna of the Amazon region. In fact, nature has adapted perfectly to this spring tide :

  • The animals in the affected area seem to feel the danger instinctively. Naturalists have been observed to move away from the river and into the rainforest long before the human ear can hear the rumble. They return about an hour after the wave.
  • The wave also helps prevent the Amazon from silting up. Due to its strength, it clears the bottom of the Amazon and deposits the sediments much further upstream. At the latest in the rainy season, when the river carries more water again, these sediments are relocated again.
  • The Pororoca is just as important for the agriculture of the indigenous people as the Nile floods formerly for the Egyptians. The wave carries large amounts of suspended matter and fertile mud, some of which is stuck on the banks. After the wave, the natives rush to fertilize their fields with this mud.

tourism

In the last few years, Pororoca has attracted ever larger numbers of tourists. In spring 2005, up to 1,000 people followed the wave. However, the visitors have to leave on the same day as there is no accommodation in the area and will probably not be in the future either: the area through which the Pororoca passes is a national park.

Pororoca has been popular among surfers since the 1990s . A corresponding competition has been held in São Domingos do Capim since 1999. In 2003, Adilton Mariano managed to slide the giant wave for 34 minutes. The Brazilian Picuruta Salazar surfed the wave for 37 minutes, covering more than 12 kilometers. Mathematically, this results in a wave speed of almost 20 km / h.

Web links

Individual evidence

  1. ↑ Pororoca in Nossa Língua Portuguesa (Portuguese).
  2. ^ Aurélio Buarque de Holanda Ferreira: Novo dicionário da língua portuguesa. 2nd Edition. Nova Fronteira, Rio de Janeiro 1986, p. 1368 (Portuguese).
  3. ↑ Archived copy ( memento of April 17, 2015 in the Internet Archive ) amazingstuff.co.uk: Surfing the pororoca, June 15, 2012 at the latest.