Petrohué River

The waterfalls of the river in the upper reaches. In the background of Osorno.

Narrow gorges and steep, entangled bank slopes dominate the upper reaches of the river

Chilean guava ( Ugni molinae ), at the falls " Saltos de Petrohué "

Male Torrent Duck. This species breeds on the Río Petrohué

Río Petrohué is the name of a river in the southern Chilean Seeendistrikt.

It flows going the only outflow of Lake Todos Santos is 36 km in a broad delta in the Reloncavi Fjord. Despite its small length of 36 km the mean discharge 278 m³ / sec is relatively high. This corresponds approximately to the average discharge rate of the Alpine Rhine into Lake Constance. During its run, the first, then takes place in southwestern to southern direction, the Río Petrohué takes only a few smaller streams. Probably the river has to in historical time also included water from the Lake Llanquihue, but this outflow was moved by volcanic activity of the Osorno and Calbuco. Approximately 6 kilometers after the river leaves the lake, he flips over some basalt cliffs in several thresholds more than 20 m in depth. In the upper reaches of the river has most deeply incised into the volcanic deposits, so here many river sections are bounded by steep bank slopes and difficult to access. In the lower reaches of the river widens, branches out into different, separated by deposit banks flume and finally ends in a broad, multi-branched delta sediment.

The water quality of the river Petrohué has so far awarded throughout its history due to the relative absence of pollution factors. The strong increase in the scenic fishing and water sports tourism, especially in the area of the falls could but without accompanying measures lead to deterioration.

The upper and middle reaches of the river are located in the oldest Chilean Vicente Perez Rosales National Park. The entire course of the river is within the plant formation of the Valdivian rain forest whose dense, evergreen vegetation characterizes its riverfront.

Climate

The climate is cold - temperate. The area lies in the zone of the southern westerlies, whose climate is characterized by frequent strong westerly winds, moderately cold winters and moderately warm summers and through annual precipitation amounts to 3000 mm / m². In summer the temperatures reach about twenty degrees, in winter they drop to 5-7 °. Days of frost are rare, and snow falls only on a few days and usually does not stay for a long time. As the river consists mainly of water from Lago Todos los Santos and melt water from the surrounding mountains, it does not heat up more than 15 ° Celsius; in August he is the coolest with an average of 8 °. Only in the area of some hot springs, the water temperatures are much higher.

Flora

The banks of the Río Petrohué are lined with dense vegetation of the Valdivian rain forest, whose Leitbaum the Coihue ( Nothofagus dombeyi ), an evergreen Scheinbuchenart is. Three other members of this genus occur in the area of the river, but are less frequent. Among the conifers is Fitzroya cupressoides, the Patagonian cypress can reach stature heights above 50 m and a very high age, most impressive. In autumn, the fruits of the Chilean guava ripen, which are then sold as fresh fruit or processed into jam. Overall, the flora of the Valdivian rain forest is extremely rich and varied.

Fauna

Within the river 30 mammal species are native, of which the nutria and the Southern river otter are directly bound water and occur in the river system of the Río Petrohué. There is a rich avifauna, but most birds live in the hinterland of the river. However, for the river itself is characteristic of the torrent duck, which breeds on the edge of the river and is also observed in the area of the falls. On the gravel banks of the lower reaches störmungsärmeren Bairdstrandläufer are occasionally seen on overhanging branches on the quieter stretches of water ansitz end Ringed Kingfisher. In an oceanic strongly influenced estuary area the long wing steamer duck occurs.

Originally, only four species of fish were in the upper reaches and middle reaches of the Río Petrohué home Perca trucha, a Bar Chart ( Percichtys trucha ), which can reach a length of 40 cm, bagre ( Trichomycterus sp areolatus. ? ), A Schmerlenwels, the pike Ling Peladilla ( Aplochiton taeniatus ), and the New World silverside Basilichthys australis, which is endemic to Chile and is known in the region Pejerrey. As its name suggests ( Pejerrey = Kingfish ) was the latter as a food fish particularly appreciated. The lower reaches and the estuary were and are species-rich oceanic influence by the.

Today in the lake and river system outweigh alien species, such as brook trout, rainbow trout, Atlantic salmon, silver salmon and king salmon. The original North Pacific King Salmon has self-sustaining populations and new Zugtraditionen developed since probably copies escaped in the 1980s from fish farms or were released. Rainbow trout and brown trout are now the most common fish in the river system of the Petrohué and most other Chilean rivers. They constitute more than 80 % of the biomass of fish and displace increasingly the original fish fauna.

Others

The Río Petrohué is considered one of the best fishing spots in Chile. He owes this reputation only species that were not originally native to the river system. Thus, sport for anglers so coveted representatives of salmonids in South America did not occur. Even among boaters, rafters and whitewater canoeists wins the flow increasingly popular, so at its exit from the Lago Todos los Santos, along the entire upper reaches, but especially at and in the vicinity of the falls is a tourist infrastructure is developed and will be further expanded. It remains to be seen how the negative consequences of this development can be mitigated by appropriate measures.