Santa Cruz River (Argentina)

Santa Cruz River (Spanish: Río Santa Cruz) is a river in the Argentine province of Santa Cruz. The Santa Cruz begins at the shore of the Viedma and Argentino Lakes, of glacial origin and located in the Los Glaciares National Park, and runs 385 kilometres (239 mi) eastwards before reaching the Atlantic Coast, 350 kilometres (217 mi) north of the southern tip of South America, creating a delta. It is one of the last large free-flowing rivers in Patagonia.
The river has an important flow of 790 m (1,030 cu yd) on average, and is used for irrigation. Two dams are planned for the river, the Jorge Cepernic and Nestor Kirchner Dams. They will have a combined installed capacity of 1,740 MW. Contracts to construct the dams were awarded to a consortium of Chinese and domestic companies in August 2013. It is estimated that the dams will destroy over half of the Santa Cruz River ecosystem.
Santa Cruz River was discovered by Europeans during Magellan's circumnavigation of the Earth, by Juan Serrano, captain of the Santiago, one of the ships of the Magellan fleet, by August 5, 1520. After learning of the favourable conditions that Serrano found at Santa Cruz, Ferdinand Magellan decided to move the fleet there from St. Julian, where they had stopped to overwinter, around August 24. They would spend six weeks at Santa Cruz before resuming their search for the strait that would link the Atlantic Ocean to the Pacific Ocean, now called the Magellan Strait.
By the start of April 1834, HMS Beagle had reached a stage in its survey voyage where minor repairs were needed to its keel and copper sheathing, so Captain Robert FitzRoy chose the river as a suitable place to lay the ship ashore. While this work was carried out, FitzRoy led an expedition upriver with aim of finding its source, 300 kilometers (186 mi) distant in the Andes. Three boats set out on April 18, carrying twenty-five men, including FitzRoy and naturalist Charles Darwin. All involved took turn in teams dragging the boats up river for 16 days. Darwin took careful note of everything, including the terrain around the river, the flora and fauna of the region, and the geology exposed as the river cut through the plains.
At the outset of the voyage, FitzRoy had given Darwin the first volume of Charles Lyell's Principles of Geology, which used the uniformitarian paradigm that the key to the past is the present and that led to the interpretation of present geology in the light of slow and gradual processes. Darwin was greatly impressed by the series of stepped plains of pebbles which would have formed over long periods in the sea, and went against Lyell's ideas of continuous gradual development by implying an intermittent process. When Darwin described this in his book on South America's geology, he wrote "I think we must admit, that within the recent period, the course of the Santa Cruz formed a sea-strait intersecting the continent. At this period, the southern part of South America consisted of an archipelago of islands".
In his Journal of researches, p. 218, Darwin criticised the catastrophism proposed by former geologists who, in trying to explain the erosion of the lava and other rocks of the valley,
The expedition ended due to lack of supplies and turned around, had they gone a bit further they would have discovered that the source of the river valley was the glacial lake Lago Argentino at the foot of the mountain.