Embalse Amutui Quimei is a large, deep reservoir tucked within the Andes mountains of Chubut Province, Argentina, sitting inside the boundaries of Los Alerces National Park. Created when the Futaleufú dam was completed in 1976, the reservoir flooded a narrow glaciated valley, giving rise to a body of water whose Mapuche name — "lost beauty" — pays tribute to the stunning landscape that once occupied the valley floor. Stretching approximately 38 kilometers in length and up to 3 kilometers wide, the lake covers roughly 86.7 square kilometers and holds an impressive water volume of 8.37 cubic kilometers. Its average depth of 64.7 meters (212 feet) makes it one of the deeper reservoirs in Patagonia, with the steep, glacially carved valley walls continuing well below the waterline. The reservoir sits at the heart of the Futaleufú River system, which ultimately drains westward through Lago Yelcho and the Yelcho River into the Pacific Ocean in Chile. The primary inflows are the Frey, Stange, and Canelo Rivers, while the outflow feeds the Futaleufú River downstream. The surrounding landscape is defined by glaciated Andean peaks, dense native forest, and the dramatic scenery characteristic of Los Alerces National Park — one of Patagonia's most celebrated wilderness areas.