Embalse Amutui Quimei is a large reservoir in the southern portion of Los Alerces National Park, in the Futaleufú department of northwestern Chubut Province, Patagonia, Argentina. It sits at an elevation of 485 meters above sea level, approximately 18 kilometers from the town of Trevelin. The reservoir was formed by the damming of the Futaleufú River; the dam was completed and the reservoir filled in the mid-1970s. Its Mapuche name translates to "lost beauty," a reference to the valleys and natural features submerged during flooding. The reservoir spans approximately 86.7 square kilometers, stretches up to 38 kilometers in length and 3 kilometers in width, with a mean depth of around 64.7 meters and a total volume of roughly 8.37 cubic kilometers. It occupies a narrow valley between glaciated Andean peaks, with the Situación Range to the east, where Cerro Situación rises to 2,250 meters. The surrounding landscape features dense Valdivian-influenced Patagonian forest.

The reservoir is part of the Futaleufú River system, receiving inflows from the Frey, Stange, and Canelo Rivers, and draining westward through a chain of lakes ultimately reaching the Pacific Ocean via the Yelcho River in Chile.

Paddlers should be aware of several specific regulations enforced within Los Alerces National Park. Landing, lighting fires, camping overnight, and parking vehicles or trailers at Bahía Mansa are all prohibited. Navigation is forbidden in designated safety zones around the spillway, water intake, and dam face, as well as in the area of the former Lago 3 and the Río Canelo. All paddlers are required to declare entry and exit at the checkpoint and to disinfect equipment and watercraft at the disinfection station near the Portada Sur information center. Felt-soled wading boots are prohibited. Sport fishing is permitted with a daily bag limit of three salmonids.

Annual precipitation in the reservoir's basin ranges between 1,500 and 3,000 mm, reflecting the wet Andean climate of the region. The park encompasses elevations from 480 to 2,250 meters, and the area is subject to significant wind and rain, particularly during the colder months. Paddlers should plan accordingly, as conditions on this large, exposed body of water can change quickly.